Influence of maximum-graded exercise test on maximal plantarflexion and dorsiflexion torque production in the seated and supine positions

Abstract

BACKGROUND: There have been multiple studies focusing on the relationship between ankle muscle torque and fatigue with different body positions but have found conflicting results. OBJECTIVE: We investigated the effect of body position on maximum voluntary isometric contractions (MVIC) of ankle plantarflexors (PF) and dorsiflexors (DF) in the pre and post-fatigued conditions in healthy adults. METHODS: Twenty-five participants ran on a treadmill until volitional exhaustion by performing the Bruce protocol. The participants then performed three MVICs for both PF and DF before and after volitional exhaustion. RESULTS: Peak torques of PF (p < 0.01) and DF (p < 0.01) in the pre-fatigue condition were greater than in the post-fatigue condition regardless of the body position. Peak torques of PF ( p < 0.01) and DF ( p = 0.03) in the seated position were greater than in the supine position regardless of time. Variances of peak torque differences were not significantly different between the pre and post-fatigue conditions for the seated and supine positions (p = 0.09). CONCLUSIONS: The results of this study suggest that the body position affects ankle PF and DF torques but does not influence the magnitude of PF and DF strength declines elicited by a fatiguing protocol. Therefore, to obtain the most reliable MVIC measurements, the body position during MVICs should be consistent.