ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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HOW BIOMECHANICAL ANALYSIS MAY HELP TO IDENTIFY ABDOMINAL INJURY CAUSES IN HIGH LEVEL TENNIS
Get PDFThis research studies the case of a professional tennis player who has suffered from a medical tear on the left rectus abdominis muscle after a tennis serve. The goal of the study is to understand whether the could be explained by an inappropriate technique. For this purpose, we analyzed the three dimensions kinematic and kinetic of the serve. We also performed isokinetic tests of the knees. We compared the player to five other professional players. We observed a possible deficit of energy transfer because of an important anterior pelvis tilt. Some compensations of the player during serve could be a possible higher abdominal contraction and a larger shoulder external rotation. These particularities could induce an abdominal overwork that would explain the first and may provoke a new injury
THE INFLUENCE OF TWO VARIABLES OF THE NONLINEAR CAMERA CALIBRATION ON THE 3D UNDERWATER ACCURACY
Get PDFThe purpose of this study was to control two variables of the nonlinear camera calibration to evaluate if they affect the 3D undewater accuracy. Two cameras (GoPro, 60 Hz) were fixed in the swimming pool. In order to evaluate the influence of a distance constrain (1 and 2 markers) and the movement of the wand calibration, we performed three different movements: M1 (zig zag), M2 (circular) and M3 (up and down). In each condition the 3D accuracy were assessed in seven trials of a dynamic rigid bar test (ANOVA,
VALIDITY, SENSITIVITY AND REPRODUCIBILITY OF STAGES AND GARMIN VECTOR POWER METERS WHEN COMPARED WITH SRM DEVICE
Get PDFThe measurement of power output (PO) during cycling has led some manufacturers to develop mobile power meters. However, such devices have to provide a valid, sensitive and reproducible PO. This study aimed to determine the validity, sensitivity and reproducibility of the Stages and Garmin Vector during both laboratory and field cycling tests. The results demonstrate that the Stages and the Garmin Vector systems appear to be reproducible. However, the validity and the sensitivity of the two systems must be treated with some caution
VALIDITY AND RELIABILITY OF THE MICROSOFT KINECT TO OBTAIN THE EXECUTION TIME OF THE TAEKWONDO’S FRONTAL KICK
Get PDFThe aim of this study was to verify the validity and reliability of the Microsoft Kinect® as a tool to analyze the time of the frontal kick of the Taekwondo (ap chagui). The volunteers performed 15 repetitions of this kick while the execution time data was been obtained, simultaneity, by the Microsoft Kinect® and the OptiTrack System (golden pattern). In order to verify the reliability of the durations of the kicks we calculated the Intraclass Correlation Coefficient (ICC3,k) between execution times found for each system. The Pearson Correlation was used to test the concurrent validity. The results of ICC and r Pearson presented in this study indicate that the Microsoft Kinect®, associated with a tracking algorithm, could be a feasible tool to evaluate the execution time of the frontal kick of the Taekwondo (ap-chagui)
THE EFFECT OF THE ERGOMETER DESIGN ON PELVIC TWIST AND LOWERBACK FLEXION IN ELITE ROWERS
Get PDFPelvic twist and lower-back flexion are considered as two important risk factors regarding lower-back injuries in rowers training frequently on ergometers. Mobile ergometers could be helpful because their design decreases the inertial loads that the rower has to overcome at the catch. Hence, the purpose of this study was to investigate pelvic twist and lower-back flexion with respect to the ergometer design. These two kinematic parameters were examined on ten elite rowers during one stationary and two mobile ergometer sessions performed at 20 strokes per minutes. The differences related to pelvic twist and lower-back flexion were very small. These findings suggested that further studies should be performed at higher paces and focused on the whole trunk motion and muscle activity to offer an overview of the influence of the ergometer design
GROUND REACTION FORCE AND KINEMATIC CHARACTERISTICS OF PIROUETTE IN BALLET IN FLAT SHOES VERSUS POINTE SHOES
Get PDFThe purpose of this study was to investigate the ground reaction force and kinematic variables in the ballet single turn called pirouette in both flat shoes and pointe shoes by skilled professional ballet dancers. Kinematic parameters of both legs and ground reaction force were obtained from eight skilled ballet dancers through a threedimensional motion analysis. We found significant increased ground reaction force and significant increased range of motion for both legs only for hip joint in pointe shoes, while angular velocity of hip, knee and ankle joint in pointe shoes were significantly greater in pointe shoes than those in flat shoes. From the results of this study, it is indicated that performing a single pirouette in pointe shoes would increase in ground reaction force associated with greater joint range of motion and angular velocity of lower extremity
BIOMECHANICS OF SURFING: DEVELOPMENT AND VALIDATION OF AN INSTRUMENTED SURFBOARD TO MEASURE SURFBOARD KINETICS
Get PDFThe purpose of this study was to investigate the different relations between the actions of a surfer and the kinematic behaviour of his surfboard. An instrumented surfboard has been designed with a force platform synchronized with an inertial measurement unit and acquisition system. An experimental campaign has been carried out in situ, where different waves have been surfed to validate the device. Results revealed that measured efforts of the surfer and kinematics of his surfboard are consistent regarding the expected behaviour. Instrumented surfboards will help coaches by giving them a new performance analysis tool. It will also provide an experimental database for the development of numerical models about interactions Surfer/Surfboard/Wave
TECHNICAL AND PHYSIOLOGICAL RESPONSES OF SWIMMING CRAWLSTROKE USING HAND PADDLES, FINS AND SNORKEL IN SWIMMING FLUME: A PILOT STUDY
Get PDFWe evaluated the effect on front-crawl during a 5 minutes effort in a swimming flume, at a speed 95% of 400m wearing swimming paddles, fins or frontal snorkel. It was evaluated measuring changes on stroke frequency, stroke length, ERP, lactate concentration and pulse rate post-effort. An one-way repeated measures ANOVA showed the stroke frequency was significantly affected F(2.3, 27.6) = 20.69
EFFECT OF BASKETBALL SHOES OF DIFFERENT WEIGHTS ON PERFORMANCE IN A GAME-LIKE SCENARIO
Get PDFLighter shoes have been shown to improve running economy; however this same phenomenon has not been investigated in basketball shoes. The purpose of this study was to investigate the physiological effects of basketball shoes of different masses during an on-court, game like scenario. Twelve male basketball players participated in this study. One shoe that was modified to have three different masses (Light, Medium, and Heavy) was evaluated in this study. Subjects completed a basketball-specific 20 minute fieldbased work protocol (Basketball-20) in each shoe on three different days while five physiological variables of interest were collected. The light shoe condition resulted in significantly lower oxygen consumption, ventilation, and rate of energy expenditure than the medium and heavy conditions
ACUTE EFFECTS OF TECHNICAL INSTRUCTIONS ON SPRINT ACCELERATION TECHNIQUE AND PERFORMANCE
Get PDFThis study investigated the acute effect of verbal technical instructions intended to alter attentional focus during a 10 m sprint. Team sports athletes (n = 15) completed maximal effort sprints under a control condition and two experimental conditions: internal and external focus. Lower-body kinematic and external kinetic data were collected near the 5 m mark. Total sprint time was longer in both experimental conditions than the control condition (p < 0.05). Both experimental conditions altered ankle and knee angles at touchdown and led to more vertically oriented ground reaction forces (all p < 0.05). Whilst these instructions were detrimental to performance, the results support the importance of technical ability for sprint acceleration. Future studies should seek to identify instructions, potentially used within training programmes, which could be beneficial to performance