Journal articles on the topic 'Multi-joint isometric strength testing'
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Kenville, Rouven, Tom Maudrich, Dennis Maudrich, Arno Villringer, and Patrick Ragert. "Cerebellar Transcranial Direct Current Stimulation Improves Maximum Isometric Force Production during Isometric Barbell Squats." Brain Sciences 10, no. 4 (April 14, 2020): 235. http://dx.doi.org/10.3390/brainsci10040235.
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Maximum voluntary contraction force (MVC) is an important predictor of athletic performance as well as physical fitness throughout life. Many everyday life activities involve multi-joint or whole-body movements that are determined in part through optimized muscle strength. Transcranial direct current stimulation (tDCS) has been reported to enhance muscle strength parameters in single-joint movements after its application to motor cortical areas, although tDCS effects on maximum isometric voluntary contraction force (MIVC) in compound movements remain to be investigated. Here, we tested whether anodal tDCS and/or sham stimulation over primary motor cortex (M1) and cerebellum (CB) improves MIVC during isometric barbell squats (iBS). Our results provide novel evidence that CB stimulation enhances MIVC during iBS. Although this indicates that parameters relating to muscle strength can be modulated through anodal tDCS of the cerebellum, our results serve as an initial reference point and need to be extended. Therefore, further studies are necessary to expand knowledge in this area of research through the inclusion of different tDCS paradigms, for example investigating dynamic barbell squats, as well as testing other whole-body movements.
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Warneke, Konstantin, Martin Hillebrecht, Klaus Wirth, Stephan Schiemann, and Michael Keiner. "Correlation between Isometric Maximum Strength and One Repetition Maximum in the Calf Muscle in Extended and Bended Knee Joint." IJASS(International Journal of Applied Sports Sciences) 34, no. 1 (June 30, 2022): 61–71. http://dx.doi.org/10.24985/ijass.2022.34.1.61.
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Previous research points out high relevance of maximal strength measurement in the diagnostics of different populations. However, there is inconsistency in procedures of maximum strength measurements. Thus, it must be questioned whether the results from different studies are actually comparable. Due to the aforementioned problems in standardization, the aim of this study was to assess correlations between and reproducibility of isometric and dynamic strength testing. Since there are many studies investigating maximal strength in the calf muscles, this study will examine the plantar flexors. For this purpose, 87 active participants were recruited (m: 52, f: 35, age: 28.3 ± 5.5 years, range 18-38 years, height: 178.3 ± 6.6 cm, weight: 81.5 ± 7.4 kg) who performed maximal isometric strength testing and dynamic 1RM testing in plantar flexion both with extended and bended knee joint. Pearson correlation as well as concordance correlation coefficient (CCC) were determined. In literature, CCC is used to determine reproducibility between two different testing methods. There were correlation coefficients of r = 0.63 – 0.77 and <i>ρ<sub>c</sub></i>=0.62 ‒ 0.77. Results are comparable with correlations between maximal isometric strength and 1-RM in previous studies in different movements. In consideration of CCC, isometric strength testing and 1RM seem to not measure the same parameter, therefore comparison of results measured with different procedures seems difficult. Our results exhibit a high influence of isometric maximal strength on 1RM performance. However, 1RM tests cannot be replaced by isometric strength testing. Care must be taken due to standardization of procedure when comparing results from different studies and, especially, if 1RM testing should be replaced with isometric strength measurement.
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Legg, Hayley S., Jeff Spindor, Reanne Dziendzielowski, Sarah Sharkey, Joel L. Lanovaz, Jonathan P. Farthing, and Cathy M. Arnold. "The reliability and validity of novel clinical strength measures of the upper body in older adults." Hand Therapy 25, no. 4 (September 22, 2020): 130–38. http://dx.doi.org/10.1177/1758998320957373.
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Introduction Research investigating psychometric properties of multi-joint upper body strength assessment tools for older adults is limited. This study aimed to assess the test–retest reliability and concurrent validity of novel clinical strength measures assessing functional concentric and eccentric pushing activities compared to other more traditional upper limb strength measures. Methods Seventeen participants (6 males and 11 females; 71 ± 10 years) were tested two days apart, performing three maximal repetitions of the novel measurements: vertical push-off test and dynamometer-controlled concentric and eccentric single-arm press. Three maximal repetitions of hand-grip dynamometry and isometric hand-held dynamometry for shoulder flexion, shoulder abduction and elbow extension were also collected. Results For all measures, strong test–retest reliability was shown (all ICC > 0.90, p < 0.001), root-mean-squared coefficient of variation percentage: 5–13.6%; standard error of mean: 0.17–1.15 Kg; and minimal detectable change (90%): 2.1–9.9. There were good to high significant correlations between the novel and traditional strength measures (all r > 0.8, p < 0.001). Discussion The push-off test and dynamometer-controlled concentric and eccentric single-arm press are reliable and valid strength measures feasible for testing multi-joint functional upper limb strength assessment in older adults. Higher precision error compared to traditional uni-planar measures warrants caution when completing comparative clinical assessments over time.
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Wang, Xiao Ming, Sheng Zhu, Zhi Hao Zhao, Qi Wei Wang, and Xiao Dong Zhao. "Effect of Micro-Alloyed Treatment for 5183 Welding Wire on Microstructure and Tensile Property of Welded Joint." Applied Mechanics and Materials 633-634 (September 2014): 821–25. http://dx.doi.org/10.4028/www.scientific.net/amm.633-634.821.
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5183 welding wire micro-alloyed using Sc, Zr, Er and automatic MIG welding system applied to weld 7A52 aluminum alloy. Optical microscope and universal tensile testing machine utilized to investigate microstructure and tensile property of welded joint, respectively. The results indicated that welded zone and fused zone was composed of uniform isometric crystal and tiny isometric dendrite crystal when the welded joint was fabricated by using 5183 welding wire micro-alloyed via rare earth element, respectively. Tensile strength and specific elongation of welded zone was improved utmostly when the 5183 welding wire micro-alloyed treatment via single Sc or Zr, respectively. Owing to mirco-alloyed treatment of 5183 welding wire by using Sc, Zr or Er, a large number of Al3Sc, Al3Zr, Al3Er granules had generated in micro-poll, which played heterogeneous nucleation role and refined microstructure of welded zone. Meanwhile, there emerged nanoscaled A13Sc, A13Zr, Al3Er strengthening phase dispersed in welded zone, which had led welded joint to exhibit exclent tensile strength.
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Thompson, Brennan, Morgan Whitson, Eric Sobolewski, and Matt Stock. "Effects of Age, Joint Angle, and Test Modality on Strength Production and Functional Outcomes." International Journal of Sports Medicine 39, no. 02 (November 17, 2017): 124–32. http://dx.doi.org/10.1055/s-0043-121149.
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AbstractThis study investigated the impact of age, knee joint angle, and strength testing modality on lower body maximal and rapid strength production and assessed the transferability of these characteristics to mobility-related function. Twenty young (age=21.9 yrs) and eighteen elderly (71.1 yrs) adults performed single-joint and multiple-joint isometric maximal voluntary contractions at three knee angles. Outcome measures included peak torque (PT), rate of torque development (RTD), jump height, power, 10 and 400 m walk, and timed chair stand. Older adults exhibited greater reductions in RTD for the multiple-joint (45%) than for the single-joint mode (18%). The 10 m walk was best predicted by multiple-joint RTD at 90°, the 400 m walk by jump height, and the chair stand by single-joint PT at 20°. Single-joint strength tests may underestimate age-related rapid strength impairments, likely due to requirements to exert muscular force in excess of one’s body mass in an upright position.
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Van Every, Derrick W., Max Coleman, Daniel L. Plotkin, Hugo Zambrano, Bas Van Hooren, Stian Larsen, Greg Nuckols, Andrew D. Vigotsky, and Brad J. Schoenfeld. "Biomechanical, Anthropometric and Psychological Determinants of Barbell Bench Press Strength." Sports 10, no. 12 (December 5, 2022): 199. http://dx.doi.org/10.3390/sports10120199.
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The purpose of this study was to improve our understanding of the relative contributions of biomechanical, anthropometric, and psychological factors in explaining maximal bench press (BP) strength in a heterogeneous, resistance-trained sample. Eighteen college-aged participants reported to the laboratory for three visits. The first visit consisted of psychometric testing. The second visit assessed participants’ anthropometrics, additional psychometric outcomes, and bench press one repetition maximum (1RM). Participants performed isometric dynamometry testing for horizontal shoulder adduction and elbow extension at a predicted sticking point joint position. Multiple linear regression was used to examine the relationships between the biomechanical, anthropometric, and psychological variables and BP 1RM. Our primary multiple linear regression accounted for 43% of the variance in BP strength (F(3,14) = 5.34, p = 0.01; R2 = 0.53; adjusted R2 = 0.43). The sum of peak isometric net joint moments from the shoulder and elbow had the greatest standardized effect (0.59), followed by lean body mass (0.27) and self-efficacy (0.17). The variance in BP 1RM can be similarly captured (R2 = 0.48) by a single principal component containing anthropometric, biomechanics, and psychological variables. Pearson correlations with BP strength were generally greater among anthropometric and biomechanical variables as compared to psychological variables. These data suggest that BP strength among a heterogeneous, resistance-trained population is explained by multiple factors and is more strongly associated with physical than psychological variables.
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Lee, Yung-Hui, and Yi-Lang Chen. "An Isometric Predictor for Maximum Acceptable Weight of Lift for Chinese Men." Human Factors: The Journal of the Human Factors and Ergonomics Society 38, no. 4 (December 1996): 646–53. http://dx.doi.org/10.1518/001872096778827242.
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The aim of this study was to examine the practicality of the modified isometric strength tests to predict the maximum acceptable weight of lift (MAWL) of Chinese men. The modified strength tests allow the participant to pull on the load cell in front of the body and to apply force in a functional free posture. Both the modified and the standard strength data of each participant were used as predictors for the MAWLs. The prediction models were constructed and evaluated under task conditions of two lifting ranges, two box sizes, and three lifting frequencies. To realize the effect of modifications, testing posture was recorded and the joint angles were calculated. A stepwise multiple regression analysis indicated that modified composite strength (MCS), chest circumference, and acromial height accounted for 86% to 91% of the variance. Because the strength of the upper extremity body was also recruited in the test, the weak upper extremity strength of the Chinese participants would therefore be better reflected. Evidence for the existence of a close match between MAWL and MCS values, as well as the task conditions for its existence, suggest that a simple isometric strength measure is a good predictor for the MAWL.
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Leggett, S. H., J. E. Graves, M. L. Pollock, D. M. Carpenter, D. Foster, B. Holmes, C. Fix, M. Shank, J. Tuccl, and M. Fulton. "115 EFFECT OF ORDER OF MULTIPLE JOINT ANGLE TESTING FOR THE QUANTIFICATION OF ISOMETRIC LUMBAR EXTENSION STRENGTH." Medicine & Science in Sports & Exercise 22, no. 2 (April 1990): S20. http://dx.doi.org/10.1249/00005768-199004000-00115.
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Michaelides, Marcos A., Koulla M. Parpa, and Anthos I. Zacharia. "Assessment of Lower Body and Abdominal Strength in Professional Soccer Players." Journal of Human Kinetics 70, no. 1 (November 30, 2019): 15–23. http://dx.doi.org/10.2478/hukin-2019-0035.
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Abstract The purpose of this study was to evaluate abdominal strength in professional soccer players and compare the findings to their lower body strength. An observational design was used to examine abdominal and lower body strength using two functional performance tests (a lower body isokinetic test and an isometric abdominal test, respectively). One hundred and thirty-two professional male soccer players from Cyprus’s first and second divisions participated in this study. Testing included three and twenty-five maximal concentric flexion and extension repetitions at angle speeds of 60°/s (degrees/second) and 300°/s, respectively. On a separate occasion, participants completed two trials on an isometric device (ABTEST Gen. 3 system) for evaluation of abdominal strength. At both isokinetic speeds of 300°/s and 60°/s, abdominal strength had low to moderate significant correlations (p < .05) with quadriceps and hamstring strength. Coefficients of determination (R2) demonstrated that the variability in isokinetic variables accounted for only 14-16% of the variability of abdominal strength. Abdominal strength appears to be high in professional soccer players, but is not dependent on the sports level and/or a playing position. The results of this study demonstrate that abdominal strength and knee joint strength need to be evaluated separately.
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Kozinc, Žiga, Darjan Smajla, and Nejc Šarabon. "The relationship between lower limb maximal and explosive strength and change of direction ability: Comparison of basketball and tennis players, and long-distance runners." PLOS ONE 16, no. 8 (August 18, 2021): e0256347. http://dx.doi.org/10.1371/journal.pone.0256347.
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Change-of-direction (CoD) ability is an important determinant of athletic performance. Muscle strength is among the most important determinants of CoD ability. However, previous studies investigating the relationship between CoD ability and muscle strength focused mostly on flexor and extensor muscle groups, or used multi-joint exercises, such as jumps, squats or mid-thigh pull. The purpose of the present study was to investigate the relationship between CoD ability and strength of ankle, knee, hip and trunk maximal and explosive strength. The participants (n = 327), consisting of male and female basketball players, tennis players and long-distance runners completed isometric strength assessments and CoD testing (90° and 180° turn tests). The times of both CoD tests were associated with muscle strength (peak torques and the rate of torque development variables), with correlation coefficients being mostly weak to moderate (r = 0.2–0.6). Strength variables explained 33%, 62% and 48% of the variance in the 90° turn task, and 42%, 36% and 59% of the variance in the 180° turn task, in basketball players, long-distance runners and tennis players, respectively. Hip and trunk muscle strength variables were the most prevalent in the regression models, especially hip adduction and abduction strength. Our results suggest that the strength of several lower limb muscles, in particular of the hip abductors and adductors, and trunk muscles, but also hip rotators, extensors and flexors, as well as knee and ankle flexors and extensors should be considered when aiming to improve CoD performance.
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Altun, Muammer. "Effects of 2 Different External Loads on Joint Position Sense and the Relationship Between Muscle Strength and Force Sense." Journal of Sport Rehabilitation 29, no. 8 (November 1, 2020): 1115–20. http://dx.doi.org/10.1123/jsr.2019-0025.
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Context: Joint position sense (JPS) tests of proprioception lack ecological validity because the testing conditions are so different from the normal function that they can contribute little to understanding the role proprioception plays in daily and sporting activities. Objective: To evaluate the effect of low and high external load on the knee JPS and to investigate the relationship between maximum voluntary isometric contraction and force sense (FS). Design: Experimental study. Setting: Research laboratory. Participants: A total of 47 volunteers with no history of knee pathology. Interventions: Three active JPS tests performed with no load, low load, and high load were compared at the 45° target angle. For isometric FS test, 50% load was used. For isotonic low load and high load JPS tests, 30% and 70% loads were applied, respectively. Main Outcome Measures: To analyze obtained data set 2-way multiple analysis of variance, repeated measures of analysis of variance, paired sample t test, and the Pearson correlation coefficient were used. Results: JPS was not affected by gender (male and female) and activity levels (sedentary, recreational, and trained). Results of the repeated measure of analysis of variance demonstrated the significant main effect of loads (P = .001). Significant differences were found between no load, low load, and high load JPS (P = .001). A positive and significant correlation was found between maximum voluntary isometric contraction and FS error values (r = .41, P = .001). Conclusions: The results suggest that as the load level increases, the knee JPS improves. Knee JPS assessed under external load may be a more appropriate alternative to the nature of the sport. Those with higher muscle strength have a worse FS.
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Güleçyüz, Mehmet F., Matthias F. Pietschmann, Stefan Michalski, Ferdinand M. Eberhard, Alexander Crispin, Christian Schröder, Maximilian J. Mittermüller, and Peter E. Müller. "Reference Values of Flexion and Supination in the Elbow Joint of a Cohort without Shoulder Pathologies." BioMed Research International 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/1654796.
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Background. After surgery of the long head of the biceps tendon, the examination of the biceps brachii muscle function and strength is common clinical practice. The muscle strength is usually compared with the uninjured contralateral side or with a matched pair group assuming that the uninjured side can be used as an appropriate reference.Hypothesis/Purpose. The purpose of this study was to define reference values of the supination and flexion strength in the elbow joint and to investigate the influence of the arm positions and various anthropometric factors.Methods. 105 participants without any shoulder pathologies were enrolled. A full medical history was obtained and a physical examination was performed. The bilateral isometric testing included the supination torque in various forearm positions and elbow flexion strength with a custom engineered dynamometer. Multiple linear regression analysis was used to investigate the correlation of the strength and anthropometric factors.Results. Only age and gender were significant supination and flexion strength predictors of the elbow. Hence, it was possible to calculate a gender-specific regression line for each forearm position to predict the age-dependent supination torque. The supination strength was greatest with the arm in 90° elbow flexion and the upper arm in full pronation.
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Gage, Matthew, Kevin Phillips, Byungjoo Noh, and Tejin Yoon. "Choline-Based Multi-Ingredient Supplementation Can Improve Explosive Strength during a Fatiguing Task." International Journal of Environmental Research and Public Health 18, no. 21 (October 29, 2021): 11400. http://dx.doi.org/10.3390/ijerph182111400.
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Various choline-based multi-ingredient supplementations (CMS) have been suggested in the current market, but the research is limited. The purpose of this study was to investigate the acute effect of a CMS on physical performance. Fourteen male college football players (20.4 ± 1.0 years) participated in a randomized double-blind crossover experiment separated by 7 days. Subjects were given a CMS or a placebo 60 min before physical performance testing measures, including maximum vertical jumps, maximum voluntary isometric contractions (MVIC), maximal voluntary concentric contractions (MVCC), and fatiguing contractions. Four MVICs and seven sets of two MVCCs at various loads (1 N·m to 60% MVIC torque) were performed with the knee extensor muscles while seated on a dynamometer before and after the fatiguing tasks. During the fatiguing tasks, 120 MVCCs (4 sets × 30 reps) were performed with a load equivalent to 20% MVIC. Twitch interpolation technique was used to assess muscle contractile properties and voluntary activation. No significant differences were seen at baseline between sessions for all testing measures including vertical jump height, strength, power, muscle contractile properties and voluntary activation. Rate of torque development and impulse was higher in supplemental session compared to control session throughout the fatiguing contractions (p = 0.018, p < 0.001, respectively). Acute CMS can improve explosive strength by delaying the onset of fatigue.
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Spencer, Steven, Brennan J. Thompson, Eadric Bressel, Talin Louder, and David C. Harrell. "Transfer Effects of a Multiple-Joint Isokinetic Eccentric Resistance Training Intervention to Nontraining-Specific Traditional Muscle Strength Measures." Sports 11, no. 1 (January 4, 2023): 9. http://dx.doi.org/10.3390/sports11010009.
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Relatively few investigations have examined the transfer effects of multiple-joint isokinetic eccentric only (MJIE) resistance training on non-specific measures of muscle strength. This study investigated the transfer effects of a short-term MJIE leg press (Eccentron) resistance training program on several non-specific measures of lower-body strength. Fifteen participants performed Eccentron training three times/week for four weeks and were evaluated on training-specific Eccentron peak force (EccPF), nontraining-specific leg press DCER one-repetition maximum (LP 1 RM), and peak torques of the knee extensors during isokinetic eccentric (Ecc30), isokinetic concentric (Con150) and isometric (IsomPT) tasks before and after the training period. The training elicited a large improvement in EccPF (37.9%; Cohen’s d effect size [ES] = 0.86). A moderate transfer effect was observed on LP 1 RM gains (19.0%; ES = 0.48) with the magnitude of the strength improvement being about one-half that of EccPF. A small effect was observed on IsomPT and Ecc30 (ES = 0.29 and 0.20, respectively), however, pre-post changes of these measures were not significant. Con150 testing showed no effect (ES = 0.04). These results suggest a short term MJIE training program elicits a large strength improvement in training-specific measures, a moderate strength gain transfer effect to DCER concentric-based strength of a similar movement (i.e., LP 1 RM), and poor transfer to single-joint knee extension measures.
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Ganderton, Charlotte, Bonnie Kerr, Matthew King, Ross Lenssen, Sarah Warby, David Munro, Lyn Watson, Simon Balster, Jia Han, and Oren Tirosh. "Intra-Rater and Inter-Rater Reliability of Hand-Held Dynamometry for Shoulder Strength Assessment in Circus Arts Students." Medical Problems of Performing Artists 36, no. 2 (June 1, 2021): 88–102. http://dx.doi.org/10.21091/mppa.2021.2014.
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The purpose of this study was to establish the intra-rater and inter-rater reliability of isometric shoulder strength assessment using a hand-held dynamometer (HHD) in functional joint positions in student circus artists with symptomatic atraumatic shoulder instability. METHODS: Over two testing sessions, two experienced physiotherapists assessed the shoulder strength of 24 student circus artists with clinically diagnosed atraumatic shoulder instability. Both the symptomatic and asymptomatic shoulder was assessed using a HHD in 10 functional positions. Intra-class correlation coefficients (ICCs) were calculated to determine the reliability of strength measurements. RESULTS: All examined positions showed moderate-high intra-rater and inter-rater reliability. External rotation at 0 and internal rotation in horizontal flexion at 45 revealed the most reliable results, and the shrug position the least reliable. Inter-rater and intra-rater reliability was high and demonstrated similar results in symptomatic and asymptomatic shoulders by both raters. DISCUSSION: This study demonstrated clinical applicability in reliably measuring functional strength in symptomatic atraumatic instability or asymptomatic shoulders when assessed by experienced therapists using an HHD.
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Fowles, J. R., D. G. Sale, and J. D. MacDougall. "Reduced strength after passive stretch of the human plantarflexors." Journal of Applied Physiology 89, no. 3 (September 1, 2000): 1179–88. http://dx.doi.org/10.1152/jappl.2000.89.3.1179.
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The purpose of this study was to assess strength performance after an acute bout of maximally tolerable passive stretch (PSmax) in human subjects. Ten young adults (6 men and 4 women) underwent 30 min of cyclical PSmax (13 stretches of 135 s each over 33 min) and a similar control period (Con) of no stretch of the ankle plantarflexors. Measures of isometric strength (maximal voluntary contraction), with twitch interpolation and electromyography, and twitch characteristics were assessed before (Pre), immediately after (Post), and at 5, 15, 30, 45, and 60 min after PSmax or Con. Compared with Pre, maximal voluntary contraction was decreased at Post (28%) and at 5 (21%), 15 (13%), 30 (12%), 45 (10%), and 60 (9%) min after PSmax( P < 0.05). Motor unit activation and electromyogram were significantly depressed after PSmax but had recovered by 15 min. An additional testing trial confirmed that the torque-joint angle relation may have been temporarily altered, but at Post only. These data indicate that prolonged stretching of a single muscle decreases voluntary strength for up to 1 h after the stretch as a result of impaired activation and contractile force in the early phase of deficit and by impaired contractile force throughout the entire period of deficit.
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Pawlik, Damian, Wioletta Dziubek, Łukasz Rogowski, Artur Struzik, and Andrzej Rokita. "Strength Abilities and Serve Reception Efficiency of Youth Female Volleyball Players." Applied Bionics and Biomechanics 2022 (June 1, 2022): 1–7. http://dx.doi.org/10.1155/2022/4328761.
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Success in volleyball largely depends on motor abilities, particularly on maximum strength, power, jumping, and speed performance. However, a small number of studies assess the relationship between motor abilities and the effectiveness of volleyball technical skills. Therefore, the aim of the study was to assess the impact of the strength of the upper and lower limbs on the efficiency of serve reception during a 2 vs. 2 game, as well as to evaluate the results of motor measurements in the context of determining the usefulness of current testing procedures. The study involved a carefully chosen group of 12 girls aged 12–13 years (body height: 176.5 ± 4.2 cm, body mass: 58.6 ± 5.1 kg, and training experience: 43 ± 15 months) selected for the Lower Silesian Regional Volleyball Team. The following tests were conducted: handgrip strength with a hand dynamometer, bent-arm hang, 2 kg medicine ball throw, shoulder joint internal rotators (IR) peak torque, standing long jump, spike jump, and countermovement jump. The measurements of the shoulder joint IR peak torque were performed under isometric (at 10°, 35°, and 65° rotation angles) and isokinetic (at 60°/s, 180°/s, and 300°/s) conditions. The efficiency of serve reception was evaluated during a 2 vs. 2 games by using Data Volley statistical software. The strongest positive relationships were observed between the serve reception efficiency and the peak torque and power of the shoulder joint IR, the medicine ball throw distance, and handgrip strength. Jumping variables showed no associations with efficient of serve reception. Consequently, we suggest adding protocols to volleyball training that include strength exercises aimed at developing the IR muscle group. The isokinetic upper limb test should be introduced as a valid tool in selection process. Coaches who do not have access to modern research equipment should use the medicine ball throw test to evaluate strength abilities as an alternative assessment of the serve reception efficiency.
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Garner, Brian A., Jaeho Shim, and Scott Wilson. "An Apparatus and Protocol to Measure Shoulder Girdle Strength." Journal of Medical Devices 1, no. 4 (August 10, 2007): 246–53. http://dx.doi.org/10.1115/1.2796190.
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Muscles actuating the shoulder girdle are important for stabilizing the scapula and coordinating phased kinematics of the shoulder complex. If these muscles become weak or imbalanced, joint instability and injury may result. Reliable measurement of shoulder strength is thus important for prevention, diagnosis, and rehabilitation of shoulder problems. To date, studies quantifying the strength of the shoulder girdle are limited. The purpose of this work was to design and evaluate a custom apparatus and corresponding protocol for measuring maximal, voluntary, isometric strength of the shoulder girdle during various forms of shrugging exercise. A custom apparatus was constructed as a rigid frame with a vertical post supporting a seat, seat back, and horizontal beam. The beam extends laterally on either side beyond and around the shoulders of a seated subject. A pair of arm extension members pivots on the beam about an axis aligned with the shoulder flexion-extension axis. These members can be locked in place at any angle. Between them is mounted a force-sensing grip assembly, which can be adjusted proximally or distally to accommodate varying shoulder girdle positions. Subjects grasp the grip assembly handles with extended elbows and push or pull as forcefully as possible. Nine female and ten male subjects participated in a protocol using the apparatus to measure maximum isometric force generated at three positions each for elevation, depression, protraction, and retraction of the shoulder girdle (3positions×4modes=12tests). A video motion capture system was used to measure shoulder girdle angles. The reliability of the approach was evaluated based on the repeatability of measured shoulder elevation angle, protraction angle, and total force over three days of testing. The apparatus performed well during the tests, providing a stable, rigid, yet adjustable platform for measuring shoulder girdle strength. Repeatability of force measurements was interpreted as very good to excellent, with intraclass correlation coefficient (ICC) (2,1) values ranging from 0.83 to 0.95 for all tests except one (ICC=0.79). Repeatability of angle measurements was interpreted as good to excellent. For tests measuring elevation and depression strength, the ICC of elevation angle ranged from 0.85 to 0.89. For tests measuring protraction and retraction strength, the ICC of protraction angle ranged from 0.68 to 0.88. This type of apparatus could be an effective clinical tool for measuring strength in the shoulder girdle muscles. Use of the video motion capture system is optional.
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Cosic, Marko, Sasa Djuric, Milena Z. Zivkovic, Aleksandar Nedeljkovic, Bojan Leontijevic, and Slobodan Jaric. "Is Test Standardization Important when Arm and Leg Muscle Mechanical Properties are Assessed Through the Force‐Velocity Relationship?" Journal of Human Kinetics 69, no. 1 (October 18, 2019): 47–58. http://dx.doi.org/10.2478/hukin-2019-0010.
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Abstract The force‐velocity (F‐V) relationship observed in multi‐joint tasks proved to be strong and approximately linear. Recent studies showed that mechanical properties of muscles: force (F), velocity (V) and power (P) could be assessed through the F‐V relationship although the testing methods have not been standardized. The aim of the present study was to evaluate and compare F‐V relationships assessed from two tests performed on a modified Smith machine that standardizes kinematics of the movement pattern. Fifteen participants were tested on the maximum performance bench press throws and squat jumps performed against a variety of different loads. In addition, their strength properties were assessed through maximum isometric force (Fiso) and one repetition maximum (1 RM). The observed individual F‐V relationships were exceptionally strong and approximately linear (r = 0.98 for bench press throws; r = 0.99 for squat jumps). F‐V relationship parameter depicting maximum force (F0) revealed high correlations with both Fiso and 1 RM indicating high concurrent validity (p < 0.01). However, the generalizability of F‐V relationship parameters depicting maximum force (F0), velocity (V0) and power (P0) of the tested muscle groups was inconsistent and on average low (i.e. F0; r = ‐0.24) to moderate (i.e. V0 and P0; r = 0.54 and r = 0.64, respectively; both p < 0.05). We concluded that the F‐V relationship could be used for the assessment of arm and leg muscle mechanical properties when standard tests are applied, since the typical outcome is an exceptionally strong and linear F‐V relationship, as well as high concurrent validity of its parameters. However, muscle mechanical properties could be only partially generalized across different tests and muscles.
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Farrow, M., J. Biglands, S. Tanner, E. Hensor, M. H. Buch, P. Emery, and A. L. Tan. "OP0332 MUSCLE DETERIORATION DUE TO RHEUMATOID ARTHRITIS: ASSESSMENT BY QUANTITATIVE MRI AND STRENGTH TESTING." Annals of the Rheumatic Diseases 79, Suppl 1 (June 2020): 204.1–204. http://dx.doi.org/10.1136/annrheumdis-2020-eular.1348.
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Background:As well as joint damage, rheumatoid arthritis (RA) is also associated with altered body composition known as rheumatoid cachexia (RC). RC is characterised by reduced skeletal muscle and increased (white) fat mass and decreased strength. RC is associated with increased disease severity and disability (1). It is unknown at what stage muscle involvement begins in RA, and if the muscle damage is modifiable when patients achieve disease control.Quantitative MRI (qMRI) can measure the biomarkers associated with RC. MRI T2 is sensitive to fluid related to physiological changes at the molecular level, and is regarded as an indirect measure of muscle inflammation (2). MRI muscle fat fraction (FF) measurements are useful for identifying myosteatosis (3).Objectives:To obtain preliminary estimates of the extent to which muscle imaging phenotype differs between RA and healthy controls (HC); and to describe the RA phenotype at different levels of disease activity.Methods:39 RA patients (comprising three groups) and 13 age and gender directly matched HC had a MRI scan of their dominant thigh. The RA groups were:[1]13 ‘New RA’ - newly diagnosed, treatment naïve[2]13 ‘Active RA’ - diagnosed >1 year, persistent DAS28 >3.2 for >1 year[3]13 ‘Remission RA’ - diagnosed >1 year, persistent DAS28 <2.6 for >1 yearMR images of the mid-thigh were acquired using Dixon imaging to assess FF and a fat-suppressed multi-echo spin-echo to measure T2. Regions of interest were drawn around the quadriceps and hamstrings. All participants had knee extension and flexion torque measured on an isokinetic dynamometer, and isometric dynamometer to measure grip strength. One-Way ANOVA with Dunnett’s post-hoc analysis provided preliminary indication of potential differences between T2, FF, muscle volume and strength measurements between the disease stages.Results:39 RA patients were recruited: 13 new RA (mean age [years] 63 ± 15, DAS28 5.2 ± 3), 13 active RA (mean age [years] 65 ± 10, DAS28 4.8 ± 3), 13 remission RA (mean age [years] 67 ± 19, DAS28 1.7 ± 0.7) and also 13 HC. T2 and FF were higher in RA patients compared to HC (fig. 1). Within the hamstrings for T2, the mean differences between HC versus new, active and remission patients were 4.5ms (95% CI 2.5, 6.4; p<0.001), 3ms (95% CI 1.1, 4.9; p=0.001), and 5.0ms (95% CI 3.0, 6.4; p<0.001) respectively. Quadriceps results were similar. For muscle volume, the mean differences between HC versus new, active and remission patients were -517.3cm3(95% CI -751, -283; p<0.001), -370.5cm3(95% CI -605, -136; p=0.001), and -312.3cm3(95% CI -546. -77; p=0.006) respectively (fig. 2). Knee flexion/extension and handgrip strength were lower in all 3 groups of RA patients compared to HC. For knee flexion, the mean differences between HC versus new, active and remission patients were 18.4Nm (95% CI -35, -1; p=0.03), 10.1Nm (95% CI -27, 7; p=0.3), and 13.3Nm (95% CI -33, 0; p=0.1) respectively.Figure 1.Quantitative T2 and FF MRI of RA patients and healthy controlsConclusion:This pilot study suggests muscle health may be adversely affected in RA patients compared to matched HC. Our results suggest that muscle changes occur in the earliest stages of RA and persist throughout the disease duration, even in clinical remission. If confirmed, these data imply the need for adjunctive muscle intervention to current RA treatment strategies in order to improve patient outcomes.References:[1]Giles JT, et al. Arthritis Care & Research. 2008[2]Maillard SM, et al. Rheumatology (Oxford, England). 2004[3]Grimm A, et al. The Journal of Frailty & Aging. 2018.Figure 2.MRI muscle volume in RA patients and healthy controlsDisclosure of Interests:Matt Farrow: None declared, John Biglands: None declared, Steven Tanner: None declared, Elizabeth Hensor: None declared, Maya H Buch Grant/research support from: Pfizer, Roche, and UCB, Consultant of: Pfizer; AbbVie; Eli Lilly; Gilead Sciences, Inc.; Merck-Serono; Sandoz; and Sanofi, Paul Emery Grant/research support from: AbbVie, Bristol-Myers Squibb, Merck Sharp & Dohme, Pfizer, Roche (all paid to employer), Consultant of: AbbVie (consultant, clinical trials, advisor), Bristol-Myers Squibb (consultant, clinical trials, advisor), Lilly (clinical trials, advisor), Merck Sharp & Dohme (consultant, clinical trials, advisor), Novartis (consultant, clinical trials, advisor), Pfizer (consultant, clinical trials, advisor), Roche (consultant, clinical trials, advisor), Samsung (clinical trials, advisor), Sandoz (clinical trials, advisor), UCB (consultant, clinical trials, advisor), Ai Lyn Tan: None declared
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Kuenze, Christopher M., Nathaniel Foot, Susan A. Saliba, and Joseph M. Hart. "Drop-Landing Performance and Knee-Extension Strength After Anterior Cruciate Ligament Reconstruction." Journal of Athletic Training 50, no. 6 (June 1, 2015): 596–602. http://dx.doi.org/10.4085/1062-6050-50.2.11.
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Context Individuals with a history of anterior cruciate ligament reconstruction (ACLR) are at greater risk of reinjury and developing early-onset osteoarthritis due to persistent abnormal joint loading. Real-time clinical assessment tools may help identify patients experiencing abnormal movement patterns after ACLR. Objective To compare performance on the Landing Error Scoring System (LESS) between participants with ACLR and uninjured control participants and to determine the relationship between LESS score and knee-extension strength in these participants. Design Controlled laboratory study. Setting Research laboratory. Patients or Other Participants Forty-six recreationally active participants, consisting of 22 with ACLR (12 men, 10 women; age = 22.5 ± 5.0 years, height = 172.8 ± 7.2 cm, mass = 74.2 ± 15.6 kg, body mass index = 24.6 ± 4.0) and 24 healthy control participants (12 men, 12 women; age = 21.7 ± 3.6 years, height = 168.0 ± 8.8 cm, mass = 69.2 ± 13.6 kg, body mass index = 24.3 ± 3.2) were enrolled. Main Outcome Measure(s) Bilateral normalized knee-extension maximal voluntary isometric contraction (MVIC) torque (Nm/kg) and LESS scores were measured during a single testing session. We compared LESS scores between groups using a Mann-Whitney U test and the relationships between LESS scores and normalized knee-extension MVIC torque using Spearman ρ bivariate correlations. Results The ACLR participants had a greater number of LESS errors (6.0 ± 3.6) than healthy control participants (2.8 ± 2.2; t44 = −3.73, P = .002). In ACLR participants, lower normalized knee-extension MVIC torque in the injured limb (ρ = −0.455, P = .03) was associated with a greater number of landing errors. Conclusions Participants with ACLR displayed more errors while landing. The occurrence of landing errors was negatively correlated with knee-extension strength, suggesting that weaker participants had more landing errors. Persistent quadriceps weakness commonly associated with ACLR may be related to a reduced quality of lower extremity movement during dynamic tasks.
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Larouche, Richard, Charles Boyer, Mark Stephen Tremblay, and Patricia Longmuir. "Physical fitness, motor skill, and physical activity relationships in grade 4 to 6 children." Applied Physiology, Nutrition, and Metabolism 39, no. 5 (May 2014): 553–59. http://dx.doi.org/10.1139/apnm-2013-0371.
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The present study sought to quantify the relationships among physical activity (PA), health-related fitness, and motor skill in children (grades 4 to 6), and to determine whether specific tests of fitness or motor skill are independently associated with objectively measured PA level. Four hundred and ninety-one students (56.4% female) wore a Digi-Walker pedometer for 7 consecutive days. Standardized protocols were used to assess health-related fitness (body mass index percentile, waist circumference, 20-m shuttle run, plank, handgrip, and trunk flexibility). Motor skill was evaluated using a validated obstacle course. Pearson correlations (with Holm adjustments for multiple comparisons) initially assessed associations among PA, health-related fitness, and motor skill. Multi-variable linear regression was used to determine which factors were significantly associated with daily step counts, while adjusting for gender, age, testing season, and socioeconomic status. Step counts were significantly correlated with predicted aerobic power (r = 0.30), obstacle course time (r = −0.27), obstacle course score (r = 0.20), plank isometric torso endurance (r = 0.16), and handgrip strength (r = 0.12), but not with waist circumference (r = −0.10), trunk flexibility (r = 0.10), or overweight status (ρ = −0.06). In the multi-variable model, predicted aerobic power, obstacle course time, testing season, gender, and the predicted aerobic power by gender interaction were significantly associated with step counts, explaining 16.4% of the variance. Specifically, the relationship between predicted aerobic power and step counts was stronger in girls. These findings suggest that aerobic fitness and motor skill are independently associated with children’s PA. Future longitudinal studies should evaluate whether interventions to enhance aerobic fitness and motor skill could enhance daily PA among children of this age.
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Grindstaff, Terry L., Jay Hertel, James R. Beazell, Eric M. Magrum, D. Casey Kerrigan, Xitao Fan, and Christopher D. Ingersoll. "Lumbopelvic Joint Manipulation and Quadriceps Activation of People With Patellofemoral Pain Syndrome." Journal of Athletic Training 47, no. 1 (January 1, 2012): 24–31. http://dx.doi.org/10.4085/1062-6050-47.1.24.
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Context: Quadriceps weakness and inhibition are impairments associated with patellofemoral pain syndrome (PFPS). Lumbopelvic joint manipulation has been shown to improve quadriceps force output and inhibition, but the duration of the effect is unknown. Objective: To determine whether quadriceps strength and activation are increased and maintained for 1 hour after high-grade or low-grade joint mobilization or manipulation applied at the lumbopelvic region in people with PFPS. Design: Randomized controlled clinical trial. Setting: University laboratory. Patients or Other Participants: Forty-eight people with PFPS (age = 24.6±8.9 years, height = 174.3 ± 11.2 cm, mass = 78.4 ± 16.8 kg) participated. Intervention(s): Participants were randomized to 1 of 3 groups: lumbopelvic joint manipulation (grade V), side-lying lumbar midrange flexion and extension passive range of motion (grade II) for 1 minute, or prone extension on the elbows for 3 minutes. Main Outcome Measure(s): Quadriceps force and activation were measured using the burst superimposition technique during a seated isometric knee extension task. A 2-way repeated-measures analysis of variance was performed to compare changes in quadriceps force and activation among groups over time (before intervention and at 0, 20, 40, and 60 minutes after intervention). Results: We found no differences in quadriceps force output (F5,33,101,18 = 0.65, P = .67) or central activation ratio (F4.84,92.03 = 0.38, P= .86) values among groups after intervention. When groups were pooled, we found differences across time for quadriceps force (F2.66,101.18 = 5.03, P = .004) and activation (F2.42,92.03 = 3.85, P = .02). Quadriceps force was not different at 0 minutes after intervention (t40 = 1.68, P = .10), but it decreased at 20 (t40 = 2.16, P = .04), 40 (t40 = 2.87, P = .01) and 60 (t40 = 3.04, P = .004) minutes after intervention. All groups demonstrated decreased quadriceps activation at 0 minutes after intervention (t40 = 4.17, P <.001), but subsequent measures were not different from preintervention levels (t40 range, 1.53–1.83, P >.09). Conclusions: Interventions directed at the lumbopelvic region did not have immediate effects on quadriceps force output or activation. Muscle fatigue might have contributed to decreased force output and activation over 1 hour of testing.
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Wilson, Benjamin, Benton Heyworth, Ryan Coene, Dai Sugimoto, Lyle Micheli, Mininder Kocher, and Melissa Christino. "Functional Recovery after Revision Anterior Cruciate Ligament Reconstruction with a Second Autograft: A Matched Cohort Analysis in Adolescent Patients (197)." Orthopaedic Journal of Sports Medicine 9, no. 10_suppl5 (October 1, 2021): 2325967121S0030. http://dx.doi.org/10.1177/2325967121s00308.
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Objectives: Young patients are the highest risk demographic for ACL graft failure and revision surgery. Previous studies have shown higher rates of graft failure with the use of allograft tissue for ACL reconstruction (ACLR) in both primary and revision surgeries. However, questions remain regarding the functional consequence of harvesting a second autograft from the ipsilateral knee for revision ACLR. The purpose of this study was to evaluate 6-month functional testing in patients who underwent revision ACLR with use of a second autograft from the ispilateral knee, when compared to matched cohorts of primary ACLR patients. Methods: A retrospective review of prospectively collected data from patients aged 19 or younger who underwent revision ACLR with a second autograft of an opposite muscle group (either revision patellar tendon (BTB) following primary hamstring (HS) or revision HS following primary BTB) at the study institution was performed. Exclusion criteria were patients who underwent iliotibial band autograft ACLR, those with two autografts from synergistic muscle groups, grafts from the contralateral knee, debilitating injury or surgery to the contralateral lower extremity, and multi-ligamentous knee injury. All subjects underwent functional return to sports (RTS) testing 5-8 months after revision surgery, which included anthropometric measures, isometric strength, Y-Balance, and functional hop testing. Side-to-side deficits were then compared using standard limb symmetry index (LSI) metrics, after matching a cohort of primary ACLR patients based on age, sex, and body mass index (BMI). Multivariate analysis of variance (MANOVA) was used to compare RTS metrics, and if significance was detected, pairwise comparison was performed by Bonferroni post-hoc correction. Statistical significance of p<0.05 was applied. Results: The cohort of 37 revision ACLR patients were compared to cohorts of 62 primary HS and 47 BTB ACLR patients, respectively (Table 1). The revision cohort showed comparable knee extension strength deficits to the BTB cohort (-9.45±12.09% vs -8.81±13.83%, p=0.999), which were significantly greater than that of the HS cohort (-9.45±12.09% vs -0.99±12.00%, p<0.05). Greater knee flexion strength deficits were seen in the HS cohort than the revision cohort (-38.90±16.21% vs -28.13±23.22%, p=0.009), whose deficits were, in kind, significantly greater than that of the BTB cohort (-28.13±23.22% vs -1.17±12.41%, p=0.001). The HS cohort also showed greater triple hop deficit (-21.08±25.99%) than the other two cohorts (-21.08±25.99% vs -10.75±12.85 vs -6.84±23.81, p=0.024), which were not significantly different from each other. Conclusions: After revision ACLR with a second autograft from the opposing muscle group of the ipsilateral knee, adolescents show similar knee extension strength deficits compared to primary ACLR patients with BTB grafts, but improved knee flexion strength deficits compared to primary ACLR patients with HS grafts.
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Zantop, Thore, Shozaburo Terai, Przemyslaw Warminski, and Christian Zantop. "Return to sports following ACL reconstruction: prospective analysis of functional stability 3 months postoperatively in 280 patients." Orthopaedic Journal of Sports Medicine 8, no. 9_suppl7 (September 1, 2020): 2325967120S0054. http://dx.doi.org/10.1177/2325967120s00546.
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Introduction: For the last years, the terms return to play and return to competition after ACL reconstruction have been spread. Recent literature does not provide sufficient information on the approach to identify knee joint conditions that are likely to result in a recurrent injury following ACL reconstruction. Aim of this study is therefore to prospectively investigate the functional stability after ACL reconstruction by one single surgeon 3 months postoperatively. Hypotheses: The functional stability after ACL reconstruction 3 months postoperatively can safely be assessed using a multi-factorial testing analysis. Methods: All patients of the year 2018 diagnosed with a primary ACL instability and treated by one single surgeon were enrolled and prospectively assessed. Follow-up at 12 weeks postoperatively was performed using a functional “return-to-sports” analysis including isokinetic and isometric strength measurement (quad/ham ratio, BTE-primus), postural stability tests (MTF balance score), tapping test (force plate, Bertec) and a 3d-motion analysis (myomotion, Noraxon) during bilateral drop jumps and single leg hop tests (uni- and bilateral drop-jump, bilateral Counter Movement-Jump, Single-Leg Hop for Distance). Agility was assessed using speed chase (Speedcort system, Globalspeed). Jump height and distance were recorded by infra-red measuring device (Optogait, Microgate, Italy). Motion analysis to determine the quality of landing and jumping mechanisms using a real time 3d-avatar (myomotion, Noraxon) were investigated during a speedcourt and jump analysis. Contributed to the early time onset of functional analysis, any abnormalty in the bilateral jump tests or refusal of the jump test by the patient led to non-performance to the jump test with the postoperative leg. Statistical analysis were performed using a Wilcoxon-Rank-Sum-Test (p<0.05). Results: At analylsis date of 404 primary ACL reconstruction of the year 2018 a total of 324 patients particated in the functional analysis at three months postoperatively. During the “return-to-sports” no giving way symptoms or recurrent instability was to be recorded. BMI was 25,3 (+/-4,1) and 25,9 (+/-3,7) for female and male patients, respectively. Approximately 40% of all patients were able to perfom single legged jump tests. Three months postoperatively, the perfomance of the ACL reconstructed knee was significantly lower than the intact contralateral leg. Isometric and isokinetic strength analysis showed significantly lower peak maximal force for quadriceps and hamstrings compared to the intact contralateral side. No significant differences were seen in the analysis of the postural stability analysis. Even though the contact forces were significantly different between the intact leg and the postoperative leg, there was no significant differences between the quantitate analysis of the jump height and distance in the dimensions jumping and agility. As a parameter of functional valgus instability the medial knee displacement according to Krosshaug et al. 2016 was severely high, however there was no statistical significant difference to the intact leg. Conclusion: This study shows that a functional analysis at an early timepoint following ACL reconstruction reveals high abnormalities with regard to the quality of the landing mechanism. To further contribute to the high number of recurrent instabilities in the young athlete below 20 years of age, this may be crucial to intervene avoiding a medial knee displacement. To accomplish this, all patients were supported with specific training-protocols for further rehabilitation of the lower extremity. These protocols were individually set-up, however in nearly all patients a specific emphasize was on strengthening of the hip external rotators.
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Antonioli, Eliane, Felipe B. D. Oliveira, Rosana R. Campedelli, Alessandro R. Zorzi, Danielli Specialli, Sudha Agarwal, and Mario Ferretti. "Response of osteoarthritis biomarkers after a rehabilitation program: study protocol." International Journal of Clinical Trials 7, no. 1 (January 24, 2020): 35. http://dx.doi.org/10.18203/2349-3259.ijct20200205.
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<p class="abstract"><strong>Background:</strong> Knee osteoarthritis is a progressive degenerative joint disease and remains a leading cause of pain, physical impairment and decline in health-related quality of life in adults. Despite its incidence being amongst the highest in chronic diseases, effective biomarkers are not available to assist in its management. The main goal of this study is to identify mediators that serve as biomarkers and investigate if the levels of these biomarkers will be correlated to the efficacy of a rehabilitation program.</p><p class="abstract"><strong>Methods:</strong> This is a prospective cohort study with 65 participants. Patients with mild-to-moderate symptomatic knee osteoarthritis will be recruited. The Rehabilitation Program will consist of three session/week during eight weeks. Assessment about functional evaluation will be performed before and after treatment, using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and EuroQOL-5D (Euro quality of life - five dimension) scales, Visual Analog Scale (VAS), and physical function tests (time up and go, isometric strength testing and kinematic gait analysis). Serum levels of classical pro-inflammatory cytokines, hyaluronan and high mobility group box 1 protein (HMGB-1) will be evaluated. The primary outcome is the change in WOMAC scale from baseline to end. Statistical analyses will be used to determine correlation of physical improvement and serum biomarkers. Adverse events will be monitored throughout the study.</p><p class="abstract"><strong>Conclusions: </strong>This trial expect to study the correlation between the anti-inflammatory effects of rehabilitation program derived factors that may be involved in suppressing cytokine induction via suppressing HMGB-1.</p><p class="abstract"><strong>Trial registration:</strong> Clinicaltrials.gov - NCT02964624.</p>
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Güven, S. C., Ş. Metin Tarhan, and F. N. Göğüş. "AB1368 ULTRASONOGRAPHIC EVALUATION OF THE KNEE AND MUSCLE ARCHITECTURE IN OSTEOARTHRITIS AND RHEUMATOID ARTHRITIS." Annals of the Rheumatic Diseases 81, Suppl 1 (May 23, 2022): 1790.1–1790. http://dx.doi.org/10.1136/annrheumdis-2022-eular.4112.
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BackgroundInvolvement of lower extremity joints in both rheumatoid arthritis (RA) and osteoarthritis (OA) is an important cause of declined functional status. Deterioration of skeletal muscle performance further contributes to disability. Quadriceps muscle plays an important role in most daily activities. Measuring thickness and pennation angle of quadriceps compartments can provide knowledge regarding quadriceps condition.ObjectivesAim is to investigate structural and inflammatory changes in knee joint and architecture of quadriceps muscle in RA, knee OA patients and a group of healthy subjects.MethodsTwenty RA patients and 20 knee OA patients with radiographic disease meeting Kellgren-Lawrence grade 2 and above were consecutively recruited, in absence of exclusion criteria. 20 healthy volunteers with similar demographics were recruited as control group. Knee symptoms and disability were evaluated by Lequesne Knee Index (LKI). Disease activity was evaluated by DAS28-CRP in RA patients. Quadriceps muscle was evaluated by ultrasonographic measurements of muscle thickness, subcutaneous fat tissue thickness and pennation angle of vastus muscles. Suprapatellar, lateral and medial compartments of knee joint were examined for effusion, synovial hypertrophy, power Doppler (PD) activity and degenerative changes.ResultsDemographics and clinical features of subjects and results of ultrasonographic evaluation are presented in Table 1. LKI scores were significantly higher in OA patients when compared to RA patients (p=0.004). Rate of degenerative changes was increased in RA and OA groups in comparison to controls (p=0.013). None of the subjects had PD activity. No differences were observed in thickness of rectus femoris, vastus muscles and subcutaneous fat between groups. Vastus medialis and intermedius pennation angles were reduced in OA and RA groups when compared to controls, but reached statistical significance only in vastus intermedius (3.56 ± 6.37 vs 4.89 ± 7.14 vs 7.29 ± 4.93, p=0.038).Table 1.Demographics, clinical features and ultrasonographic findings of subjectsOA (n=20)RA (n=20)Control (n=20)pAge, years¶58.44 ± 6.6854.67 ± 7.1555.11 ± 5.890.178Gender, femaleµ17 (85)15 (75)16 (80)0.732BMI¶30.05 ± 3.8828.29 ± 4.7828.27 ± 3.340.343Duration of diagnosis, months¶11.95 ± 17.1514.80 ± 8.500.023LKI¶9.37 ± 2.656.95 ± 3.380.004DAS28-CRP¶2.59 ± 1.10Presence of effusion µ9 (45)9 (45)4 (20)0.166Presence of SH µ9 (45)11 (55)8 (40)0.626Presence of degeneration µ16 (80)13 (65)7 (35)0.013Muscle thickness, mm¶ VM14.09 ± 4.1715.38 ± 5.1514.57 ± 3.410.243 VL17.17 ± 3.5316.96 ± 4.9816.66 ± 3.180.985 VI10.54 ± 2.6510.49 ± 3.3210.67 ± 1.830.926 RF13.01 ± 3.9213.74 ± 3.7813.63 ± 3.490.879SFT thickness, mm¶12.59 ± 5.7913.81 ± 7.1012.53 ± 5.200.969Pennation angle, degree ¶ VM5.50 ± 7.016.94 ± 8.299.05 ± 5.100.244 VL13.61 ± 5.1513.44 ± 3.4013.29 ± 3.250.703 VI3.56 ± 6.374.89 ± 7.147.29 ± 4.930.038¶: mean ± SD, µ: number (%),LKI: Lequesne Knee Index, KL: Kellgren – Lawrence grade, SH: synovial hypertrophy, VM: vastus medialis, VL: vastus lateralis, VI: vastus intermedius, RF: rectus femoris, SFT: subcutaneous fat tissueConclusionIn our study ultrasound evaluation findings of knee joint and quadriceps muscle were similar between knee OA and RA patients.VM and VI pennation were reduced when compared to healthy subjects in both groups. These findings may indicate a similar degree of functional impairment in OA and RA due to knee joint involvement.References[1]Hsieh LF, et al. Isokinetic and isometric testing of knee musculature in patients with rheumatoid arthritis with mild knee involvement. Arch Phys Med Rehabil. 1987;68:294-7.[2]Ruhdorfer A, et al. Association of knee pain with a reduction in thigh muscle strength - a cross-sectional analysis including 4553 osteoarthritis initiative participants. Osteoarthritis Cartilage. 2017;25:658-666.AcknowledgementsI have no acknowledgements to declare.Disclosure of InterestsNone declared
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Lum, Danny, G. Gregory Haff, and Tiago M. Barbosa. "The Relationship between Isometric Force-Time Characteristics and Dynamic Performance: A Systematic Review." Sports 8, no. 5 (May 15, 2020): 63. http://dx.doi.org/10.3390/sports8050063.
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The purpose of this article was to review the data on the relationship between multi-joint isometric strength test (IsoTest) force-time characteristics (peak force, rate of force development and impulse) and dynamic performance that is available in the current literature. Four electronic databases were searched using search terms related to IsoTest. Studies were considered eligible if they were original research studies that investigated the relationships between multi-joint IsoTest and performance of dynamic movements; published in peer-reviewed journals; had participants who were athletes or active individuals who participate in recreational sports or resistance training, with no restriction on sex; and had full text available. A total of 47 studies were selected. These studies showed significant small to large correlations between isometric bench press (IBP) force-time variables and upper body dynamic performances (r2 = 0.221 to 0.608, p < 0.05) and significant small to very large correlation between isometric squat (ISqT) (r2 = 0.085 to 0.746, p < 0.05) and isometric mid-thigh pull (IMTP) (r2 = 0.120 to 0.941, p < 0.05) force-time variables with lower body dynamic performances. IsoTest force-time characteristics were shown to have small to very large correlations with dynamic performances of the upper and lower limbs as well as performance of sporting movements (r2 = 0.118 to 0.700, p < 0.05). These data suggest that IsoTest force-time characteristics provide insights into the force production capability of athletes which give insight into dynamic performance capabilities.
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Martinopoulou, Klimentini, Olyvia Donti, William A. Sands, Gerasimos Terzis, and Gregory C. Bogdanis. "Evaluation of the Isometric and Dynamic Rates of Force Development in Multi-Joint Muscle Actions." Journal of Human Kinetics 81, no. 1 (January 28, 2022): 135–48. http://dx.doi.org/10.2478/hukin-2021-0130.
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Abstract The rate of force development (RFD) in the isometric leg press (ILP), the countermovement jump (CMJ) and the squat jump (SJ) were examined in twenty-three (9 females) team sport athletes aged 21-24 years. Peak force (Fpeak), peak rate of force development (RFDpeak) and RFD at different time epochs (0-50, 50-100, 100-150, 150-200) were calculated from the force-time curve, as well as CMJ and SJ height and the center of mass displacement. RFDpeak, RFD at 0-50, 50-100 and 100-150 ms and Fpeak were similar between the CMJ and the SJ (p = 0.26 to 0.99). Furthermore, RFD0-50 ms was similar between the ILP, the CMJ, and the SJ (p = 0.99 to 0.57). Higher values were observed in the ILP compared with the CMJ and the SJ in RFD50-100 ms and RFD100-150 ms (p < 0.001) and these differences were maintained even when RFD was scaled to body mass. The higher RFD normalized to Fpeak was attained at the 50-100 ms time interval with no differences between the ILP, CMJ and SJ and between males and females. These results suggest that the ability to exert rapid force is similar between the CMJ and the SJ, irrespective of the type of muscle action. Furthermore, RFD normalized to Fpeak is a muscle-force independent index of explosive force production, facilitating comparisons between individuals with different levels of muscle strength. The similarities between the CMJ and the SJ in RFDpeak, Fpeak, and RFD at different time epochs may imply that these types of jumps could be used interchangeably to assess explosive lower limb performance.
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Raza, Haroon, Hafiz Rana Muhammad Arslan, Ambreen Iqbal, Muhammad Faizan Hamid, Asna Waseem, and Sana Manzoor. "Comparison of Gluteal Muscle Strengthening versus Conventional Isometrics in Pain Management of Piriformis Syndrome." Pakistan Journal of Medical and Health Sciences 15, no. 11 (November 30, 2021): 2963–65. http://dx.doi.org/10.53350/pjmhs2115112963.
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Aim: To analyze the effectiveness of gluteal muscles strengthening in piriformis syndrome. Study design: Experimental study Place and duration of study: Department of Physiotherapy, Mayo Hospital, Lahore from 1st February 2019 to 31st July 2019. Methodology: Fifty patients presenting with piriformis syndrome were enrolled. They were divided in two groups. Control group received piriformis stretching, ultrasound and conventional isometrics. Experimental group received piriformis stretching, ultrasound and a gluteal strengthening program. The baseline parameters were assessed using the Visual Analogue Scale (VAS) and Manual Muscle Testing (MMT). Patients were treated for 40 minutes 3 times a week for 4weeks. Results: Reduction in intensity of pain as well as improvement in ROM was seen in both groups. There was significant improvement in lateral rotation of hip in experimental group, and as piriformis is also a lateral rotator of hip joint, hence improvement in range of lateral rotation shows that a gluteal strengthening program has significant in increasing ROM of joint. There was significant improvement in MMT grade of gluteal muscles comparatively in the experimental group. Conclusion: Experimental group showed improvements in decreasing pain and improvements in strength, with a significant improvement in lateral rotation shows that gluteal strengthening program can be used to treat pts with piriformis syndrome. Key words: Manual Muscle Testing, Visual analog scale
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Hussain, Sida, Hamna Shakeel, Asif Ali, Muhammad Rizwan, and Naveed Ahmad. "Shaking Table Testing of a Low-Rise Reinforced Concrete Intermediate Moment Resisting Frame." Buildings 12, no. 12 (December 1, 2022): 2104. http://dx.doi.org/10.3390/buildings12122104.
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Multi-level shaking table tests were performed on a 1:3 reduced scale two-story reinforced concrete (RC) intermediate moment resisting frame (IMRF) conforming to the requirements given in the ACI-318-19. The exterior joints lacked shear reinforcement to assess the viability of the ACI model recommended for determining the design shear strength of the beam–column joint panel. One of the horizontal components of the 1994 Northridge earthquake accelerogram (090 CDMG Station 24278, Source: PEER strong motion database) was input to the frame for multi-level shaking table testing. Plastic hinges developed in beams under base input motion with a maximum acceleration equal to 0.40 g. The exterior joints incurred extensive damage under base input motion with a maximum acceleration equal to 0.70 g. The frame achieved displacement ductility and overstrength factors (determined as the ratio of the maximum resistance of the frame to the design base share force) equal to 2.40 and 2.50, respectively. This gives a response modification factor equal to 6. The satisfactory performance of the frame is attributed to the high efficiency of the beam–column joint, which was confined by spandrel beams on two faces and the high strength of the concrete. The inherent minimal confinement is sufficient to ensure satisfactory seismic behavior. The analysis confirmed overstrength equal to 1.58 for joint shear strength in comparison to the design strength determined using the ACI model. The data might serve as a reference for calibrating and validating numerical modeling techniques for performance evaluation, which are crucial in the context of performance-based engineering.
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Martin, Eric A., and George K. Beckham. "Isometric Mid-Thigh Pull Performance in Rugby Players: A Systematic Literature Review." Journal of Functional Morphology and Kinesiology 5, no. 4 (December 8, 2020): 91. http://dx.doi.org/10.3390/jfmk5040091.
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The isometric mid-thigh pull (IMTP) is a multi-joint test of whole-body force production relevant to rugby players. “Rugby AND (mid-thigh pull OR midthigh pull OR mid thigh pull” were searched in PubMed, Sportdiscus, Academic Search Premier, CINAHL Plus with Full Text, and Google Scholar; the final date of search was 24 January 2018. Data extraction from 24 articles included subject characteristics, force data, and IMTP testing procedures. Select ranges of peak forces reported were: Youth: 1162–2374 N; Academy: 1855–3104 N; Professional: 2254–3851 N. Rate of force development (RFD) at 100 and 200 ms ranged from 5521 to 11,892 N and 5403 to 8405 N, respectively, among professional rugby players. Studies’ research design were of moderate quality, but most studies lacked detailed reporting of IMTP procedures. Variability of force characteristics derived from the IMTP within similar populations (e.g., approximately 200% difference in peak force between samples of professional rugby league players) as well as large and unexpected overlaps between dissimilar populations, limit conclusions about force production capabilities relative to playing level, likely due to limitations and lack of standardization of IMTP procedures. Greater uniformity in IMTP testing procedures and reporting is needed. This manuscript provides a guide for reporting needs when presenting results from an IMTP in research.
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Hammond, Alexander, Craig Perrin, James Steele, Jürgen Giessing, Paulo Gentil, and James P. Fisher. "The effects of a 4-week mesocycle of barbell back squat or barbell hip thrust strength training upon isolated lumbar extension strength." PeerJ 7 (July 26, 2019): e7337. http://dx.doi.org/10.7717/peerj.7337.
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Objectives Common exercises such as the barbell back squat (BBS) and barbell hip thrust (BHT) are perceived to provide a training stimulus to the lumbar extensors. However, to date there have been no empirical studies considering changes in lumbar extension strength as a result of BBS or BHT resistance training (RT) interventions. Purpose To consider the effects of BBS and BHT RT programmes upon isolated lumbar extension (ILEX) strength. Methods Trained male subjects (n = 14; 22.07 ± 0.62 years; 179.31 ± 6.96 cm; 79.77 ± 13.81 kg) were randomised in to either BBS (n = 7) or BHT (n = 7) groups and performed two training sessions per week during a 4-week mesocycle using 80% of their 1RM. All subjects were tested pre- and post-intervention for BBS and BHT 1RM as well as isometric ILEX strength. Results Analyses revealed that both BBS and BHT groups significantly improved both their BBS and BHT 1RM, suggesting a degree of transferability. However, the BBS group improved their BBS 1RM to a greater degree than the BHT group (p = 0.050; ∼11.8 kg/10.2% vs. ∼8.6 kg/7.7%, respectively). And the BHT group improved their BHT 1RM to a greater degree than the BBS group (p = 0.034; ∼27.5 kg/24.8% vs. ∼20.3 kg/13.3%, respectively). Neither BBS nor BHT groups significantly improved their isometric ILEX strength. Conclusions The present study supports the concept of specificity, particularly in relation to the movement mechanics between trunk extension (including pelvic rotation) and ILEX. Our data suggest that strength coaches, personal trainers, and trainees can self-select multi-joint lower-body trunk extension exercises based on preference or variety. However, evidence suggests that neither the BBS nor BHT exercises can meaningfully increase ILEX strength. Since strengthening these muscles might enhance physical and sporting performance we encourage strength coaches and personal trainers to prescribe ILEX exercise.
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Supar, Khairi, and Hilton Hilton Ahmad. "2-D Strength Prediction of Single-row Multi-bolted Joints Woven Fabric Kenaf Composites." International Journal of Engineering & Technology 7, no. 3.7 (July 4, 2018): 21. http://dx.doi.org/10.14419/ijet.v7i3.7.16198.
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Implementation of multi-bolts arrangements in structures connections are commonplace in steel design to allow for joint efficiency and stronger connections. Woven fabric kenaf fibers are potentially used as reinforcement in composite materials due to excellent specific strength, renewability and less hazardous during handling as compared to commercial fibers. A two-dimensional Extended Finite Element Method (XFEM) framework of single-row multi-bolted joints has been developed to study the stress distribution and predict the joint bearing stress at failure. Stress distribution among adjacent bolts were compared along the hole boundary and net-tension plane, suggesting net-tension failure occurred at end-bolt. The predicted bearing strength from finite element modelling are validated against experimental framework. The testing series under investigated consists of four datasets from single-row 2 bolts and 3 bolts single-lap joints. Current study showed that the XFEM models demonstrated good agreements with the experimental results.
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Ekrem, Mürsel, Ömer Sinan Şahin, Salim Eğemen Karabulut, and Ahmet Avcı. "Thermal stability and adhesive strength of boron nitride nano platelets and carbon nano tube modified adhesives." Journal of Composite Materials 52, no. 11 (August 16, 2017): 1557–65. http://dx.doi.org/10.1177/0021998317726147.
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The effect of multi-walled carbon nanotube and/or boron nitride nano platelets usage on shear strength and thermal stability of epoxy based adhesives have been investigated. Commercially available diglycidyl ether of bisphenol A based epoxy was used as matrix and reinforced by using nanofillers. The resulting adhesive was tested for its shear-lap adhesion to aluminum alloy sheets (2024-T3). The nano particles modified epoxy adhesives were characterized by Fourier transform infrared, differential scanning calorimetry, and thermal gravity analyses analysis. These characterizations revealed that incorporation of nano particles can result in enhancement in chemical stability. Single lap strength joint testing was conducted in accordance with ASTM-D-1002-10 standard. Fracture morphologies and the effects of multi-walled carbon nanotubes and boron nitride nano platelets on epoxy adhesive were investigated after shear tests by means of scanning electron microscopy. Compared to neat epoxy, increases of 30% in shear strength and 57% in energy required to break joints have been obtained by multi-walled carbon nanotube/boron nitride nano platelet modification.
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Öztoprak, Nahit, and Gökçe Mehmet Gençer. "Effect of elevated test temperature on the tensile strength and failure mechanism of hot-pressed dissimilar joints of laser ablation-treated AA5754-H111 and thermoplastic composite." Materials Testing 64, no. 8 (August 1, 2022): 1192–201. http://dx.doi.org/10.1515/mt-2021-2191.
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Abstract Evaluation of directly bonded single-lap joint (SLJ) obtained using Al5754 alloy and 20 wt% long glass fiber-reinforced polypropylene (PP) is performed via the lap-shear testing at various temperatures. A fiber laser is used to form a multi-groove microstructure on the aluminum (Al) surface. The bonding regions are investigated microscopically before and after the mechanical testing. Dissimilar joint is manufactured under a 100 kN force at 200 °C for 60 min through hot-pressing technique without using any adhesives. Afterward, lap-shear strength of the joints is determined under elevated working temperatures (25, 75 and 125 °C). Damaged surfaces are also scrutinized for studying the failure mechanism of the joints. According to the experimental results, mechanical anchoring between the Al alloy substrate and thermoplastic composite (TPC) is formed at the interface through the applied laser treatment. Strength exhibits a significant decrease with the test temperature increasing from 25 to 125 °C. Fiber/matrix debonding is the dominant failure mode in the composite adherend. The SEM observations also highlight the pulled-out fibers in the PP composite at the elevated temperatures.
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Peterson, Carrie L., Lynn M. Rogers, Michael S. Bednar, Anne M. Bryden, Michael W. Keith, Eric J. Perreault, and Wendy M. Murray. "Posture-Dependent Corticomotor Excitability Differs Between the Transferred Biceps in Individuals With Tetraplegia and the Biceps of Nonimpaired Individuals." Neurorehabilitation and Neural Repair 31, no. 4 (December 8, 2016): 354–63. http://dx.doi.org/10.1177/1545968316680488.
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Background. Following biceps transfer to enable elbow extension in individuals with tetraplegia, motor re-education may be facilitated by greater corticomotor excitability. Arm posture modulates corticomotor excitability of the nonimpaired biceps. If arm posture also modulates excitability of the transferred biceps, posture may aid in motor re-education. Objective. Our objective was to determine whether multi-joint arm posture affects corticomotor excitability of the transferred biceps similar to the nonimpaired biceps. We also aimed to determine whether corticomotor excitability of the transferred biceps is related to elbow extension strength and muscle length. Methods. Corticomotor excitability was assessed in 7 arms of individuals with tetraplegia and biceps transfer using transcranial magnetic stimulation and compared to biceps excitability of nonimpaired individuals. Single-pulse transcranial magnetic stimulation was delivered to the motor cortex with the arm in functional postures at rest. Motor-evoked potential amplitude was recorded via surface electromyography. Elbow moment was recorded during maximum isometric extension trials, and muscle length was estimated using a biomechanical model. Results. Arm posture modulated corticomotor excitability of the transferred biceps differently than the nonimpaired biceps. Elbow extension strength was positively related and muscle length was unrelated, respectively, to motor-evoked potential amplitude across the arms with biceps transfer. Conclusions. Corticomotor excitability of the transferred biceps is modulated by arm posture and may contribute to strength outcomes after tendon transfer. Future work should determine whether modulating corticomotor excitability via posture promotes motor re-education during the rehabilitative period following surgery.
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Strzelinski, Melissa, Lori Thein Brody, Jo Armour Smith, and Shaw Bronner. "Reliability of a Barre-Mounted Dynamometer-Stabilizing Device in Measuring Dance-Specific Muscle Performance." Medical Problems of Performing Artists 36, no. 1 (March 1, 2021): 27–33. http://dx.doi.org/10.21091/mppa.2021.1004.
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BACKGROUND: Hand-held dynamometry is considered an efficient, effective, and portable means of objectively measuring lower extremity strength; however, it has yet to be studied specific to dance-relevant muscle performance. Also, dynamometry is often criticized for variability in results based on tester strength and sex. Use of an external stabilizing device has been suggested to minimize differences in outcomes between male and female testers by reducing variability associated with tester strength limitations. Therefore, this study used a barre-mounted, portable dynamometer stabilizing device to improve consistency of results among different testers for assessing hip and lower extremity muscle performance in dance-relevant positions. OBJECTIVE: To assess the intra and inter-rater reliability of a barre-mounted dynamometer stabilizing device in measuring muscle performance in common dance maneuvers. METHODS: Two testers assessed muscle performance of three common dance maneuvers-—développé en avant, à la secondé, and arabesque-—on 11 pre-professional and professional dancers on two separate occasions to establish intra- and inter-rater reliability of the barre-mounted dynamometer stabilizing device. RESULTS: Intra-rater reliability was moderate to high and inter-rater reliability of the device was excellent, with intraclass correlation coefficients ranging from 0.527–0.851 and 0.834–0.953, respectively, for all positions. CONCLUSIONS: The barre-mounted stabilizing device shows promise in mitigating tester strength or fatigue in assessing muscle performance of dancers. Initial assessment of the device suggests further study may be indicated to improve generalizability to applications of larger-scale muscle performance screening and assessment in dancers or other athletic populations who engage in movements that require extensive hip range of motion and multi-joint stability. CLINICAL RELEVANCE: Using a portable, barre-mounted stabilizing device in assessing multi-joint lower extremity muscle performance in dancers improves consistency of testing results. Application of this testing device into wider scale screenings could assist in developing normative data for a population that is lacking.
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Snezgkov, D. Yu, and S. N. Leonovich. "MULTI-WAVE ULTRASONIC CONTROL OF CONCRETE." Science & Technique 16, no. 4 (July 6, 2017): 289–97. http://dx.doi.org/10.21122/2227-1031-2017-16-4-289-297.
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The existing non-destructive testing system of structure concrete is actually orientated on the usage of longitudinal acoustical waves. This is due to simplicity of technical realization for measuring velocity (time) of acoustical pulse propagation in bulk concrete. But a reverse side of simple measuring procedure is a loss of additional information on concrete which is contained in the accepted acoustical signal. Therefore usage of an ultrasonic concrete testing method is limited by assessment of its strength. Joint usage of several wave types, so-called multi-wave testing, allows to refine metrology parameters of the ultrasonic method and to gain more information while determining physical and mechanical properties of concrete in laboratory and in situ conditions. The paper considers testing of elongated concrete elements and structures by an ultrasonic pulsing method on the basis of longitudinal subsurface and Rayleigh waves. It has been proposed to use methodology for time selection of wave components according to amplitude parameter and it has been applied for standard acoustical transformers with considerable reverberation time and not possessing spatial selectivity Basic principle of the proposed methodology is visual (according to oscillogram of the received signal) determination of characteristic time moments which are used for calculation of differential value of a propagation velocity in the Rayleigh wave impulse. The paper presents results pertaining to simulation of acoustical pulse propagation on the basis of 0.15 m and data of concrete ultrasonic in situ testing on measuring bases from 0.25 to 1.75 m. Advantage of large baseline for sonic test is a possibility for execution of a hundred percent inspection for surface of large-sized elements and structures, and so there is no need to make a selective inspection in some control areas as it is stipulated by provided by existing regulations. Responsivity of the Rayleigh wave parameters to near surface concrete defects permits quickly and efficiently to detect crack areas in a reinforced structure. Energy localization of a surface wave in a layer having width λ/2–λ provides a possibility to ignore reinforcement availability under appropriate selection of oscillation frequency. In addition to this, large measuring baseline makes it possible to lower effect of concrete structural inhomogeneity on statistical stability for pulse velocity assessment that ultimately reveals a possibility to register an appearance of concrete acoustical elasticity effect under in situ conditions.
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Gebauer, Jana, Rico Drehmann, Kevin Eisner, David Kupke, and Andrés Fabian Lasagni. "Development of Multi-Material-Joint Made of Copper-Coated FRP and Steel by Innovative Technology Fusion." Technologies for Lightweight Structures (TLS) 5, no. 1 (April 1, 2022): 104–14. http://dx.doi.org/10.21935/tls.v5i1.169.
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Several technologies have been developed to join metal and polymer, such as adhesive bonding, clinching or screwing. These have disadvantages in terms of creep tendency of the adhesives or structural damage to the fiber-reinforced plastic (FRP). An innovative process chain consisting of laser pre-treatment of the FRP before metallization by thermal spraying and the subsequent low-temperature soldering process enable a reliable multi-material bond, without structural damage either of the FRP or the metal part. In addition to a rough joining surface, the laser pre-treatment enables the deep interlocking of the thermally sprayed copper coating with the carbon fibre-reinforced plastic (CFRP) substrate. After the adhesion strength of the copper-coated CFRP could be doubled to 18 MPa compared to grit-blasting, this hybrid was joined to a steel counterpart with a soft solder BiSnAg1 using infrared heating. Additionally, the hybrid achieved a flexural stress of 1128.0 MPa in a 4-point-bending test without coating impairment. The multi-material joint achieved up to 15.5 MPa in the tensile shear test. During fatigue testing, the specimens withstood 5.000.000 load cycles at a maximum stress of 15 MPa and a mean stress of 8.6 MPa without any measurable structural damage. After salt water aging, the joining zone remained unaffected.
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Zhou, Shujun, Tingyan Yan, Waqas Muneer, Xuan Yin, Qiyu Gao, and Xiaohong Zhan. "Effect of Heat Input on LMHMW Joint of Carbon Steel." Applied Sciences 12, no. 1 (December 29, 2021): 301. http://dx.doi.org/10.3390/app12010301.
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Laser-MIG hybrid multi-layer welding (LMHMW) technology has been employed in paraxial configuration with laser leading for the welding of 20 mm thick Q235 carbon steel plates to exploit the hybridization effect that addresses the shortcomings of the individual process as well as to compliment their merits. The bilateral effects of arc augmented laser welding have resulted in complete joint penetration, process efficiency, stability and gap bridge ability. Samples welded under varying heat inputs in multiple passes have been analyzed for their microstructure evaluation using an optical microscope followed by tensile and Vickers hardness testing in various regions of the weld zones. This process was conducted to characterize the effect of heat input on the mechanical properties of the welded joints. The experimental results illustrate that different heat inputs have significant effects on the microstructure, heat affected zone width and mechanical properties of welded joints. The microhardness near the fusion line decreases dramatically due to the influence of the phase transformation process, and the highest microhardness value is obtained in the center of the weld seam. By using reasonable process parameters, the strength of the welded joint can obtain 458.5 MPa.
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MacLaughlin, Mary, Steve Berry, Michael Petro, Katherine Berry, and Anders Bro. "Characterization of peak shear strength of rough rock joints using limited displacement multi-stage direct shear (LDMDS) tests." E3S Web of Conferences 92 (2019): 13011. http://dx.doi.org/10.1051/e3sconf/20199213011.
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Current standard direct shear test methods for rock joints do not account for damage to the specimens' asperity profiles; tests require shearing of a single specimen to large displacements under successive normal stresses (the multistage test), or the use of similar specimens in multiple tests. Due to the inherently unique nature of rock joints and corresponding difficulty in obtaining specimens with identical or even similar geometries, multistage tests are more common. A major issue with the multistage test is that successive shearing of the specimen damages the surface asperities and changes its overall roughness profile, reducing the peak shear stress and consequently resulting in underestimation of the friction angle and overestimation of the joint shear intercept (cohesion). The limited displacement multistage direct shear (LDMDS) test method minimizes these testing imperfections by allowing shearing of a single specimen without extensive asperity damage, accomplished by immediately pausing shear displacement once peak shear stress has been reached, then proceeding to shear the specimen under the following normal stress value, and shearing into the post-peak region only after identifying multiple values of peak shear strength. The authors have validated the LDMDS procedure using cement replicates of rock joints, demonstrating that it yields more accurate strength parameters than the standard multistage direct shear test.
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Levadnyi, Ievgen, Jan Awrejcewicz, Yan Zhang, and Yaodong Gu. "Comparison of femur strain under different loading scenarios: Experimental testing." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 235, no. 1 (August 18, 2020): 17–27. http://dx.doi.org/10.1177/0954411920951033.
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Bone fracture, formation and adaptation are related to mechanical strains in bone. Assessing bone stiffness and strain distribution under different loading conditions may help predict diseases and improve surgical results by determining the best conditions for long-term functioning of bone-implant systems. In this study, an experimentally wide range of loading conditions (56) was used to cover the directional range spanned by the hip joint force. Loads for different stance configurations were applied to composite femurs and assessed in a material testing machine. The experimental analysis provides a better understanding of the influence of the bone inclination angle in the frontal and sagittal planes on strain distribution and stiffness. The results show that the surface strain magnitude and stiffness vary significantly under different loading conditions. For the axial compression, maximal bending is observed at the mid-shaft, and bone stiffness is also maximal. The increased inclination leads to decreased stiffness and increased magnitude of maximum strain at the distal end of the femur. For comparative analysis of results, a three-dimensional, finite element model of the femur was used. To validate the finite element model, strain gauges and digital image correlation system were employed. During validation of the model, regression analysis indicated robust agreement between the measured and predicted strains, with high correlation coefficient and low root-mean-square error of the estimate. The results of stiffnesses obtained from multi-loading conditions experiments were qualitatively compared with results obtained from a finite element analysis of the validated model of femur with the same multi-loading conditions. When the obtained numerical results are qualitatively compared with experimental ones, similarities can be noted. The developed finite element model of femur may be used as a promising tool to estimate proximal femur strength and identify the best conditions for long-term functioning of the bone-implant system in future study.
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Grimm, Tyler J., Derek Shaffer, and Ihab Ragai. "Utilization of a Curly Toolpath in Friction Stir Welding." Advanced Materials Research 1165 (July 23, 2021): 15–29. http://dx.doi.org/10.4028/www.scientific.net/amr.1165.15.
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Friction stir welding (FSW) is an advanced solid-state metal joining technique. This operation fuses adjacent materials through the use of a non-consumable, rotating tool, which is plunged into and travels along the seam of the materials. Since this joining method avoids the bulk melting of the base materials, it is considered a relatively energy efficient process. Additionally, the strength of the base material is often improved due to significant grain refinement resulting from the stirring action of the tool at relatively low temperatures. Another inherent benefit is that the joint thickness, which is dependent on the length of the pin, can be much greater than most other joining processes and can also be well controlled. This joining method conventionally relies on the friction at the tool-base material interface to stir materials. Other research has implemented complex tooling to mechanically enhance this stirring action. However, these tools are often expensive, requiring a high level of capability within industry. In order to improve the weld strength of FSW, a novel toolpath is utilized which significantly improves the mechanical mixing of the constituent materials without the need for complex tooling, such as tools with threaded pins. The path currently investigated forms a curl as it travels both perpendicular and parallel to the joint. This motion is used to extend the stirring action of the tool to regions outside the immediate joint area. It was found that this tool path is effective in improving weld strength under specific process parameters. Constraining the tool's axis normal to the workpiece surface resulted in a void that was formed in the majority of tests; however, this void was eliminated with modification of the process parameters. An uneven distribution of heat was recognized within this testing in which one side of the joint was hotter than the other. This observation may be used in future studies to perform multi-material joining where it is often necessary to increase the temperature of one material more than the other.
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Li, Zhen, Zecheng Zhuang, Xuehai Qian, Yong Xiang, Lei Zeng, and Jianping Tan. "Interface Microstructure and Properties of Vacuum-Hot-Rolled 55#/316L Clad Rebars." Materials 16, no. 2 (January 6, 2023): 571. http://dx.doi.org/10.3390/ma16020571.
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The existing process for the preparation of cladded rebars is too complicated for large-scale industrial production. Therefore, this paper proposes a 55#/316L rebar preparation method based on vacuum hot rolling. The microstructure and mechanical properties of the composite interface of the rebar, along with the connecting technique, were studied using transmission electron microscopy, X-ray diffraction, and Vickers hardness testing. The obtained results showed that the minimum thickness of the 55#/316L rebar cladding was 0.25 mm, which was twice that of the M 329M/M 329-11 design standard used in the United States of America. Due to the diffusion of carbon, large numbers of second-phase particles were precipitated on the stainless-steel side, which resulted in intergranular chromium depletion. After multi-pass hot rolling, the minimum bonding strength of the composite interface reached 316.58 MPa, which was considerably higher than the specified value of 210 MPa. In addition, we designed three different types of rebar connection joints: sleeve, groove-welded, and bar-welded. According to the tensile test, the bar-welded joint had higher yield strength (385 MPa) and tensile strength (665 MPa) than the base rebar (376.6 MPa and 655 MPa), as well as a very high corrosion resistance.
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Wu, Cheng-Hsien, Kun-Chun Chen, Yang-Sung Lin, Yuan-Chih Liu, and Chun-Li Lin. "Functional Evaluation of a Novel Multi-Axial Alveolar Distractor—Preliminary In Vivo Animal Study." Applied Sciences 11, no. 4 (February 22, 2021): 1898. http://dx.doi.org/10.3390/app11041898.
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This study evaluates the biomechanical performance of a new multi-axial alveolar distractor using an animal study. The multi-axial alveolar distractor is designed with a ball and socket joint mechanism that can rotate up to 60° toward the buccal/lingual and mesial/distal sides intra-operatively to achieve vector control. The transport segment can be moved through activating the transport screw with 0.25 pitch, allowing 13 mm in distraction height. This distractor was fixed at the right angulus mandibular of experimental rabbits and adjusted 15° toward the mesial side and 25° toward the buccal side as Group TMB (toward mesial-buccal) (n = 3), and 15° toward the mesial side as Group TM (toward mesial) (n = 3). Group TC (control) was the control group. The distractors were activated 1 mm/day for 13 days. Living bone growth was observed at various periods. The total bone growth length at the angulus region and buccal side distraction thickness after distraction were calculated. The variations in bone growth geometric shape at the mandible angulus were also recorded. Fracture testing was performed to understand the variations in the mechanical strength between the distracted and intact bone specimens. The digital radiography results showed that the osteotomy areas at the mandible angulus were healed and the bone growth completed after surgery. The average bone growth length of Group TMB was 17.68 mm. This was greater than that of Group TM at 14.79 mm. The corresponding buccal side distractor thicknesses for Group TMB and TM after distraction were 5.12 ± 0.52 mm and 3.32 ± 0.37 mm, respectively. The tensile strengths of the bone specimens after distraction of Groups TMB, TM and TC were 172.13 N, 119.27 N and 304.24 N, respectively, and the percentage of distraction bone tensile strength to normal bone was 57% and 39% for Groups TMB and TM, respectively. This study concluded that this new multi-axial alveolar bone distractor can drive bones to grow in accordance with the direction/angle of the distraction plan. The bone growth healed gradually and presented insufficient mechanical strength.
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Xu, Congchang, Ke Liu, Hong He, Hanlin Xiang, Xinxin Zhang, and Luoxing Li. "Mechanical Performance Evaluation of the Al-Mg-Si-(Cu) Aluminum Alloys after Transient Thermal Shock through an Novel Equivalent Structure Design and Finite Element Modeling." Metals 10, no. 4 (April 21, 2020): 537. http://dx.doi.org/10.3390/met10040537.
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In this paper, the microstructure evolution and mechanical performance of the Al-Mg-Si-(Cu) aluminum alloy after transient thermal shock were investigated through experimental tests and finite element simulations. A novel equivalent structure was designed as a typical case in which one side of the plate was welded therefore the other side was thermally shocked with different temperature distribution and duration. The temperature gradient which influences most importantly the mechanical properties was simulated and experimentally verified. Through cutting layers and tensile testing, the mechanical response and material constitutive relation were obtained for each layer. Gurson-Tvergaard-Needlemen (GTN) damage parameters of these samples under large strains were then obtained by the Swift law inverse analysis approach. By sorting the whole welded joint into multi-material composed structure and introducing the obtained material constitutive relation and damage parameters, tensile properties were precisely predicted for typical types of weld joint such as butt, corner, and lap joints. The results show that precipitate coarsening, phase transformation from β″ phase to Q′ phase, and dissolving in the temperature range of 243.3–466.3 °C during the thermal shock induced a serious deterioration of the mechanical properties. The highest reduction of the ultimate tensile strength (UTS) and yield strength (YS) would be 38.6% and 57.4% respectively. By comparing the simulated and experimentally obtained force-displacement curves, the error for the above prediction method was evaluated to be less than 8.1%, indicating the proposed method being effective and reliable.
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Grosskopf, Curtis. "JEDEC's Generation of Wire Bond Pull Test Methods to Address Pulling of Copper Wire Bonds." International Symposium on Microelectronics 2021, no. 1 (October 1, 2021): 000249–55. http://dx.doi.org/10.4071/1085-8024-2021.1.000249.
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Abstract More than 50 years ago when the wire pull test method was initially added to Mil-Std 883, in Condition D of Method 2011, Bond Strength (Destructive Bond Pull Test), the test procedure and minimum pull force values were based on pull testing of mostly ultrasonic wedge bonded aluminum and gold wires of just a few different diameters. The minimum pull force values from that original data were extrapolated to cover a much wider range of wire diameters for both gold and aluminum wires. Since the release of this test method the electronics industry has manufactured copper ultrasonic wedge bonds, widely adopted copper thermosonic ball bonding roughly 15 years ago, and even developed a niche market for silver thermosonic ball bonding. The industry also developed specialty bonds such as security bonds, reverse bonds also called "stitch on ball", and even multi-loop wires and ribbons. In all that time neither the test procedure nor the minimum pull force values in Method 2011 were reviewed to determine their appropriateness for these new materials or new types of bonds, even though the industry widely referenced the test method for all of them and thus, by default, accepted its use for all of them. In late 2013, I led a working group within JEDEC's JC14.1 subcommittee, Reliability Test Methods for Packaged Devices, to update JEDEC JESD22-B116, Ball Bond Shear Test Method, to expand its scope to include the shearing of Cu ball bonds. It took the working group three years to address the necessary technical issues to ensure that the revised test method adequately addressed the shearing of copper ball bonds and propose minimum acceptable shear values. The working group produced a greatly improved document with drawings and images depicting the different shear fail modes of both gold and copper bonds and added several informative annexes to aid in the performing of the test method. By 2018 it was apparent that none of the most commonly referenced wire pull test methods in the electronics industry had made any significant progress in updating their documents to include Cu wire bonds. Therefore, the JC14.1 working group agreed to work jointly with the JC-13.7 Subcommittee, New Electronic Device Technology, to create a new, wire pull test method document under JC14.1 that would be a companion to the JESD22-B116. This new document will use Method 2011, Conditions C and D as its basis, but expand on its scope to cover copper wire bonds, both ultrasonic wedge and thermosonic ball bonds. The new test method will describe the process for a ball pull test and a stitch pull test that are referenced for copper bonds by AEC Q006, Qualification Requirement for Component Using Copper (Cu) Wire Interconnection. The test method will also provide guidance on how to perform pull testing on several different bond types used today including reverse bonds, multi-loop bonds, and stacked die. The working group plans to propose minimum pull values for copper wire bonds which JC14.1 will reference in JESD47, Stress-Test-Driven Qualification of Integrated Circuits. After the joint working group completes its work, which is targeted for some time in 2022, JC13.7 would then be able to use the output of this working group to update Method 2011 Conditions C & D. This paper will first briefly discuss the updates made to B116 to cover Cu wire bonds, but mainly focus on the work that has so far been completed by the joint working group, including a general outline of the proposed new document, JESD22-B120, Wire Bond Pull Test Methods.
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Hansen-Jaumard, Delphine, Caroline Elfassy, Kathleen Montpetit, Bayan Ghalimah, Reggie Hamdy, and Noemi Dahan-Oliel. "A review of the orthopedic interventions and functional outcomes among a cohort of 114 children with arthrogryposis multiplex congenita." Journal of Pediatric Rehabilitation Medicine 13, no. 3 (November 23, 2020): 263–71. http://dx.doi.org/10.3233/prm-190657.
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PURPOSE: Arthrogryposis multiplex congenita (AMC) refers to a large heterogeneous group of conditions involving joint contractures in two or more different areas of the body. Contractures can lead to decreased range of motion and strength, and affect ambulation and autonomy. The aim of this study was to describe the orthopedic interventions and functional outcomes of a large cohort of children with AMC followed in a pediatric orthopedic center. METHODS: A retrospective chart review of all children diagnosed with AMC followed at Shriners Hospital for Children – Canada (SHC) between January 1979 and July 2016 was conducted. One hundred twenty patients were identified, of whom six were excluded due to misdiagnosis or insufficient chart information. One hundred fourteen were retained. Patient demographics, AMC classification, comorbidities, operative and non-operative treatments received as well as community ambulation status, level of autonomy in self-care and transfers at latest follow-up were recorded. RESULTS: There were 54 males and 60 females with a mean age at last clinic visit of 10 years 3 months. Amyoplasia and distal arthrogryposis (DA) were equally represented in our sample, 47 (41.2%) and 49 (43.0%) participants respectively, with the category Other comprising the remaining 18 (15.8%) participants. Children with DA had less involvement of the proximal joints than those in the two other groups. Contractures and deformities of the foot and ankle were the most prevalent, affecting 91.5% with Amyoplasia, 85.7% with DA and 83.3% in the Other category. Contractures of the shoulder and elbow were more common among individuals with Amyoplasia and those categorized Other than those with DA. In terms of walking ability, 98% of participants with DA were independent ambulators. Walking ability varied among the Other participants. Similarly, most children with DA were independent in self-care and transfers at the most recent follow-up. CONCLUSION: The relatively large sample size of this study allowed for a better insight into the challenges associated with AMC management. These findings demonstrated the need for genetic testing to provide accurate diagnosis and classification, along with the use of standardized outcome tools to measure effectiveness of interventions. As AMC is rare, multi-site prospective studies are needed to improve research opportunities, develop functional measures specific to AMC and disseminate findings on a wider scale.
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Wegener, Konrad, and Atsushi Matsubara. "Special Issue on Advanced Material Driven Design of Machine Tools." International Journal of Automation Technology 14, no. 2 (March 5, 2020): 261–63. http://dx.doi.org/10.20965/ijat.2020.p0261.
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The design of machine tools strongly depends on the materials chosen. Increasing requirements on machine tools require the joint optimization of material and design and thus also drive the development of new materials in this field. Digital technologies finally creating a digital shadow of the machine in development also enable the required co-development taking into consideration dynamic, thermal and long term influences and behavior, enabling state and health monitoring to increase the performance of the machine tool to the maximum possible. The choice of material for the different components of machine tools is today even more difficult than ever. The recent review paper by Möhring et al. [1] sheds light on the vast field of properties and decision opportunities of combining materials at hand with design features. In former times, cast iron was the predominant material for machine bodies and has left its footprints on the design of machine tool bodies lasting still up to now. Because massive machine bodies have been the wealth of good properties, high accuracy, stiffness, good material damping properties have been attributed to cast iron design, then with increasing strength requirements higher strength cast irons came into fashion having much less material damping and finally lead to welded frames. Today requirements of dynamics and thermal behavior change the scene again. The goal is to achieve high productivity with high accuracy, which typically is a contradiction. But increasing dynamics requires distinguishing between moving bodies and their non-moving counterparts, and opens the floor for multimaterial design. For moving parts, which have to move with high dynamics meaning, high speed, high acceleration, high jerk, light weight design prevailed with the utilization of standard materials. Because manufacturability plays a major role, the bionic structures have to be degraded to thin walled rib structures as demonstrated in Fig. 1, while in future additive manufacturing will remove that restriction and enable some real bionic structures. Furthermore material choice has a huge impact on inertia savings which opens the door for CFRP, which becomes especially interesting, when the anisotropy of this material is exploited as shown in Fig. 2. From the manufacturability truss structures then result shown in Fig. 3. For the nonmoving elements, the base body, cast iron, welded steel, polymer cast, and concrete are typical materials chosen. Also aluminium structures are discussed despite the fact that aluminium has only one third of the stiffness of steel, but it offers much better thermal conductivity equalizing temperature differences faster and thus reduces the warp of the structure, which typically causes larger errors than an isotropic thermal expansion. For the choice of materials no generalizable guideline exists. The question which material is the better choice is not answerable in generality, because design follows material, which means that a sound comparison requires completely new design approaches for the different materials, where the difference between metal and polymer concrete or CFRP is really large, offering different potentials. As an example, a design of a fast moving bridge of a gantry machine might be considered. The guiding of a support on this bridge with roller guidings imposes severe problems to the design due to the material mix and different thermal expansion coefficients. Thus the choice of CFRP for the bridge necessarily must be followed up by a decision of the guiding principle, where in this case aerostatic bearings were considered as the most promising possibility. Also the potentials for function integration into the material are of major interest for the material choice, as this is easily possible for low temperature castings like for mineral cast, CFRP, or concrete. This integration of functionalities actually is a fairly new approach and relates again the machine body design to inspiration from biology, as for instance trees or leaves are from the point of view of materials weaker than our technical materials, but have a fine integration of functionalities as transmittance of information and nourriture. Sensor integration opens the field for “feeling machines” also inspired from biology, which enables the machine to detect its embedding environment and react accordingly. Cheap and miniaturized sensors are on the other side the developments that enable this approach of machine design. In the age of compensation, Industrie 4.0 and biological transformation, this functional integration will have a huge impact on material choice. Also in terms of thermal issues in machine tools, the material choice plays a major role, as thermal elongation is a physical property which is influenced by material choice. A much larger influence comes from design as indicated already above. With growing importance of compensation besides sensor integration, especially the thermal linearity and reproducibility are of crucial importance, which makes multi material design a non-trivial design task. The discussion on the superiority of thermally fast reacting machines or thermally slow reacting machines has not come to an end yet. Problematic are machines composed of components that react fast and those that react slow. A major step in that direction is the discovery of thermal resonances in [5], which shows that temperature change frequencies can depending on the machine design lead to higher or lower thermal displacements of the TCP and therefore need to be taken into account in the design phase and are significantly influenced by the choice of materials. Restrictions and influences are also coming from the process a machine tool has to enable. The material choice must take into account the influence of different media as for instance the metal working fluids as well as the debris like hot chips etc. The aforementioned discussion is mainly a discussion of main structural parts of machine tools. It must be pointed out that a machine tool is more than the sum of its structural elements, as also covers, which typically get forgotten in all academic discussion of behaviors of machine tools, but are significant for the influence of the environment on the machine tool. Also here the material choice plays a major role. Finally material choice to a large extent decides on the costs of a machine tool, but due to the huge amount of influence factors a sound fact based decision requires a nearly full design elaboration of various material choices and the summation of costs at the end of this process. This special issue with its various individual papers elucidates different aspects of the influence of materials on the design of machine tools without being capable of offering clear rules for material choice. ===danraku===1) Isolating material to exclude environmental influences on machine tools is proposed. ===danraku===2) A new guiding system with rollers and sliding guidings is proposed and the different materials for the sliding part are investigated. ===danraku===3) Gears from bamboo fibres are proposed and the manufacturability as well as their performance are discussed. The gears offer great advantages from the environmental point of view. ===danraku===4) CFRP for spindle shafts is evaluated and CFRP spindles are compared with steel spindles within the same geometric boundary conditions. The performance increase in compliance and thermal stability is significant. ===danraku===5) A topological optimization of a grinding machine tool structure is presented and showed drastically increased performance. The difficulty to transfer it to a mass producible machine tool structure is pointed out. ===danraku===6) A design of a CFRP ram for a high speed stamping press is presented and testing procedures to ensure the ability of the ram to withstand billions of impacts are designed and carried out. ===danraku===7) CFRP can beneficially applied for the cutting tool structure and besides enhancing dynamics in terms of mass and damping the material also is a valuable basis for smart tools. There are good arguments for each of the materials, which cover the whole scope of machine tool functionality: manufacturability, stiffness, strength, specific mass, thermal properties, function integrability, reproducibility, availability, environmental friendliness, and costs.