Stance limb ground reaction forces in high functioning stroke and healthy subjects during gait initiation

• GRFs during gait initiation are analyzed in healthy subjects and stroke patients.
• In healthy subjects, stance limb GRFs differ between left and right sides.
• In stroke patients, side-of-lesion affects stance limb peak lateral GRFs.
• Right paretic left stance limb lateral GRFs were greater than in healthy left limbs.

BackgroundFollowing stroke, little is known about ground reaction forces during gait initiation.ObjectiveTo compare stroke patients' with healthy subjects' anterior, medial, and lateral ground reaction forces generated during gait initiation.MethodsPatients with left paresis, right paresis, and age-similar healthy subjects were recruited. During gait initiation the average peak anterior, medial, and lateral ground reaction forces acting on each lower limb were calculated when it was the stance limb.FindingsAnterior ground reaction forces acting on the right and left stance limbs of healthy subjects were greater than anterior forces acting on the nonparetic and paretic limbs of stroke patients. Medial ground reaction forces for the nonparetic and paretic limbs of stroke patients and for the right and left stance limbs of healthy subjects were equivalent. While lateral ground reaction forces acting on the nonparetic and paretic limbs were equivalent for left paretic patients, for right paretic patients lateral forces acting on the nonparetic limb were greater compared to the paretic limb and also greater compared to the left limb of healthy subjects.InterpretationAn effect of side-of-lesion was revealed in average peak lateral ground reaction force data. Larger lateral ground reaction forces acting on the left nonparetic stance limb of right paretic patients compared to the right nonparetic stance limb of left paretic patients during gait initiation may be an indication of differing adaptations that depend on the side-of-lesion.