Once-weekly resistance exercise improves muscle strength and neuromuscularperformance in older adults

OBJECTIVE: To determine the effect of frequency of resistive training on ga in in muscle strength and neuromuscular performance in healthy older adults . DESIGN: A randomized controlled trial with subjects assigned either to high -intensity resistance training 1 (EX1), 2 (EX2), or 3 (EX3) days per week f or 24 weeks or to a control group (CO). SETTING: An exercise facility at an academic medical center. SUBJECTS: Forty-six community-dwelling healthy men (n = 29) and women (n = 17) aged 65 to 79 years. INTERVENTION: Progressive resistance training consisting of three sets of e ight exercises targeting major muscle groups of the upper and lower body, a t 80% of one-repetition maximum (1-RM) for eight repetitions, either 1, 2, or 3 days per week. MEASURES: Dynamic muscle strength (1-RM) using isotonic equipment every 4 w eeks, bone mineral density and body composition by dual energy X-ray absorp tiometry (DXA), and neuromuscular performance by timed chair rise and B-met er backward tandem walk. RESULTS: For each of the eight exercises, muscle strength increased in the exercise groups relative to CO (P < .01), with no difference among EX1, EX2 and EX3 groups at any measurement interval. Percent change averaged 3.9 +/ -: 2.4 (CO), 37.0 +/- 15.2 (EX1), 41.9 +/- 18.2 (EX2), and 39.7 +/- 9.8 (EX 3). The time to rise successfully from the chair 5 times decreased signific antly (P < .01) at 24 weeks, whereas improvement in the 6-meter backward ta ndem walk approached significance (P = .10) in the three exercise groups co mpared with CO. Changes in chair rise ability were correlated to percent ch anges in quadriceps strength (r = -0.40, P < .01) and lean mass (r = -0.40, P < .01). CONCLUSIONS: A program of once or twice weekly resistance exercise achieves muscle strength gains similar to 3 days per week training in older adults and is associated with improved neuromuscular performance. Such improvement could potentially reduce the risk of falls and fracture in older adults.