Energy consumption during level walking with arm and knee immobilized.

Abstract

To determine whether there is an increase in energy use for able-bodied subjects with their arm and/or knee immobilized, while walking on a level surface at comfortable walking speed (CWS). Prospective, quantitative, with randomly sequenced experimental trials. Rehabilitation center. Ten healthy subjects, none of whom had gait abnormality. Subjects walked on a treadmill at CWS under 4 conditions: (1) without an arm or knee immobilized (N); (2) with an arm immobilized (AI); (3) with a knee immobilized (KI); and (4) with both arm and ipsilateral knee immobilized (KAI). Breath-by-breath oxygen cost; differences in energy consumption in trials during which constraints were used were compared with energy consumed under the N condition and the percentage of change was calculated. Mean oxygen cost increased by 22.7% with a knee immobilized compared with N values (mean difference,.044 mL x kg(-1) x m(-1), p <.0001), and increased by 24.7% with a knee and arm immobilized (mean difference,.048 mL x kg(-1) x m(-1), p <.0001). However, no significant differences existed in oxygen cost with AI compared with N, or with KAI compared with KI. The differences in CWS between the stages followed a similar pattern. Arm immobilization does not increase energy expenditure during level walking at CWS, and does not further increase energy expenditure when the ipsilateral knee also is immobilized.