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Matsuzaki, Yukiko, Madison R. Heath, Julianne M. Khan, Elad Spitzer, and Peter D. Fabricant. "Reliability of Two-Dimensional Video-Based Analysis in Adolescent Runners." Orthopaedic Journal of Sports Medicine 9, no. 7_suppl3 (July 1, 2021): 2325967121S0007. http://dx.doi.org/10.1177/2325967121s00072.
Повний текст джерелаАнотація:
Background: Running analysis is an essential component of evaluation of both injured runners and uninjured runners seeking advice on injury prevention. Reliability of two-dimensional (2D) video analysis has been reported in the adult running population. However, these findings may not apply to youth runners given their unique state during growth and development. The reliability of quantitative and qualitative video-based running gait analysis in the adolescent population is unknown. Purpose: The purpose of this study was to determine the intra-rater and inter-rater reliability of sagittal and frontal plane kinematics using 2D video analysis in healthy adolescent runners. Methods: High-definition videos were recorded of 10 healthy runners between 14-18 years old running on a treadmill at self-selected speed with markers attached to the thoracic spine, pelvis, and lower extremities. Kinematic variables in the sagittal and frontal planes were measured using Dartfish Motion Analysis Software™ (Fribourg, Switzerland) by three raters. Intra- and inter-rater reliability were calculated using Intraclass Correlation Coefficients (ICCs). Results: Of the 10 runners, 4 (40%) were male and the mean age was 16 ± 1.5 years. The intra-rater ICC for all kinematic variables ranged from 0.574 to 0.999 for the primary sports physical therapist, and 0.367 to 0.973 for the inexperienced research assistant. The inter-rater ICC for all raters ranged from -0.01 to 0.941. Eleven kinematic variables showed substantial agreement and 4 showed almost perfect agreement. Step width and foot progression showed fair and poor agreement, respectively. Conclusion: The results of this study demonstrate that a 2D video-based running analysis can be reliably performed in an adolescent population on all kinematic variables except for step width and foot progression. Inexperienced raters can be properly trained in the video analysis of running kinematics using Dartfish Software in order to consistently assess the same runner. [Table: see text][Table: see text]
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Geonea, Ionut Daniel, Nicolae Dumitru, and Alexandru Margine. "Motion Evaluation Of A Wheelchair Prototype For Disabled People." ACTA Universitatis Cibiniensis 67, no. 1 (September 1, 2015): 44–50. http://dx.doi.org/10.1515/aucts-2015-0062.
Повний текст джерелаАнотація:
Abstract In this paper is presented the design solution and experimental prototype of a wheelchair for disabled people. Design solution proposed to be implemented uses two reduction gears motors and a mechanical transmission with chains. It’s developed a motion controller based on a PWM technology, which allows the user to control the wheelchair motion. The wheelchair has the ability of forward – backward motion and steering. The design solution is developed in Solid Works, and it’s implemented to a wheelchair prototype model. Wheelchair design and motion makes him suitable especially for indoor use. It is made a study of the wheelchair kinematics, first using a kinematic simulation in Adams. Are presented the wheelchair motion trajectory and kinematics parameters. The experimental prototype is tested with a motion analysis system based on ultra high speed video cameras recording. The obtained results from simulation and experimentally tests, demonstrate the efficiency of wheelchair proposed solution.
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Zahradka, Nicole, Khushboo Verma, Ahad Behboodi, Barry Bodt, Henry Wright, and Samuel C. K. Lee. "An Evaluation of Three Kinematic Methods for Gait Event Detection Compared to the Kinetic-Based ‘Gold Standard’." Sensors 20, no. 18 (September 15, 2020): 5272. http://dx.doi.org/10.3390/s20185272.
Повний текст джерелаАнотація:
Video- and sensor-based gait analysis systems are rapidly emerging for use in ‘real world’ scenarios outside of typical instrumented motion analysis laboratories. Unlike laboratory systems, such systems do not use kinetic data from force plates, rather, gait events such as initial contact (IC) and terminal contact (TC) are estimated from video and sensor signals. There are, however, detection errors inherent in kinematic gait event detection methods (GEDM) and comparative study between classic laboratory and video/sensor-based systems is warranted. For this study, three kinematic methods: coordinate based treadmill algorithm (CBTA), shank angular velocity (SK), and foot velocity algorithm (FVA) were compared to ‘gold standard’ force plate methods (GS) for determining IC and TC in adults (n = 6), typically developing children (n = 5) and children with cerebral palsy (n = 6). The root mean square error (RMSE) values for CBTA, SK, and FVA were 27.22, 47.33, and 78.41 ms, respectively. On average, GED was detected earlier in CBTA and SK (CBTA: −9.54 ± 0.66 ms, SK: −33.41 ± 0.86 ms) and delayed in FVA (21.00 ± 1.96 ms). The statistical model demonstrated insensitivity to variations in group, side, and individuals. Out of three kinematic GEDMs, SK GEDM can best be used for sensor-based gait event detection.
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Hannah, Iain, Andy Harland, Dan Price, Heiko Schlarb, and Tim Lucas. "Evaluation of a Kinematically-Driven Finite Element Footstrike Model." Journal of Applied Biomechanics 32, no. 3 (June 2016): 301–5. http://dx.doi.org/10.1123/jab.2015-0002.
Повний текст джерелаАнотація:
A dynamic finite element model of a shod running footstrike was developed and driven with 6 degree of freedom foot segment kinematics determined from a motion capture running trial. Quadratic tetrahedral elements were used to mesh the footwear components with material models determined from appropriate mechanical tests. Model outputs were compared with experimental high-speed video (HSV) footage, vertical ground reaction force (GRF), and center of pressure (COP) excursion to determine whether such an approach is appropriate for the development of athletic footwear. Although unquantified, good visual agreement to the HSV footage was observed but significant discrepancies were found between the model and experimental GRF and COP readings (9% and 61% of model readings outside of the mean experimental reading ± 2 standard deviations, respectively). Model output was also found to be highly sensitive to input kinematics with a 120% increase in maximum GRF observed when translating the force platform 2 mm vertically. While representing an alternative approach to existing dynamic finite element footstrike models, loading highly representative of an experimental trial was not found to be achievable when employing exclusively kinematic boundary conditions. This significantly limits the usefulness of employing such an approach in the footwear development process.
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Vladimir, Potop. "Improving Sports Technique of Jaeger Salto on Uneven Bars Based on Biomechanical Indicators." New Trends and Issues Proceedings on Advances in Pure and Applied Sciences, no. 8 (December 22, 2017): 83–91. http://dx.doi.org/10.18844/gjapas.v0i8.2820.
Повний текст джерелаАнотація:
This paper aims at improvement of key sports technique elements using kinematic and dynamic indicators of Jaeger salto on uneven bars during the training stages. The methods used in this research include analysis of the literature; evaluation of techniques of gymnastics exercises using algorithmic structural–systemic analysis of movement; video-computerised methods using ‘Pinnacle Studio’, ‘Kinovea’ and ‘Physics ToolKit’; movement postural orientation and evaluation of sports technique with complex coordination of movement structure; linear-branched programming of learning and improvement; and the ‘KyPlot’ program. Correlative analysis of the indicators of Jaeger salto and performances by 12–15-year-old gymnasts highlighted the connection between the kinematic and dynamic characteristics of sports techniques and the scores in competitions. Video-computerised methods, the method of movement postural orientation and algorithmic analysis of sports technique of Jaeger salto on uneven bars contributed to effective development of long-term learning programmes, improvement of technical execution and achievement of better performances. Keywords: Gymnastics, uneven bars, biomechanics, key elements, long-term programmes of learning, performance.
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Theoret, C. L., S. M. Barber, R. D. Curie, and Hilary M. Clayton. "Effects of Carpal Synovectomy on Stride Kinematics of Trotting Horses." Veterinary and Comparative Orthopaedics and Traumatology 11, no. 02 (1998): 80–84. http://dx.doi.org/10.1055/s-0038-1632615.
Повний текст джерелаАнотація:
SummaryA group of eight horses was used to study the effects of synovectomy of one antebrachiocarpal joint on stride kinematics of the trot. Two months after the operation, four of the horses started a progressive exercise program lasting two months. A standardised lameness evaluation and videographic gait analysis were performed on three occasions: two days before the operation, two days after the operation and four months after the operation when the exercise programme had been completed. There were no significant differences in clinical lameness score, amplitude of poll motion, maximal metacarpophalangeal angle, maximal carpal angle, or minimal carpal angle between the synovectomized limb and the unoperated limb on any of the three evaluation days. It is concluded that carpal synovectomy did not cause lameness in the immediate post-operative period, and that strenuous exercise can safely be commenced after a two month recovery period, unless underlying cartilaginous lesions dictate otherwise.Gait analysis was performed qualitatively using a standard clinical examination and quantitatively using videographic analysis to measure kinematic variables that have previously been associated with lameness. Following synovectomy of one antebrachiocarpal joint no signs of lameness were observed on clinical examination and there were no asymmetrics in the kinematic variables. A strenuous exercise program, which commenced 2 months after surgery and lasted for 2 months, was completed without the development of clinical or video-graphic signs of lameness.
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Litvinenko, Y. V., Tomasz Niznikowski, and V. N. Boloban. "Evaluation of the kinematic structure of indicators key elements of sports equipment exercise by postural orientation movements." Physical education of students 18, no. 6 (December 28, 2014): 29–36. http://dx.doi.org/10.15561/20755279.2014.0606.
Повний текст джерелаАнотація:
Purpose : Examine the kinematic structure of indicators key elements of sports equipment exercise (difficult to coordinate). The method of postural orientation movements. Material : The study involved acrobats jumpers on the path of high qualification (n = 7). The method used video - computer recording the movements of the athlete. Results : Identified nodal elements of sports equipment double back somersault tuck. Exercise performed after rondat and double back flip and stretch after rondat - flick (coup ago). In the preparatory phase of motor actions acrobatic exercises isolated and studied central element of sports equipment - starting posture of the body; in the phase of the main motor action - animation poses of the body; in the final phase - the final body posture (stable landing). Conclusions : The method of video - computer registration allowed to perform a biomechanical analysis and evaluation of key elements of sports equipment double back somersault tuck and a double back flip and stretch. Also gain new knowledge about the mechanism of the phase structure of movements when performing double somersaults.
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POTOP, Vladimir, and Elena –. Diana SIMA. "Learning the Swimming Start by Students in Higher Education of other Profiles." Revista Romaneasca pentru Educatie Multidimensionala 10, no. 1 (April 2, 2018): 109. http://dx.doi.org/10.18662/rrem/22.
Повний текст джерелаАнотація:
This paper aims to highlight how to use the computerized video analysis for learning the sports technique key elements of the start in swimming in the case of the students in higher education of other profiles. This scientific approach entailed the organization of an ascertaining experimental study, using the following research methods: bibliographic study of the specialized literature, video computerized method by means of Pinnacle Studio, Kinovea and Physics ToolKit programs, method of movement postural orientation, statistical-mathematical method which uses the KyPlot program and the method of graphical representation of results. The research was conducted from October 2017 to January 2018 and included 12 students (second-year - series no. 2) of the Faculty of General Medicine. The results of the study show the muscle strength development of arms, abdomen and legs of the students under research. The use of the video computerized method highlights and identifies the kinematic and dynamic characteristics of sports technique key elements used in swimming start regarding the launching posture, multiplication of body posture (flying through the air) and concluding body posture (entering the water). The propulsion and going out of water will be studied depending on the specific swimming style chosen by the students. The effective use of the computerized video analysis that deepens the understanding of sports technique phasic structure will allow the processing of the modern didactical programs for swimming learning. The modern research methods used in the video computerized analysis of sports technique of the start in swimming are an important help for the measurement, analysis and evaluation of the kinematic and dynamic structure of all swimming styles.
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Bartlett, Roger, Erich Müller, Stefan Lindinger, Fritz Brunner, and Calvin Morriss. "Three-Dimensional Evaluation of the Kinematic Release Parameters for Javelin Throwers of Different Skill Levels." Journal of Applied Biomechanics 12, no. 1 (February 1996): 58–71. http://dx.doi.org/10.1123/jab.12.1.58.
Повний текст джерелаАнотація:
This study compared three-dimensional release parameters and important features of the throwing technique for male javelin throwers of three different skill levels (elite, club, novice), recorded using three-dimensional cine or video. As expected, significant differences (p < .01) in throw distances and release speeds were found between all three groups. The only other release parameter for which a significant difference was found (between club and novice groups) was the yaw angle. The increase in release speed with increasing skill across the groups may be attributable in part to greater run-up speeds. Also important were significantly greater peak speeds of the throwing shoulder, elbow, and hand during the delivery stride for the elite group compared to the other groups. Significantly longer acceleration paths at the start of the delivery stride and a delay in elbow flexion until after final foot strike for the elite throwers were also important in generating greater release speeds.
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Russo, Caterina, Elena Puppo, Stefania Roati, and Aurelio Somà. "Proposal of an Alpine Skiing Kinematic Analysis with the Aid of Miniaturized Monitoring Sensors, a Pilot Study." Sensors 22, no. 11 (June 4, 2022): 4286. http://dx.doi.org/10.3390/s22114286.
Повний текст джерелаАнотація:
The recent growth and spread of smart sensor technologies make these connected devices suitable for diagnostic and monitoring in different fields. In particular, these sensors are useful in diagnostics for control of diseases or during rehabilitation. They are also extensively used in the monitoring field, both by non-expert and expert users, to monitor health status and progress during a sports activity. For athletes, these devices could be used to control and enhance their performance. This development has led to the realization of miniaturized sensors that are wearable during different sporting activities without interfering with the movements of the athlete. The use of these sensors, during training or racing, opens new frontiers for the understanding of motions and causes of injuries. This pilot study introduced a motion analysis system to monitor Alpine ski activities during training sessions. Through five inertial measurement units (IMUs), placed on five points of the athletes, it is possible to compute the angle of each joint and evaluate the ski run. Comparing the IMU data, firstly, with a video and then proposing them to an expert coach, it is possible to observe from the data the same mistakes visible in the camera. The aim of this work is to find a tool to support ski coaches during training sessions. Since the evaluation of athletes is now mainly developed with the support of video, we evaluate the use of IMUs to support the evaluation of the coach with more precise data.
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Sandlund, Marlene, Erik Domellöf, Helena Grip, Louise Rönnqvist, and Charlotte K. Häger. "Training of goal directed arm movements with motion interactive video games in children with cerebral palsy – A kinematic evaluation." Developmental Neurorehabilitation 17, no. 5 (July 17, 2013): 318–26. http://dx.doi.org/10.3109/17518423.2013.776124.
Повний текст джерела
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Khizhnikova, A. E., A. S. Klochkov, A. M. Kotov–Smolenskiy, N. A. Suponeva, and M. A. Piradov. "Dynamics of post-stroke hand paresis kinematic pattern during rehabilitation." Exosomes, no. 4 (August 31, 2019): 32–38. http://dx.doi.org/10.24075/brsmu.2019.056.
Повний текст джерелаАнотація:
According to the literature data, only 5–20% of post-stroke patients are able to restore the hand motor function completely. Correct goal setting and individual approach to the patient's functional recovery are important. Our study aimed to develop an algorithm of impaired hand motor functioning assessment for post-stroke patients and to determine the principles of the rehabilitation tactics choosing based on the biomechanical analysis. Twenty five patients with hemispheric stroke and 10 healthy volunteers participated in the study. Formal clinical observation scales (Fugl-Meyer Assessment, Ashworth Scale, ARAT) and video motion analysis were used for evaluation of the hand motor function. Patients were divided into 2 groups according to the hand paresis severity (mild/moderate and pronounced/severe). Rehabilitation was carried out in both groups, including mechanotherapy, massage and physical therapy. It was revealed that in the 1st group of patients the motor function recovery in the paretic hand was due to movement performance recovery: biomechanical parameters restoration directly correlated with a decrease in the paresis degree according to the Fugl-Meyer Assessment Scale (r = 0.94; p = 0.01). In the 2nd group of patients, the motor function recovery in the paretic hand was due to motor deficit compensation: according to biomechanical analysis, the pathological motor synergies inversely correlated with a decrease in the paresis degree (r = –0.9; p = 0.03). As a result of the study, an algorithm for selecting the patient management tactics based on the baseline clinical indicators was developed.
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Rozzi, Giacomo, Francesco P. Lo Muzio, Camilla Sandrini, Stefano Rossi, Lorenzo Fassina, Giuseppe Faggian, Michele Miragoli, and Giovanni Battista Luciani. "Real-time video kinematic evaluation of the in situ beating right ventricle after pulmonary valve replacement in patients with tetralogy of Fallot: a pilot study." Interactive CardioVascular and Thoracic Surgery 29, no. 4 (June 9, 2019): 625–31. http://dx.doi.org/10.1093/icvts/ivz120.
Повний текст джерелаАнотація:
Abstract OBJECTIVES The timing for pulmonary valve replacement (PVR) after tetralogy of Fallot repair is controversial, due to limitations in estimating right ventricular dysfunction and recovery. Intraoperative imaging could add prognostic information, but transoesophageal echocardiography is unsuitable for exploring right heart function. Right ventricular function after PVR was investigated in real time using a novel video-based contactless kinematic evaluation technology (Vi.Ki.E.), which calculates cardiac fatigue and energy consumption. METHODS Six consecutive patients undergoing PVR at 13.8 ± 2.6 years (range 6.9–19.8) after the repair of tetralogy of Fallot were enrolled. Mean right ventricular end-diastolic and end-systolic volume at magnetic resonance imaging were 115.6 ± 16.2 ml/m2 and 61.5 ± 14.6 ml/m2, respectively. Vi.Ki.E. uses a fast-resolution camera placed 45 cm above the open chest, recording cardiac kinematics before and after PVR. An algorithm defines cardiac parameters, such as energy, fatigue, maximum contraction velocity and tissue displacement. RESULTS There were no perioperative complications, with patients discharged in satisfactory clinical conditions after 7 ± 2 days (range 5–9). Vi.Ki.E. parameters describing right ventricular dysfunction decreased significantly after surgery: energy consumption by 45% [271 125 ± 9422 (mm/s)2 vs 149 202 ± 11 980 (mm/s)2, P = 0.0001], cardiac fatigue by 12% (292 671 ± 29 369 mm/s2 vs 258 755 ± 42 750 mm/s2, P = 0.01), contraction velocity by 54% (3412 ± 749 mm/s vs 1579 ± 400 mm/s, P = 0.0007) and displacement by 23% (27 ± 4 mm vs 21 ± 4 mm, P = 0.01). Patients undergoing PVR at lower end-diastolic volumes, had greater functional recovery of Vi.Ki.E. parameters. CONCLUSIONS Intraoperative Vi.Ki.E shows immediate recovery of right ventricular mechanics after PVR with less cardiac fatigue and energy consumption, providing novel insights that may have a prognostic relevance for functional recovery.
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Lewczuk, Dorota, and Ewa Metera-Zarzycka. "Horse phenotyping based on video image analysis of jumping performance for conservation breeding." PeerJ 7 (August 9, 2019): e7450. http://dx.doi.org/10.7717/peerj.7450.
Повний текст джерелаАнотація:
Background Many horse breeds in the world are reserved as genetic resources; however, their characteristics seem to be insufficiently clarified, especially in terms of horse performance. Two jumping ability evaluation methods have been used to compare different types of performance breeds and on this basis their applicability for precision phenotyping has been determined. Methods Jumping data of 186 young Polish Warmblood stallions (27 with an endangered status) bred for sport and multipurpose use was collected during their performance tests organised under identical environmental conditions following the same guidelines. Jumping data consisted of objective measurements of free jumping parameters and the marks for jumping. Video recordings of 514 jumps (73 records for 27 stallions with an endangered status) were collected using a digital Panasonic AG-EZ 35 camera (25 fr/sec). Filming was recorded during a free jumping test in the line on a doublebarre obstacle (100–120 cm × 100 cm). Spatial and temporal variables of the jump were measured. The analysis of variance was performed (SAS, General Linear Model and Mixed procedures) using the statistical model, which included the random effect of the horse and fixed effects of the year of test, breeding status, height of jump and the successive number of the jump for objective kinematic data. The fixed effects of the year of test and breeding status were included in the model for subjective performance test data. Results Performance marks for free jumping were lower in the endangered group of stallions in the trainers’ opinion (p ≤ 0.05), while no statistically significant differences were found in the judges’ opinions. Statistically significant differences in jumping variables were measured for the bascule points—the elevations of the withers and croup were higher in the endangered group (p ≤ 0.001) and the take-off time was prolonged (p ≤ 0.05), which explained the subjective evaluation. Discussion The use of objective evaluation methods provides important information for practice, as phenotypic differences between horses may be unclear in the subjective evaluation. The objective evaluation should be used to characterise the performance potential of different breeds, because the information from the evaluators might not be consistent. Such characteristics should be recorded at least for every new population.
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Vladimir, Potop, Dorgan Viorel, and Jurat Valeriu. "Improvement of Sports Technique Based on Biomechanical Indicators of Yurchenko Handspring Vault in Women’s Artistic Gymnastics." European Journal of Interdisciplinary Studies 3, no. 1 (January 21, 2017): 42. http://dx.doi.org/10.26417/ejis.v3i1.42-52.
Повний текст джерелаАнотація:
The main purpose of this paper is the biomechanical analysis of the kinematic and dynamic indicators of sports technique used in Yurchenko handspring vault by means of the macro methods for exercises learning during the training basic specialization stage. This scientific approach led to the organization of an experimental study, using the research methods as follows: 1. Method of theoretical and methodological analysis of literature related to artistic gymnastics. 2. Method of evaluation of gymnastics exercises sports technique using the algorithmic analysis of the motion. 3. Video computerized method, using” Pinnacle Studio”,” Kinovea” and” Physics ToolKit” programs. 3. Method of movement postural orientation and evaluation of key elements of sports technique with complex coordination of movement structure. 4. Method of linear-branched programming of gymnastics exercises learning and improving. 5. Statistical method, by means of” KyPlot” program. The research was conducted from 2012 to 2014, when gymnasts’ performances were monitored in three national competitions - handspring vaults event; a number of 7 athletes aged 12 to 15 participated in these competitions, all of them members of junior national team of Romania. The results of the research highlighted and identified the kinematic and dynamic characteristics of sports technique key elements of Yurchenko vault in women’s artistic gymnastics. The implementation of the macro methods of learning in young gymnasts’ training contributed to the improvement of sports technique and the effective experimental distribution of the difficult and highly difficult basic vaults.
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Vladimir, Potop, Dorgan Viorel, and Jurat Valeriu. "Improvement of Sports Technique Based on Biomechanical Indicators of Yurchenko Handspring Vault in Women’s Artistic Gymnastics." European Journal of Interdisciplinary Studies 3, no. 1 (January 21, 2017): 42. http://dx.doi.org/10.26417/ejis.v3i1.p42-52.
Повний текст джерелаАнотація:
The main purpose of this paper is the biomechanical analysis of the kinematic and dynamic indicators of sports technique used in Yurchenko handspring vault by means of the macro methods for exercises learning during the training basic specialization stage. This scientific approach led to the organization of an experimental study, using the research methods as follows: 1. Method of theoretical and methodological analysis of literature related to artistic gymnastics. 2. Method of evaluation of gymnastics exercises sports technique using the algorithmic analysis of the motion. 3. Video computerized method, using” Pinnacle Studio”,” Kinovea” and” Physics ToolKit” programs. 3. Method of movement postural orientation and evaluation of key elements of sports technique with complex coordination of movement structure. 4. Method of linear-branched programming of gymnastics exercises learning and improving. 5. Statistical method, by means of” KyPlot” program. The research was conducted from 2012 to 2014, when gymnasts’ performances were monitored in three national competitions - handspring vaults event; a number of 7 athletes aged 12 to 15 participated in these competitions, all of them members of junior national team of Romania. The results of the research highlighted and identified the kinematic and dynamic characteristics of sports technique key elements of Yurchenko vault in women’s artistic gymnastics. The implementation of the macro methods of learning in young gymnasts’ training contributed to the improvement of sports technique and the effective experimental distribution of the difficult and highly difficult basic vaults.
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Vladimir, Potop, Dorgan Viorel, and Jurat Valeriu. "Improvement of Sports Technique Based on Biomechanical Indicators of Yurchenko Handspring Vault in Women’s Artistic Gymnastics." European Journal of Interdisciplinary Studies 7, no. 1 (January 21, 2017): 42. http://dx.doi.org/10.26417/ejis.v7i1.p42-52.
Повний текст джерелаАнотація:
The main purpose of this paper is the biomechanical analysis of the kinematic and dynamic indicators of sports technique used in Yurchenko handspring vault by means of the macro methods for exercises learning during the training basic specialization stage. This scientific approach led to the organization of an experimental study, using the research methods as follows: 1. Method of theoretical and methodological analysis of literature related to artistic gymnastics. 2. Method of evaluation of gymnastics exercises sports technique using the algorithmic analysis of the motion. 3. Video computerized method, using” Pinnacle Studio”,” Kinovea” and” Physics ToolKit” programs. 3. Method of movement postural orientation and evaluation of key elements of sports technique with complex coordination of movement structure. 4. Method of linear-branched programming of gymnastics exercises learning and improving. 5. Statistical method, by means of” KyPlot” program. The research was conducted from 2012 to 2014, when gymnasts’ performances were monitored in three national competitions - handspring vaults event; a number of 7 athletes aged 12 to 15 participated in these competitions, all of them members of junior national team of Romania. The results of the research highlighted and identified the kinematic and dynamic characteristics of sports technique key elements of Yurchenko vault in women’s artistic gymnastics. The implementation of the macro methods of learning in young gymnasts’ training contributed to the improvement of sports technique and the effective experimental distribution of the difficult and highly difficult basic vaults.
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Tanaka, Toshiaki, Ryo Matsumura, and Takahiro Miura. "Influence of Varied Load Assistance with Exoskeleton-Type Robotic Device on Gait Rehabilitation in Healthy Adult Men." International Journal of Environmental Research and Public Health 19, no. 15 (August 6, 2022): 9713. http://dx.doi.org/10.3390/ijerph19159713.
Повний текст джерелаАнотація:
This study aimed to clarify how the power-assist function of the hybrid assistive limb (HAL®), an exoskeleton-type gait-assist device, affected the gait characteristics of patients who wear it, specifically focusing on the “misalignment” of the robot joints and landmarks with the corresponding body parts. Five healthy adult men were video-recorded wearing the HAL® as they walked normally on a treadmill under seven conditions corresponding to the strengths and sites of robotic power assistance. For kinematic analysis, reflective markers were attached to the HAL® and the wearer at key locations, and participants were recorded walking past a set of four video cameras for each condition. A motion analysis system was used for analysis. The walking motion was segmented into eight-phase gait cycles. Knee misalignment, or the relative offset in position of the HAL®/wearer knee joints, was calculated from kinematic data and joint angles. These values were compared with respect to two factors: assist level and gait phase. Statistical analysis consisted of parametric and nonparametric tests for comparing the values of misalignment of each gait phase, followed by multiple comparisons to confirm significant differences. The results showed that the knee misalignment was greatest in the pre-swing phase and was significantly lower overall in conditions with high levels of power assistance. The result of greater knee misalignment in the pre-swing phase may be attributed to the structural properties of the HAL® lower-limb exoskeleton. This provides valuable insight regarding the walking stages that should be given special attention during the evaluation of synchrony between exoskeleton-type gait-assist robots and their wearers.
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Alekseev, Vladimir V., Anna V. Tsareva, and Natalia V. Romantsova. "VIRTUAL DIGITAL 3D SENSOR. EVALUATION OF THE ACCURACY OF MEASURING THE PARAMETERS OF THE KINEMATIC PORTRAIT OF A PERSON." SOFT MEASUREMENTS AND COMPUTING 11, no. 60 (2022): 13–29. http://dx.doi.org/10.36871/2618-9976.2022.11.002.
Повний текст джерелаАнотація:
The article is devoted to the issue of a formalized description of the components of the uncertainty of the virtual digital scale of the control system built on the basis of video recorders in order to present it as a means of measurement. The analysis of the structure of the system is carried out in order to determine the hardware and methodological components, uncertainty. The modes of calibration, certification, control, the issues of creating digital twins based on the kinematic portrait of a person for use in rehabilitation systems in medicine and sports are considered. The creation of digital twins of objects, systems, processes is widely used to improve the accuracy of monitoring their condition, forecasting, improving the quality and reliability of management decisions. At the same time, an important aspect is to reduce the uncertainty of the boundaries of patterns, which increases the reliability of the system application and the development of a control action or a prediction result. Uncertainty reduction is provided by means of measurement, with the help of which control procedures are carried out.
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Liu, Long, Hui-Hui Wang, Sen Qiu, Yun-Cui Zhang, and Zheng-Dong Hao. "Paddle Stroke Analysis for Kayakers Using Wearable Technologies." Sensors 21, no. 3 (January 29, 2021): 914. http://dx.doi.org/10.3390/s21030914.
Повний текст джерелаАнотація:
Proper stroke posture and rhythm are crucial for kayakers to achieve perfect performance and avoid the occurrence of sport injuries. The traditional video-based analysis method has numerous limitations (e.g., site and occlusion). In this study, we propose a systematic approach for evaluating the training performance of kayakers based on the multiple sensors fusion technology. Kayakers’ motion information is collected by miniature inertial sensor nodes attached on the body. The extend Kalman filter (EKF) method is used for data fusion and updating human posture. After sensor calibration, the kayakers’ actions are reconstructed by rigid-body model. The quantitative kinematic analysis is carried out based on joint angles. Machine learning algorithms are used for differentiating the stroke cycle into different phases, including entry, pull, exit and recovery. The experiment shows that our method can provide comprehensive motion evaluation information under real on-water scenario, and the phase identification of kayaker’s motions is up to 98% validated by videography method. The proposed approach can provide quantitative information for coaches and athletes, which can be used to improve the training effects.
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De Jesus, Kelly, Larissa M. Cardoso, and Karla De Jesus. "Metabolic, kinematic and coordinative behavior of a para swimmer with cerebral palsy." Brazilian Journal of Motor Behavior 16, no. 1 (March 1, 2022): 57–68. http://dx.doi.org/10.20338/bjmb.v16i1.265.
Повний текст джерелаАнотація:
BACKGROUND: It has been increasingly necessary to assess and monitor the physiological and biomechanics variables of para swimmers to enlarge the current knowledge on how different impairments limit swimming performance and explain each competition class variability in metabolic and technical terms. AIM: To characterize the front crawl metabolic, kinematic, and coordination behaviors of a trained para swimmer subjected to an incremental protocol. METHOD: A 44-year-old male, with moderate right side hemiparesis of the body, performed a 200-m front crawl at 5 incrementally paces until exhaustion (0.05 m/s increases and 30-s intervals), with images from two cycles at each step recorded by two video cameras (one surface and one underwater). Kinematic and coordinative variables were collected. Lactate concentrations, heart rate, and blood pressure were also measured. RESULTS: The para swimmer achieved the anaerobic threshold at the fourth 200-m step, followed by an increase in heart rate and blood pressure. Speed and stroke frequency were higher and stroke length was lower along the 200-m steps. In contrast, a slight increase in stroke index and stability in intracyclic velocity variations occurred across intensity increments, and index of interlimb coordination was maintained as a superposition mode. CONCLUSION: The findings suggest that the swimming intensity seems to influence the para swimmer metabolic, kinematic, and coordinative behavior, with sharper alterations after the point when AnT is achieved. In addition to having practical interest for adapted swimming, coaches should emphazise the physiological and biomechanical evaluation on training monitoring to better prescribe and improve the adapted swimming performance.
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Skiba, Agnieszka, Jakub Marchewka, Amadeusz Skiba, Szymon Podsiadło, Iwona Sulowska, Wiesław Chwała, and Anna Marchewka. "Evaluation of the Effectiveness of Nordic Walking Training in Improving the Gait of Persons with Down Syndrome." BioMed Research International 2019 (April 15, 2019): 1–11. http://dx.doi.org/10.1155/2019/6353292.
Повний текст джерелаАнотація:
People with Down syndrome (DS) show dysfunction of gait, expressed by disturbed character of angular changes and values of the spatiotemporal parameters as compared to the physiological norm. It is known that exercises and various activities have positive effect on balance and gait, but there are only a few scientific proofs concerning above-mentioned in people with DS. Furthermore, the effect of Nordic Walking (NW) training on gait in people with DS is unexplored. We enrolled 22 subjects with DS, aged 25-40 years, with moderate intellectual disability. Participants were randomly divided into 2 groups: NW training group which underwent 10 weeks of training at a frequency of 3 times a week and control group with no specific intervention. Subjects were examined twice: 1 week before training and a week immediately after intervention. Gait was evaluated by the Vicon 250: a computerized system of three-dimensional analysis of motion, connected to 5 infrared video cameras. We conducted mixed-design ANOVA model to assess the effects of time and type of training on spatiotemporal parameters. We found significant favorable time by group interaction in the following parameters: step length in right leg: F(1,15) =14,47, p=0.002; left leg accordingly F(1,15) =5,15, p=0.038, cycle length in right leg: F(1,15) =14,48, p=0.002; left leg accordingly F(1,15) =15,09, p=0.001; and gait standardised speed F(1,15) =5,35, p=0.035. Statistically significant changes were observed in numerous kinematic parameters of ankle, knee, pelvis, and shoulder in NW group. Regular NW training has positive influence on selected spatiotemporal and kinematic parameters in people with Down Syndrome and may be an attractive and safe form of rehabilitation.
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Stenum, Jan, Cristina Rossi, and Ryan T. Roemmich. "Two-dimensional video-based analysis of human gait using pose estimation." PLOS Computational Biology 17, no. 4 (April 23, 2021): e1008935. http://dx.doi.org/10.1371/journal.pcbi.1008935.
Повний текст джерелаАнотація:
Human gait analysis is often conducted in clinical and basic research, but many common approaches (e.g., three-dimensional motion capture, wearables) are expensive, immobile, data-limited, and require expertise. Recent advances in video-based pose estimation suggest potential for gait analysis using two-dimensional video collected from readily accessible devices (e.g., smartphones). To date, several studies have extracted features of human gait using markerless pose estimation. However, we currently lack evaluation of video-based approaches using a dataset of human gait for a wide range of gait parameters on a stride-by-stride basis and a workflow for performing gait analysis from video. Here, we compared spatiotemporal and sagittal kinematic gait parameters measured with OpenPose (open-source video-based human pose estimation) against simultaneously recorded three-dimensional motion capture from overground walking of healthy adults. When assessing all individual steps in the walking bouts, we observed mean absolute errors between motion capture and OpenPose of 0.02 s for temporal gait parameters (i.e., step time, stance time, swing time and double support time) and 0.049 m for step lengths. Accuracy improved when spatiotemporal gait parameters were calculated as individual participant mean values: mean absolute error was 0.01 s for temporal gait parameters and 0.018 m for step lengths. The greatest difference in gait speed between motion capture and OpenPose was less than 0.10 m s−1. Mean absolute error of sagittal plane hip, knee and ankle angles between motion capture and OpenPose were 4.0°, 5.6° and 7.4°. Our analysis workflow is freely available, involves minimal user input, and does not require prior gait analysis expertise. Finally, we offer suggestions and considerations for future applications of pose estimation for human gait analysis.
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Balkó, Štefan, Iva Balkó, and Vladimír Süss. "Analýza pohybové struktury výpadu u dvou výkonnostně odlišných skupin šermířů." Studia sportiva 8, no. 1 (July 14, 2014): 85–92. http://dx.doi.org/10.5817/sts2014-1-9.
Повний текст джерелаАнотація:
This study is focused on kinematic analysis in fencing lunge of different performance-related groups of fencers. The first group (n=7) consists of elite fencers of the Czech Republic, who are active in fencing an average of 12 years (±3,4). In the second group (n=7), there are fencers who are active in fencing up to two years. Subjects of our study performed lunge on a visual stimulus of LEDs, which is part of the Fitrosword device. The end of lunge was defined by hit of the target. The aim of this study was detection and charactrerization of movement structure in fencing lunge. Video recording and Dartfish TeamPro 6 Data software were used to evaluation of kinematic the lunge. The investigation revealed significant differences in the structure of individual phases of the lunge given to monitored groups of fencers. Between the the groups of fencers was identified difference in reaction time, speed of extension at the elbow joint and range of the movement in lunge. The results of our study may be useful for coaches who may this results due optimal pedagogical and methodological influence successfully applied in the training process. We assume that they can help in improving the performance of young and novice fencers who take into account the movement structure of lunge used by elite fencers.
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Kennedy, Robert S., Kevin S. Berbaum, William P. Dunlap, and Lawrence J. Hettinger. "Developing Automated Methods to Quantify the Visual Stimulus for Cybersickness." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 40, no. 22 (October 1996): 1126–30. http://dx.doi.org/10.1177/154193129604002204.
Повний текст джерелаАнотація:
Simulator sickness is a significant human factors issue in simulator and virtual environment systems. The extent to which users are adversely affected by sickness-inducing stimuli in virtual environments may hinder the behavioral goals sought (training, systems evaluation, etc.). To alleviate the problem, it is first necessary to accurately and reliably quantify the amount and type of visual motion stimulation that leads to motion sickness-like discomfort. This paper describes a human performance-based approach to the development of a system capable of measuring the visual stimulus for motion sickness. Military flight simulator trainees reported severity levels of sickness. A video camera was used to capture a significant portion of the simulated out-the-window visual stimuli to which they were exposed and a PC-mounted, frame-grabber algorithm was used to score the kinematic characteristics of that stimulation. Results show a significant positive correlation between roll motion and overall sickness. Development of these and other methods to quantify the visual stimulus for cybersickness are discussed.
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Sandmo, Stian Bahr, Andrew S. McIntosh, Thor Einar Andersen, Inga Katharina Koerte, and Roald Bahr. "Evaluation of an In-Ear Sensor for Quantifying Head Impacts in Youth Soccer." American Journal of Sports Medicine 47, no. 4 (February 25, 2019): 974–81. http://dx.doi.org/10.1177/0363546519826953.
Повний текст джерелаАнотація:
Background: Wearable sensor systems have the potential to quantify head kinematic responses of head impacts in soccer. However, on-field use of sensors (eg, accelerometers) remains challenging, owing to poor coupling to the head and difficulties discriminating low-severity direct head impacts from inertial loading of the head from human movements, such as jumping and landing. Purpose: To test the validity of an in-ear sensor for quantifying head impacts in youth soccer. Study Design: Descriptive laboratory study. Methods: First, the sensor was mounted to a Hybrid III headform and impacted with a linear impactor or a soccer ball. Peak linear acceleration (PLA), peak rotational acceleration (PRA), and peak rotational velocity (PRV) were obtained from both systems; random and systematic errors were calculated with Hybrid III as reference. Then, 6 youth soccer players wore sensors and performed a structured training protocol, including heading and nonheading exercises; they also completed 2 regular soccer sessions. For each accelerative event recorded, PLA, PRA, and PRV outputs were compared with video recordings. Receiver operating characteristic curves were used to determine the sensor’s discriminatory capacity in both on-field settings, establishing cutoff values for predicting outcomes. Results: For the laboratory tests, the random error was 11% for PLA, 20% for PRA, and 5% for PRV; the systematic error was 11%, 19%, and 5%, respectively. For the structured training protocol, heading events resulted in higher absolute values (PLA = 15.6 g± 11.8 g) than nonheading events (PLA = 4.6 g± 1.2 g); the area under the curve was 0.98 for PLA. In regular training sessions, the area under the curve was >0.99 for PLA. A 9 g cutoff value yielded a positive predictive value of 100% in the structured training protocol versus 65% in the regular soccer sessions. Conclusion: The in-ear sensor displayed considerable random error and substantially overestimated head impact exposure. Despite the sensor’s excellent on-field accuracy for discriminating headings from other accelerative events in youth soccer, absolute values must be interpreted with caution, and there is a need for secondary means of verification (eg, video analysis) in real-life settings. Clinical Relevance: Wearable sensor systems can potentially provide valuable insights into head impact exposures in contact sports, but their limitations require careful consideration.
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Ruiz-García, Isidoro, Ismael Navarro-Marchal, Javier Ocaña-Wilhelmi, Alberto J. Palma, Pablo J. Gómez-López, and Miguel A. Carvajal. "Development and Evaluation of a Low-Drift Inertial Sensor-Based System for Analysis of Alpine Skiing Performance." Sensors 21, no. 7 (April 2, 2021): 2480. http://dx.doi.org/10.3390/s21072480.
Повний текст джерелаАнотація:
In skiing it is important to know how the skier accelerates and inclines the skis during the turn to avoid injuries and improve technique. The purpose of this pilot study with three participants was to develop and evaluate a compact, wireless, and low-cost system for detecting the inclination and acceleration of skis in the field based on inertial measurement units (IMU). To that end, a commercial IMU board was placed on each ski behind the skier boot. With the use of an attitude and heading reference system algorithm included in the sensor board, the orientation and attitude data of the skis were obtained (roll, pitch, and yaw) by IMU sensor data fusion. Results demonstrate that the proposed IMU-based system can provide reliable low-drifted data up to 11 min of continuous usage in the worst case. Inertial angle data from the IMU-based system were compared with the data collected by a video-based 3D-kinematic reference system to evaluate its operation in terms of data correlation and system performance. Correlation coefficients between 0.889 (roll) and 0.991 (yaw) were obtained. Mean biases from −1.13° (roll) to 0.44° (yaw) and 95% limits of agreements from 2.87° (yaw) to 6.27° (roll) were calculated for the 1-min trials. Although low mean biases were achieved, some limitations arose in the system precision for pitch and roll estimations that could be due to the low sampling rate allowed by the sensor data fusion algorithm and the initial zeroing of the gyroscope.
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Velázquez, Jose S., Arsenio M. Iznaga-Benítez, Amanda Robau-Porrúa, Francisco L. Sáez-Gutiérrez, and Francisco Cavas. "New Affordable Method for Measuring Angular Variations Caused by High Heels on the Sagittal Plane of Feet Joints during Gait." Applied Sciences 11, no. 12 (June 17, 2021): 5605. http://dx.doi.org/10.3390/app11125605.
Повний текст джерелаАнотація:
Gait is influenced by many factors, but one of the most prominent ones is shoe heel height. Optical motion tracking technology is widely used to analyze high-heeled gait, but it normally involves several high-quality cameras and licensed software, so clinics and researchers with low budgets cannot afford them. This article presents a simple, effective technique to measure the rotation angles on the sagittal plane of the ankle (tibiotalar) and toe (metatarsophalangeal) joints when no shoes (0 cm heel) and high-heeled shoes (2, 6 and 10 cm heels) are worn. The foot’s position was determined by a set of equations based on its geometry and video analysis techniques with free software (Tracker). An evaluation of the spatio-temporal variables confirmed observations from previous studies: increasing heel heights reduces gait cycle length and speed but does not change cadence. The range of movement at the tibiotalar joint progressively narrowed from 28° when no heel height was worn to 9° when a 10 cm heel was used, and these reductions ranged from 30° to 5° for metatarsophalangeal joints, respectively. This aligns with other authors’ previous studies, and confirms that the proposed method accurately measures kinematic ankle–foot set changes when wearing high heels.
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Ang, Cheng Loong, and Pui Wah Kong. "Field-Based Biomechanical Assessment of the Snatch in Olympic Weightlifting Using Wearable In-Shoe Sensors and Videos—A Preliminary Report." Sensors 23, no. 3 (January 19, 2023): 1171. http://dx.doi.org/10.3390/s23031171.
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Traditionally, the biomechanical analysis of Olympic weightlifting movements required laboratory equipment such as force platforms and transducers, but such methods are difficult to implement in practice. This study developed a field-based method using wearable technology and videos for the biomechanical assessment of weightlifters. To demonstrate the practicality of our method, we collected kinetic and kinematic data on six Singapore National Olympic Weightlifters. The participants performed snatches at 80% to 90% of their competition one-repetition maximum, and the three best attempts were used for the analysis. They wore a pair of in-shoe force sensors loadsol® (novel, Munich, Germany) to measure the vertical ground reaction forces under each foot. Concurrently, a video camera recorded the barbell movement from the side. The kinematics (e.g., trajectories and velocities) of the barbell were extracted using a free video analysis software (Kinovea). The power–time history was calculated from the force and velocity data. The results showed differences in power, force, and barbell velocity with moderate to almost perfect reliability. Technical inconsistency in the barbell trajectories were also identified. In conclusion, this study presented a simple and practical approach to evaluating weightlifters using in-shoe wearable sensors and videos. Such information can be useful for monitoring progress, identifying errors, and guiding training plans for weightlifters.
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Egenvall, Agneta, Hilary M. Clayton, Marie Eisersiö, Lars Roepstorff, and Anna Byström. "Rein Tension in Transitions and Halts during Equestrian Dressage Training." Animals 9, no. 10 (September 23, 2019): 712. http://dx.doi.org/10.3390/ani9100712.
Повний текст джерелаАнотація:
In dressage, the performance of transitions between gaits and halts is an integral part of riding sessions. The study aimed to evaluate rein tension before, during and after the transitions between different gaits and the transitions into halts. The kinematic (inertial measurement units) data for the head and croup, and rein tension data, were collected (128 Hz) from six professional riders each riding three of their own horses, training levels varying from basic to advanced, during normal training sessions. The activities were categorised into gaits, halts and transitions based on video evaluation. The transitions were categorised as without (type 1) or with (type 2) intermediate steps that are not normally present in the gaits preceding or following the transition. The differences in the median rein tension before/during/after transitions, between the types and left/right reins were analysed in mixed models. The rein tension just before the transition was the strongest determinant of tension during the transition. The rein tension was slightly lower during upward transitions compared to downward transitions, reflecting the pattern of the preceding gait. Type 1 and 2 downward transitions were not different regarding rein tension. The left rein tension was lower than right rein tension. The rein tension associated with the transitions and halts varied substantially between riders and horses. The generally strong association of the gaits and their inherent biomechanics with rein tension should be taken into account when riding transitions and halts.
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Shalmanov, Anatoly, Vitaly Skotnikov, Elena Lukunina, and Janis Lanka. "EFFICIENCY OF SNATCH TECHNIQUE IN HIGH LEVEL WEIGHTLIFTERS." Baltic Journal of Sport and Health Sciences 2, no. 97 (2015): 27–33. http://dx.doi.org/10.33607/bjshs.v2i97.85.
Повний текст джерелаАнотація:
Background. Rich theoretical and experimental evidence on the biomechanics of weightlifting exercises has currently been collected (Bauman, Gross, & Quade, 1988; Garhammer, 1991; Gourgoulis, Aggelousis, & Mavromatis, 2000; Isaka, Okada, & Funato, 1996; Шалманов, Скотников, & Панин, 2012). Most of the studies were mainly carried out in laboratory settings, with long-term treatment of the obtained data. In recent years, scientists’ interest has shifted to the study and evaluation of the technical mastery of athletes in the setting of the highest level competition, in the extreme conditions of sport fight. This was facilitated by the development of specialized hardware and program sets (Шалманов & Скотников, 2013; Шалманов, Скотников & Ланка, 2013), opening the possibility for biomechanical control of athletes technical and speed-strength fitness both during the technical training process and competition. One of the ways of evaluating the effectiveness of techniques is based on the idea of using motor capacity by an athlete, which is called efficiency of realization. Methods. To register the trajectory of the bar and calculate kinematic and dynamic parameters of its movement a specialized hardware-program complex (APC) has been developed. In the APC, a photo-video camera “Canon” is included; a marker is fixed on the end of the bar as well as a computer with software. Recording was carried out during major competitions (Cup of Russia, the Russian Championship, and the XХVII World Summer Universiade) in 2012–2014. The total number of athletes surveyed was 331 people (184 men, 147 women). The paper presents the results obtained in the snatch in men. Results. The regularities in the change of kinematic and dynamic bar movement parameter with an increase in weight category and sport result were determined. The main indicator determining sports result in a classic snatch was the absolute maximum power developed by the athlete during acceleration of the bar in the final phase of its lifting: r = .75, p < .001. The indicator of absolute power is the most informative to assess the level of athlete speed- strength fitness, realized due to the efficiency of sports technique and prediction of sports result. Conclusions. The regression equation between the result in the snatch and the maximum absolute power in the final acceleration of the bar give a possibility to evaluate the technique of the effectiveness of each athlete: if it is better or worse than the average one and to what extent. This analysis gave one more possibility – to compare the set up performance with the performance that the athlete, taking into account their level of physical conditioning (maximal power), would achieve if they improve their technique.
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Darzian Rostami, Alireza, Anagha Katthe, Aryan Sohrabi, and Arash Jahangiri. "Predicting Critical Bicycle-Vehicle Conflicts at Signalized Intersections." Journal of Advanced Transportation 2020 (December 2, 2020): 1–16. http://dx.doi.org/10.1155/2020/8816616.
Повний текст джерелаАнотація:
Continuous development of urban infrastructure with a focus on sustainable transportation has led to a proliferation of vulnerable road users (VRUs), such as bicyclists and pedestrians, at intersections. Intersection safety evaluation has primarily relied on historical crash data. However, due to several limitations, including rarity, unpredictability, and irregularity of crash occurrences, quantitative and qualitative analyses of crashes may not be accurate. To transcend these limitations, intersection safety can be proactively evaluated by quantifying near-crashes using alternative measures known as surrogate safety measures (SSMs). This study focuses on developing models to predict critical near-crashes between vehicles and bicycles at intersections based on SSMs and kinematic data. Video data from ten signalized intersections in the city of San Diego were employed to train logistic regression (LR), support vector machine (SVM), and random forest (RF) models. A variation of time-to-collision called T2 and postencroachment time (PET) were used to specify monitoring periods and to identify critical near-crashes, respectively. Four scenarios were created using two thresholds of 5 and 3 s for both PET and T2. In each scenario, five monitoring period lengths were examined. The RF model was superior compared to other models in all different scenarios and across different monitoring period lengths. The results also showed a small trade-off between model performance and monitoring period length, identifying models with monitoring period lengths of 10 and 20 frames performed slightly better than those with lower or higher lengths. Sequential backward and forward feature selection methods were also applied that enhanced model performance. The best RF model had recall values of 85% or higher across all scenarios. Also, RF prediction models performed better when considering just the rear-end near-crashes with recalls of above 90%.
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Barbosa, Tiago M., Kelly de Jesus, J. Arturo Abraldes, João Ribeiro, Pedro Figueiredo, João Paulo Vilas-Boas, and Ricardo J. Fernandes. "Effects of Protocol Step Length on Biomechanical Measures in Swimming." International Journal of Sports Physiology and Performance 10, no. 2 (March 2015): 211–18. http://dx.doi.org/10.1123/ijspp.2014-0108.
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Background:The assessment of energetic and mechanical parameters in swimming often requires the use of an intermittent incremental protocol, whose step lengths are corner stones for the efficiency of the evaluation procedures.Purpose:To analyze changes in swimming kinematics and interlimb coordination behavior in 3 variants, with different step lengths, of an intermittent incremental protocol.Methods:Twenty-two male swimmers performed n × di variants of an intermittent and incremental protocol (n ≤ 7; d1 = 200 m, d2 = 300 m, and d3 = 400 m). Swimmers were videotaped in the sagittal plane for 2-dimensional kinematical analysis using a dualmedia setup. Video images were digitized with a motion-capture system. Parameters that were assessed included the stroke kinematics, the segmental and anatomical landmark kinematics, and interlimb coordination. Movement efficiency was also estimated.Results:There were no significant variations in any of the selected variables according to the step lengths. A high to very high relationship was observed between step lengths. The bias was much reduced and the 95%CI fairly tight.Conclusions:Since there were no meaningful differences between the 3 protocol variants, the 1 with shortest step length (ie, 200 m) should be adopted for logistical reasons.
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Oppelt, Konrad, Aidan Hogan, Felix Stief, Paul Alfred Grützner, and Ursula Trinler. "Movement Analysis in Orthopedics and Trauma Surgery – Measurement Systems and Clinical Applications." Zeitschrift für Orthopädie und Unfallchirurgie 158, no. 03 (July 10, 2019): 304–17. http://dx.doi.org/10.1055/a-0873-1557.
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Abstract Background Technical development lead to an enhancement of clinical movement analysis in the last few decades and expanded its research and clinical applications. Since the mid 20th century, human movement analysis has made its way into clinical practice, e.g. in treating poliomyelitis and infantile cerebral palsy. Today, it has a wide range of applications in various clinical areas. The aim of this narrative review is to illustrate the variety of camera-based systems for human movement analysis and their clinical applications, specifically in the field of orthopaedics and trauma surgery (O/U). Benefits and limitations of each system are shown. Future development and necessary improvements are discussed. Material and Methods A selective literature review was undertaken with the databases PubMed and Google Scholar using keywords related to clinical human movement analysis in the field of orthopaedics and trauma surgery. Furthermore standard book references were included. Results Common video camera systems (VS) are used for basic visual movement analysis. Instrumented movement analysis systems include marker-based systems (MBS), markerless optical systems (MLS) and rasterstereographic analysis systems (VRS). VS, MBS and MLS have clinical use for dynamic examination of patients with various disorders in movement and gait. Among such are e.g. neuro-orthopaedic disorders, muscular insufficiencies, degenerative and post-trauma deficiencies with e.g. resultant pathologic leg axis. Besides the measurement of kinematic data by MBS and MLS, the combination with kinetic measurements to detect abnormal loading patterns as well as the combination with electromyography (EMG) to detect abnormal muscle function is a great advantage. Validity and reliability of kinematic measurements depend on the camera systems (MBS, MLS), the applied marker models, the joints of interest and the observed movement plane. Movements in the sagittal plane of the hip and knee joint, pelvic rotation and tilt as well as hip abduction are generally measured with high reliability. In the frontal and transverse planes of the knee and ankle joint substantial angular variabilities were noted due to the small range of motion of the joints in these planes. Soft tissue artefacts and marker placement are the biggest sources of errors. So far MLS did not improve these limitations. MBS are most accurate and remain the gold-standard in clinical and scientific movement analysis. VRS is used clinically for static 3D-analysis of the trunk posture and spine deformities. Current systems allow the dynamic measurement and visualisation of trunk and spine movement in 3D during gait and running. Planar x-ray-imaging (Cobbʼs angle) and to some extent cross sectional imaging with CT-scan or MRI are commonly used for the evaluation of patients with spinal deformities. VRS offers functional 3D data of trunk and spine deformities without radiation exposure, thus allowing safer clinical monitoring of the mainly infantile and adolescent patients. The accuracy, validity and reliability of measurements of different VRS-systems for the clinical use has been proven by several studies. Conclusion The instrumented movement analysis is an additional tool that aids clinical practitioners of O/U in the dynamic assessment of pathologic movement and loading patterns. In conjunction with common radiologic imaging it aids in the planning of type and extent of corrective surgical interventions. In the field of orthopaedics and trauma surgery movement analysis can help as an additional diagnostic tool to develop therapeutic strategies and evaluate clinical outcomes.
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Armstrong, Benjamin D., Mitchell L. Cordova, Christopher D. Ingersoll, and Nancy F. Lawrence. "Delayed-Onset Muscle Soreness Does Not Alter the Kinematics and Kinetics of the Squat-Lifting Technique." Journal of Sport Rehabilitation 10, no. 3 (August 2001): 184–95. http://dx.doi.org/10.1123/jsr.10.3.184.
Повний текст джерелаАнотація:
Context:Little research has been done evaluating the effects of muscle soreness on a lifting task.Objective:To examine the effects of delayed-onset muscle soreness (DOMS) in the thigh musculature on kinematic and kinetic variables associated with the squat-lifting technique.Design:Pretest–posttest repeated measures, with treatment as the independent variable (DOMS and no DOMS of the thigh musculature).Setting:Research laboratory.Participants:Twenty healthy college students.Intervention:Subjects were videotaped lifting a 157-N crate before and after DOMS inducement.Main Outcome Measures:A 2-dimensional sagittal-plane video analysis was used to calculate 7 kinematic and kinetic variables.Results:DOMS had no effect on L5/S1 torque and shear or compression, hip torque and range of motion, or knee torque and range of motion during lifting.Conclusions:DOMS does not appear to alter kinematic and kinetic variables associated with the squat-lifting technique.
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Lo Muzio, Francesco Paolo, Giacomo Rozzi, Stefano Rossi, Giovanni Battista Luciani, Ruben Foresti, Aderville Cabassi, Lorenzo Fassina, and Michele Miragoli. "Artificial Intelligence Supports Decision Making during Open-Chest Surgery of Rare Congenital Heart Defects." Journal of Clinical Medicine 10, no. 22 (November 16, 2021): 5330. http://dx.doi.org/10.3390/jcm10225330.
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The human right ventricle is barely monitored during open-chest surgery due to the absence of intraoperative imaging techniques capable of elaborating its complex function. Accordingly, artificial intelligence could not be adopted for this specific task. We recently proposed a video-based approach for the real-time evaluation of the epicardial kinematics to support medical decisions. Here, we employed two supervised machine learning algorithms based on our technique to predict the patients’ outcomes before chest closure. Videos of the beating hearts were acquired before and after pulmonary valve replacement in twelve Tetralogy of Fallot patients and recordings were properly labeled as the “unhealthy” and “healthy” classes. We extracted frequency-domain-related features to train different supervised machine learning models and selected their best characteristics via 10-fold cross-validation and optimization processes. Decision surfaces were built to classify two additional patients having good and unfavorable clinical outcomes. The k-nearest neighbors and support vector machine showed the highest prediction accuracy; the patients’ class was identified with a true positive rate ≥95% and the decision surfaces correctly classified the additional patients in the “healthy” (good outcome) or “unhealthy” (unfavorable outcome) classes. We demonstrated that classifiers employed with our video-based technique may aid cardiac surgeons in decision making before chest closure.
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Stravogianni, Vasiliki, Theodoros Samaras, Constantin M. Boscos, Athina Basioura, Ioannis Markakis, and Ioannis A. Tsakmakidis. "Investigating Visual Monitoring of the Scrotum as a Supplementary Tool for Boar Semen Quality Evaluation." Veterinary Sciences 10, no. 1 (December 24, 2022): 9. http://dx.doi.org/10.3390/vetsci10010009.
Повний текст джерелаАнотація:
Farm animals behavior research uses video cameras, mainly for visual observation and recording. The purpose of this feasibility study was to enrich the predictable methods of boar semen production capacity by correlating sperm variables with the scrotal contractions (SC) frequency and intensity. A video camera was used to record the reaction of the scrotum during ejaculation. The respective collected ejaculates were evaluated and semen parameters, such as viability, morphology, membranes functional integrity and kinematics, were determined. The camera recorded the scrotal contractions/relaxations and the video was handled by the Image Processing Toolbox of Matlab (Mathworks Inc., Natick, MA, USA). The SC intensity was verified as a percentage change in the scrotum size among the video frames of maximum contraction and relaxation. The archived data from the frames were analyzed statistically, using a linear mixed effects model that involved sperm assessed parameters. Correlations of the SC intensity with the average path velocity, VAP (R2 = 0.591, p = 0.043) and with the percentage of the cytoplasmic droplets (R2 = 0.509, p = 0.036) were noticed. Previous studies reported the positive correlation of VAP with the number of live-born piglets. In conclusion, video monitoring of the boar scrotal function during ejaculation is useful, but more research is needed to establish its appropriateness as a supplementary method for the prognosis of boar ability to produce high-quality semen.
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Liu, Zhenming. "Application of Long-Term and Short-Term Memory Neural Network in Technical Evaluation of Hurdle Track and Field." Security and Communication Networks 2022 (May 6, 2022): 1–11. http://dx.doi.org/10.1155/2022/3095032.
Повний текст джерелаАнотація:
In order to study the application of long-term and short-term memory neural networks in the technical evaluation of hurdle track and field, firstly, the related contents of long-term and short-term memory neural networks and hurdle track and field sports are analyzed, the variation characteristics of kinematics and surface electromyography of swinging leg in the landing link of lower hurdle are analyzed, and the relationship between surface electromyography and kinematics parameters is analyzed. Then, the kinematics and surface EMG data of three male hurdlers in the hurdle team and two men in the College of Physical Education were collected when completing the technical link of pressing down and landing. The subject data were processed and analyzed by using the Simi motion video analysis system and DASY lab10.0 EMG analysis software. Finally, SPSS13.0 and origin are used to analyze the average, standard deviation, and correlation of the data results and draw a graph. Experiments show that neural network theory and finite element method, as the new forces of sports biomechanics, have been used to diagnose track and field technology. With the popularization of this method, it will play a greater role in the research of track and field technology.
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Butler, Lauren, Alexa Martinez, Dai Sugimoto, Charles Wyatt, Eryn Milian, Alex Loewen, Ashley Erdman, et al. "The Reliability of Two Dimensional Kinematic Assessment of a 45-Degree Side Step Cut." Orthopaedic Journal of Sports Medicine 10, no. 5_suppl2 (May 1, 2022): 2325967121S0052. http://dx.doi.org/10.1177/2325967121s00523.
Повний текст джерелаАнотація:
Background: Up to 70% of all anterior cruciate ligament (ACL) injuries occur via a non-contact mechanism involving deceleration and direction change on a planted foot. Clinical screening tools analyzing movement patterns during a cutting task are reliable and valid. The Expanded Cutting Alignment Scoring Tool (E-CAST) is a reliable tool to qualitatively assess trunk and lower extremity (LE) alignment during a 45-degree side step cut (SSC). Previous works found two-dimensional (2D) kinematic analysis more reliable than qualitative assessments when evaluating jumping and squatting movements. However, there is limited evidence on the reliability of 2D assessments to evaluate SSC tasks. Hypothesis/Purpose: To determine if using 2D kinematic analysis with the E-CAST improves the tool’s reliability for evaluating trunk and LE alignment during a 45-degree SSC. Methods: 25 healthy females (age 13.8 ± 1.4 years, mass 52.4 ± 9.3 kg, height 161.7 ± 6.0 cm) who regularly participated in cutting or pivoting sports were included. A repeated measures study design was used. Each subject performed three SSC trials with one trial randomly selected for analysis. Trials were recorded in the frontal and sagittal planes. Two physical therapist raters independently viewed and scored each video on two separate occasions. Videos orders were randomized and a two-week wash out period occurred between rounds. The E-CAST evaluates six movement variables (Figure 1). The assessment criteria for each variable was adapted to utilize the Dartfish motion analysis application on a smart phone (Figure 2). If a movement variable falls outside of the motion analysis definition, the subject scores a point, therefore a higher score represents poorer technique. Intraclass correlation coefficients (ICC) and 95% confident intervals (95% CI) were calculated for the E-CAST total score, and a kappa coefficient was calculated for each variable. Correlations were converted to z scores and compared for significance. Results: The cumulative intra-rater reliability was good (ICC= 0.821, 95% CI 0.687 – 0.898) and the cumulative inter-rater reliability was moderate (ICC= 0.752, 95% CI 0.565-0.859). Intra-rater kappa coefficients ranged from moderate to almost perfect for all variables (k= 0.505-0.875) and inter-rater kappa coefficients ranged from slight to good for all variables (k=0.336-0.733). Conclusion: The use of 2D kinematic analysis resulted in higher intra-and inter-rater reliability compared to the traditional qualitative E-CAST (ICC: 0.77, 95% CI 0.59-0.96 and ICC: 0.71, 95% CI 0.50-0.91), however, the difference was not significant (Zobs = -0.46 and Zobs = -0.30). References: 1. Butler LS, Milian EK, DeVerna A, et al. Reliability of the Cutting Alignment Scoring Tool (CAST) to Assess Trunk and Limb Alignment During a 45-Degree Side-Step Cut. Int J Sports Phys Ther. 2021;16(2):312-321. Published 2021 Apr 1. doi:10.26603/001c.21419 2. Dempsey AR, Lloyd DG, Elliott BC, Steele JR, Munro BJ, Russo KA. The effect of technique change on knee loads during sidestep cutting. Med Sci Sports Exerc. 2007;39(10):1765-1773. doi:10.1249/mss.0b013e31812f56d1 3. Donelon TA, Dos’Santos T, Pitchers G, Brown M, Jones PA. Biomechanical Determinants of Knee Joint Loads Associated with Increased Anterior Cruciate Ligament Loading During Cutting: A Systematic Review and Technical Framework. Sports Med Open. 2020;6(1):53. Published 2020 Nov 2. doi:10.1186/s40798-020-00276-5 4. Dos’Santos T, McBurnie A, Donelon T, Thomas C, Comfort P, Jones PA. A qualitative screening tool to identify athletes with ‘high-risk’ movement mechanics during cutting: The cutting movement assessment score (CMAS). Phys Ther Sport. 2019;38:152-161. doi:10.1016/j.ptsp.2019.05.004 5. Sutton KM, Bullock JM. Anterior cruciate ligament rupture: differences between males and females. J Am Acad Orthop Surg. 2013;21(1):41-50. doi:10.5435/JAAOS-21-01-41 6. Weir G, Alderson J, Smailes N, Elliott B, Donnelly C. A Reliable Video-based ACL Injury Screening Tool for Female Team Sport Athletes. Int J Sports Med. 2019;40(3):191-199. doi:10.1055/a-0756-9659 [Figure: see text][Figure: see text]
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Fassina, Lorenzo, Antonio Di Grazia, Fabio Naro, Lucia Monaco, Maria Gabriella Cusella De Angelis, and Giovanni Magenes. "Video Evaluation of the Kinematics and Dynamics of the Beating Cardiac Syncytium: An Alternative to the Langendorff Method." International Journal of Artificial Organs 34, no. 7 (July 2011): 546–58. http://dx.doi.org/10.5301/ijao.2011.8510.
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Atmajati, ED, and RA Salam. "Feasibility of Smartphone Camera Utilization and Power Point-based Video Analyzer on Kinematic Motion Experiment: An Inexpensive Method." International Journal of Applied Sciences and Smart Technologies 2, no. 2 (December 5, 2020): 67–78. http://dx.doi.org/10.24071/ijasst.v2i2.2696.
Повний текст джерелаАнотація:
This study reports on the use of smartphone camera and power point application to analyze the kinematic motion experiment. This method is intended to make a better understanding of student’s concept using the tools that are commonly owned by students. The experiments performed in this study were one-dimensional (1-D) represented by falling motion and two-dimensional (2-D) using parabolic motion. In evaluating the experimental results, the obtained data were compared to the theoretical values that were calculated using analytical approach. The use of this method shows great measurement results in showing dependency of falling motion to gravitational acceleration and proofing the constant velocity at projectile motion on its horizontal plane in which it is comparable to the theoretical value. The video analyzation method also can be used as an alternative solution to the established software, even better when the higher resolution camera and frame rate was used. Noting that the tools used in the experiment were common tools around, thus, this can be used as a replacement for the advance tools.
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Sawacha, Zimi, Fabiola Spolaor, Weronika Joanna Piątkowska, Federica Cibin, Alfredo Ciniglio, Annamaria Guiotto, Marco Ricca, Roberta Polli, and Alessandra Murgia. "Feasibility and Reliability Assessment of Video-Based Motion Analysis and Surface Electromyography in Children with Fragile X during Gait." Sensors 21, no. 14 (July 12, 2021): 4746. http://dx.doi.org/10.3390/s21144746.
Повний текст джерелаАнотація:
Fragile X Syndrome (FXS), the leading form of inherited intellectual disability and autism, is characterized by specific musculoskeletal conditions. We hypothesized that gait analysis in FXS could be relevant for the evaluation of motor control of gait, and help the understanding of a possible correlation between functional and intellectual abilities. Typical deficits in executive control and hyperactivity have hampered the use of standard gait analysis. The aim of our study was to quantitatively assess musculoskeletal alterations in FXS children in standard ambulatory conditions, in a friendly environment. Ten FXS children and sixteen controls, with typical neurodevelopment, were evaluated through four synchronized video cameras and surface electromyography; lower limb joints rotations, spatiotemporal parameters, duration of muscle contraction, activation timing and envelope peaks were determined. Reliability and repeatability of the video based kinematics analysis was assessed with respect to stereophotogrammetry. The Kruskal–Wallis Test (p < 0.05) or SPM1D were used to compare different groups of subjects. Results show a consistently altered gait pattern associated with abnormal muscle activity in FXS subjects: reduced knee and excessive hip and ankle flexion, and altered duration and activity onset on all the recorded muscles (Rectus/Biceps Femoris, Tibialis Anterior, Gastrocnemius Lateralis). Results of this study could help with planning personalized rehabilitations.
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Christovão, F. G., R. M. L. Barros, C. B. Martins, M. A. G. Silva, E. V. V. Freitas, J. C. Lacerda Neto, and A. Queiroz-Neto. "Three-dimensional kinematic analysis of head and limb movements of lame and non-lame colts." Equine and Comparative Exercise Physiology 4, no. 1 (February 2007): 31–36. http://dx.doi.org/10.1017/s1478061507750259.
Повний текст джерелаАнотація:
AbstractLameness manifests itself during the movement of the animal or at rest, indicating a structural or functional disturbance in one or more limbs. Videographic analyses allow the qualitative and quantitative investigation of the movement, reducing the subjectivity of evaluations. The objective was to record the alterations in the movement of the head and limbs of horses in a lame and non-lame condition. Video cameras (60 Hz) and computational methods were used. Six Purebred Arabian colts were filmed on a treadmill, at walk and at trot, before and after induction of lameness. Lameness was induced in the left forelimb utilizing a transient lameness model. Markers were placed on the zygomatic process of the temporal bone, spiny process of the sixth thoracic and first lumbar vertebrae and on the proximal phalange. Nine strides were analysed. At walk and at trot, the animals demonstrated two vertical head movements per stride, while after induction of lameness only one head movement was observed per stride, where this movement was of greater amplitude. The head was shown to be in a more elevated position when the lame limb made first contact with the treadmill belt, which was not observed in the case of the healthy limbs. Only with trotting did the lame animals manifest a prolonged duration of the stance phase for all limbs. The lame animals had a longer support time, lifted the non-lame limbs and showed a shorter stride. Videographic analyses offered details of the alterations in the movement of horses, which are important in the diagnosis of lameness.
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Staniak, Zbigniew, Krzysztof Buśko, Michał Górski, and Anna Pastuszak. "Accelerometer profile of motion of the pelvic girdle in breaststroke swimming." Journal of Human Kinetics 52, no. 1 (September 1, 2016): 147–56. http://dx.doi.org/10.1515/hukin-2016-0002.
Повний текст джерелаАнотація:
Abstract The aim of the study was to develop a method for measurement and analysis of kinematics of the pelvic girdle movement in breaststroke swimming to support training of technical skills. The measurements were performed in five elite breaststroke swimmers. A recording device for triaxial accelerations and triaxial rotational angular velocity was mounted on the dorsal part of the pelvic girdle of the athlete. The task of the athlete was to swim one length of the 50 m swimming pool with the intensity similar to competition. From the consecutive cycles of swimming motion, we developed individual mean graphical and numerical profiles of the kinematics of the pelvic girdle movement within the average cycle. Mean basic values of the characteristics were compared with the values documented in the literature obtained by means of the video analysis or using the method of measurement of the velocity of the unwound rope. The comparison revealed that the results in the group studied were very similar to the results obtained using other methods and were typical of elite athletes. Analysis of the motion profiles for the pelvic girdle in breaststroke swimmers indicated that the results obtained reflected individual technique of performing individual phases of swimming cycles. The proposed measurement method, presentation and analysis of the profile of the pelvic girdle motion in breaststroke swimming represents a good tool for fast and effective biomechanical evaluation of motion technique components.
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Maskeliūnas, Rytis, Audrius Kulikajevas, Robertas Damaševičius, Julius Griškevičius, and Aušra Adomavičienė. "Biomac3D: 2D-to-3D Human Pose Analysis Model for Tele-Rehabilitation Based on Pareto Optimized Deep-Learning Architecture." Applied Sciences 13, no. 2 (January 13, 2023): 1116. http://dx.doi.org/10.3390/app13021116.
Повний текст джерелаАнотація:
The research introduces a unique deep-learning-based technique for remote rehabilitative analysis of image-captured human movements and postures. We present a ploninomial Pareto-optimized deep-learning architecture for processing inverse kinematics for sorting out and rearranging human skeleton joints generated by RGB-based two-dimensional (2D) skeleton recognition algorithms, with the goal of producing a full 3D model as a final result. The suggested method extracts the entire humanoid character motion curve, which is then connected to a three-dimensional (3D) mesh for real-time preview. Our method maintains high joint mapping accuracy with smooth motion frames while ensuring anthropometric regularity, producing a mean average precision (mAP) of 0.950 for the task of predicting the joint position of a single subject. Furthermore, the suggested system, trained on the MoVi dataset, enables a seamless evaluation of posture in a 3D environment, allowing participants to be examined from numerous perspectives using a single recorded camera feed. The results of evaluation on our own self-collected dataset of human posture videos and cross-validation on the benchmark MPII and KIMORE datasets are presented.
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Supej, Matej. "Differential Specific Mechanical Energy as a Quality Parameter in Racing Alpine Skiing." Journal of Applied Biomechanics 24, no. 2 (May 2008): 121–29. http://dx.doi.org/10.1123/jab.24.2.121.
Повний текст джерелаАнотація:
An important question in alpine skiing is how to determine characteristics of well-performed ski turns, an issue that has become more crucial with the arrival of new carving skis. This article introduces a new method for estimating the quality of skiing at each point of observation based on mechanical energy behavior that can be measured using established motion analysis techniques. It can be used for single-or multiple-skier analyses for evaluation of skiing technique as well as racing tactics. An illustration of its use is shown by analyzing 16 top-level racers using a 3-D kinematical system and video recorded during an alpine ski world cup race. Based on energy behavior of several racers, it is demonstrated that the most direct line with shortest radius of turn is not necessarily the most effective strategy in contrast to what some coaches believe.
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Leonardi, Alessandro, Marina Pirulli, Monica Barbero, Fabrizio Barpi, Mauro Borri-Brunetto, Oronzo Pallara, Claudio Scavia, and Valerio Segor. "Impact of Debris Flows on Filter Barriers: Analysis Based on Site Monitoring Data." Environmental and Engineering Geoscience 27, no. 2 (March 30, 2021): 195–212. http://dx.doi.org/10.2113/eeg-d-20-00013.
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ABSTRACT Debris flows are one of the most complex and devastating natural phenomena, and they affect mountainous areas throughout the world. Structural measures are currently adopted to mitigate the related hazard in urbanized areas. However, their design requires an estimate of the impact force, which is an open issue. The numerous formulae proposed in the literature require the assignment of empirical coefficients and an evaluation of the kinematic characteristics of the incoming flow. Both are generally not known a priori. In this article, we present the Grand Valey torrent site (Italian Alps). A monitoring system made up of strain gauges was installed on a filter barrier at the site, allowing the evaluation of impact forces. The system provides pivotal information for calibrating impact formulae. Two debris flows occurred during the monitoring period. We present the interpretation of videos, impact measurements, and the results of numerical analyses. The combined analysis allows a back calculation of the events in terms of forces, flow depth, and velocity. Thus, we investigate the applicability of the impact formulae suggested in the literature and of the recommended empirical coefficients. The results highlight that hydrostatic effects dominated the impact during the first event, while hydrodynamic effects prevailed in the second one.
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Isakov, E., O. Keren, and N. Benjuya. "Transtibial amputee gait: Timedistance parameters and EMG activity." Prosthetics and Orthotics International 24, no. 3 (December 2000): 216–20. http://dx.doi.org/10.1080/03093640008726550.
Повний текст джерелаАнотація:
Gait analysis of transtibial (TT) amputees discloses asymmetries in gait parameters between the amputated and sound legs. The present study aimed at outlining differences between both legs with regard to kinematic parameters and activity of the muscles controlling the knees. The gait of 14 traumatic TT amputees, walking at a mean speed of 74.96 m/min, was analysed by means of an electronic walkway, video camera, and portable electromyography system. Results showed differences in kinematic parameters. Step length, step time and swing time were significantly longer, while stance time and single support time were significantly shorter on the amputated side. A significant difference was also found between knee angle in both legs at heel strike. The biceps femoris/vastus medialis ratio in the amputated leg, during the first half of stance phase, was significantly higher when compared to the same muscle ratio in the sound leg. This difference was due to the higher activity of the biceps femoris, almost four times higher than the vastus medialis in the amputated leg. The observed differences in timedistance parameters are due to stiffness of the prosthesis ankle (the SACH foot) that impedes the normal forward advance of the amputated leg during the first half of stance. The higher knee flexion at heel strike is due to the necessary socket alignment. Unlike in the sound leg, the biceps femoris in the amputated leg reaches maximal activity during the first half of stance, cocontracting with the vastus medialis, to support body weight on the amputated leg. The obtained data can serve as a future reference for evaluating the influence of new prosthetic components on the quality of TT amputee's gait.
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Močnik, Grega, Zdravko Kačič, Riko Šafarič, and Izidor Mlakar. "Capturing Conversational Gestures for Embodied Conversational Agents Using an Optimized Kaneda–Lucas–Tomasi Tracker and Denavit–Hartenberg-Based Kinematic Model." Sensors 22, no. 21 (October 29, 2022): 8318. http://dx.doi.org/10.3390/s22218318.
Повний текст джерелаАнотація:
In order to recreate viable and human-like conversational responses, the artificial entity, i.e., an embodied conversational agent, must express correlated speech (verbal) and gestures (non-verbal) responses in spoken social interaction. Most of the existing frameworks focus on intent planning and behavior planning. The realization, however, is left to a limited set of static 3D representations of conversational expressions. In addition to functional and semantic synchrony between verbal and non-verbal signals, the final believability of the displayed expression is sculpted by the physical realization of non-verbal expressions. A major challenge of most conversational systems capable of reproducing gestures is the diversity in expressiveness. In this paper, we propose a method for capturing gestures automatically from videos and transforming them into 3D representations stored as part of the conversational agent’s repository of motor skills. The main advantage of the proposed method is ensuring the naturalness of the embodied conversational agent’s gestures, which results in a higher quality of human-computer interaction. The method is based on a Kanade–Lucas–Tomasi tracker, a Savitzky–Golay filter, a Denavit–Hartenberg-based kinematic model and the EVA framework. Furthermore, we designed an objective method based on cosine similarity instead of a subjective evaluation of synthesized movement. The proposed method resulted in a 96% similarity.
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Hansen, Rudi, Mathilde Lundgaard-Nielsen, and Marius Henriksen. "Visual assessment of dynamic knee joint alignment in patients with patellofemoral pain: an agreement study." PeerJ 9 (October 19, 2021): e12203. http://dx.doi.org/10.7717/peerj.12203.
Повний текст джерелаАнотація:
Background Assessment of knee kinematics plays an important role in the clinical examination of patients with patellofemoral pain (PFP). There is evidence that visual assessments are reliable in healthy subjects, but there is a lack of evidence in injured populations. The purpose of this study was to examine the intra- and interrater agreement in the visual assessment of dynamic knee joint alignment in patients with PFP. Methods The study was a cross-sectional agreement study. Sixty participants (42 females) were included. We assessed the intra- and interrater agreement of two functional tests: The single leg squat (SLS) and the forward lunge (FL). One investigator scored the movement according to preset criteria while video recording the movement for retest. Moreover, the performance was scored by another investigator using the video recording. Agreement was assessed using weighted kappa statistics. Results The intrarater agreement ranged from moderate to good (Kappa 0.58 (FL) to 0.70 (SLS)) whereas the interrater agreement ranged from fair to moderate (Kappa 0.22 (SLS) to 0.50 (FL)). Conclusion The agreement within raters was better than between raters, which suggests that assessments should preferably be performed by the same tester in research and in a clinical setting, e.g., to evaluate any treatment effect. We promote FL as a reliable clinical tool for evaluating dynamic knee alignment, since it shows equally good intra- and interrater agreement, and it is an inexpensive and easy method to use.