Measurement and validation of exercise induced fatigue through inertial motion analysis
Exercise-induced fatigue evolves from the initiation of physical work. Nonetheless, the development of an objective method for detecting fatigue based on variation in ambulatory motion parameters measured during exercise is yet to be explored. In this study, the ambulatory motion parameters consisting of kinematic parameters of 23 body segments in addition to muscle tissue oxygen saturation (SmO2), heart rate, and vertical work of eight healthy male subjects during stair climbing tests (SCT) were measured before and after a fatigue protocol utilizing Wingate cycling test. The impacts of fatigue on ambulatory motion and postural behaviors were analyzed using an unsupervised machine learning method classifying angular joint motions. The average of total distance traveled by subjects and the overall body postural behavior showed about 25% decline and 90% variation after fatigue protocol, respectively. Also, higher relative desaturation in SCT1 64.0 (1.1) compared SCT2 54.8 (1.1) was measured. Measurements of differences in motion postural states and metabolic indexes after exercises-induced fatigue proved a strong correlation which validates the advantages of inertial motion analysis method for fatigue assessment.