Author(s): KANG, J.H., KANG, J., PARK, S., YOON, S., Institution: KOREA NATIONAL SPORT UNIVERSITY, Country: KOREA, SOUTH, Abstract-ID: 674

INTRODUCTION:
Since running is a fundamental and core movement in all sports, there is a lot of research on motion analysis to quantify the lower limb movements during running to improve performance, prevent injuries, and develop shoes for runners(1). However, the equipment used for motion analysis is expensive, requires time-consuming data processing, is not portable, and is limited to laboratories. To solve this problem, wearable devices are being used to analyze movements in real-world situations, such as sports(2). Previous studies using wearables have analyzed movement at slow speeds or at a single, fixed high speed, so it was deemed necessary to verify the reliability of IMUs as speed increases. Therefore, the purpose of this study was to check the reliability of IMUs at various speeds in real sports situations(3).
METHODS:
Twelve healthy adult males (age: 27.3±3.8 years, height: 173.1±4.3 cm, weight: 75.3±9.3 kg) with no history of musculoskeletal injury or surgery within the last 6 months participated in this study. Participants were asked to perform running on a treadmill at three different speeds (2.7 m/s, 3.3 m/s, and 4.0 m/s). A 3 dimensional motion analysis was performed using eight infrared cameras (sampling rate: 100 Hz) and four IMUs (sampling rate: 100 Hz) to determine kinematic differences in the lower extremity joints measured by infrared cameras and IMUs with increasing speed. A two-way ANOVA with repeated measures with the statistical significance level set at α=.05.
RESULTS:
In RoM of ankle joint, equipment, and an interaction effects between running speed and equipment showed significant differences. Post hoc tests showed that the RoM of the ankle joint was larger for motion capture than IMU at all speeds.
The RoM of the knee and hip joints showed a main effect of speed, equipment, and an interaction effect between speed and equipment. Post hoc tests showed that the RoM of the knee and hip joints increased as running speed increased for both Motion Capture and IMU. Finally like ankle joint, Motion Capture had a larger RoM than IMU for both the knee and hip joints.
CONCLUSION:
The results of this study showed that the RoM of the lower extremity joints differed between motion capture and IMU with increasing speed, and larger in Motion Capture. Therefore, when analyzing IMU equipment in the field, it is necessary to apply it with the knowledge that there is an error from the Motion Capture. However, since this study compared the overall RoM in the running section, it was not possible to compare within the entire running cycle. Therefore, in future studies, it is necessary to determine the reliability of the entire section through SPM analysis.

REFERENCES:
1) Perry, J., & Burnfield, J. M. Gait analysis. Normal and pathological function 2nd ed. California: Slack. 2010
2) Park, S., Yoon, S, Sensors, 2021
3) Jeon, T., Lee. J. Journal of the Korean Society for Precision Engineering. 2018