INTER-JOINT DIFFERENCES EXIST IN KINETIC DEMAND FOR PERFORMANCE IN HIGH JUMP

We aimed to clarify the lower-limb kinetic determinants of inter-individual variability in flight height in the high jump. We hypothesised that although the take-off of the high jump requires great external power, the proximal (hip) joint is required to function as a stabiliser rather than as a power generator for higher performance. We analysed high jump motions by 16 male high jumpers. For the hip joint, only maximum torque significantly correlated with the flight height. Meanwhile, for the knee joint, both peak positive power and peak torque were correlated with the flight height, with a stronger correlation for power than for torque. We found that the kinetic requirement for performance differs between joints, which provides the practical implication that the musculoskeletal functions to be trained differ between joints, such as torque exertion for the hip and power exertion for the knee

HIP AND LUMBOSACRAL JOINT CENTRE LOCATIONS IN ASIAN POPULATION: BIASES BY EXISTING REGRESSIONS AND DEVELOPMENT OF NEW METHODS

Accurate prediction of the lumbosacral and hip joint centres (LSJC, HJC) is crucial for the analysis of lumbo-pelvic-hip dynamics in various movements. Here we show that pre-existing regressions proposed by European research groups produce biased estimates of the LSJC and HJC in Japanese males and females (n = 23, 24), and that the biases in LSJC depend on sex. When compared to locations directly measured by MRI, the pre-existing regressions estimated the LSJC to be more posterior in males and more inferior and posterior in females, and the HJC to be more medial for both sexes. We suggest the importance of considering racial and sexual differences in morphology. We propose new regressions for Asians and validate them using leave-one-out cross-validation. Our regression can be a powerful solution for accurate motion analysis in Asians