Walking mechanics of persons who use reciprocating gait orthoses.

Although ambulation with a reciprocating gait orthosis (RGO) may provide physical benefits to people with lower-limb paralysis, the high metabolic energy cost associated with ambulation limits orthosis use. The purpose of this case series was to investigate the dynamics of ambulation with RGOs to identify and better understand the potential causes of the high energy cost. Data were acquired from five regular users of RGOs. Kinematics and kinetics were measured, and the moments and powers acting at the hips and shoulders calculated. All RGO users walked with a flexed trunk and bore a large proportion of body weight through the arms during single support. Moments at the shoulder encouraged trunk extension, while moments at the hip encouraged trunk flexion. An extension moment acted on the hip at the beginning of swing, which was antagonistic to the goal of swing and contradicted the intent of the reciprocal link: to advance the swing leg. These results suggest that characteristics of RGO ambulation are consistent across users. The relationship between posture, forces acting on the walking aids, and the action of the RGO reciprocal link should be further explored because these factors likely contribute to the high metabolic cost of ambulation with an RGO.