ISBS (International Society of Biomechanics in Sports): Conference Proceedings Archive
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MEASURING BILATERAL ASYMMETRY IN A LONGTERM ATHLETE MONITORING
Full text linkThe purpose of this lecture is to provide examples of how biomechanical testing methods are used to analyse bilateral asymmetry from a longterm athlete monitoring program. This lecture includes the results of bilateral asymmetry data to examine the physical status of both highly competitive and recreational athletes. Athlete monitoring is a vital component of achieving a successful athletic career. It is important to understand how the magnitude of bilateral asymmetry is potentially detrimental to performance. The bilateral asymmetry data has been analysed to understand physical demands of athletes in various sports. Different types of jumping, landing, and isometric tests have provided data showing effectiveness of the tests in displaying the athlete’s physical characteristics. Bridging the gap between science and practice is mentioned in the lecture
USING A WIRELESS INERTIAL SENSOR TO MEASURE TIBIAL SHOCK DURING RUNNING: AGREEMENT WITH A SKIN MOUNTED SENSOR
Full text linkMonitoring and feedback of tibial shock using wireless skin mounted sensors could reduce the risk of injury in runners. The purpose of this study was to assess the agreement between a wireless sensor and a skin mounted accelerometer in measuring peak tibial acceleration during running. A skin mounted laboratory standard accelerometer was mounted to a wireless inertial sensor and attached to the tibia. Peak positive tibial accelerations of 13 participants were compared at 2.5 ms-1, 3.5 ms-1 and 4.5 ms-1. Intraclass correlation coefficient demonstrated good agreement. Limits of agreement showed accuracy to within 1.2 – 1.65 g. The inertial sensor can be used as a tool to measure peak tibial accelerations during running for the purpose of real-time feedback in a gait training system
DOES FORCEFUL EXTENSION OF THE SUPPORT LEG DURING THE KICKING STRIDE ENHANCE MAXIMAL INSTEP KICK PERFORMANCE IN A SKILLED SOCCER PLAYER?
Full text linkThe purpose of this study was to apply a technique intervention to the maximum instep kick to increase performance. A carefully constructed intervention was based on evidence from motor learning studies. A single semi-professional player undertook a single subject design to investigate the effectiveness of the intervention, and analyse the mechanisms which underpin the technical improvements. Kinetic and kinematic data was collected pre and post intervention. Ball speed (26.9 ± 1.3m.s-1 to 29.2 ± SD 0.9m.s-1) and knee extension velocity increased following the intervention. The mechanisms presented display a greater active contraction of support leg musculature led to increased energy transfer across the pelvis, and a greater subsequent passive energy transfer through the kicking limb
KINETIC AND KINEMATIC ANALYSIS OF THE LEG POSITIONING IN THE FREESTYLE TRACK START IN SWIMMING
Full text linkIn swimming competitions, the track start is an important part of the race. The aim of this study was to assess and compare the relative positioning of the dominant leg in the preferential freestyle track start. The data was collected using the (Kistler) Performance Analysis System for Swimming (PAS-S) that includes a force measurement and motion analysis system. The results taken from 15 high level competitive swimmers showed that 67.7 % of the subjects naturally position their dominant leg in front. Starting with the dominant leg in front (6.67±0.24) was significantly (p < 0.001) faster than in the rear position (7.25±0.23). However swimmers had faster starts when using their preferential track start. Detailed analysis of the swimming start and the footedness allows coaches and athletes to train the fastest starting technique
BEND SPRINTING AT DIFFERENT RADII OF AN OUTDOOR ATHLETICS TRACK
Full text linkAthletes in the inners lanes may be at a disadvantage during sprint races that contain a bend portion. This study investigated the effect on performance when sprinting on the different radii of an outdoor track. There was an approximately 2% reduction in mean race velocity from lane 8 (left step: 9.56 m/s, right step: 9.49 m/s) to lane 5 (left step: 9.36 m/s, right step: 9.30 m/s), with only slight further reductions from lane 5 to lane 2 (left step: 9.34 m/s, right step: 9.30 m/s). This was mainly due to reductions in step frequency as radius decreased. The disadvantage of the inner lane compared to the outer lane may be greater than previously suspected. Larger race velocity standard deviations as radius decreased may be indicative of athletes being differently able to accommodate running at tighter radii than others. This may have implications for training and competition
ARE DANCERS SYMMETRICAL DURING SINGLE LEG AND DOUBLE LEGGED LANDINGS?
Full text linkThe effect of limb preference on lower extremity function and performance was examined in young healthy dancers. Fifteen elite adolescent dancers performed 15 consecutive single leg hops on each leg and 3 rebound jumps onto two triaxial force platforms. To identify limb preference the Waterloo Footedness Questionnaire was administered. Functional symmetry indices (SI) were calculated for the peak landing forces, and limb dominance was identified as the limb producing the greatest take-off power during the rebound jumps. Significant asymmetry was identified in the landing performance of the dancers. However no relationship was found between limb preference and limb dominance of the dancers. In conclusion, dance teachers should aim to achieve safer landing strategies by developing ambidextrous movement in young dancers
NO BILATERAL ASYMMETRY DURING PEDALLING IN HEALTHY CYCLISTS OF DIFFERENT PERFORMANCE LEVELS
Full text linkThe main purpose of this study was to analyse the pedalling force symmetry in cycling, and the possible influence of performance level and pedalling power on it; additionally, the 2D pedalling kinematics symmetry was analysed. Forty-seven road cyclists of different competitive levels (Study 1) and eighty-four club cyclists (Study 2) participated. Their bikes were replicated in a cycle ergometer with instrumented cranks, and they pedalled at 200-250-300 W (Study 1) and a self-selected power ?185 W (Study 2). In both studies 2D kinematics of the right leg was analysed, and in the Study 1 the left leg was also analysed. In conclusion, the pedalling movement could be considered symmetric from kinematic and kinetic points of view; and the slight force differences found in the dominant leg (below 2%) could be related to the chainring location and the right-dominance of general population, which constitutes further investigation
KINEMATIC DIFFERENCES BETWEEN UPKICK AND DOWNKICK IN UNDULATORY UNDERWATER SWIMMING
Full text linkUndulatory underwater swimming (UUS) is performed for up to 15 m of each lap in a swimming race, and is important for overall performance. This undulatory motion has two phases- the upkick (knee flexion and hip extension) and the downkick (the converse). This study assessed kinematic differences between the two phases, and determined whether these differences were related to performance in an elite sample. Each of the ten participants performed three 20 m UUS trials, and seven landmarks were manually digitised from the single camera view perpendicular to swimming direction. Differences between phases were found for vertical toe velocity, body wave velocity, hip and knee angular velocities and phase duration (p < 0.05), with differences in mean hip angular velocity and phase duration (p < 0.05) being strongly related to UUS performance
A KINEMATIC STUDY ON HOW TO KICK QUICKLY IN TAEKWONDO
Full text linkThe purpose of this study was to evaluate techniques for increasing kicking speed in a Taekwondo roundhouse kick according to different target distance conditions. The results were summarized as follows: i) With short condition, there was no significant correlation between kicking speed and pelvic speed; ii) Good subjects attained greater extension angular velocity of the knee joint with individual kinematic chain technique regardless of different distance conditions; and iii) subjects changed motion of the support leg in order to adapt the translational motion according to different distance conditions. Taken together, our data suggest that coaches should pay greater attention to the support leg when adapting the technique for kicking distance as well as the motions of the pelvis and hip joint of the kicking leg when adapting the technique to increase kicking speed
A COMPARISON OF FOOT STRIKE EVENTS USING THE FORCE PLATE AND PEAK IMPACT ACCELERATION MEASURES
Full text linkA popular method for measuring initial contact (foot-strike) during running is the force platform. It has been proposed that the foot contact events can be estimated using peak impact related accelerations of the leg using accelerometers. Various studies have been conducted to compare force platform and accelerometer methods in walking and running. The aim of this study was to develop a method for identifying peak impact accelerations in the anterior- posterior axis using the Delsys Trigno System during running and compare this with initial contact via force plates. Seven national and international sprinters completed runs across a force platform with an accelerometer fixed to their shin. The results showed the acceleration of the anterior-posterior axis approximated footstrike within ±0.017 s of the foot-strike event detected by the force plate