Author(s): HO, T.H., LIN, L., LI, C., CHUANG, C., Institution: NATIONAL CHENG KUNG UNIVERSITY, Country: TAIWAN, Abstract-ID: 2466

INTRODUCTION:
The 5-time chair stand test is the best option to reflect lower muscle strength, physical performance, and function. This is the trend to focus on Inertial Measurement Units (IMUs) and surface Electromyography(sEMG) in wearable devices to assess Sarcopenia in primary prevention. Therefore, this study aimed to explore the trend and application of the kinematic performance of the lower extremity in the 5-time chair stand test using wearable IMU and sEMG-based devices for different risks of Sarcopenia in community-dwelling older adults.
METHODS:
53 adults (71.26 ±7.34 years) participated in this study were divided into two groups depending on those whose standing seconds in 5-rep were less than 10 seconds and Skeletal Muscle Index(SMI) did not meet the risk factors for Sarcopenia were classified into the low-risk group (n=27, LRG), the others were classified into the high-risk group(n=26, HRG). The 5-time chair stand test collected the surface electromyographic signals of each vastus lateralis and vastus medialis muscle and collected the hip and knee’s angular signals using 3 nine-axis inertial measurement units. The gender was used as a covariate for multivariate analysis of variance, MANOVA. Pearson’s correlation analysis was used to analyze the correlation between SMI, the seconds of 5-rep chair stand, sEMG and IMU signals. Furthermore, the multiple stepwise regression analysis predicted the key factors of the seconds of 5-rep chair stand.
RESULTS:
The LRG was better at SMI (+12.68%), the 5-rep seconds (-30.91%)( p<.001), and the left EMG signals, which were mean potential difference and potential difference area of vastus lateralis(+40.83%, p=.046) and vastus medialis muscle(+32.39%, p=.028 ), etc. The mean angular velocity of hip(+37.3%) and knee joint (+37.5%)were significantly different(p<.001). The mean potential difference of vastus medialis muscle in both right(r=-0.356, p=.007) and left(r=-0.341, p=.01), the mean peak potential difference of the vastus medialis muscle in both right(r=-0.350, p =.008) and left(r=-0.323, p=.015), the mean angular velocity of hip (r=-0.829, p<.001) and knee joint (r=-0.820, p<.001) were all significant correlated with the seconds of 5-time chair stand. Furthermore, it could be predicted by hip joint’s mean angular velocity and total angular changes. The formula is y= (-0.86) *mean angular velocity of hip joint+(0.157) *total angular changes of hip joint+4.705(R2=0.701, p<.001).
CONCLUSION:
This study recommended that the EMG signal be given priority on the vastus medialis muscle. In the application of IMU, the angular velocity (muscle strength) and changes (activity/ROM) of the hip joint were the key factors that affected the performance. In the future, there can be measured 5-time chair stand test with EMG and IMU, not only be used to analyze the data simultaneously but also to help determine Sarcopenia risk factors and movement performance factors more accurately to refer the prevention and improvement suggestions.