Motor skill learning of concentric and eccentric isokinetic movements in older adults

Neuromuscular adaptation at the onset of resisted exercise can be observed as ina eases in. torque and surface electromyography. The effect of learnin g the motor task has been hypothesized to contribute to these early increas es, especially for older people. Thus, the purpose of this study was to inv estigate the facilitatory effects of practice on motor performance in older adults during short-term isokinetic training of the ankle dorsiflexors (DF ). Twenty-eight men and women (M = 76.3 +/- 4.6 years) volunteered for a 2- week, 3-days/week strength training program. They were tested in a sitting position on a KinCom isokinetic dynamometer at 30, 90, and 180 degrees s(-1 ) through 40 degrees of DF movement (concentric and eccentric contractions) . Criterion curves of lever arm angle patterns were cross-correlated with s ubject-generated angle patterns, showing significantly better correlations on posttest versus baseline. Smoothness and proficiency of muscle contracti on improved with practice by fewer hesitations in movement and increased ab ility to change between concentric and eccentric muscle contractions. Incre ased agonist electromyography and torque were hypothesized to be secondary to greater neural drive and/or synchronisation of motor unit firing rate an d/or recruitment during maximal voluntary contraction, improved coordinatio n, and adapted neural control of concentric and eccentric muscle contractio n.