Recovery of gait after quadriceps muscle fatigue

• Fatigue changed gait parameters: stability, gait propulsion and muscle activity.
• 20 min of rest was not enough for recovery of the gait parameters related to stability.
• Gait modulations seemed to be an effect of the decline of force generating capacity.

The aim of this study was to investigate the effect of recovery time after quadriceps muscle fatigue on gait in young adults. Forty young adults (20–40 years old) performed three 8-m gait trials at preferred velocity before and after muscle fatigue, and after 5, 10 and 20 min of passive rest. In addition, at each time point, two maximal isometric voluntary contractions were preformed. Muscle fatigue was induced by repeated sit-to-stand transfers until task failure. Spatio-temporal, kinetic and muscle activity parameters, measured in the central stride of each trial, were analyzed. Data were compared between before and after the muscle fatigue protocol and after the recovery periods by one-way repeated measures ANOVA. The voluntary force was decreased after the fatigue protocol (p < 0.001) and after 5, 10 and 20 min of recovery compared to before the fatigue protocol. Step width (p < 0.001) and RMS of biceps femoris (p < 0.05) were increased immediately after the fatigue protocol and remained increased after the recovery periods. In addition, stride duration was decreased immediately after the fatigue protocol compared to before and to after 10 and 20 min of rest (p < 0.001). The anterior–posterior propulsive impulse was also decreased after the fatigue protocol (p < 0.001) and remained low after 5, 10 and 20 min of rest. We conclude that 20 min is not enough to see full recovery of gait after exhaustive quadriceps muscle fatigue.