Effects of short-term multicomponent exercise intervention on muscle power in hospitalized older patients: A secondary analysis of a randomized clinical trial

Background Bed rest during hospitalization can negatively impact functional independence and clinical status of older individuals. Strategies focused on maintaining and improving muscle function may help reverse these losses. This study investigated the effects of a short-term multicomponent exercise intervention on maximal strength and muscle power in hospitalized older patients.Methods This secondary analysis of a randomized clinical trial was conducted in an acute care unit in a tertiary public hospital. Ninety (39 women) older patients (mean age 87.7 +/- 4.8 years) undergoing acute-care hospitalization [median (IQR) duration 8 (1.75) and 8 (3) days for intervention and control groups, respectively]) were randomly assigned to an exercise intervention group (n = 44) or a control group (n = 46). The control group received standard care hospital including physical rehabilitation as needed. The multicomponent exercise intervention was performed for 3 consecutive days during the hospitalization, consisting of individualized power training, balance, and walking exercises. Outcomes assessed at baseline and discharge were maximal strength through 1 repetition maximum test (1RM) in the leg press and bench press exercises, and muscle power output at different loads (<= 30% of 1RM and between 45% and 55% of 1RM) in the leg press exercise. Mean peak power during 10 repetitions was assessed at loads between 45% and 55% of 1RM.Results At discharge, intervention group increased 19.2 kg (Mean A% = 40.4%) in leg press 1RM [95% confidence interval (CI): 12.1, 26.2 kg; P < 0.001] and 2.9 kg (Mean Delta% = 19.7%) in bench press 1RM (95% CI: 0.6, 5.2 kg; P < 0.001). The intervention group also increased peak power by 18.8 W (Mean Delta% = 69.2%) (95% CI: 8.4, 29.1 W; P < 0.001) and mean propulsive power by 9.3 (Mean Delta% = 26.8%) W (95% CI: 2.5, 16.1 W; P = 0.002) at loads <= 30% of 1RM. The intervention group also increased peak power by 39.1 W (Mean Delta% = 60.0%) (95% CI: 19.2, 59.0 W; P < 0.001) and mean propulsive power by 22.9 W (Mean Delta% = 64.1%) (95% CI: 11.7, 34.1 W; P < 0.001) at loads between 45% and 55% of 1RM. Mean peak power during the 10 repetitions improved by 20.8 W (Mean Delta% = 36.4%) (95% CI: 3.0, 38.6 W; P = 0.011). No significant changes were observed in the control group for any endpoint.Conclusions An individualized multicomponent exercise program including progressive power training performed over 3 days markedly improved muscle strength and power in acutely hospitalized older patients.