Volitional protective responses to reduce impact severity during falls: A systematic review and meta-analysis

Volitional protective responses during falls, which are voluntary motor skills that can be learned by older adults, may reduce the impact severity of a fall. The objective of this study is to classify protective responses into load sharing, body-segment flexion and muscle relaxation categories based on their biomechanical characteristics and to examine their effectiveness in reducing the impact severity during a fall.

Studies were searched from the inception of each database to mid-June 2024 through PubMed, Web of Science, Cochrane Library, SPORTDiscus, and Cumulative Index to Nursing and Allied Health Literature. Cross-sectional studies examined the effects of volitional protective responses on reducing the impact severity of falls from standing or lower heights in adults.

Totally 23 studies were included in the systematic review and 14 of them were included in meta-analyses. Meta-analyses showed that the category of load sharing had a pooled effect size of 1.02 (95 % CI = 0.51 to 1.52, P < 0.001), and the category of body-segment flexion had a pooled effect size of 2.43 (95 % CI = 0.48 to 4.38, P = 0.01). Protective responses with muscle relaxation had no significant pooled effect on reducing the impact severity (P = 0.36).

Protective responses with load sharing were effective. Body-segment flexion responses were effective overall, but their effect on reducing the impact severity of a fall varied depending on the fall direction and impact body parts. The effect of muscle relaxation on reducing impact severity is still not clear and requires further research.