Quantification of Physical Activities Simulated Exercise Therapy in Ambulatory Inpatients Using Surface Electromyogram from the Vastus Medialis
Author(s): Tomoaki Tsuji, Chiaki Wada, Makoto Kawanishi, Yasuhisa Fujita, Yoshi-ichiro Kamijo, Yasunori Umemoto, Ken Kouda, Kazunari Nishiyama, Fumihiro Tajima, Yukihide Nishimura
The present study aimed to assess whether surface electromyogram (sEMG) signal from the vastus medialis could be a candidate method to quantify physical activities during combined activities in ambulatory persons (ergometer exercise, treadmill walking, and squatting). In the first trial, eleven healthy men performed a graded cycle ergometer exercise at 0%, 30%, 60%, and 80% of peak oxygen consumption rate (VO2peak), followed by treadmill walking at 0, 2, 4, and 6 km/h for 3 min of each, and each exercise was intermitted by 3 min of rest. sEMG from the Vastus Medialis Oblique Longus (VML) was collected, and the integrated amplitude of spikes (sEMGAMP) were calculated every minute. Positive correlations were observed between ΔVO2 and ΣsEMGAMP; data at sampling frequency of 250Hz in both exercise types were plotted (r=0.888; P<0.0001; y=339.04x+4.0267). In the second trial, thirteen healthy participants (three women) performed the combined exercise comprising 3 min each for optimal walking (3 km/h), fast walking (5 km/h and 6 km/h for women and men, respectively), squatting, second optimal walking, and ergometer exercise at 30% VO2peak, which were intermitted by 30 sec. Finally, they performed ergometer exercise at 100% VO2peak for 1 min followed by 3-min cool-down (0W). Changes (Δ) in VO2 from the resting value and sEMGAMP during exercise were summed throughout the exercise period (ΣΔVO2 and ΣsEMGAMP). ΣΔsEMGAMP was positively correlated with ΣΔVO2 (r=0.68, p=0.011, @250Hz). Monitoring sEMG from VML may be a candidate method for the evaluation of physical activities for exercise therapy in ambulatory persons.