Impact of ageing, fall history and exercise on postural reflexes following unpredictable perturbations: A systematic...

This review examined the impact of ageing, fall history and exercise on postural reflexes and adaptation to unpredictable perturbations.

MEDLINE, EMBASE, Scopus, SportDiscus and Web of Science were systematically searched for cross-sectional and intervention studies that assessed muscle onset latency following unpredictable postural perturbations in adults (CRD42020170861).

Thirty-seven articles (n = 1257) were included in this review. Older adults had slower onset latencies compared to young adults (mean difference 14 ms, 95% CI: 10, 18, P < 0.001). Regular exercisers had faster onset latencies compared to sedentary/untrained participants (mean difference 11 ms, 95%CI: -19, -4, P = 0.002). Exercise interventions delivered in randomised control trials (RCTs) led to faster onset latencies (mean difference -4 ms, 95%CI: -9, 0, P = 0.04) compared to controls. Uncontrolled clinical trials of exercise (mainly short-term) did not show changes in onset latency in pre-post tests (mean difference -2 ms, 95%CI: -5, 1, P = 0.36).

This review demonstrated that in response to postural perturbation, muscle activation is significantly delayed in older compared to young adults, and that adults who regularly exercised had faster muscle activation compared to their less active counterparts. No significant changes in onset latencies were evident in uncontrolled clinical trials of short duration, but longer-term RCTs indicated postural reflexes are responsive to training.