Building on previous data that tentatively supports the possibility that power training could induce changes in neuromuscular activation during level walking in older adults, researchers tested the effects of a 10-week program of lower extremity power training on gait velocity and neuromuscular activation of lower extremity muscles during level walking in healthy older adults. The researchers hypothesized that power training produces correlated improvements in gait velocity and increases in agonist activation, or decreases in antagonist coactivation.
Study subjects were age 65 or older and were drawn from the Potsdam Gait Study. The lower extremity power-training program consisted of 30 sessions over 10 weeks designed to improve lower extremity power with a program of leg press, ankle press, knee extension, and knee flexion exercises, using bilateral movements, performing 3 sets of 6-10 repetitions at 40-60% of 3-repetition maximum.
Surface EMG activity was recorded from 5 muscles of the right leg. Data from 12 participants were included for the analysis of the power training intervention, and 13 from the control group. The researchers found that in addition to gains in maximal EMG amplitudes and isometric strength, older adults demonstrated elevated knee extensor activation and coactivation during early stance, and elevated plantarflexor activation during push-off. The data suggest that the power training-induced increases in agonist muscle activation underlay the increases in isometric muscle strength and gait velocity.
While noting that future studies should determine if power training increases hip muscle activation during gait, the researchers concluded that a 10-week power-training program improved agonist muscle activation during isometric actions and during walking, and that the power training-induced increases in agonist muscle activation may have a role in isometric strength and fast gait velocity.
Beijersbergen, CMI, Granacher U, Gäbler M, et al. Power training-induced increases in muscle activation during gait in old adults. Med Sci Sports Exerc. 2017;49:2198-2025.