The role of reinvestment in conservative gait in older adults

Previous research suggests that reinvestment (i.e. conscious control of movements) is associated with inefficient information processing and compromised movement strategies in older adults during walking. We examined whether reinvestment propensity is associated with conservative gait behaviour in older adults. Trait Reinvestment propensity was measured using the Movement Specific Reinvestment Scale (Chinese version) (MSRS-C). Thirty-eight older adults were categorized into 'Low Reinvestor Group' (LRG) (MSRS-C < 27) and another 38 were categorized into 'High Reinvestor Group' (HRG) (MSRS-C > 38). There were no significant differences in physical and cognitive abilities between groups. Participants were asked to walk along a 6-m straight level-ground walkway at a self-selected pace under conditions of no instruction (Baseline), instruction related to self-focus on body movements (BI), and instruction related to the external environment (EI). No significant difference was found in gait behaviour between LRG and HRG at Baseline. However, significant changes, indicative of conservative gait patterns, were found in LRG when given instructions that prompted them to consciously control their body movements. No changes were observed in HRG under external-related instructions that are assumed to reduce conscious motor processing and improve motor performance. Our findings contradict previous views on the association between trait reinvestment propensity and compromised motor performance in older adults, which potentially reduces justification for reducing trait reinvestment propensity in older adults. We also suggest that MSRS is insensitive to reflect the degree of conscious control during gait tasks. Our findings also implicate the potential detrimental effect of applying inward-focus-related instructions in healthcare rehabilitation settings.