The relationship between muscle and balance performance as a function of age

Aging is associated with decreases in strength and muscle mass. In addition, the ability to maintain balance decreases with age. Few studies have examined the relationship between isokinetic muscle performance and balance performance. It was the purpose of this study to determine if there is a relationship between muscle and balance performance, and to discover how this relationship is affected by age. Fifty-five healthy females were recruited from two different age groups, 28 females who were 18-30 years of age {mean age = 22.9 years ( ± 3.4), height = 163.5 cm (±6.5), weight = 64.8 kg (± 15.7)) and 26 females who were > 60 years of age {mean age = 68.1 years (+ 4.8), height = 159.7 cm (± 10.0), weight = 68.0 kg (± 11.4)1. Concentric and eccentric isokinetic muscle performance for the hip, knee, and ankle was measured using the KinCom isokinetic dynamometer. Balance performance was measured using the sharpened Romberg and one-legged stance tests. Younger subjects performed significantly better than older subjects on all muscle and balance performance variables (P = 0.05 to P = 0.0001), except the sharpened Romberg test with the eyes open. The older group exhibited significant relationships between balance and muscle performance measures (r — 0.10 to r — 0.57). In the older group, hip muscle performance was shown to correlate significantly better with balance performance than knee or ankle muscle performance. Also noted was a significantly greater relationship between muscle performance and balance performance with the eyes closed in the older group, as compared to the younger group. This is the first study known to thoroughly examine the relationship between muscle and balance performance. The presence of significant relationships warrants further examination. It is recommended that this relationship be examined in a broad spectrum of young, old, healthy and disabled populations.