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Abstract
INTRODUCTION: The purpose of this study is to evaluate the relationship between lower leg muscle function and changes in fall risk factors after walk-induced fatigue among PwMS and older adults. The study also assessed their recovery after 20 minutes of rest. METHODS: Six persons with MS (PDDS 3-5), 10 older adults and 6 younger adults participated in the study. Baseline measures on fatigue, fall efficacy, and demographic information were taken. Muscle function (fatigability and mitochondria capacity) was measured in the lower leg muscles before walking. Reported fatigue (VAFS, 0-10), gait variability, gait asymmetry, and static balance were measured before and immediately after a self-paced 6-minute treadmill walk for PwMS and 30 minutes’ walk for older and younger adults. Measures were repeated after 20 minutes of rest.RESULTS: For the PwMS, there was a 180% increase in reported fatigue after walking. Gait and balance were impaired with a ~26% increase in gait variability and ~40% increase in gait asymmetry immediately after walking. There was also ~69% increase in postural sway with eyes opened and a ~20% increase with eyes closed. Gait and balance remained impaired after 20 minutes of rest. The decline in gait parameters after walking had a negative correlation with muscle endurance (r=-0.80, p=0.03), and mitochondrial capacity (r=-0.92, p<0.01). For the older adults, gait and balance were impaired with a ~12% increase in gait variability and ~27% increase in gait asymmetry immediately after walking. There was also ~26% increase in postural sway with eyes opened and a ~20% increase with eyes closed. Gait and balance remained impaired after 20 minutes of rest. Gait and balance were impaired in younger adults after the walk but recovered after 20 minutes of rest.
CONCLUSION: Self-paced walking worsened gait and balance among the participants, this did not completely recover after 20 minutes of rest among lower functioning PwMS and older adults. The changes in gait after walking were associated with lower leg muscle function. Therefore, understanding the role of muscle function, and alterations in gait and balance after physical activity might be important information needed to identify a therapeutic approach to reduce falls.