RESUMEN
BACKGROUND: Unstable board intervention for patients with stroke improves sitting balance and trunk function. However, because patients with severe stroke are at high risk of falling, it is mostly adapted in mild cases. OBJECTIVE: We aimed to examine the effect of standing unstable board intervention for the non-paralyzed lower limbs on sitting balance in patients with hemiplegia. METHODS: The participants were 42 patients with stroke who were randomly assigned to a control or intervention group. In the intervention group, the non-paralyzed leg was placed on an unstable board, and the patient wore a knee-ankle-foot orthosis on the paralyzed side and practiced standing and weight-bearing exercises on the unstable board for 3 days. The outcomes were the angle of righting reaction of the neck, trunk, and both lower legs and the movement distance of the center of pressure of the righting reaction from lateral tilted sitting. RESULTS: In the intervention group, the righting reaction angle of the trunk to the paralyzed and non-paralyzed sides and the movement distance of the center of pressure were increased significantly after the unstable board intervention. CONCLUSION: The standing unstable board intervention for the non-paralyzed lower limb increased sensory input to the non-paralyzed side of the trunk weight-bearing on the lower limb of the paralyzed side. The increase in the righting reaction angle and the movement distance of the center of pressure contributed to improved sitting balance.