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Electromyographic Data Do Not Support A Progressive Recruitment Of Muscle Fibers During Exercise Exhibiting A Vo2 Slow Component, Daniel T. Cannon, Fred W. Kolkhorst, Daniel Cipriani

Physical Therapy Faculty Articles and Research

The origin of the slow component (SC) of oxygen uptake kinetics, presenting during exercise above the ventilatory threshold (VT), remains unclear. Possible physiologic mechanisms include a progressive recruitment of type II muscle fibers. The purpose of this study was to examine alterations in muscle activity through electromyography (EMG) and mean power frequency (MPF) analysis during heavy cycling exercise. Eight trained cyclists (mean±S.E.; age=30±3 years, height=177±4 cm, weight=73.8±6.5 kg, VO2max=4.33±0.28lmin−1) completed transitions from 20 W to a workload equaling 50% of the difference between VT and VO2max. VO2 was monitored using a breath-by-breath measurement system, and EMG data were gathered from …