Age-related changes in static and dynamic postural balance performance

Age-related changes in the neuromuscular and sensory systems compromise the control of balance and stability. Static balance assessments may overlook deficits that appear when coping with unexpected perturbations. This cross-sectional study aimed to compare static and dynamic balance performance in younger and older adults to assess age-related differences in postural control between the two age groups.

Sixty-nine younger adults (24.3 ± 0.4 years) and sixty-one older adults (72.1 ± 0.6 years) performed balance assessments under static and dynamic conditions on a force platform. Center of pressure (CoP) was calculated during quiet standing for static balance and during an unexpected perturbation of the base of support for dynamic balance. In the perturbation-based task, the following CoP-related parameters were analyzed within a 2.5-s window from perturbation onset: displacement (Area95D), Mean VelocityD, anterior-posterior first peak (FP), post-perturbation variability (PPV), and maximal oscillations (ΔCoPMax). Sample Entropy (SampEn X and Y) was computed to infer the automaticity of postural control.

In the static test, balance performance did not differ between younger and older adults, although older adults exhibited reduced efficiency (p < 0.05). Dynamic balance showed age-related differences, with older adults highlighting larger Area95D (p < 0.001), higher Mean VelocityD (p < 0.001), and greater FP (p < 0.05). SampEn X did not differ between groups, whereas SampEn Y was lower in older adults (p < 0.001).

Age-related changes in balance control are task dependent. Older adults preserved static balance performance but demonstrated impaired reactive balance responses in dynamic tasks. Furthermore, static and dynamic balance rely on distinct control mechanisms, highlighting the need for separate assessments.