ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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KINEMATICS AND KINETICS OF SQUATS, DROP JUMPS AND IMITATION JUMPS OF SKI JUMPERS
Get PDFThe purpose of this study was to find objective factors in athleticism training which influence the performance of ski jumpers on the hill. Therefore, barbell squats, drop jumps and imitation jumps were measured in a laboratory environment for ten ski jumpers. Force and motion capture data was gathered and forces, velocities as well as an index for the knee valgus were calculated. The results show that especially for the imitation jumps there is a good correlation of the take-off velocity with the performance on the hill. What surprised more is that the more the athletes tended to a knee valgus during all measured movements, the worse the performance. Therefore, athleticism training should concentrate more on improving the knee stability
MEASURING SQUASH HITTING ACCURACY USING THE ‘HUNT SQUASH ACCURACY TEST’
Get PDFThe purpose of this study was to determine the reliability and validity of the Hunt Squash Accuracy Test (HSAT). Reliability: ten male squash players performed the HSAT twice within seven days. Each test consisted of 375 shots across 13 different types of squash strokes on both the forehand and backhand side. Reliability was measured using a typical error (TE) score from consecutive pairs of trials. The overall TE score for the test was 1.82%, demonstrating that the HSAT is very reliable at the 90% confidence limit. Validity: measured using a correlation analysis comparing the results of 8 individual’s HSAT scores against a round-robin tournament ranking where all 8 players played against each other, as well as coach rankings of player ability. Validity was considered high with correlation coefficients of 0.93 for both the round-robin and coach ranking
LANDING TRAINING WITH CONCURRENT TACTILE FEEDBACK INCREASED MAXIMUM KNEE FLEXION ANGLE AND DECREASED IMPACT FORCES
Get PDFThe current study evaluated the effects of landing training with a tactile feedback device on knee flexion angles and impact ground reaction forces (GRF). Twenty-two recreational athletes performed 3 landing trials without the device (baseline), 6 landing trials with the device (training), and 3 landing trials without the device (retention). The maximum knee flexion angle during landing was greater for the training and retention conditions compared to the baseline condition. The vertical GRF at peak posterior ground reaction force (PPGRF) was smaller for the training condition compared to the baseline condition. The sagittal plane resultant force at PPGRF was smaller for the training and retention conditions compared to the baseline condition. The tactile feedback device might be used in landing training to modify movement patterns and decrease the risk of ACL injury
THE EFFICACY OF VIDEO-BASED MARKER-LESS TRACKING SYSTEM IN GAIT ANALYSIS
Get PDFAn alternative to the 3D motion capture is the marker-less 3D video tracking system. Though not rigorously tested yet, the 3D marker-less video tracker would break new grounds if it is possible of extracting similar kinematic parameters as the gold standard 3D marker based motion capturers. The aim of our study is to explore the feasibility of a video based marker-less system. A series of gait analysis tests were carried out on ten subjects with a marker and marker-less system simultaneously. The study suggests potential applications in gait analysis in the academic classrooms and clinical settings where observations of anatomical motions provide meaningful feedback
KINETIC DIFFERENCES IN LOWER EXTREMITY BETWEEN BASEBALL PITCHING FROM PITCHER’S MOUND AND FLAT-GROUND
Get PDFThe purpose of this study was to investigate the kinetic differences in lower extremity between pitching from a mound and flat-ground. A motion capture system and two force plates were used simultaneously to collect the dynamic data of 8 baseball male pitchers. The results revealed that pitching from the mound generated higher propulsive force at the trailing leg as well as greater braking force and vertical ground reaction force at the lead leg (p< .05). The trailing leg in the mound condition generated greater knee posterior joint force while the lead leg had greater axial joint force at ankle and knee, as well as greater extension moment at ankle, knee and hip (p< .05). It was concluded that pitching from the mound generated higher ground reaction force, which resulted in higher joint forces and moments and thus might increase stresses at lower extremity
Research Informing Practice: Current Issues in Gymnastics Research “Injury, skill development, elite performer and fundamental movements”
Get PDFThe aim of this applied session is to explore four key themes relating to current research in gymnastics. The themes include Injury occurrence (Professor Patria Hume), Skill development (Professor Gareth Irwin), Working with the Elite Gymnast (Professor William Sands) and Fundamental movements in gymnastics (Dr Toshiyuki Fujihara). Each speaker will explore their area, as experts in this applied science, drawing on a body of research evidence and gymnastics practice to report findings that impact understanding and hence have the potential inform coaching. Research has previously demonstrated that a conceptual understanding of how a skill works biomechanically can provide a coach and clinician with knowledge of effective, efficient and safe technique development (Irwin et al., 2005). Bridging the gap between the fundamental axioms of science and real world practice is a key aim of the Society’s approach to sports biomechanics. To achieve this bio-fidelity the approach must be one that is rich in ecological validly. Professor Hume will explore injury rates and current issues associated with biological failure due to technique and maturation. Professor Irwin will draw on research to outline the impact of technique selection on injury potential and skill development. Professor Sands will draw on his wealth of experience as a biomechanist and applied scientist working with Olympic gymnasts to highlight issues associated with this fundamental scientific role. Dr Fujihara will complete the session by examining “fundamental skills”. His talk will focus on rotational mechanics and include practical considerations for circles on pommel horse including the influence of a suspension aid in the development of skill
FMAXIMUM ISOMETRIC STRENGTH IN PATIENTS WITH ACUTE UNILATERAL ANTERIOR CRUCIATE LIGAMENT RUPTURE
Get PDFThis study evaluated isometric leg extension strength in a group of ACL patients. The specific aims of this work were to determine whether differences in leg extension strength existed between the injured and uninjured leg, and whether a between-gender difference existed for the ratio of the maximum force generated by the injured and uninjured legs (the maximum force ratio). Thirty patients of both genders with an acute unilateral ACL rupture were recruited. Maximum isometric force was measured for both legs in a leg press machine at a knee angle of 100°. Results showed significant differences existed between the injured and uninjured legs, while no gender differences were evident for the maximum force ratio. In conclusion, an ACL rupture affects leg extension strength and including both males and females in one group may be possible in future work
THE EFFECTS OF NEUROMUSCULAR TRAINING ON COUNTER-MOVEMENT JUMP PERFORMANCE IN HEALTHY YOUNG STUDENTS
Get PDFNeuromuscular training (NT) programs are effective for improving measures of performance and used by athletes in all types of sports to increase sports performance. The purpose of this study was to evaluate the effects of NT on arm counter-movement jump (CMJ) performance in healthy young students. Thirteen healthy collegiate female students volunteered and underwent a series of NT exercise. The NT was performed for 50 minutes three times per week, for six weeks. Paired t-tests were used to analyze the differences in each parameter before and after training. The arm CMJ in explosive power, flight time, and jump height was statistically improved in post-training compared to pretraining. It is concluded that six weeks NT can improve the arm CMJ performance in young female students
EVALUATION OF RELIABILITY AND CONCURRENT VALIDITY OF INEXPENSIVE AND EXPENSIVE SYSTEMS USED FOR RECORDING MAXIMUM VERTICAL JUMP PERFORMANCE
Get PDFThe reliability and validity of two alternative systems used for jumping performance measurement was evaluated. Two groups of subjects consisted of 15 male adults and the 16 female volleyball players. We used three different systems of data collection: Optojump Next (optoelectric) referred as the inexpensive system, BTS Smart-E (motion capture) as the expensive system. Concurrent validity of these systems was checked with the use of standard force platform. All systems were used to estimate the height of vertical jumps. Both systems showed highly reliability with the ICCs=0.98 for Optojump and 0.90 for BTS Smart. Their concurrent validity with the force platform data was also very high r=0.99 and r=0.97 respectively. Comparison of these two systems demonstrated distinct differences between the two systems: Optojump system is more suitable for quick and reliable sports testing
LEARNING GOLF DRIVE: NATURAL SWING PATH TENDENCY TO SLICE, FADE OR PULL
Get PDFThe purpose of this study was to identify if there is a natural tendency to deviate from a parallel-to-target line at impact, while learning the drive swing. During coaching, on a reduced-size driving range, the participants (n=10) only received augmented feedback related to knowledge of performance by combining Leadbetter Interactive and SmartSwing analysis software. To capture motion data, augmented coaching equipment included two video cameras and a SmartSwing™ club (3D sampling at 1000 Hz). To overcome SmartSwing’s inability to export swing datasets directly into a spreadsheet file and to eliminate human error, the swing reports (s=328) were exported using independently developed software. Findings related to the natural tendency to slice, fade or pull can aid golf coaching activities, club-fitting and golf technology