Does prolonged walking cause greater muscle fatigability in individuals with incomplete spinal cord injury compared with matched-controls?

Abstract

Background: Individuals with incomplete spinal cord injury (iSCI) might show muscle fatigability during walking, primarily over long distances. The cause can be related to the motor impairment and walking compensations identified in this population. However, evidence on the occurrence of muscle fatigability after prolonged walking in individuals with iSCI is conflicting.

Research question: Does prolonged walking cause higher muscle fatigability in individuals with iSCI compared with matched-controls?

Methods: We adopted a repeated measures design, in which maximal voluntary isometric contractions were performed before and after a walking test to induce the fatigability, in 24 individuals with iSCI and 24 matched-controls. Body weight-normalized peak torque (PT/BW), rate of force development (RFD), root mean square (RMS) and neuromuscular efficiency were used to assess the muscle fatigability. A mixed model ANOVA (2 × 2) was used for between-group and within-group comparisons. The significance was set in 5%.

Results: Individuals with iSCI showed a greater decline in the PT/BW and RMS after the walking test. However, the RFD presented a greater decrease in the control group.

Significance: Our results showed that prolonged walking caused higher muscle fatigability in individuals with iSCI compared to healthy individuals. Therefore, muscle fatigability should be considered during the rehabilitation planning and in activities of daily living of individuals with iSCI. Moreover, the identification of muscle fatigability in individuals with iSCI might be useful to prevent high levels of physical exertion and, possibly, the risk of fall.

Keywords: Electromyography; Muscle strength dynamometer and musculoskeletal system; Spinal cord injuries; Walking.