The impacts of muscle strength, body composition, and lateral stabilization on walking in people with spina bifida.

Abstract

Spina bifida (SB) is a neural tube defect that causes significant walking problems. The purposes were to understand the gait performance and to investigate the impacts of muscle strength, body composition, and external lateral stabilization on walking in this population. We examined twelve people with SB who could perform at least 4 to 6 independent steps. Our results showed they walked with decreased normalized stride length, stride velocity, cadence and increased step width, stance phase, and double support phase compared to healthy people. The strongest relationship between a specific muscle group and gait was seen in the abductor muscles, which suggests that strong hip abductors are important in allowing people with SB to better control the position of the stance leg and generate longer strides. Our EMG results showed that they utilized increased leg muscle co-activation during walking compared to healthy people. They utilized increased ankle muscles co-activation during walking correlated to their muscle weakness. The inverse relation between body mass index (BMI) and normalized cadence suggests that they tended to be overweight for their height walk with a smaller cadence. Overall, strength in the proximal leg muscles tended to have inverse correlation with stance and double support phases that were positively correlated to thigh to shank segment proportion. The long stance and double support phases related to decreased muscle strength and relatively heavier upper leg compared to lower leg might induce muscle fatigue and joint pain. The rehabilitation interventions for people with SB should take the impacts of body composition and muscle strength into consideration. By decreasing the medial-lateral control demands in people with SB, the external lateral stabilization significantly improved their gait with smaller step width, larger step length, reduced COM and pelvic range of motions in the frontal plane. The external lateral stabilization assisted in decreasing energy cost and muscle co-activation of soleus and quadriceps (vastus lateralis) that may help in diminishing the chances of joint pain and fatigue in people with SB. Exploring the effect of the external lateral stabilization provided us information that might be used to increase mobility safety in people with SB.