Grab bar loading resulting from unexpected balance loss during bathing transfers

Bathtub transfers can be challenging for older adults, and may result in balance loss. While grab bars can be used to help prevent a fall during a balance perturbation, it is unclear what loading demands are placed on grab bars during balance recovery, and how loading differs between proactive and reactive grasp strategies, or between older and younger adults.

Twenty healthy younger adults (20-33 years) and 10 healthy older adults (65-74 years) underwent simulated bathing transfers in a slippery bathtub. The younger adults used proactive or reactive grasp strategies, and the older adults used proactive grasp strategies only. Three grab bar configurations (high and low horizontal, vertical) were evaluated. In randomly-selected trials, a balance perturbation was delivered, and grab bar loading was measured and normalized to body weight.

No falls were observed. Overall resultant forces averaged 21.1% body weight (maximum 43.7%), and were greater for the low horizontal grab bar than the vertical grab bar. Forces were greatest in the downwards direction. Grab bar loading was similar between older and younger adults, except for forces pulling the grab bar away from the wall. Younger adult participants who used a proactive grasp strategy were able to generate greater loads on the grab bar, than those who used a reactive grasp strategy.

Grasp strategy and grab bar configuration impact grab bar loading, with implications for clinical recommendations for grab bar installation. Grab bars installed in low configurations may require greater structural strength from grab bars, walls and supporting materials.