Effects of Three Different Low-intensity Exercise Interventions on Physical Performance, Muscle CSA and Activities of Daily Living: a Randomized Controlled Trial

Objectives: To evaluate the short-term effects of three different resistance training programs, conducted at low intensity, on physical performance, muscle cross-sectional area (CSA) and the capacity to perform daily tasks in older adults living in a geriatric nursing home.

Design: Randomized controlled trial, with a 4-month intervention period.

Setting: A geriatric nursing home in Valencia, Spain.

Participants: Eighty-nine adults aged 75 to 96 who were independent in their daily activities.

Intervention: After a baseline assessment, the participants were randomly assigned to the control group or one of the three intervention groups: volitional contraction (VC; n=22), neuromuscular electrical stimulation (NMES; n=22), or neuromuscular electrical stimulation superimposed onto voluntary contractions (NMES+; n=22). The intervention focused on knee extension exercises and its intensity was set at 40% of one-repetition maximum (1RM).

Measurements: The primary outcome measure was mobility. Secondary outcomes were rectus femoris CSA, balance, aerobic endurance, upper-body strength and the capacity to perform daily tasks. All data were collected at baseline and after the 4-month intervention period.

Results: The two-way ANOVA analysis showed a significant group×time interaction effect for the mobility (P=.022), rectus femoris CSA (P=.001), and the capacity to perform daily tasks (P=.05). The within-group analysis found a more prominent effect in the NMES+ group. Significant improvements were seen in rectus femoris CSA and the capacity to perform daily tasks in all intervention groups. Mobility only improved in the NMES+ group (P=.026).

Conclusion: From a short-term perspective, NMES+ exercise training, performed at low intensity, can improve physical performance, muscle CSA, and the capacity to perform daily activities, and to partially mitigate age-related consequences in older adults.