Ankle force and rate of force production increase following high intensity strength training in frail older adults

Abstract

Background and aims: The most common cause of accidental injury and death in people over age 65 results from impacts associated with falling. Balance impaired older adults have poorer balance control than healthy young adults or healthy older adults. Lack of sufficient lower extremity strength and inability to rapidly produce muscle force may contribute to diminished balance control in the elderly. This study evaluated the effect of a 10-week high intensity strength-training program targeting key lower extremity muscles for the purpose of improving postural control in frail older adults.

Methods: Thirteen experimental and fourteen control subjects, all balance impaired older adults were evaluated in response to unexpected platform perturbations that simulated slips.

Results: Following strength training the experimental group was significantly stronger than the control group. Mean ankle moments improved in the experimental group following strength training during forward sway (Right: p=0.067, Left: p=0.009) and backward sway (Right: p=0.031, Left: p=0.058). For the backward sway condition the ankle rate of torque production increased significantly in the experimental group (Right: p=0.016, Left: p=0.031).

Conclusions: Enhancement of lower extremity strength contributed to improvements in balance stability demonstrated by greater ankle force production, in response to balance threats.