Electromyography of rapid forearm flexion and extension and aging

This investigation examined several parameters of agonist- and antagonist-muscle activity and movement time in young and old males during rapid, forearm flexion and extension tasks. Maximal isometric strength of the forearm flexors and extensors and limb-volume measurements were also procured. The subject sample included sixteen males in each of the following groups: 1) thirty to forty year olds, 2) fifty to sixty year olds, and 3) sixty-one to seventy year olds. The averaged, electromyographic patterns (AEMG) of the biceps brachii and triceps brachii muscles were recorded during unloaded and loaded trials of forearm flexion and extension to a predetermined target. Sixteen temporal and ten quantitative parameters were examined. Significant differences between age groups were observed for only the quantitative-parameter accuracy. The conclusions were that an individual's agonist- and antagonist-muscle-activity parameters are maintained into the seventh decade. Flexion and extension strengths decrease progressively with age. Analysis of the limb-volume measures revealed that the oldest group had the greatest amount of fat in each of the segments evaluated.