February 16, 2016
One area in which older adults can easily make a difference in their health is to add exercise—particularly strength training—to their daily routine. Physical training has been shown to improve muscle activation in older individuals, yet, it is unknown whether this translates into improvements in physical performance.
Investigators from the University of Southern Denmark and the University of Pittsburgh presented a study of mobility-limited older individuals participating in the Healthy Ageing Network of Competences (HANC) study who were assessed for: (1) knee extensor muscle strength (maximal voluntary isometric contraction, 70° knee joint angle) using the KinCom isokinetic dynamometer; (2) muscle activation using the superimposed twitch technique; and (3) 2-minute maximal walk test speed (2MWT) using a 10-m corridor.
Participants were randomly allocated to either the control group (n=21; mean age, 82±1 years) or the train group (n=16; mean age, 82±1 years), with the latter group undergoing 12 weeks of progressive high-intensity power training.
The investigators reported greater improvements in the train group versus the control group for strength (14.14±4.3 Nm vs 0.77±2.66 Nm; P < 0.05), muscle activation (6.05±2.31% vs -0.16±1.89%; P < 0.05), and 2MWT (0.09±0.02 m/s vs -0.03±0.02 m/s; P < 0.05). Changes in muscle activation correlated with changes in strength (r=0.54; P < 0.05) and in 2MWT (r=0.67; P < 0.05). The present findings verify that improvements in knee extensor muscle activation induced by power training translate into improvements in muscle strength and walking speed in mobility-limited older individuals.