Changes in posture associated with postural control impairment induced by ankle plantarflexor fatigue during unipedal quiet standing

• Fatigue and vision removal altered postural control, including a backward COP shift.
• Fatigue and vision removal induced increases in ankle, knee and back flexion.
• With fatigue, the free lower limb and pelvis moved backward and upper limbs forward.
• Postural strategies may be used to optimize the role of non-fatigued muscles/joints.

The aim of the present study was to investigate changes in joint angles and limb positions accompanying postural control impairments induced by fatigue of the ankle plantarflexor muscles and vision removal. Thirteen subjects performed unipedal standing tasks with and without vision before and after isometric fatigue of the plantarflexor muscles. Results indicated that to compensate for the negative effects of fatigue and vision removal on postural control, participants increased flexion at the ankle, knee and back while the free lower limb and the pelvis moved backward and the upper limbs forward. These strategies could be performed to increase the role of non-fatigued muscles and optimize the use of all the joints implicated in unipedal standing.