ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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KINEMATIC ANALYSIS OF BASEBALL BATTING MOTION WHEN BATTING PITCHES WITH VARYING VELOCITIES
Full text linkThe purpose of this study was to identify effect of moving the center of gravity of the body and rotating the torso when batting pitches with varying velocity. The subjects were 10 experienced university baseball player. The subjects batted toward the center field, both fastballs and slowballs, aimed near the center of the strike zone from a pitching machine. Data were collected using a three dimensional automatic motion analysis system (Vicon MX). The rotation angle of the torso and displacement of the center of gravity were computed. Due to differences in the shoulder rotation from the latter half of stepping leg touchdown through impact, we believe that the motion is adapted to pitch differences starting from the latter half of stepping leg touchdown. Comparing the shift in the center of gravity of the body during fastballs and slowballs, the forward motion and downward sinking of the center of gravity were significantly larger for slowballs
MECHANICAL DETERMINANTS OF SPRINT PERFORMANCE IN ELITE AND SUB-ELITE FIELD HOCKEY PLAYERS
Full text linkThe aim of the present study was to investigate the difference in the horizontal mechanical determinants of sprint performance in highly-trained elite field hockey players versus sub-elite field hockey players. Thirty-five highly trained field hockey players (1 8 elite international players and 17 sub-elite players) were tested during the competitive season. They performed a maximal 40 meter sprint. Distance was tracked over time via a 312 Hz laser (Laser Technology, Inc) and used to calculate, for each individual, a horizontal force-velocity profile. Elite players showed a larger theoretical maximal horizontal velocity (vO) compared to the sub-elite hockey players. No significant differences in theoretical maximal horizontal force (FO) and horizontal power (Pmax) between the groups were observed. Large variability especially in the sub-elite groups was observed in FO and vO, indicating the potential for individualized training program focusing on the weaker parameter
KINEMATICS OF WOMEN\u27S SPRINT CANOEING TECHNIQUE
Full text linkLittle is known about the biomechanics of sprint canoeing, especially for women\u27s canoeing, and a quantitative kinematic description of the motion would help coaches to develop valid technique coaching models. Five highly-trained female canoeists were filmed at 150 Hz while undertaking a 50 s maximal effort on a canoe ergometer, whose trolley motions were taken to represent those of the boat. Selected boat, body and paddle kinematics were evaluated at three key stroke cyde events (Contact, Paddle Vertical, and End of Drive) and their patterns monitored across the stroke cycle. While no clear trends between the kinematics and power output emerged, a range of strategies were identified and the data represent an initial step in the construction of detailed technique models that can be used to evaluate and monitor individual athletes
DIFFERENCES OF POSTURE ON PUSH-OFF PHASE BETWEEN ACTUAL SPEED SKATING AND SLIDE-BOARD TRAINING
Full text linkThe slide-board training is a feasible technology to exercise skating during the off-season. While slide-board is much different from ice surface of the actual skating situation, it may distort actual skating posture. The purpose of this study was to analyze the differences in posture during push-off phase between an actual speed skating condition and on slideboard. The result showed that on the slide-board distance between two feet were shorter, so were the rotation angles of both feet, the hip angle was lower during the whole phase, while knee and ankle angles were higher. In conclusion, the restriction of the space on slide-board affected the position and rotation of both stable and push-off feet as well as the joint extension of the stable leg. Hence, the structural design of slide-board needs to be improved to facilitate the extension of knee and ankle in the medial-lateral direction
CALIBRATION OF PRESSURE SENSORS FOR HAND GRIP MEASUREMENT
Full text linkThe purpose of this study was to assess the accuracy of grip force sensors. Methods: Several standard weights were used to calibrate the grip sensor in the static condition, The descriptive statistics and linear regression were used to present the accuracy and errors. Results: Results of this study showed a high level of sensing areas linear relationship under static loading. Conclusion: Data from this study showed high accuracy of the pressure sensor. The pressure sensor could te used for hand grip measurement
SEX DIFFERENCES IN LOWER LIMB MOVEMENT VARIABILITY DURING A FATIGUING REPETITIVE LOADING TASK
Full text linkThis study evaluated differences in lower limb joint coupling variability between recreationally-active male (n = 21) and female participants (n = 20) during single-leg hopping to exhaustion. Spatio-temporal characteristics and variability of the knee-ankle and hip-knee joint couplings were determined over the duration of hopping. As fatigue progressed joint coupling variability increased by a greater magnitude in females compared to males. Females had significantly lower variability compared to males in the knee-ankle couplings during the propulsion phase at the beginning of the trial but this effect progressively disappeared during the trial. These findings suggest that as fatigue progresses, there is a regression to a similar magnitude of joint coupling variability which may represent a common level of synchronous joint interaction between sexes
INFLUENCE OF ARCH SUPPORT INSOLE ON PEOPLE WITH FLATFOOT DURING UPHILL AND DOWNHILL WALKING
Full text linkThe purpose of this study was to investigate the effect of the arch support insole for people with flatfoot during uphill and downhill walking. Sixteen healthy collegiate students with flatfoot were recruited in this study. The heart rate, V02max, and median frequency of surface EMG were recorded and analyzed in this study. Non-parametric Wilcoxon signed-rank test was used for statistics. The derived main results were outlined as follows: (a) V02max had significantly decreased in arch support insole compare to flat foot insole during uphill and downhill walking; (b) arch support insole could reduce the fatigue of rectus femoris muscle during downhill walking which might be associated with the decreased V02max. The integrated research results could effectively be applied to the measurement of muscle fatigue
ACUTE EFFECTS OF MASSAGE ON PASSIVE ANKLE STIFFNESS FOLLOWING AN EXHAUSTIVE STRET CHSHORTEN CYCLE TASK: A PILOT STUDY
Full text linkThis preliminary study evaluated the effect of massage on the passive stiffness of the calf muscle complex following single-leg hopping to volitional exhaustion. Four young and healthy male participants had their ankle taken through full joint excursion to determine the resistance to ankle dorsiflexion both prior to and immediately following hopping. A 10 minute rest and massage were then applied in a random order and follow up measures taken immediately Mer each intervention. Calf muscle stiffness increased in three of the four participants following hopping and two participants had a decrease following massage. This study suggests that changes in calf muscle stiffness are sensitive to both exercise and massage. It is important to determine the underlying mechanism(s) to changes in calf stiffness following exercise and whether massage offers any benefit
THE EFFECT OF CONCUSSiON HISTORY ON POSITIONAL BALANCE ABILITY IN RUGBY UNION ATHLETES
Full text linkHead traumas account for 29% of all injuries in professional rugby. Concussions are thought to have only a short-term effect on balance. The purpose of this study was to investigate whether concussion history affected a rugby team\u27s ability to maintain balance and determine which sensory system was most affected. Thirty male academy rugby athletes separated into backs and forwards performed the m-CTSIB on the Biodex Balance SD system. The forwards, who had more rugby experience and concussions in comparison to the backs, produce substantially larger sway index scores (worse balance) in all four conditions. Useful future research could involve a longitudinal study which allowed baseline balance scores to be established and compared over time
EFFECTS OF VISUAL GAIT-RETRAINING ON DIFFERENT RUNNING CONDITIONS AND SPEEDS
Full text linkIn running athletes suffer a certain amount of injuries in a given year. Gait-Retraining therefore has been a proposed method to decrease impact loads in runners. Consequently, the purpose of this study was to confirm the effectiveness of gaitretraining, observe kinematic changes and establish transfer between overground (OG) and treadmill (TD) running as well as different velocities. Results confirmed that gaitretraining can reduce tibial impact shock. This was found during TD running (pre/post) across 3 different speeds with lower effect in OG running. Kinematics changes were found in footstrike (TD and OG), ankle (TD) and trunk (TD) angles. To increase transfer effects, we should poof new methods for motor learning and/or improve the devices for feedback training in overground running