Task difficulty modulates motor learning benefits of balance exercises in community-dwelling older adults

Balance disorders are a major modifiable risk factor for falls, and balance exercises reduce fall rates. However, the effectiveness of balance exercises may depend on the relationship between the task difficulty and individual skill levels. This study aimed to explore the impact of task difficulty on the motor learning benefits of balance exercises.

A sex-stratified, randomized, and non-blinded study was conducted among 40 community-dwelling older adults assigned to either a low- or high-difficulty balance exercise group. The task difficulty was manipulated by altering the support component affixed to an unstable board. Balance performance was measured using a stability index, and functional task difficulty was assessed using the National Aeronautics and Space Administration Task Load Index (NASA-TLX). The experiment included a pre-test, practice trials, and post-test conducted 24 h later. Statistical analyses included analysis of variance and regression analyses to examine the impact of task difficulty on motor learning and the relationship between motor learning benefits and task difficulty.

While both groups showed improved balance performance with practice, the low-difficulty group demonstrated greater motor learning benefits at the 24-h post-test (p < 0.001). Regression analysis showed a curvilinear relationship between the performance dimension score of the NASA-TLX and motor learning benefits (y = -0.017x² + 1.843x - 26.711, adjusted R² = 0.380, p < 0.001).

In balance exercises for community-dwelling older adults, task difficulty significantly influences exercise intervention effectiveness. Our findings contribute to the development of personalized fall prevention programs that adjust task difficulty according to individual skill levels.