The effects of sand surface training on changes in the muscle activity of the paretic side lower limb and the improvement of dynamic stability and gait endurance in stroke patients

Subjects were divided into two groups, for sand or general surface training. The gait abilities of the patients were evaluated with the Timed Up and Go (TUG) tests and the 6-min walk test (6MWT). Muscle activity in the lower limbs was evaluated with surface electromyography obtained during general surface gait. Gait ability and muscle activity were re-evaluated after gait training for 6 weeks on a sand or general surface. The TUG test was performed 3 times, and an average of the three values was used for analysis. 6MWT was measured once under maximum effort. Electromyography was evaluated using average gait cycle values. In the TUG test, performance times decreased in both groups, while in the 6MWT, performance distance significantly increased only in the sand surface training group. Results from surface electromyography showed that activity of the rectus femoris, biceps femoris, and tibialis anterior muscles of the paretic side lower limb significantly decreased after the both interventions. When environments are similar, gait training is helpful for increasing dynamic stability; however, repeated training does not significantly improve gait endurance. Training on a continuously unstable bearing surface such as sand can improve gait endurance by utilizing diverse muscle groups and increasing joint motility. Sand surface training recruited the activity of more muscle groups than did general surface training, and sand-trained participants showed longer gait distances with lower muscle activity levels when they resumed general training than their general-surface-trained counterparts.