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Merrigan, Justin J., Jason D. Stone, W. Guy Hornsby i Joshua A. Hagen. "Identifying Reliable and Relatable Force–Time Metrics in Athletes—Considerations for the Isometric Mid-Thigh Pull and Countermovement Jump". Sports 9, nr 1 (31.12.2020): 4. http://dx.doi.org/10.3390/sports9010004.
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The purpose of this study was to evaluate intrasession reliability of countermovement jump (CMJ) and isometric mid-thigh pull (IMTP) force–time characteristics, as well as relationships between CMJ and IMTP metrics. Division I sport and club athletes (n = 112) completed two maximal effort CMJ and IMTP trials, in that order, on force plates. Relative and absolute reliability were assessed using intraclass correlation coefficients (ICCs) > 0.80 and coefficients of variation (CVs) < 10%. Intrasession reliability was acceptable for the majority of the CMJ force–time metrics except for concentric rate of force development (RFD), eccentric impulse and RFD, and lower limb stiffness. The IMTP’s time to peak force, instantaneous force at 150 ms, instantaneous net force, and RFD measures were not reliable. Statistically significant weak to moderate relationships (r = 0.20–0.46) existed between allometrically scaled CMJ and IMTP metrics, with the exception of CMJ eccentric mean power not being related with IMTP performances. A majority of CMJ and IMTP metrics met acceptable reliability standards, except RFD measures which should be used with caution. Provided CMJs and IMTPs are indicative of distinct physical fitness capabilities, it is suggested to monitor athlete performance in both tests via changes in those variables that demonstrate the greatest degree of reliability.
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Brady, Claire J., Andrew J. Harrison, Eamonn P. Flanagan, G. Gregory Haff i Thomas M. Comyns. "The Relationship Between Isometric Strength and Sprint Acceleration in Sprinters". International Journal of Sports Physiology and Performance 15, nr 1 (1.01.2020): 38–45. http://dx.doi.org/10.1123/ijspp.2019-0151.
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Purpose:To examine the relationships between the isometric midthigh pull (IMTP), isometric squat (ISqT), and sprint acceleration performance in track-and-field sprinters and to determine whether there are differences between men and women.Methods:Fifteen male and 10 female sprinters performed 3 maximal-effort IMTPs, ISqTs, and 3 × 30-m sprints from blocks.Results:Among the men, the results showed significant negative correlations between IMTP and ISqT peak force; relative peak force; force at 100, 150, and 200 ms; rate of force development (0–150 and 0–200 ms); and impulse (0–200 ms) and 0- to 5-m time (r = −.517 to −.714;P < .05). IMTP impulse (B = −0.582,P = .023) and ISqT relative peak force (B = −0.606,P = .017) significantly predicted 0- to 5-m time. Among the women, no IMTP or ISqT variables significantly correlated with any sprint times. Men measured significantly higher than women for all IMTP measures except relative peak force. Men were significantly faster than women at all splits. When comparing measures of the ISqT, there were no significant differences between men and women.Conclusions:Variables measured during the IMTP and ISqT significantly correlated with 0- to 5-m sprint performance in male athletes. Isometric strength can have a sizable influence on 0- to 5-m time, but in some cases, the maximum effect could be very small.
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Frigerio, Beatrice, José P. Werba, Mauro Amato, Alessio Ravani, Daniela Sansaro, Daniela Coggi, Lorenzo Vigo, Elena Tremoli i Damiano Baldassarre. "Traditional Risk Factors are Causally Related to Carotid Intima-Media Thickness Progression: Inferences from Observational Cohort Studies and Interventional Trials". Current Pharmaceutical Design 26, nr 1 (25.02.2020): 11–24. http://dx.doi.org/10.2174/1381612825666191213120339.
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In the present review, associations between traditional vascular risk factors (VRFs) and carotid intimamedial thickness progression (C-IMTp) as well as the effects of therapies for VRFs control on C-IMTp were appraised to infer causality between each VRF and C-IMTp. Cohort studies indicate that smoking, binge drinking, fatness, diabetes, hypertension and hypercholesterolemia are associated with accelerated C-IMTp. An exception is physical activity, with mixed data. Interventions for the control of obesity, diabetes, hypertension and hypercholesterolemia decelerate C-IMTp. Conversely, scarce information is available regarding the effect of smoking cessation, stop of excessive alcohol intake and management of the metabolic syndrome. Altogether, these data support a causative role of several traditional VRFs on C-IMTp. Shortcomings in study design and/or ultrasonographic protocols may account for most negative studies, which underlines the importance of careful consideration of methodological aspects in investigations using C-IMTp as the outcome.
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Giles, Garrett, Greg Lutton i Joel Martin. "Scoping Review of the Isometric Mid-Thigh Pull Performance Relationship to Dynamic Sport Performance Assessments". Journal of Functional Morphology and Kinesiology 7, nr 4 (15.12.2022): 114. http://dx.doi.org/10.3390/jfmk7040114.
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Attempting to understand on-field sport performance from dynamic performance tests of athleticism (i.e., sprinting, jumping, strength) is common practice in sport. In recent years, the isometric mid-thigh pull (IMTP) has gained popularity in the sport performance community as an assessment tool. This scoping review examined the relationship of the IMTP to common dynamic sports assessments to evaluate the robustness of the IMTP to profile lower body force production characteristics. The literature search was conducted according to PRISMA-ScR guidelines. Articles were selected from 5 electronic databases. Data was extracted and synthesized to evaluate the reported relationships between IMTP and common dynamic sport performance assessments. Forty-eight publications were identified and included in the review. Articles reviewed were all within the past 25 years with most (66.7%) published within the past 5 years. Multiple researchers utilized the IMTP across numerous sports and generally reported consistent results. Strong correlations (41.8% of reported, r = 0.71 to 1.00) between the IMTP and the dynamic sport performance assessments were found. The available evidence suggests the IMTP is a viable option for practitioners and researchers to use to profile athletic ability. Furthermore, based on the publication year of included articles, IMTP research is relatively young and warrants further investigation.
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Hogarth, Luke, Mark McKean, Max McKenzie i Tyler Collings. "Utility of an Isometric Midthigh Pull Test to Assess Lower Body Muscular Strength in Professional Netball Players". International Journal of Sports Physiology and Performance 16, nr 5 (1.05.2021): 719–26. http://dx.doi.org/10.1123/ijspp.2019-0900.
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Purpose: This study established the relationship between isometric midthigh pull (IMTP) peak force and court-based jumping, sprinting, and change of direction (COD) performance in professional netball players. The change in IMTP peak force in response to sport-specific training was also examined. Methods: IMTP peak force and court-based jumping, sprinting, and COD were collected in 18 female athletes contracted to a Suncorp Super Netball team. Linear regression models established the relationship between absolute and normalized strength values and court-based performance measures in the participant cohort. Changes in IMTP peak force and court-based performance measures were examined following 2 consecutive preseason training blocks in a subset of participants. Results: The IMTP peak force values normalized to body mass were found to be determinants of court-based jumping, sprinting, and COD performance in the participant cohort (R2 = .34–.65, P ≤ .016). The participants showed increases in absolute (mean ± SE = 398 ± 68.5 N, P < .001, Hedge g = 0.70 [−0.05 to 1.35]) and normalized IMTP peak force (mean ± SE = 4.6 ± 0.78 N·kg−1, P < .001, Hedge g = 0.47 [−0.04 to 0.97]) over 2 consecutive training blocks that coincided with improvements in jumping, sprinting, and COD performances. Conclusion: IMTP peak force is a determinant of court-based jumping, sprinting, and COD performance and is sensitive to training in professional netball players. These results support the utility of the IMTP test to monitor the development and maintenance of maximal lower body muscular strength in these athletes.
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Martin, Eric A., i George K. Beckham. "Isometric Mid-Thigh Pull Performance in Rugby Players: A Systematic Literature Review". Journal of Functional Morphology and Kinesiology 5, nr 4 (8.12.2020): 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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Scanlan, Aaron T., Neal Wen, Joshua H. Guy, Nathan Elsworthy, Michele Lastella, David B. Pyne, Daniele Conte i Vincent J. Dalbo. "The Isometric Midthigh Pull in Basketball: An Effective Predictor of Sprint and Jump Performance in Male, Adolescent Players". International Journal of Sports Physiology and Performance 15, nr 3 (1.03.2020): 409–15. http://dx.doi.org/10.1123/ijspp.2019-0107.
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Purpose: To examine correlations between peak force and impulse measures attained during the isometric midthigh pull (IMTP) and basketball-specific sprint and jump tests. Methods: Male, adolescent basketball players (N = 24) completed a battery of basketball-specific performance tests. Testing consisted of the IMTP (absolute and normalized peak force and impulse at 100 and 250 ms); 20-m sprint (time across 5, 10, and 20 m); countermovement jump (CMJ; absolute and normalized peak force and jump height); standing long jump (distance); and repeated lateral bound (distance). Correlation and regression analyses were conducted between IMTP measures and other attributes. Results: An almost perfect correlation was evident between absolute peak force attained during the IMTP and CMJ (r = .94, R2 = 56%, P < .05). Moderate to very large correlations (P < .05) were observed between IMTP normalized peak force and 5-m sprint time (r = −.44, R2 = 19%), 10-m sprint time (r = −.45, R2 = 20%), absolute (r = .57, R2 = 33%), normalized (r = .86, R2 = 73%) CMJ peak force, and standing long-jump distance (r = .51, R2 = 26%). Moderate to very large correlations were evident between impulse measures during the IMTP and 5-m sprint time (100 ms, r = −.40, R2 = 16%, P > .05) and CMJ absolute peak force (100 ms, r = .73, R2 = 54%; 250 ms, r = .68, R2 = 47%; P < .05). Conclusions: The IMTP may be used to assess maximal and rapid force expression important across a range of basketball-specific movements.
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Lee, Jong Baek, i Young Kyun Kim. "The Relationship between Isokinetic Trunk, Leg Strength and Isometric Mid-Thigh Pull Test, Counter Movement Jump in National Rowing Athletes". Asian Journal of Kinesiology 22, nr 3 (31.07.2020): 34–42. http://dx.doi.org/10.15758/ajk.2020.22.3.34.
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OBJECTIVES The purpose of this study was to analyze the relationship between isokinetic leg strength and maximum Isometric Med-Thigh Pull Test(IMTP) and maximum height of Counter Movement Jump (CMJ) in Korean national rowers.METHODS Each eight male and female athletes were participated in the study. Isometric IMTP, CMJ, and isokinetic trunk, hip, and knee strength were measured to analyze the relationship between the IMTP, CMJ and isokinetic strength. The correlation between variables was analyzed by the step-wise method of multiple regression analysis after analyzing the correlation between dependent and independent variables.RESULTS Knee, Hip and trunk isokinetic flexion and extension strength showed high correlation with maximum IMTP with the all participants. Knee extension and trunk flexion isokinetic strength showed higher correlation with IMTP. Knee extension isokinetic strength showed high correlation with CMJ.CONCLUSIONS For strengthening exercise of National rowers, ipsilateral strength balance and agonistantagonist strength balance of leg and trunk should be considered to improve performance efficiently.
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Thomas, Christopher, Paul A. Jones i Paul Comfort. "Reliability of the Dynamic Strength Index in College Athletes". International Journal of Sports Physiology and Performance 10, nr 5 (lipiec 2015): 542–45. http://dx.doi.org/10.1123/ijspp.2014-0255.
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Purpose:To determine the reliability of the Dynamic Strength Index (DSI) in college athletes.Method:Nineteen male college athletes performed the squat jump (SJ) and isometric midthigh pull (IMTP) to determine peak force, on 2 separate days. Reliability was assessed by intraclass correlation coefficient (ICC), typical error (TE), percentage change in the mean, smallest worthwhile change (SWC), and coefficient of variation (%CV).Results:Peak force for the SJ was 2137 ± 499 N and 2781 ± 435 N for the IMTP, resulting in a mean DSI of 0.78 ± 0.19. Peak forces in the SJ (ICC = .99, TE = 57.22 N, change in mean = 0.2%, SWC = 4.7%, CV = 2.6%) and IMTP (ICC = .95, TE = 104.22 N, change in mean = 0.5%, SWC = 3.1%, CV = 3.8%) were considered highly reliable between sessions. However, IMTP peak force was the only variable with an overall TE < SWC. The DSI was also highly reliable (ICC = .97, TE = 0.03, change in mean = −0.3%, SWC = 5.1%, CV = 4.6%) between sessions.Conclusion:This study demonstrates that peak force in the SJ and IMTP are reliable, resulting in a reliable assessment of dynamic-force-production capabilities via the DSI. The DSI may be used to guide individualized training interventions and monitor specific adaptations to training. Changes in SJ peak force, IMTP peak force, and DSI were >4.67%, 3.13%, and 5.13%, respectively, identifying meaningful changes in response to training or competition.
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Dos’Santos, Thomas, Paul A. Jones, Jonathan Kelly, John J. McMahon, Paul Comfort i Christopher Thomas. "Effect of Sampling Frequency on Isometric Midthigh-Pull Kinetics". International Journal of Sports Physiology and Performance 11, nr 2 (marzec 2016): 255–60. http://dx.doi.org/10.1123/ijspp.2015-0222.
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Purpose:Skeletal-muscle function can be evaluated using force–times curves generated via the isometric midthigh pull (IMTP). Various sampling frequencies (500–1000 Hz) have been used for IMTP assessments; however, no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investigate the influence of sampling frequency on kinetic variables during the IMTP, including peak force, time-specific force values (100, 150, and 200 ms), and rate of force development (RFD) at 3 time bands (0–100, 0–150, 0–200 ms).Methods:Academy rugby league players (n = 30, age 17.5 ± 1.1 y, height 1.80 ± 0.06 m, mass 85.4 ± 10.3 kg) performed 3 IMTP trials on a force platform sampling at 2000 Hz, which was subsequently down-sampled to 1500, 1000, and 500 Hz for analysis.Results:Intraclass correlation coefficients (ICC) and coefficients of variation (CV) demonstrated high within-session reliability for all force and RFD variables across all sampling frequencies (ICC ≥ .80, CV ≤ 10.1%). Repeated-measures analysis of variance revealed no significant differences (P > .05, Cohen d ≤ 0.009) in kinetic variables between sampling frequencies. Overall, high reliability was observed across all sampling frequencies for all kinetic variables, with no significant differences (P > .05) for each kinetic variable across sampling frequencies.Conclusions:Practitioners and scientists may consider sampling as low as 500 Hz when measuring peak force, time-specific force values, and RFD at predetermined time bands during the IMTP for accurate and reliable data.
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Dos’Santos, Thomas, Christopher Thomas, Paul A. Jones i Paul Comfort. "Assessing Muscle-Strength Asymmetry via a Unilateral-Stance Isometric Midthigh Pull". International Journal of Sports Physiology and Performance 12, nr 4 (kwiecień 2017): 505–11. http://dx.doi.org/10.1123/ijspp.2016-0179.
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Purpose:To investigate the within-session reliability of bilateral- and unilateral-stance isometric midthigh-pull (IMTP) force–time characteristics including peak force (PF), relative PF, and impulse at time bands (0–100, 0–200, 0–250, and 0–300 milliseconds) and to compare isometric force–time characteristics between right and left and dominant (D) and nondominant (ND) limbs.Methods:Professional male rugby league and multisport male college athletes (N = 54; age, 23.4 ± 4.2 y; height, 1.80 ± 0.05 m; mass, 88.9 ± 12.9 kg) performed 3 bilateral IMTP trials and 6 unilateral-stance IMTP trials (3 per leg) on a force plate sampling at 600 Hz.Results:Intraclass correlation coefficients (ICCs) and coefficients of variation (CVs) demonstrated high within-session reliability for bilateral and unilateral IMTP PF (ICC = .94, CV = 4.7–5.5%). Lower reliability measures and greater variability were observed for bilateral and unilateral IMTP impulse at time bands (ICC = .81–.88, CV = 7.7–11.8%). Paired-sample t tests and Cohen d effect sizes revealed no significant differences for all isometric force–time characteristics between right and left limbs in male college athletes (P >.05, d ≤ 0.32) and professional rugby league players (P > .05, d ≤ 0.11); however, significant differences were found between D and ND limbs in male college athletes (P < .001, d = 0.43–0.91) and professional rugby league players (P < .001, d = 0.27–0.46).Conclusion:This study demonstrated high within-session reliability for unilateral-stance IMTP PF, revealing significant differences in isometric force–time characteristics between D and ND limbs in male athletes.
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Dos’Santos, Thomas, Paul A. Jones, Jonathan Kelly, John J. McMahon, Paul Comfort i Christopher Thomas. "Effect of Sampling Frequency on Isometric Midthigh-Pull Kinetics". International Journal of Sports Physiology and Performance 14, nr 4 (1.04.2019): 525–30. http://dx.doi.org/10.1123/ijspp.2019-2015-0222.
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Purpose: Skeletal-muscle function can be evaluated using force-times curves generated via the isometric midthigh pull (IMTP). Various sampling frequencies (500–1000 Hz) have been used for IMTP assessments; however, no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investigate the influence of sampling frequency on kinetic variables during the IMTP, including peak force, time-specific force values (100, 150, and 200 ms), and rate of force development (RFD) at 3 time bands (0–100, 0–150, 0–200 ms). Methods: Academy rugby league players (n = 30, age 17.5 ± 1.1 y, height 1.80 ± 0.06 m, mass 85.4 ± 10.3 kg) performed 3 IMTP trials on a force platform sampling at 2000 Hz, which was subsequently down-sampled to 1500, 1000, and 500 Hz for analysis. Results: Intraclass correlation coefficients (ICC) and coefficients of variation (CV) demonstrated high within-session reliability for all force and RFD variables across all sampling frequencies (ICC ≥ .80, CV ≤ 14.4%) except RFD 0–100 and 0–150, which demonstrated slightly greater levels of variance (CV = 18.0–24.1%). Repeated-measures analysis of variance revealed no significant differences (P > .05, Cohen d ≤ 0.0171) in kinetic variables between sampling frequencies. Overall, high reliability was observed across all sampling frequencies for peak force, time-specific force, and RFD 0- to 200-ms variables, with no significant differences (P > .05) for each kinetic variable across sampling frequencies. Conclusions: Practitioners and scientists may consider sampling as low as 500 Hz when measuring peak force, time-specific force values, and RFD at predetermined time bands during the IMTP for accurate and reliable data.
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Suchomel, Timothy J., Christopher J. Sole, Christopher R. Bellon i Michael H. Stone. "Dynamic Strength Index: Relationships with Common Performance Variables and Contextualization of Training Recommendations". Journal of Human Kinetics 74, nr 1 (31.08.2020): 59–70. http://dx.doi.org/10.2478/hukin-2020-0014.
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Abstract The purposes of this study were to examine the relationships between dynamic strength index (DSI) and other strength-power performance characteristics and to contextualize DSI scores using case study comparisons. 88 male and 67 female NCAA division I collegiate athletes performed countermovement jumps (CMJ) and isometric mid-thigh pulls (IMTP) during a pre-season testing session as part of a long-term athlete monitoring program. Spearman’s correlations were used to assess the relationships between DSI and CMJ peak force, height, modified reactive strength index, peak power and IMTP peak force and rate of force development (RFD). Very large relationships existed between DSI and IMTP peak force (r = -0.848 and -0.746), while small-moderate relationships existed between DSI and CMJ peak force (r = 0.297 and 0.313), height (r = 0.108 and 0.167), modified reactive strength index (r = 0.174 and 0.274), and IMTP RFD (r = -0.341 and -0.338) for men and women, respectively. Finally, relationships between DSI and CMJ peak power were trivial-small for male (r = 0.008) and female athletes (r = 0.191). Case study analyses revealed that despite similar DSI scores, each athlete’s percentile rankings for each variable and CMJ force-time characteristics were unique, which may suggest different training emphases are needed. Based on the explained variance, an athlete’s IMTP performance may have a larger influence on their DSI score compared to the CMJ. DSI scores should be contextualized using additional performance data to ensure each individual athlete receives the appropriate training stimulus during different training phases throughout the year.
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Cocco, Eleonora, Claudia Sardu, Gabriella Spinicci, Luigina Musu, Rita Massa, Jessica Frau, Lorena Lorefice i in. "Influence of treatments in multiple sclerosis disability: A cohort study". Multiple Sclerosis Journal 21, nr 4 (25.09.2014): 433–41. http://dx.doi.org/10.1177/1352458514546788.
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Background and objective: A critical aspect of multiple sclerosis (MS) treatments is understanding the effect of disease-modifying drugs (DMDs) on the long-term risk of disability and whether the effect is related to disability at start of treatment. Methods: We performed an observational study on 3060 MS patients. The effect of therapy on progression to Expanded Disability Status Scale (EDSS) 3.0 and 6.0 from onset was analysed in treated vs untreated (UTP) patients using Cox regression analysis adjusted for propensity score and immortal time bias. Results: Compared to UTP, the risks of EDSS 3.0 were 94% and 73% lower in immunomodulant (IMTP-) and immunosuppressant (ISTP-) treated patients, respectively, while the risk of EDSS 6.0 was 86% lower in IMTP. The risk of EDSS 6.0 was, respectively, 91% and 75% lower in 1275 IMTP before and 114 after EDSS 3.0 than in 539 UTP; the risk was higher in IMTP starting therapy after EDSS 3.0 than before (HR = 4.42). Conclusions: DMDs delayed long-term disability in MS patients treated either in the early or, to a lesser extent, in the later phase of the disease. Thus, the window of therapeutic opportunity is relatively extended, assuming that early is better than late treatment, but late is better than never.
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Norris, Dean, David Joyce, Jason Siegler, James Clock i Ric Lovell. "Recovery of Force–Time Characteristics After Australian Rules Football Matches: Examining the Utility of the Isometric Midthigh Pull". International Journal of Sports Physiology and Performance 14, nr 6 (1.07.2019): 765–70. http://dx.doi.org/10.1123/ijspp.2018-0349.
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Purpose: This study assessed the utility of force–time characteristics from the isometric midthigh pull (IMTP) as a measure of neuromuscular function after elite-level Australian rules football matches. It was hypothesized that rate characteristics of force development would demonstrate a different response magnitude and recovery time course than peak force measurements. Methods: Force–time characteristics of the IMTP (peak force, 0- to 50-ms rate of force development [RFD], 100- to 200-ms RFD) were collected at 48 (G+2), 72 (G+3), and 96 h (G+4) after 3 competitive Australian rules football matches. Results: Meaningful reductions (>75% of the smallest worthwhile change) were observed at G+2, G+3, and G+4 for RFD 0–50 milliseconds (−25.8%, −17.5%, and −16.9%) and at G+2 and G+3 for RFD 100–200 milliseconds (−15.7% and −11.7%). No meaningful reductions were observed for peak force at any time point (G+2 −4.0%, G+3 −3.9%, G+4 −2.7%). Higher week-to-week variation was observed for RFD 0–50 milliseconds (G+2 17.1%, G+3 27.2%, G+4 19.3%) vs both RFD 100–200 milliseconds (G+2 11.3%, G+3 11.5%, G+4 7.2%) and peak force (G+2 4.8%, G+3 4.4%, G+4 8.4%). Conclusions: These findings highlight the potential use of rate characteristics from the IMTP as measures of neuromuscular function in elite sport settings, and in particular RFD 100–200 milliseconds due to its higher reliability. Interestingly, peak force collected from the IMTP was not meaningfully suppressed at any time point after elite Australian rules football match play. This suggests that rate characteristics from IMTP may provide more sensitive and valuable insight regarding neuromuscular function recovery kinetics than peak measures.
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Bailey, Christopher A., Kimitake Sato, Angus Burnett i Michael H. Stone. "Force-Production Asymmetry in Male and Female Athletes of Differing Strength Levels". International Journal of Sports Physiology and Performance 10, nr 4 (maj 2015): 504–8. http://dx.doi.org/10.1123/ijspp.2014-0379.
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The purpose of this investigation was to determine the existence of bilateral strength and force-production asymmetry and evaluate possible differences based on sex, as well as strength level. Asymmetry was assessed during weight-distribution (WtD) testing, unloaded and lightly loaded static- (SJ) and countermovement-jump (CMJ) testing, and isometric midthigh-pull (IMTP) strength testing. Subjects included 63 athletes (31 male, 32 female) for WtD, SJ, and CMJ tests, while 129 athletes (64 male, 65 female) participated in IMTP testing. Independent-samples t tests were used to determine possible differences in asymmetry magnitude between males and females, as well as between strong and weak athletes. Cohen d effect-size (ES) estimates were also used to estimate difference magnitudes. Statistically different asymmetry levels with moderate to strong ESs were seen between males and females in WtD, 0-kg SJ (peak force [PF]), 20-kg SJ (peak power [PP]), 0-kg CMJ (PF, PP, net impulse), and 20-kg CMJ (PF), but no statistical differences were observed in IMTP variables. Dividing the sample into strong and weak groups produced statistically significant differences with strong ES estimates in IMTP PF and rate of force development, and many ESs in jump symmetry variables increased. The results of this investigation indicate that females may be more prone to producing forces asymmetrically than males during WtD and jumping tasks. Similarly, weaker athletes displayed more asymmetry than stronger athletes. This may indicate that absolute strength may play a larger role in influencing asymmetry magnitude than sex.
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Brady, Claire J., Andrew J. Harrison, Eamonn P. Flanagan, G. Gregory Haff i Thomas M. Comyns. "A Comparison of the Isometric Midthigh Pull and Isometric Squat: Intraday Reliability, Usefulness, and the Magnitude of Difference Between Tests". International Journal of Sports Physiology and Performance 13, nr 7 (1.08.2018): 844–52. http://dx.doi.org/10.1123/ijspp.2017-0480.
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Purpose: To examine the reliability and usefulness of the isometric midthigh pull (IMTP) and isometric squat (ISqT) performed at the same knee and hip angles. The scores produced in each test were compared to determine the magnitude of differences between tests. Methods: Twenty-six male and female athletes (age, 23.6 [4.3] y; height, 1.75 [0.07] m; and body mass, 68.8 [9.7] kg) performed 2 maximal repetitions of the IMTP and ISqT following a specific warm-up. Results: Maximum force, absolute peak force (PF), relative PF, allometrically scaled PF, rate of force development (0–200 and 0–250 ms), and impulse (0–300 ms) were deemed reliable (intraclass correlation coefficient [ICC] ≥.86 and coefficient of variation [CV] ≤9.4%) in the IMTP and ISqT based on predetermined criteria (ICC ≥.8 and CV ≤10%). Impulse (0–200 and 0–250 ms) was reliable in the ISqT (ICC ≥.92 and CV ≤9.9%). Participants produced significantly (P < .05) greater PF and impulse (0–300 ms) during the ISqT compared with the IMTP. When split by sex, female participants produced significantly greater PF (P = .042) during the ISqT, with no significant differences among male participants (P = .245). Both tests are capable of detecting changes in performance in maximum force and absolute PF. Conclusions: Both tests are reliable for non-time-dependent maximal strength measures when measured at the same knee and hip angles. The ISqT may be preferred when coaches want to test an athlete’s true maximum lower-limb strength, especially female athletes.
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Tseng, Kuo-Wei, Jyun-Ru Chen, Jun-Jie Chow, Wei-Chin Tseng, Giancarlo Condello, Hsia-Ling Tai i Szu-Kai Fu. "Post-activation Performance Enhancement after a Bout of Accentuated Eccentric Loading in Collegiate Male Volleyball Players". International Journal of Environmental Research and Public Health 18, nr 24 (12.12.2021): 13110. http://dx.doi.org/10.3390/ijerph182413110.
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The purpose of this study was to investigate the benefit of post-activation performance enhancement (PAPE) after accentuated eccentric loading (AEL) compared to traditional resistance loading (TR). Sixteen male volleyball athletes were divided in AEL and TR group. AEL group performed 3 sets of 4 repetitions (eccentric: 105% of concentric 1RM, concentric: 80% of concentric 1RM) of half squat, and TR group performed 3 sets of 5 repetitions (eccentric & concentric: 85% of 1RM). Countermovement jump (CMJ), spike jump (SPJ), isometric mid-thigh pull (IMTP), and muscle soreness test were administered before (Pre) exercise, and 10 min (10-min), 24 h (24-h), and 48 h (48-h) after exercise. A two-way repeated measures analysis of variance was used to analyze the data. Peak force and rate of development (RFD) of IMTP in AEL group were significantly greater (p < 0.05) than TR group. The height, peak velocity, and RFD of CMJ, height of SPJ, and muscle soreness showed no interaction effects (p > 0.05) groups x time. AEL seemed capable to maintain force production in IMTP, but not in CMJ and SPJ. It is recommended the use of accentuated eccentric loading protocols to overcome the fatigue.
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Davis, Greggory R., Gabrielle J. Gallien, Kaitlyn M. Moody, Nina R. LeBlanc, Peter R. Smoak i David Bellar. "Cognitive Function and Salivary DHEA Levels in Physically Active Elderly African American Women". International Journal of Endocrinology 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/219046.
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Serum and plasma dehydroepiandrosterone sulfate (DHEAS) concentration has been associated with several health parameters associated with aging including cognitive function, bone mineral density, and muscular strength. However, the effectiveness of salivary DHEA for the prediction of cognitive function, bone mineral density, and muscular strength in older adults is currently unknown. Thirty elderly African American females provided early morning salivary samples and DHEA levels were determined using a commercially available immunoassay. Participants completed testing for psychomotor and executive function via Trail Making Tests (TMT) A and B, respectively. Bone ultrasound attenuation (BUA) was used to bone density and an isometric mid-thigh pull (IMTP) was used to determine isometric strength. Age significantly correlated with time on TMT A (r=0.328) and B (r=0.615) but was not related to DHEA, BUA, or IMTP outcomes. Elevated DHEA was associated with longer time to completion for TMT A (χ2=5.14) but not to TMT B. DHEA levels were not associated with BUA or IMTP outcomes. While elevated levels of DHEA were correlated with impaired psychomotor function, salivary DHEA is not associated with executive function, bone mineral density, or isometric strength in elderly African American women.
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Best, Russ, Dani Temm, Holly Hucker i Kerin McDonald. "Repeated Menthol Mouth Swilling Affects Neither Strength nor Power Performance". Sports 8, nr 6 (17.06.2020): 90. http://dx.doi.org/10.3390/sports8060090.
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This study aimed to assess the effects of repeated menthol mouth swilling upon strength and power performance. Nineteen (10 male) participants completed familiarisation and experimental trials of repeated menthol mouth swilling (0.1% concentration) or control (no swill) in a randomised crossover design. Participants performed an isometric mid-thigh pull (IMTP; peak and mean force; N), vertical jump (peak; cm) and six second sprint (peak and mean power; W) under each condition. Participants completed three efforts per exercise task interspersed with three-minute recoveries. Mean best values were analysed via a two-way mixed repeated measures ANOVA, and differences reported as effect sizes ± 95% confidence intervals, with accompanying descriptors and p values. Differences in peak IMTP values were unclear between familiarisation and experimental trials, and between menthol and control conditions. Mean IMTP force differed between familiarisation and control (0.51; −0.15 to 1.14; p = 0.001) and familiarisation and menthol conditions (0.50; −0.15 to 1.14; p = 0.002) by a small degree, but were unclear between control and menthol conditions. Unclear differences were also noted on vertical jump performance compared to familiarisation and between experimental conditions, with repeated six second peak and average power performance also showing unclear effects across all comparisons. We conclude that repeated menthol mouth swilling does not improve strength or power performance.
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Lockie, Robert, Brett Post i J. Dawes. "Physical Qualities Pertaining to Shorter and Longer Change-of-Direction Speed Test Performance in Men and Women". Sports 7, nr 2 (16.02.2019): 45. http://dx.doi.org/10.3390/sports7020045.
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This study investigated relationships between shorter (505, change-of-direction (COD) deficit as a derived physical quality) and longer (Illinois agility test; IAT) COD tests with linear speed, lower-body power (multidirectional jumping), and strength in recreationally-trained individuals. Twenty-one males and 22 females (similar to collegiate club-sport and tactical athletes) were assessed in: 505 and COD deficit from each leg; IAT; 20 m sprint; vertical jump (VJ height, peak anaerobic power measured in watts (PAPw), power-to-body mass ratio); standing broad jump; lateral jump (LJ) from each leg; and absolute and relative isometric midthigh pull (IMTP) strength. Partial correlations calculated sex-determined relationships between the COD and performance tests, with regression equations calculated (p < 0.05). The 505 and IAT correlated with all tests except PAPw and absolute IMTP (r = ±0.43–0.71). COD deficit correlated with the LJ (r = −0.34–0.60). Left- and right-leg 505 was predicted by sex, 20 m sprint, and left-leg LJ (70–77% explained variance). Right-leg COD deficit was predicted by sex and left-leg LJ (27% explained variance). IAT was predicted by sex, 20 m sprint, right-leg LJ, and relative IMTP (84% explained variance). For individuals with limited training time, improving linear speed, and relative lower-body power and strength, could enhance shorter and longer COD performance.
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Lloyd, Rhodri S., Ian J. Dobbs, Megan A. Wong, Isabel S. Moore i Jon L. Oliver. "Effects of Training Frequency During a 6-Month Neuromuscular Training Intervention on Movement Competency, Strength, and Power in Male Youth". Sports Health: A Multidisciplinary Approach 14, nr 1 (15.10.2021): 57–68. http://dx.doi.org/10.1177/19417381211050005.
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Background: Youth populations benefit from neuromuscular training; however, the extent to which training frequency, baseline fitness, and maturity status moderate the response to long-term neuromuscular training in male youth remains unclear. Hypothesis: Twice-weekly training (G2x) would induce larger improvements in movement competency and strength and power kinetics compared with once-weekly training (G1x). Maturity status and baseline fitness would also moderate the training response in strength and power kinetics. Study Design: Nonrandomized, repeated-measures design. Level of Evidence: Level 3 Methods: Ninety-five male athletes of varying maturity status (pre– or post–peak height velocity) were divided into G2x, G1x, or control (CON) groups. Training groups received G2x or G1x for 28 weeks. Back squat assessment (BSA) movement competency and isometric mid-thigh pull (IMTP), squat jump (SJ), and countermovement jump (CMJ) kinetics were measured pre- and postintervention. Results: The G2x achieved significantly greater adaptations in BSA total score, IMTP allometrically scaled peak force (PFallo), IMTP peak rate-of-force development (PRFD), SJ PFallo and PRFD compared with G1x and CON ( P < 0.05; d = 0.3-0.9). Baseline fitness, training frequency and maturity status were significant predictors of IMTP PFallo ( R2 = 27.5%) and PRFD ( R2 = 42.9%), while a combination of training frequency and baseline fitness explained a small amount of variance in SJ PFallo ( R2 = 12.2%) and SJ PRFD ( R2 = 6.5%). There were no significant predictors of CMJ kinetics. Conclusion: G2x achieved significantly larger improvements in movement competency, isometric strength and concentric jump variables compared with G1x, with the training response greater in those youth with lower baseline fitness and more advanced maturity status. Clinical Relevance: Exposure to neuromuscular training twice-weekly elicits a greater response than G1x in young male athletes. Practitioners should take maturity status, training frequency, and baseline fitness levels of young male athletes into account when interpreting testing data, as these variables appear to moderate training responsiveness.
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Rogers, Rebecca R., Tyler D. Williams, Emma B. Nester, Grace M. Owens i Christopher G. Ballmann. "The Influence of Music Preference on Countermovement Jump and Maximal Isometric Performance in Active Females". Journal of Functional Morphology and Kinesiology 8, nr 1 (14.03.2023): 34. http://dx.doi.org/10.3390/jfmk8010034.
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Previous studies have shown that listening to preferred music during resistance and endurance exercises improves performance. However, it is unknown if these phenomena translate to short-duration explosive exercises. The purpose of this study was to investigate the influences of preferred and non-preferred music on countermovement jump (CMJ) performance, isometric mid-thigh pull (IMTP), and psychological responses to music during explosive movements. Physically active females (age 18–25) volunteered to take part in the study. In a counterbalanced, crossover design, participants completed three trials: (1) no music (NM), (2) non-preferred (NP), and (3) preferred (PV) music. Participants completed three maximal IMTP tests on a force-plate-equipped IMTP apparatus with an immovable bar. Attempts lasted 5 s and were separated by 3 min of rest. Furthermore, participants completed three single maximal CMJ attempts separated by 3 min of rest on force plates. All attempts were averaged for analysis. At the commencement of IMTP and CMJ testing, participants were asked to rate how motivated and psyched up they felt during the exercise portion using a visual analog scale. For isometric performance, listening to PM resulted in increased peak force (p = 0.039; d = 0.41) and rate of force development at 200 ms (p = 0.023; d = 0.91) compared with NP. For CMJ, there were no differences between conditions for jump height (p = 0.912; η2 = 0.007) or peak power during the propulsive phase (p = 0.460; η2 = 0.003). Levels of motivation were significantly higher with PM compared with NM (p < 0.001; d = 2.3) and NP (p = 0.001; d = 2.0). Feelings of being psyched up were significantly higher with PM compared with NM (p < 0.001; d = 4.2) and NP (p = 0.001; d = 2.8). Findings suggest that preferred music enhances isometric strength and increases motivation and feelings of being psyched up. Thus, PM may be used as an ergogenic aid during short-duration maximal-effort activities.
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Guppy, Stuart, Claire Brady, Yosuke Kotani, Michael Stone, Nikola Medic i Guy Haff. "The Effect of Altering Body Posture and Barbell Position on the Between-Session Reliability of Force-Time Curve Characteristics in the Isometric Mid-Thigh Pull". Sports 6, nr 4 (30.11.2018): 162. http://dx.doi.org/10.3390/sports6040162.
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Seventeen strength and power athletes (n = 11 males, 6 females; height: 177.5 ± 7.0 cm, 165.8 ± 11.4 cm; body mass: 90.0 ± 14.1 kg, 66.4 ± 13.9 kg; age: 30.6 ± 10.4 years, 30.8 ± 8.7 years), who regularly performed weightlifting movements during their resistance training programs, were recruited to examine the effect of altering body posture and barbell position on the between-session reliability of force-time characteristics generated in the isometric mid-thigh pull (IMTP). After participants were familiarised with the testing protocol, they undertook two testing sessions which were separated by seven days. In each session, the participants performed three maximal IMTP trials in each of the four testing positions examined, with the order of testing randomized. In each position, no significant differences were found between sessions for all force-time characteristics (p = >0.05). Peak force (PF), time-specific force (F50, F90, F150, F200, F250) and IMP time-bands (0–50, 0–90, 0–150, 0–200, 0–250 ms) were reliable across each of the four testing positions (ICC ≥ 0.7, CV ≤ 15%). Time to peak force, peak RFD, RFD time-bands (0–50, 0–90, 0–150, 0–200, 0–250 ms) and peak IMP were unreliable regardless of the testing position used (ICC = <0.7, CV = >15%). Overall, the use of body postures and barbell positions during the IMTP that do not correspond to the second pull of the clean have no adverse effect on the reliability of the force-time characteristics generated.
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Banaszek, Amy, Jeremy R. Townsend, David Bender, William C. Vantrease, Autumn C. Marshall i Kent D. Johnson. "The Effects of Whey vs. Pea Protein on Physical Adaptations Following 8-Weeks of High-Intensity Functional Training (HIFT): A Pilot Study". Sports 7, nr 1 (4.01.2019): 12. http://dx.doi.org/10.3390/sports7010012.
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This study examined the effects of whey and pea protein supplementation on physiological adaptations following 8-weeks of high-intensity functional training (HIFT). Fifteen HIFT men (n = 8; 38.6 ± 12.7 y, 1.8 ± 0.1 m, 87.7 ± 15.8 kg) and women (n = 7; 38.9 ± 10.9 y, 1.7 ± 0.10 m, 73.3 ± 10.5 kg) participated in this study. Participants completed an 8-week HIFT program consisting of 4 training sessions per week. Participants consumed 24 g of either whey (n = 8) or pea (n = 7) protein before and after exercise on training days, and in-between meals on non-training days. Before and after training, participants underwent ultrasonography muscle thickness measurement, bioelectrical impedance analysis (BIA), two benchmark WODs (workout of the day), 1-Repetition Maximum (1RM) squat and deadlift testing, and Isometric Mid-thigh Pull (IMTP) performance. Separate analyses of covariance (ANCOVA) were performed on all measures collected at POST. Both groups experienced increased strength for 1RM back squat (p = 0.006) and deadlift (p = 0.008). No training effect (p > 0.05) was found for body composition, muscle thickness, IMTP peak force, IMTP rate of force development, or performance in either WOD. Using PRE values as the covariate, there were no group differences for any measured variable. We conclude that ingestion of whey and pea protein produce similar outcomes in measurements of body composition, muscle thickness, force production, WOD performance and strength following 8-weeks of HIFT.
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Bender, David, Jeremy R. Townsend, William C. Vantrease, Autumn C. Marshall, Ruth N. Henry, Stephen H. Heffington i Kent D. Johnson. "Acute beetroot juice administration improves peak isometric force production in adolescent males". Applied Physiology, Nutrition, and Metabolism 43, nr 8 (sierpień 2018): 816–21. http://dx.doi.org/10.1139/apnm-2018-0050.
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The purpose of this study was to examine the effects of acute beetroot juice (BR) administration on repeated sprint performance and isometric force production in adolescent males. Twelve male adolescents (age, 16.8 ± 1.0 years; height, 178.8 ± 9.2 cm; mass, 74.8 ± 12.5 kg; peak height velocity, 2.53 ± 1.2 years) participated in this double-blind, placebo-controlled, crossover designed study. Participants consumed 2 × 70 mL of BR (∼12.9 mmol NO3−; Beet It Sport) or a nitrate-depleted placebo (PL) at 2.5 h prior to performing isometric mid-thigh pulls (IMTP) and 4 repeated 20-s Wingate sprints interspersed with 4 min of rest. Sprint data were analyzed by a 2 × 4 (group × time) repeated-measures ANOVA while a dependent t test was used to compare conditions for IMTP peak force. A significant main effect for time (p < 0.05) was observed for peak power (PP), average power (Pavg), and fatigue index (FI) across sprints. Compared with sprint 1, sprint 4 resulted in significant decreases in PP (p < 0.000; −16.6%) and Pavg (p = 0.000; −21.8%) and FI was significantly elevated (p < 0.000; 15.2%). No significant group × time interactions were observed between conditions for PP (p = 0.402), Pavg (p = 0.479), or FI (p = 0.37). IMTP peak force was significantly higher (p = 0.004; 13.9%) following BR consumption compared with PL. The repeated sprint protocol resulted in significant fatigue while BR did not influence sprint performance. However, it appears BR administration may improve peak force production in adolescent males.
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Dabbs, Nicole C., Sergio Espericueta, Sean Bonilla i Margaret T. Jones. "The Effects of Whole-Body Vibration on Fatigue in Vertical Jump Performance and Isometric Mid-Thigh Pull Measures". Vibration 4, nr 4 (25.09.2021): 759–67. http://dx.doi.org/10.3390/vibration4040042.
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The purpose of this study is to determine the effects of coupling WBV and acute muscular fatigue to determine its effects on countermovement vertical jump (CMVJ) performance and isometric mid-thigh pull (IMTP). Twenty-eight healthy active adults volunteered for five-day study. Testing sessions 2–5 included one of four conditions: No WBV and no fatigue (CON), WBV and fatigue (WBV + FAT), WBV and no fatigue (WBV), and no WBV and fatigue (FAT). WBV was performed using a frequency of 50 Hz and a low amplitude while performing quarter squats for a total of 4 min with a 30 s rest or work ratio. Lower-body fatigue induced using Bosco fatigue protocol. CMVJ and IMTP were performed on force plates. SPSS was used to perform a 2 × 2 Repeated Measures ANOVA. Significant main effects were found for fatigue in CMVJ-height and CMVJ-peak ground reaction force, no significant main effect for WBV, and no significant interactions. Lower-body fatigue decreases vertical jump performance, and WBV did not attenuate the detrimental effects of lower-body fatigue.
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Thomas, Christopher, Paul Comfort, Thomas Dos’Santos i Paul Jones. "Determining Bilateral Strength Imbalances in Youth Basketball Athletes". International Journal of Sports Medicine 38, nr 09 (2.08.2017): 683–90. http://dx.doi.org/10.1055/s-0043-112340.
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AbstractThe aims of this study were: 1) to compare the strongest (D) and weakest (ND) limbs in determining muscle strength asymmetry (MSA) ratios among various muscle strength qualities and 2) to determine the relationships among various muscle strength qualities. 17 youth male basketball athletes (age=17.5±0.8 years; height=187.1±9.4 cm; body mass=81.4±10.1 kg) participated in this study. Knee flexor and extensor strength at 60°·s−1 was assessed for both limbs with the use of isokinetic dynamometry. Other tests involved single-leg hop (SLH), countermovement jump (CMJ) and isometric mid-thigh pull (IMTP). Statistically significant differences (p<0.05; d=0.40-0.98) were found between D and ND limbs for all strength measures. Imbalance ratio of the IMTP was significantly related to those of SLH (r=0.75, p=0.01) whereas no significant relationships between D:ND ratios were found from all other tests. Percentage agreements of MSA ranged from 64.7–88.2% between muscle strength qualities. The findings provide support for the use of field tests to detect lower-limb strength imbalances. Future research should examine the effect of different asymmetry thresholds on percentage agreements to diagnose MSA and determine its relationship to athletic performance.
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Suarez, Dylan G., Satoshi Mizuguchi, William Guy Hornsby, Aaron J. Cunanan, Donald J. Marsh i Michael H. Stone. "Phase-Specific Changes in Rate of Force Development and Muscle Morphology Throughout a Block Periodized Training Cycle in Weightlifters". Sports 7, nr 6 (28.05.2019): 129. http://dx.doi.org/10.3390/sports7060129.
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The purpose of this study was to investigate the kinetic and morphological adaptations that occur during distinct phases of a block periodized training cycle in weightlifters. Athlete monitoring data from nine experienced collegiate weightlifters was used. Isometric mid-thigh pull (IMTP) and ultrasonography (US) results were compared to examine the effects of three specific phases of a training cycle leading up to a competition. During the high volume strength-endurance phase (SE) small depressions in rate of force development (RFD) but statistically significant (p ≤ 0.05) increases in vastus lateralis cross-sectional area (CSA), and body mass (BM) were observed. The lower volume higher intensity strength-power phase (SP) caused RFD to rebound above pre-training cycle values despite statistically significant reductions in CSA. Small to moderate increases only in the earlier RFD time bands (<150 ms) occurred during the peak/taper phase (PT) while CSA and BM were maintained. Changes in IMTP RFD and CSA from US reflected the expected adaptations of block periodized training phases. Changes in early (<100 ms) and late (≥150 ms) RFD time bands may not occur proportionally throughout different training phases. Small increases in RFD and CSA can be expected in well-trained weightlifters throughout a single block periodized training cycle.
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Ross, James A., Justin W. L. Keogh i Christian Lorenzen. "Reliability of kettlebell swing one and five repetition maximum". PeerJ 10 (21.11.2022): e14370. http://dx.doi.org/10.7717/peerj.14370.
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Background Research into the kettlebell swing has increased in the last decade. There has been a paucity of literature assessing an individual’s ability to perform the kettlebell swing exercise. The purpose of this study was to determine the test-retest reliability of the one and five repetition maximum (1RM and 5RM) kettlebell swing. Materials & Methods Twenty four recreational resistance-trained participants performed an isometric mid-thigh pull (IMTP) and two familiarization sessions followed by three test sessions for each RM load approximately one week apart, using a custom-built plate-loaded kettlebell. On each test occasion, subjects completed a series of warm-up sets followed by 3–4 progressively heavier kettlebell swings to a standardized height until 1RM or 5RM was reached. Test-retest reliability was calculated using the intra-class correlation (ICC) and typical error was represented as the coefficient of variation (CV%) with 90% confidence limits (90% CL). The smallest worthwhile change (SWC%) representing the smallest change of practical importance, was calculated as 0.2 × between-subject standard deviation. The relationship of kettlebell swing performance and maximum strength was determined by Pearson correlation with ±90% CL between the absolute peak force recorded during IMTP and 1RM or 5RM. Results Results demonstrated a high test-retest reliability for both the 1RM (ICC = 0.97, 90% CL [0.95–0.99]; CV = 2.7%, 90% CL [2.2–3.7%]) and 5RM (ICC = 0.98, 90% CL [0.96–0.99]; CV = 2.4%, 90% CL [1.9–3.3%]), respectively. The CV% was lower than the SWC for both the 1RM (SWC = 2.8%, 90% CL [1.9–3.5]) and 5RM (SWC = 2.9%, 90% CL [1.9–3.6]) kettlebell swing. The correlation between IMTP absolute peak force and the 1RM (r = 0.69, 90% CL 0.43–0.83) was large and very large for the 5RM (r = 0.75, 90% CL [0.55–0.87]). Conclusions These results demonstrate the stability of 1RM and 5RM kettlebell swing performance after two familiarization sessions. Practitioners can be confident that changes in kettlebell swing 1RM and 5RM performance of >3.6 kg represent a practically important difference, which is the upper limit of the 90% CL.
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Irizarry, Juan, Alba Rivera-Diaz, Miriam Padilla-Diaz, Patricia Fernandez-Hawa, Lissette Jimenez-Davila i William Rodriguez-Cintron. "0914 Perception of Sleep Medicine (SM) Training among Internal Medicine (IM) Trainees in Puerto Rico". SLEEP 46, Supplement_1 (1.05.2023): A403. http://dx.doi.org/10.1093/sleep/zsad077.0914.
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Abstract Introduction Awareness of the importance of SM among trainees at our IM Training Program (IMTP) has not been documented, despite the high prevalence of Sleep Disordered Breathing (SDB) within our clinical population. Recently, the Indiana University Sleep Questionnaire (IUSQ) was administered to quantify the perception of SM in IM residents. Methods We administered the IUSQ questionnaire through an anonymous computer survey sample of IM residents at our ACGME accredited IMTP. Results A total of 52/61 (85%) residents from the Veterans Administration Caribbean Health Care System (VACHS) IMTP participated. There were 18 PGY-1, 16 PGY-2, 15 PGY-3 and 3 PGY-4 residents whom the majority strongly agreed or agreed that the burden of SDB was large in the general population (63% & 35%), that it is important for their training (48% & 46%) and for their general practice (54% & 38%). They were mostly neutral or disagreed about getting adequate training in SDB during residency (38% & 40%). The majority strongly agreed or agreed that sleep specialist is needed for managing SDB (27% & 48%) and 9.6% disagreed with this. Many do not have interest in pursuing a sleep medicine fellowship answering neutral, disagree and strongly disagree (23%, 38% &23%). The majority strongly agree and agree that a sleep fellowship is important in treating sleep disorders (48% & 33%). The residents are mostly neutral or disagree when it comes to their confidence in treating sleep apnea (40% & 48%) and treating other sleep disorders (46% & 38%). Conclusion Despite the high prevalence of SDB in the population they manage, residents do not feel they are getting enough training in the management of sleep disorders. They acknowledge the importance of SM education for the latter purpose, but the majority does not want to pursue formal subspecialty training in SM. In addition, they do not feel comfortable managing SDB and other sleep disorders. Interestingly this mismatch between burden of disease and the need for disease management proficiency is similar to one found previously in a different resident population to which the same IUSQ was administered. An educational approach toward residents may furtherly change these perceptions. Support (if any)
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Ishida, Ai, Kyle Rochau, Kyle P. Findlay, Brandon Devero, Marco Duca i Michael H. Stone. "Effects of an Initial Muscle Strength Level on Sports Performance Changes in Collegiate Soccer Players". Sports 8, nr 9 (15.09.2020): 127. http://dx.doi.org/10.3390/sports8090127.
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The purposes of this study were to investigate effects of partial block periodized strength training on physical performance and to examine relationships between initial muscle strength measured with isometric mid-thigh pull (IMTP) and performance changes after 7 weeks of strength training. Seventeen collegiate male soccer players participated. Initial muscle strength was determined using IMTP while physical performance included 10 m and 20 m sprints and static vertical jump with a polyvinyl chloride pipe (SJ0), 20 kg barbell (SJ20), and barbell loaded to 40 kg bar (SJ40). Performance testing was performed at three points: before first week (baseline), fourth week (T1), and seventh week (T2). Statistically small to moderate changes were found from baseline to T2 in peak power (PP; p < 0.001, ES = 0.49), net impulse (NI; p < 0.001, ES = 0.49), peak velocity (PV; p < 0.001, ES = 0.62), allometrically scaled PP (PPa; p < 0.001, ES = 0.62) in SJ20 and jump height (JH) in SJ40 (p < 0.001, ES = 0.36). Moderate to large correlations were found between isometric peak force and the changes from baseline to T2 in SJ20 PP (p = 0.04, r = −0.49), SJ20 PF (p = 0.03, r = −0.52), PPa (p = 0.04, r = −0.50), and SJ20 allometrically scaled peak force (p = 0.04, r = −0.49). Properly structured strength training maximizes task-specific physical performance. Initial muscle strength negatively affects the magnitudes of adaptations to physical performance.
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Schneider, Kevin, David Zimmer, Henrik Nielsen, Johannes M. Herrmann i Timo Mühlhaus. "iMLP, a predictor for internal matrix targeting-like sequences in mitochondrial proteins". Biological Chemistry 402, nr 8 (1.07.2021): 937–43. http://dx.doi.org/10.1515/hsz-2021-0185.
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Abstract Matrix targeting sequences (MTSs) direct proteins from the cytosol into mitochondria. Efficient targeting often relies on internal matrix targeting-like sequences (iMTS-Ls) which share structural features with MTSs. Predicting iMTS-Ls was tedious and required multiple tools and webservices. We present iMLP, a deep learning approach for the prediction of iMTS-Ls in protein sequences. A recurrent neural network has been trained to predict iMTS-L propensity profiles for protein sequences of interest. The iMLP predictor considerably exceeds the speed of existing approaches. Expanding on our previous work on iMTS-L prediction, we now serve an intuitive iMLP webservice available at http://iMLP.bio.uni-kl.de and a stand-alone command line tool for power user in addition.
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Buchheit, Martin, Will Morgan, Jarryd Wallace, Matthew Bode i Nick Poulos. "Physiological, Psychometric, and Performance Effects of the Christmas Break in Australian Football". International Journal of Sports Physiology and Performance 10, nr 1 (styczeń 2015): 120–23. http://dx.doi.org/10.1123/ijspp.2014-0082.
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Purpose:The aim of the current study was to quantify the physiological, psychometric, and performance effects of a 2-wk Christmas break in a professional Australian Football League club.Methods:A series of physiological (eg, heart-rate [HR] response to a 5-min submaximal run and skinfold thicknesses), psychometric (rating-of-perceived-exertion [RPE] responses and wellness variables), and performance (running activity during standardized handball games, isometric midthigh pull [IMTP] peak force, and countermovement jump [CMJ]) measures were conducted in the weeks before and after the break.Results:There was a possible and small increase in the sum of 7 skinfolds, while body mass and fat-free mass remained possible and likely unchanged, respectively. Sleep and stress scores remained likely to almost certainly unchanged, but there were some small, possible to likely decreases in fatigue and soreness scores. HR and RPE responses to the 5-min submaximal run were likely slightly lower (ie, improved) after the break. High-intensity running and acceleration distance during a standard handball game were very likely slightly greater, while HR and RPE responses to the game were possibly to very likely unchanged. HR responses to a high-intensity training session remained very likely unchanged. There was also a likely small increase in IMTP peak force but likely to very likely no change in CMJ variables.Conclusions:The results show that players returned from a 2-wk break during preseason well recovered, with preserved to improved levels of strength and cardiorespiratory fitness, despite small increases in skinfold thickness.
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Aben, Hendrickus G. J., Samuel P. Hills, Darren Higgins, Carlton B. Cooke, Danielle Davis, Ben Jones i Mark Russell. "The Reliability of Neuromuscular and Perceptual Measures Used to Profile Recovery, and the Time-Course of Such Responses Following Academy Rugby League Match-Play". Sports 8, nr 5 (22.05.2020): 73. http://dx.doi.org/10.3390/sports8050073.
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In professional academy rugby league (RL) players, this two-part study examined; (A) the within- and between-day reliability of isometric mid-thigh pulls (IMTP), countermovement jumps (CMJ), and a wellness questionnaire (n = 11), and (B) profiled the responses with acceptable reliability (no between-trial differences and between-day coefficient of variation (CV) ≤10% and intraclass correlation coefficient (ICC) ≥0.8) for 120 h (baseline: −3, +24, +48, +72, +96, +120 h) following RL match-play (n = 10). In part A, force at 200, and 250 ms, and peak force (PF) demonstrated acceptable within- (CV%: 3.67–8.41%, ICC: 0.89–0.93) and between-day (CV%: 4.34–8.62%, ICC: 0.87–0.92) reliability for IMTP. Most CMJ variables demonstrated acceptable within-day reliability (CV%: 3.03–7.34%, ICC: 0.82–0.98), but only six (i.e., flight-time, PF, peak power (PP), relative PP, velocity at take-off (VTO), jump-height (JH)) showed acceptable between-day reliability (CV%: 2.56–6.79%, ICC: 0.83–0.91). Only total wellness demonstrated acceptable between-day reliability (CV%: 7.05%, ICC: 0.90) from the questionnaire. In part B, reductions of 4.75% and 9.23% (vs. baseline; 2.54 m∙s−1; 0.33 m) occurred at +24 h for CMJ VTO, and JH, respectively. Acceptable reliability was observed in some, but not all, variables and the magnitude and time-course of post-match responses were test and variable specific. Practitioners should therefore be mindful of the influence that the choice of recovery monitoring tool may have upon the practical interpretation of the data.
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Comfort, Paul, Christopher Thomas, Thomas Dos’Santos, Paul A. Jones, Timothy J. Suchomel i John J. McMahon. "Comparison of Methods of Calculating Dynamic Strength Index". International Journal of Sports Physiology and Performance 13, nr 3 (1.03.2018): 320–25. http://dx.doi.org/10.1123/ijspp.2017-0255.
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Purpose: To determine the reliability and variability of the Dynamic Strength Index (DSI) calculated from squat-jump (SJ) vs countermovement-jump (CMJ) peak force (PF) and to compare DSI values between methods. Methods: Male youth soccer and rugby league players (N = 27; age 17.2 ± 0.7 y, height 173.9 ± 5.7 cm, body mass 71.1 ± 7.2 kg) performed 3 trials of the SJ, CMJ, and isometric midthigh pull (IMTP) on 2 separate days. DSI was calculated by dividing the PF during each jump by the IMTP PF. Results: DSI-SJ exhibited moderate (intraclass correlation coefficient [ICC] = .419) within-session reliability and high variability (percentage coefficient of variation [%CV] = 15.91) during session 1; however, this improved noticeably during session 2 (ICC = .948, %CV = 4.03). In contrast, DSI-CMJ showed nearly perfect within-session reliability (ICC = .920–.952) and low variability (%CV = 3.80–4.57) for both sessions. Moreover, DSI-SJ values demonstrated a small yet significant increase between sessions (P = .01, d = 0.37), whereas only a trivial and nonsignificant increase was observed for DSI-CMJ between sessions (P = .796, d = 0.07). Between-sessions reliability was very high for the DSI-SJ (ICC = .741) and nearly perfect for the DSI-CMJ (ICC = .924). There was no significant or meaningful difference (P = .261, d = 0.12) between DSI-SJ (0.82 ± 0.18) and DSI-CMJ (0.84 ± 0.15). Conclusions: Practitioners should use DSI-CMJ, as it is a more reliable measure than DSI-SJ, although it produces similar ratios.
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Helms, Eric R., Caryn Zinn, David S. Rowlands, Ruth Naidoo i John Cronin. "High-Protein, Low-Fat, Short-Term Diet Results in Less Stress and Fatigue Than Moderate-Protein, Moderate-Fat Diet During Weight Loss in Male Weightlifters: A Pilot Study". International Journal of Sport Nutrition and Exercise Metabolism 25, nr 2 (kwiecień 2015): 163–70. http://dx.doi.org/10.1123/ijsnem.2014-0056.
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Purpose:Athletes risk performance and muscle loss when dieting. Strategies to prevent losses are unclear. This study examined the effects of two diets on anthropometrics, strength, and stress in athletes.Methods:This double-blind crossover pilot study began with 14 resistance-trained males (20-43 yr) and incurred one dropout. Participants followed carbohydrate-matched, high-protein low-fat (HPLF) or moderate-protein moderate-fat (MPMF) diets of 60% habitual calories for 2 weeks. Protein intakes were 2.8g/kg and 1.6g/kg and mean fat intakes were 15.4% and 36.5% of calories, respectively. Isometric midthigh pull (IMTP) and anthropometrics were measured at baseline and completion. The Daily Analysis of Life Demands of Athletes (DALdA) and Profile of Mood States (POMS) were completed daily. Outcomes were presented statistically as probability of clinical benefit, triviality, or harm with effect sizes (ES) and qualitative assessments.Results:Differences of effect between diets on IMTP and anthropometrics were likely or almost certainly trivial, respectively. Worse than normal scores on DALDA part A, part B and the part A “diet” item were likely more harmful (ES 0.32, 0.4 and 0.65, respectively) during MPMF than HPLF. The POMS fatigue score was likely more harmful (ES 0.37) and the POMS total mood disturbance score (TMDS) was possibly more harmful (ES 0.29) during MPMF than HPLF.Conclusions:For the 2 weeks observed, strength and anthropometric differences were minimal while stress, fatigue, and diet-dissatisfaction were higher during MPMF. A HPLF diet during short-term weight loss may be more effective at mitigating mood disturbance, fatigue, diet dissatisfaction, and stress than a MPMF diet.
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Comfort, Paul, Paul A. Jones, John J. McMahon i Robert Newton. "Effect of Knee and Trunk Angle on Kinetic Variables During the Isometric Midthigh Pull: Test–Retest Reliability". International Journal of Sports Physiology and Performance 10, nr 1 (styczeń 2015): 58–63. http://dx.doi.org/10.1123/ijspp.2014-0077.
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The isometric midthigh pull (IMTP) has been used to monitor changes in force, maximum rate of force development (mRFD), and impulse, with performance in this task being associated with performance in athletic tasks. Numerous postures have been adopted in the literature, which may affect the kinetic variables during the task; therefore, the aim of this investigation was to determine whether different knee-joint angles (120°, 130°, 140°, and 150°) and hip-joint angles (125° and 145°), including the subjects preferred posture, affect force, mRFD, and impulse during the IMTP. Intraclass correlation coefficients demonstrated high within-session reliability (r ≥ .870, P < .001) for all kinetic variables determined in all postures, excluding impulse measures during the 130° knee-flexion, 125° hip-flexion posture, which showed a low to moderate reliability (r = .666–.739, P < .001), while between-sessions testing demonstrated high reliability (r > .819, P < .001) for all kinetic variables. There were no significant differences in peak force (P > .05, Cohen d = 0.037, power = .408), mRFD (P > .05, Cohen d = 0.037, power = .409), or impulse at 100 ms (P > .05, Cohen d = 0.056, power = .609), 200 ms (P > .05, Cohen d = 0.057, power = .624), or 300 ms (P > .05, Cohen d = 0.061, power = .656) across postures. Smallest detectable differences demonstrated that changes in performance of >1.3% in peak isometric force, >10.3% in mRFD, >5.3% in impulse at 100 ms, >4.4% in impulse at 200 ms, and >7.1% in impulse at 300 ms should be considered meaningful, irrespective of posture.
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Chassé, Etienne, Hans Christian Tingelstad, Sarah C. Needham-Beck i Tara Reilly. "Factors Affecting Performance on an Army Urban Operation Casualty Evacuation for Male and Female Soldiers". Military Medicine 184, nr 11-12 (20.04.2019): e856-e862. http://dx.doi.org/10.1093/milmed/usz075.
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Abstract Introduction This study was conducted to determine what physical and physiological characteristics contribute to the performance of an urban operation casualty evacuation (UO) and its predictive test, FORCE combat (FC) and describe the metabolic demand of the UO in female soldiers. Methods Seventeen military members (9 M and 8 F) completed a loaded walking maximal aerobic test, the UO and FC. Heart rate reserve (HRR) and completion time were used as efficiency/performance measures. Oxygen consumption (VO2) was directly measured for UO on five female participants with a portable indirect calorimetry system, and analyzed using descriptive statistics. Stepwise multiple regression analysis was used to determine the contribution of the non-modifiable (age, sex, height) and modifiable characteristics (lean body mass to dead mass ratio (LBM:DM), VO2max corrected for load (L.VO2max), peak force (PF) measured on an isometric mid-thigh pull (IMTP) and medicine ball chest throw distance (Dist) on to the performance of each exercise. Results LBM:DM and PF were the only factors included in the stepwise regression model for UO, predicting 70% of UO performance (p < 0.01). For FC, L.VO2max only was included in the stepwise regression model predicting 54% of FC performance (p < 0.01). Sex, age and height were not included in the regression model. The average metabolic cost of UO was 21.4 mL of O2*kg−1*min−1 in female soldiers while wearing PPE. Conclusion This study showed that modifiable factors such as body composition, PF on IMTP and L.VO2max are key contributors to performance on UO and FC performance.
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Secomb, Josh L., Sophia Nimphius, Oliver R. L. Farley, Lina Lundgren, Tai T. Tran i Jeremy M. Sheppard. "Lower-Body Muscle Structure and Jump Performance of Stronger and Weaker Surfing Athletes". International Journal of Sports Physiology and Performance 11, nr 5 (lipiec 2016): 652–57. http://dx.doi.org/10.1123/ijspp.2015-0481.
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Purpose:To identify whether there are any significant differences in the lower-body muscle structure and countermovement-jump (CMJ) and squat-jump (SJ) performance between stronger and weaker surfing athletes.Methods:Twenty elite male surfers had their lower-body muscle structure assessed with ultrasonography and completed a series of lower-body strength and jump tests including isometric midthigh pull (IMTP), CMJ, and SJ. Athletes were separated into stronger (n = 10) and weaker (n = 10) groups based on IMTP performance.Results:Large significant differences were identified between the groups for vastus lateralis (VL) thickness (P = .02, ES = 1.22) and lateral gastrocnemius (LG) pennation angle (P = .01, ES = 1.20), and a large nonsignificant difference was identified in LG thickness (P = .08, ES = 0.89). Furthermore, significant differences were present between the groups for peak force, relative peak force, and jump height in the CMJ and SJ (P < .01−.05, ES = 0.90−1.47) and eccentric peak velocity, as well as vertical displacement of the center of mass during the CMJ (P < .01, ES = 1.40−1.41).Conclusion:Stronger surfing athletes in this study had greater VL and LG thickness and LG pennation angle. These muscle structures may explain their better performance in the CMJ and SJ. A unique finding in this study was that the stronger group appeared to better use their strength and muscle structure for braking as they had significantly higher eccentric peak velocity and vertical displacement during the CMJ. This enhanced eccentric phase may have resulted in a greater production and subsequent utilization of stored elastic strain energy that led to the significantly better CMJ performance in the stronger group.
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James, Lachlan P., Emma M. Beckman, Vincent G. Kelly i G. Gregory Haff. "The Neuromuscular Qualities of Higher- and Lower-Level Mixed-Martial-Arts Competitors". International Journal of Sports Physiology and Performance 12, nr 5 (maj 2017): 612–20. http://dx.doi.org/10.1123/ijspp.2016-0373.
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Purpose:To determine whether the maximal strength, impulse, and power characteristics of competitive mixed-martial-arts (MMA) athletes differ according to competition level.Methods:Twenty-nine male semiprofessional and amateur MMA competitors were stratified into either higher-level (HL) or lower-level (LL) performers on the basis of competition grade and success. The 1-repetition-maximum (1RM) squat was used to assess lower-body dynamic strength, and a spectrum of impulse, power, force, and velocity variables were evaluated during an incremental-load jump squat. In addition, participants performed an isometric midthigh pull (IMTP) and 1RM bench press to determine whole-body isometric force and upper-body dynamic strength capabilities, respectively. All force and power variables were expressed relative to body mass (BM).Results:The HL competitors produced significantly superior values across a multitude of measures. These included 1RM squat strength (1.84 ± 0.23 vs 1.56 ± 0.24 kg BM; P = .003), in addition to performance in the incremental-load jump squat that revealed greater peak power (P = .005–.002), force (P = .002–.004), and velocity (P = .002–.03) at each load. Higher measures of impulse (P = .01–.04) were noted in a number of conditions. Average power (P = .002–.02) and velocity (P = .01–.04) at all loads in addition to a series of rate-dependent measures were also superior in the HL group (P = .005–.02). The HL competitors’ 1RM bench-press values approached significantly greater levels (P = .056) than the LL group’s, but IMTP performance did not differ between groups.Conclusions:Maximal lower-body neuromuscular capabilities are key attributes distinguishing HL from LL MMA competitors. This information can be used to inform evidenced-based training and performance-monitoring practices.
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Stephens, Jessica M., Shona L. Halson, Joanna Miller, Gary J. Slater, Dale W. Chapman i Christopher D. Askew. "Effect of Body Composition on Physiological Responses to Cold-Water Immersion and the Recovery of Exercise Performance". International Journal of Sports Physiology and Performance 13, nr 3 (1.03.2018): 382–89. http://dx.doi.org/10.1123/ijspp.2017-0083.
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Purpose: To explore the influence of body composition on thermal responses to cold-water immersion (CWI) and the recovery of exercise performance. Methods: Male subjects were stratified into 2 groups: low fat (LF; n = 10) or high fat (HF; n = 10). Subjects completed a high-intensity interval test (HIIT) on a cycle ergometer followed by a 15-min recovery intervention (control [CON] or CWI). Core temperature (Tc), skin temperature, and heart rate were recorded continuously. Performance was assessed at baseline, immediately post-HIIT, and 40 min postrecovery using a 4-min cycling time trial (TT), countermovement jump (CMJ), and isometric midthigh pull (IMTP). Perceptual measures (thermal sensation [TS], total quality of recovery [TQR], soreness, and fatigue) were also assessed. Results: Tc and TS were significantly lower in LF than in HF from 10 min (Tc, LF 36.5°C ± 0.5°C, HF 37.2°C ± 0.6°C; TS, LF 2.3 ± 0.5 arbitrary units [a.u.], HF 3.0 ± 0.7 a.u.) to 40 min (Tc, LF 36.1°C ± 0.6°C, HF 36.8°C ±0.7°C; TS, LF 2.3 ± 0.6 a.u., HF 3.2 ± 0.7 a.u.) after CWI (P < .05). Recovery of TT performance was significantly enhanced after CWI in HF (10.3 ± 6.1%) compared with LF (3.1 ± 5.6%, P = .01); however, no differences were observed between HF (6.9% ±5.7%) and LF (5.4% ± 5.2%) with CON. No significant differences were observed between groups for CMJ, IMTP, TQR, soreness, or fatigue in either condition. Conclusion: Body composition influences the magnitude of Tc change during and after CWI. In addition, CWI enhanced performance recovery in the HF group only. Therefore, body composition should be considered when planning CWI protocols to avoid overcooling and maximize performance recovery.
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Gonzalez, Adam M., Yang Yang, Gerald T. Mangine, Anthony G. Pinzone, Jamie J. Ghigiarelli i Katie M. Sell. "Acute Effect of L-Citrulline Supplementation on Resistance Exercise Performance and Muscle Oxygenation in Recreationally Resistance Trained Men and Women". Journal of Functional Morphology and Kinesiology 8, nr 3 (22.06.2023): 88. http://dx.doi.org/10.3390/jfmk8030088.
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L-citrulline serves as a nitric oxide precursor with the potential to increase blood flow and improve resistance exercise performance, yet more research is needed to examine its ergogenic potential. To examine the effect of L-citrulline supplementation on resistance exercise performance, muscle oxygenation, and the subjective perception of effort, energy, focus, fatigue, and muscle pump, eighteen resistance-trained men (n = 11) and women (n = 7) (21.4 ± 1.8 years; 172.3 ± 7.5 cm; 76.9 ± 10.8 kg) were randomly assigned for supplementation with 8 g of L-citrulline (CIT) or a placebo (PL) in a cross-over fashion one hour prior to testing. Participants completed an isometric mid-thigh pull test (IMTP), a ballistic bench press protocol [two sets of two repetitions at 75% 1-repetition maximum (1 RM) with maximum ballistic intent], and a strength-endurance bench press protocol [five repetition-maximum sets at 75% 1RM]. Barbell velocity and power were measured via a linear position transducer during the ballistic protocol, while the repetitions completed, volume load and muscle oxygenation were quantified during the strength-endurance protocol. Subjective measures were assessed at the baseline and immediately pre- and post-exercise. Repeated measures of the analysis of variance and Bayesian equivalents revealed no significant interactions, providing evidence favoring the null hypothesis (BF10 < 1) for IMTP (PL 497.5 ± 133.6 vs. CIT 492.5 ± 129.4 N), barbell velocity, and power, and repetitions completed (PL 36.7 ± 7.2 vs. CIT 36.9 ± 8.1 repetitions). There were also no significant interactions for muscle oxygenation parameters or subjective measures except perceived fatigue. Women reported greater fatigue across all time points compared to men (~1.88 au, p = 0.045, BF10 = 0.2). The results indicate that a single 8 g dose of L-citrulline did not enhance isometric force production, muscle endurance, or muscle oxygenation parameters during the protocol implemented in this study.
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Montoro-Bombú, Raynier, Beatriz Branquinho Gomes, Amândio Santos i Luis Rama. "Validity and Reliability of a Load Cell Sensor-Based Device for Assessment of the Isometric Mid-Thigh Pull Test". Sensors 23, nr 13 (22.06.2023): 5832. http://dx.doi.org/10.3390/s23135832.
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In recent years, there has been an exponential increase in the number of devices developed to measure or estimate physical exercise. However, before these devices can be used in a practical and research environment, it is necessary to determine their validity and reliability. The purpose of this study is to test the validity and reliability of a load cell sensor-based device (LC) for measuring the peak force (PFr) and the rate of force development (RFD) during the isometric mid-thigh pull (IMTP) test, using a force plate (FP) as the gold standard. Forty-two undergraduate sport science students (male and female) participated in this study. In a single session, they performed three repetitions of the IMTP test, being tested simultaneously with an LC device and a Kistler force platform (FP). The PFr and RFD data were obtained from the force-time curve of the FP and compared with the LC data, provided automatically by the software of the device (Smart Traction device©). The mean difference between the results obtained by the LC device and the gold-standard equipment (FP) was not significantly different (p > 0.05), for both PFr and RFD, which suggests the validity of the ST results. Bland–Altman analysis showed a small mean difference in PFr = 1.69 N, upper bound = 47.88 N, and lower bound = −51.27 N. RFD showed that the mean difference was −5.27 N/s, upper limit = 44.36 N/s, and lower limit = −54.91 N/s. Our results suggest that the LC device can be used in the assessment of the isometric-mid-thigh-pull test as a valid and reliable tool. It is recommended that this device’s users consider these research results before putting the ST into clinical practice.
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Crichton, R., i I. Van den Bergh. "Publication of the results of the InternationalMusaTesting Programme, Phase III (IMTP III)". Acta Horticulturae, nr 1114 (marzec 2016): 191–96. http://dx.doi.org/10.17660/actahortic.2016.1114.26.
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Irish, Brian M., Ricardo Goenaga, Sirena Montalvo-Katz, Bernardo Chaves-Cordoba i Inge Van den Bergh. "Host Response to Black Leaf Streak and Agronomic Performance of Banana Genotypes in Puerto Rico". HortScience 54, nr 10 (październik 2019): 1808–17. http://dx.doi.org/10.21273/hortsci13876-19.
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Bananas are one of the most important fruits, serving as a cash crop and staple food in many regions of the world. In Puerto Rico, bananas are an important agricultural industry, supplying all the fruit needed for local demand. Diseases significantly limit production, and the evaluation and adoption of improved genetic resistance in bananas might provide an avenue for long-term sustainable production. To this end, nine enhanced genotypes from international selection and breeding programs were introduced and evaluated for their response to black leaf streak (BLS) (Pseudocercospora fijiensis Morelet) and for their agronomic performance. Bananas were evaluated as part of a collaborative effort between the U.S. Department of Agriculture Agricultural Research Service (USDA-ARS) Tropical Agriculture Research Station (TARS) and Bioversity International’s International Musa Testing Program (IMTP). Improved genotypes were compared with disease-resistant and disease-susceptible reference genotypes across two cropping cycles. Field plants were grown following commercial production practices with no BLS management. Significant differences in disease reactions were observed during both cropping cycles for test and reference genotypes. Under high disease pressure, ‘FHIA-21’, ‘FHLORBAN 916’, and ‘FHLORBAN 920’ test genotypes showed higher numbers of functional leaves and lower disease severity at harvest in both cycles. Short cycling times were also observed for the two FHLORBAN genotypes. Larger bunches with a high number of fruits were produced by the ‘IBP 12’, ‘IBP 5-B’, and ‘IBP 5-61’ selections. Several of the GCTCV test genotypes were extremely susceptible to BLS, did not perform as expected, and appeared to be off-types. Several of the test genotypes performed well, although currently none possessed all needed traits for a commercial banana substitute. Regardless, several test genotypes have agronomic potential because they have been selected for disease resistance to other important pathogens (e.g., fusarium wilt) and therefore have become part of the permanent TARS collection. Future efforts will continue to focus on the IMTP collaboration and introduction of promising banana genotypes for evaluations.
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Tai, Joshua Qi Jun, Shu Fen Wong, Steve Kin Ming Chow, Darine Hui Wen Choo, Hui Cheng Choo, Sofyan Sahrom i Abdul Rashid Aziz. "Assessing Physical Fitness of Athletes in a Confined Environment during Prolonged Self-Isolation: Potential Usefulness of the Test of Maximal Number of Burpees Performed in 3 Minutes". International Journal of Environmental Research and Public Health 19, nr 10 (13.05.2022): 5928. http://dx.doi.org/10.3390/ijerph19105928.
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Due to a prolonged period of quarantine during the COVID-19 pandemic, it is essential to monitor the physical condition of athletes isolated at home with a fitness tool that measures various aspects of physical fitness, which does not require any special equipment, and can be performed within a small space. This study assessed the reliability and validity of the test of performing the maximal number of burpees in 3 min (or 3-MBT) to monitor strength, power, and aerobic endurance in trained athletes. For Part I (reliability of the 3-MBT), 20 (10 male, 10 female) national athletes from various sports performed the 3-MBT on two separate test sessions. Athletes performed as many burpees as possible within 3 min and the primary performance criteria was the number of burpees completed (where a higher number reflected a better performance). The 3-MBT displayed excellent relative reliability in the athletes, with an intraclass correlation coefficient (ICC) and coefficient of variation (CV %) of >0.92, and <3.0%, respectively. For Part II (validity of the 3-MBT), 40 (20 M, 20 F) athletes performed the 3-MBT, and the countermovement jump (CMJ), isometric mid-thigh pull (IMTP), seated medicine ball throw (SMBT), isometric bench (IBP) and maximal aerobic power (VO2max) tests on separate sessions. When data of male and female athletes were pooled, there were significant correlations between relative 3-MBT and relative CMJ height (r = 0.65, large; p < 0.001), relative IMPT peak force (r = 0.50, large; p < 0.001), relative IBP peak force (r = 0.36, moderate, p = 0.02), and relative VO2max (r = 0.50, large; p < 0.001). In conclusion, the 3-MBT is a reliable and reasonably useful test and is a valid assessment of lower body power and strength, upper body strength and aerobic fitness in trained male and female athletes.
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Ochoa-Covarrubias, Gabriela, Alejandro Luis Grindlay i Carmen Lizarraga. "Does the Mass Public Transport System Cover the Social Transport Needs? Targeting SDG 11.2 in Guadalajara, Mexico". Applied Sciences 11, nr 16 (21.08.2021): 7709. http://dx.doi.org/10.3390/app11167709.
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This paper analyses how SITEUR, the Mass Public Transport System (MPTS) in the Guadalajara Metropolitan Area (GMA), covers transport social needs, contributing to achieve Sustainable Development Goals (SDG) 11.2. In order to facilitate this, an Index of Mass Transport Provision (IMTP) was measured through proximity, frequency, and capacity. Then, an Index of Social Transport Needs (ISTN) was calculated by means of transport disadvantage indicators. Finally, the Index of Social Transport Needs Covered (ICSTN) was calculated. The calculations used geographic information systems and principal component analysis in 1834 geographic sections. Findings highlight that 50.3% of the inhabitants have a very high level of social transport needs, while only 6.8% of the population have very low social transport needs. Results show that SITEUR promotes advancement in public transport systems within the GMA relative to quality, security, and reliability and it also contributes to tackling social exclusion in the GMA. A proposal related to transport systems integration is included, to address an important aspect of social exclusion in the city.
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Almendros, Angel, Y. R. Choi, Paweł M. Bęczkowski, Kerstin Baiker, Vanessa R. Barrs i Julia A. Beatty. "Babesia gibsoni Infection in a Cat with Immune-Mediated Haemolytic Anaemia and Thrombocytopenia". Animals 13, nr 13 (27.06.2023): 2128. http://dx.doi.org/10.3390/ani13132128.
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Tick-borne haemoparasite Babesia gibsoni has been detected rarely in cats, in surveys of apparently healthy animals. In stored blood from a 6-year-old male-neutered domestic shorthair cat in Hong Kong, B. gibsoni DNA was detected retrospectively using PCR for Babesia spp. 18S rRNA and mitochondrial cytochrome B genes, followed by sequencing and basic local alignment search tool (BLAST) analysis. The cat presented with severe haemolytic anaemia and thrombocytopaenia. The cat responded to supportive care and glucocorticoids and was clinically normal despite persistent subclinical thrombocytopenia until six months after presentation, when it succumbed to a fatal haemorrhagic episode. Necropsy revealed severe intestinal and pulmonary haemorrhage and hypocellular bone marrow with megakaryocytosis but no other causes of immune-mediated thrombocytopaenia (IMTP) or immune-mediated haemolytic anaemia (IMHA). Blood stored on days 158 and 180 tested PCR negative for Babesia spp. This report demonstrates that geographic range of B. gibsoni detection in cats includes Hong Kong. The exclusion of other causes suggests that B. gibsoni might have potentially played a role in triggering immune-mediated disease in this case.
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Poulsen, Mathias, Kim Sørensen i Thomas Condra. "Comparison of Two-Phase Porosity Models for High Capacity Random Packing". E3S Web of Conferences 321 (2021): 01015. http://dx.doi.org/10.1051/e3sconf/202132101015.
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High capacity random packing is used in absorption applications where a large throughput of gas is required while simultaneously maintaining as low a pressure loss as possible. Utilising computational fluid dynamics to capture the internal flow patterns and transients when designing packed bed towers can be advantageous in respect to expected performance and cost optimisation. However, capturing the direct interaction between gas, liquid and packing is not computationally feasible and therefore the packed bed is modelled as a porous media. In this work four different porosity model are calibrated with idealised equations to data for the high capacity packing IMTP or I-Ring. The different models are evaluated based on their ability to predict pressure loss and liquid holdup in the packed bed. An Eulerian two-phase model with a porous zone representing the packed bed is setup in a cylindrical tower. The CFD results are compared to the predictions of the best performing porosity model. It was found that the best performing model had an absolute mean error of 6.7% when calibrated with the idealised equations. This error increased to 10.5% when the porosity model was implemented into the CFD model.