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KINETIC, SPATIAL, AND TEMPORAL ASSESSENT OF OVERSPEED TOWING WITH ELASTIC TUBING
Get PDFSubjects (N = 15) performed sprints over force platforms in a normal condition and in three overspeed conditions of differing elastic tube stretch length. Kinetic and kinematic data were derived. A 3 x 4 RM ANOVA was used to analyze the results. The horizontal and vertical ground reaction force (GRF), and the ratio of horizontal to vertical GRF did not differ among conditions (p ˃ 0.05). However, ground contact time was 8.3% to 10.4% shorter, time between steps was 1.4% to 2.7% lower, distance between steps was up to 1.2% greater, and velocity was 3.7% higher in some overspeed towing conditions compared to the normal condition (p ≤ 0.05). Longer tube conditions were more optimal in most cases. Compared to normal running, overspeed towing results in increased sprinting velocity despite no differences in horizontal or vertical kinetics compared to normal running
DEEP LEARNING FOR GESTURE RECOGNITION IN GYM TRAINING PERFORMED BY A VISION-BASED AUGMENTED REALITY SMART MIRROR
Get PDFThis paper illustrates the development and the validation of a smart mirror for sport training. The application is based the skeletonization algorithm MediaPipe and runs on an embedded device Nvidia Jetson Nano equipped with two fisheye cameras. The software has been evaluated considering the exercise biceps curl. The elbow angle has been measured by both MediaPipe and the motion capture system BTS (ground truth), and the resulting values have been compared to determine angle uncertainty, residual errors, and intra-subject and inter-subject repeatability. The uncertainty of the joints’ estimation and the quality of the image captured by the cameras reflect on the final uncertainty of the indicator over time, highlighting the areas of improvements for further developments
THE SEATED-SINGLE-ARM-ROW AS A POST-ACTIVATION POTENTIATION EXERCISE TO ENHANCE POWER OUTPUT DURING KAYAKING ON AN ERGOMETER
Get PDFThis study investigated if the seated-single-arm-row (SSAR) could be used as a post-activation-potentiation-exercise (PAPE) during warm up to induce enhanced power output during kayaking on an ergometer. Ten well-trained kayakers (4 females, 6 males) performed three repetitions of the SSAR at 91% one-repetition maximum as the PAPE. Participants were assessed for their peak and average power output while performing 14 maximal effort strokes on a kayak ergometer; to simulate a race start; with versus without PAPE as a warm up, at three-minute intervals up to 18 minutes. Mean peak power with PAPE was found to be approximately 6% higher (1172.5 vs 1106.8 W) compared with no PAPE, t(9)=2.61, p=0.03. No differences in mean average power were found. Six out of the 10 kayakers registered higher mean peak and average power in one of their experimental trials compared with their control trial. These kayakers could be positive responders to PAPE. The SSAR performed during warm up enabled kayakers to increase their peak power output when paddling on an ergometer, but did not result in higher average power output. The utility of the SSAR as a PAPE to enhance overall power output when paddling on an ergometer, with the perspective of applying this technique to enhance performance during on-water kayaking, requires further investigation
EFFECT OF EIGHT WEEKS VIBRATION TRAINING ON THE LOWER LIMB BASIC ABILITY AND ATHLETIC PERFORMANCE OF GYMNASTS
Get PDFThe purpose of this study explores the effects of 8 weeks vibration training on the basic ability (explosive power, speed, agility) and athletic performance (backward somersault) of the lower limbs of gymnasts. Sixteen gymnasts were randomly divided into vibration training group (VT) and control group (CON). Participants were trained for eight weeks and performed countermovement jump (CMJ), sprints, shuttle run, and backward somersault tests before the training, after 4 weeks, and 8 weeks of training. The significant level was set to α = .05. The results showed that the speed of VT increased significantly after 4 weeks of training, and the speed and agility of VT increased significantly after 8 weeks of training (p \u3c.05). In conclusion, Gymnasts can improve their speed ability through 4 weeks of vibration training, and 8 weeks vibration training can improve their speed and agility
CONTRIBUTIONS OF THE AXIAL SPINE TO KICKING BIOMECHANICS IN THE DIPPING KICK AMONG ELITE SOCCER PLAYERS
Get PDFThe aim of this study was to develop normative data for thoracic, lumbar and pelvic range of motion (ROM) during a soccer dipping kick among five NCAA Division I and high-level youth soccer players, comparing successful and unsuccessful kicks. The “dipping” kick is a complex, skill whereby a player strikes the ball so that it initially rises, but due to its top spin subsequently “dips” toward the intended target. From a repeated measures, cross-sectional design, successful kicks had a lower thoracic rotation at ball contact and average maximum thoracic rotation at 31.1±26.5º compared to the average maximum value for unsuccessful kicks at 43.7±28.6º, although not statistically significant. This study suggests that twisting the thoracic spine away from the target in an effort to “whip” and dip the ball may be suboptimal. The thoracic spine is more in line with the pelvis in successful kicks
COMPARISON OF THE PERFORMANCE AND LOWER LIMB BIOMECHANICS OF DROP JUMP AND 10-5 REPETITVE REBOUND TESTS IN ACLR ATHLETES.
Get PDFDouble and single leg drop jump (DLDJ & SLDJ) assessments tend to be performed during the later stages of rehabilitation from an anterior cruciate ligament (ACL) injury due to the mechanical demands these assessments place on the lower limbs. Double and single leg 10-5 repetitive rebound tests (DLRJT and SLRJT) may be effective alternatives to examine lower limb mechanics at an earlier stage of rehabilitation. The purpose of this study was 1) to compare inter-limb performance and biomechanical differences within each jump test and 2) to compare biomechanical differences between the double and single leg versions of each test. Significant (
ENERGY FLOW AND IMPULSE PREDICTORS OF BAT SPEED DURING BASEBALL TEE BATTING USING THE LEAST ABSOLUTE SHRINKAGE AND SELECTION OPERATOR (LASSO) REGRESSION
Get PDFThe purposes of this study were to examine how energy is generated, absorbed, and transferred through the pelvis during the baseball swing and to identify the best model of ground reaction force (GRF) and energy flow (EF) predictors of bat speed using a LASSO regression, which reduced the dataset to a model of four EF and two impulse variables that best predicts bat speed. The findings indicate that the mechanical energy flows from the trunk to the lead leg via the pelvis as these segments rotate during the swing. It is hoped that these findings will aid coaches and athletes in better understanding which elements of the swing movement are most closely related to bat speed. Thus, coaches may be able to develop and implement training strategies accordingly to improve bat speed and player performance
RELATIONSHIP BETWEEN STEP-BY-STEP FOOT KINEMATICS AND SPRINT PERFORMANCE
Get PDFThe purpose of the study was to investigate the relationship between angular foot step-by-step kinematics and sprint performance during a 50 metre sprint in experienced male sprinters. Foot kinematics were measured using IMU devices integrated with a 3-axis gyroscope and a laser gun. The main findings were that maximal angular velocities increased until strides 6-7, where it stabilised. Time from touch down to dorsal flexion velocity was similar over all strides, whereas time from dorsal flexion velocity to toe off decreased until stride 6. Plantar flexion velocities, especially in toe off, showed the greatest associations with sprint times, whereas maximal dorsal flexion velocity presented no association with sprint times. Time from dorsal flexion velocity to toe off from stride 7 onwards determined the sprint performance and were shorter for faster sprinters
EQUESTRIAN RIDER TRUNK-PELVIS STRATEGIES CAN BE IDENTIFIED USING SELF-ORGANISING MAPS
Get PDFThe purpose of the study was to explore whether equestrian riders can be grouped by their trunk-pelvis movement strategy. Riders (n = 40) with national or international competition experience in dressage were measured using motion capture on a riding simulator for ten seconds of simulated medium and extended trot. Trunk and pelvic pitch trajectories were filtered, time-normalised to the riding simulator’s vertical displacement cycle, and scaled. A self-organising map, with subsequent k-means clustering, identified three groups of rider-trunk pelvis movement. These groups related to the relative timing between peak posterior trunk and pelvis pitch. The study identified movement-based classifications of riders for future studies, which may have implications for rider injury risk and training
A CASE STUDY OF THROWING MOTION OF A MALE PARA- SHORT STATURE JAVELIN THROWER
Get PDFThe purpose of the present study was to investigate the throwing motion of a male para- short stature javelin thrower (F41) in a real competition using the 3D DLT method, compared with male able-bodied javelin throwers as reference. At the 119th Nippon Sport Science University Athletic Meet (March 27, 2021), one para- athlete who participated in the men\u27s javelin throw was videotaped with two video cameras. The release parameters of javelin such as the initial velocity and projection angle at the release, and body segments angle were calculated for the only one trial, the best. The features of para-athlete were clarified by comparing them with the able-bodied javelin throwers (n=13) as reference. The release parameters of javelin showed that there was large difference in the horizontal velocity of javelin between the para-athlete and the reference throwers (12.59 and 19.35 m/s). The para-athlete of short stature in the present study showed the delayed withdrawal of the left leg at R-on, the delayed initiation of the rotation of the hips and trunk during throwing phase, and the left foot pointing to the right at L-on