In this paper, we present an analysis to identify a sensor location for an inertial measurement unit (IMU) on the body of a skier and propose the best location to capture turn motions for training. We also validate the manner in which the data from the IMU sensor on the proposed location can characterize ski turns and performance with a series of statistical analyses, including a comparison with data collected from foot pressure sensors. The goal of the study is to logically identify the ideal location on the skier’s body to attach the IMU sensor and the best use of the data collected for the skier. The statistical analyses and the hierarchical clustering method indicate that the pelvis is the best location for attachment of an IMU, and numerical validation shows that the data collected from this location can effectively estimate the performance and characteristics of the skier. Moreover, placement of the sensor at this location does not distract the skier’s motion, and the sensor can be easily attached and detached. The findings of this study can be used for the development of a wearable device for the routine training of professional skiers.

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Background: Physical frailty and impaired executive function of the brain show similar pathophysiology. Both of these factors lead to dysfunction of neuromuscular and abilities in elderly. High-speed power training (HSPT) has been determined to have positive effects on neuromuscular function and gait performance, as well as executive function in the elderly. Objectives: The purpose of this study was to investigate the effects of 8-week HSPT on neuromuscular, gait and executive functions in frail elderly with mild cognitive impairment (MCI). Design, setting and participants: We performed a randomized controlled trial of frail elderly from community and medical center in republic of Korea. Forty-two physically frail elderly with MCI were randomly allocated to control (n=22, age=74.22±4.46) and intervention groups (n=18, age=73.77±4.64). The intervention group was subjected to HSPT, 3 times weekly for 8 weeks. Measurements: Isometric contraction of knee extension and flexion with electromyography (EMG) was measured to determine the neuromuscular function such as knee extensor strength, rate of torque development, movement time, pre-motor time, motor time, rate of EMG rise, and hamstrings antagonist co-activation. Additionally, the 4.44-meter gait and timed up-and-go (TUG) test were administered to assess gait performance. A frontal assessment battery was measured in this study. Results: The 8-week HSPT regimen improved the knee extensor strength from 1.13±0.08 to 1.25±0.07 (p<0.05), the 200-ms RTD from 3.01±0.3 to 3.55±0.24 (p<0.05) and the rate of EMG rise from 166.48±13.31 to 197.94±11.51 (p<0.05), whereas the movement time and motor time were statistically decreased from 921.69±40.10 to 799.51±72.84, and 271.40±19.29 to 181.15±38.08 (p<0.05), respectively. The 4.44-m gait speed and TUG significantly decreased from 6.39±0.25 to 5.5±0.24, and 11.05±0.53 to 9.17±0.43 respectively (p<0.05). Conclusion: The findings of this study suggest the favorable effects of 8-week HSPT on the neuromuscular function and the gait performance in the frail elderly with MCI without increase in the executive function.