Cadence Modulation during Eccentric Cycling Affects Perception of Effort But Not Neuromuscular Alterations.

INTRODUCTION: A recent study showed that cadence modulation during short eccentric (ECC) cycling exercise affects oxygen consumption (VO2), muscular activity (EMG), and perception of effort (PE). This study examined the effect of cadence on VO2, EMG and PE during prolonged ECC cycling and exercise-induced neuromuscular alterations.

METHODS: 22 participants completed three sessions 2-3 weeks apart: 1) determination of the maximal concentric peak power output (PPO), familiarization with eccentric cycling at two cadences (30 and 60 rpm at 60%PPO) and neuromuscular testing procedure; 2) and 3) 30 min of eccentric cycling exercise at a cadence of 30 or 60 rpm. PE, cardiorespiratory parameters, and vastus lateralis and rectus femoris EMG were collected during exercise. The knee extensors' maximal voluntary contraction (MVC) torque, the torque evoked by double stimulations at 100 Hz (Dt100) and 10 Hz (Dt10), and the voluntary activation level (VAL) were evaluated before and after exercise.

RESULTS: VO2, EMG and PE were greater at 30 than 60 rpm (all p < 0.05). MVC torque, evoked torque and Dt10/Dt100 ratio decreased (all p < 0.01) without cadence effect (all p > 0.28). VAL remained constant after both eccentric cycling exercises (p = 0.87).

CONCLUSIONS: When performed at the same power output, eccentric cycling exercise at 30 rpm elicited a greater PE, EMG and cardiorespiratory demands than pedaling at 60 rpm. Exercise-induced fatigability was similar in both eccentric cycling conditions without neural impairments, suggesting that eccentric cycling seemed to alter more specifically muscular function, such as the excitation-contraction coupling process. In a rehabilitation context, eccentric cycling at 60 rpm seems more appropriate because it will induce lower PE for similar strength loss compared to 30 rpm.