Rapid Inhibition Accuracy and Leg Strength Are Required for Community-Dwelling Older People to Recover Balance From Induced Trips and Slips: An Experimental Prospective Study.

Abstract

Background and purpose: Falls can result in bone fractures and disability, presenting a serious threat to quality of life and independence in older adults. The majority of falls in community-living older adults occur while walking and are often caused by trips and slips. The study aimed to identify the specific sensorimotor and psychological factors required for older adults to recover balance from trips and slips.

Methods: Forty-one older adults aged 65 to 87 years were assessed on sensorimotor (knee extension strength, proprioception, postural sway, and edge contrast sensitivity), reaction (simple reaction time, stepping, and catching reaction inhibition), and psychological (general anxiety and concern about falling) measures. Using a harness system, participants walked at 90% of their usual pace on a 10-m walkway that could induce trips and slips in concealed and changeable locations. Post-perturbation responses resulting in more than 30% of body weight being recorded by the harness system were defined as falls. Poisson regressions were used to test associations between the sensorimotor, reaction, and psychological measures and number of falls.

Results: Fifty-one falls occurred in 25 of 41 participants. Poisson regression revealed body mass index, lower-limb proprioception, knee extension strength, rapid inhibition accuracy, concern about falling, and anxiety were significantly associated with the rate of falls. Other measures including postural sway were not statistically significant. Using stepwise Poisson regression analyses, normalized knee extension strength (rate ratio [RR]: 0.68, 95% confidence interval [CI]: 0.47-0.98), and rapid inhibition accuracy (RR: 0.64, 95% CI: 0.46-0.87) were independently associated with falls.

Conclusion: Our findings suggest rapid inhibition accuracy and adequate leg strength are required for older adults to recover balance from trips and slips. The mechanisms for balance recovery during daily life activities are likely different from those for static balance, suggesting the need for task-specific assessments and interventions for fall prevention in older adults.