The influence of sex, training intensity, and frequency on muscular adaptations to 40 weeks of resistance exercise in older adults

Exp Gerontol. 2021 Jan:143:111174. doi: 10.1016/j.exger.2020.111174. Epub 2020 Nov 26.


The purpose of this investigation was to identify the influence that sex, training intensity, and frequency have on long-term resistance exercise (RE) outcomes in older adults.

Methods: One-hundred eleven older adults (men: 41, women: 70) completed either: high-intensity RE 2d/week (HI-2D; n = 29), low-intensity RE 2d/week (LI-2D; n = 32), high-intensity RE 3d/week (HI-3D, n = 20), or low-intensity RE 3d/week (LI-3D, n = 30). HI protocols completed 3 sets of 8 repetitions with 80% one-repetition maximum (1-RM) while LI completed 3 sets of 16 repetitions with 40% 1-RM. Total and regional bone free lean body mass (BFLBM) were assessed via dual-energy x-ray absorptiometry and cross-sectional area (mCSA) of the rectus femoris.

Results: mCSA was the only muscle quantity parameter to increase (p = 0.043). Significant trial effects for upper body, lower body, and specific strength were observed (all p < 0.001). Significant sex × time interactions (p < 0.001) were observed for upper and lower body strength, however, men and women displayed similar increases in lower body (45.7 ± 29.6 vs 46.4 ± 34.9%), upper body (33.1 ± 21.0 vs 33.4 ± 24.7%), and specific strength (36.5 ± 28.5 vs 40.1 ± 28.7%). A group × time interaction for lower body strength indicated that at 20-weeks HI-2D and LI-3D displayed greater lower body strength than LI-2D (both p < 0.009), and at 40-weeks HI-2D, HI-3D, and LI-3D displayed significantly greater lower body strength than LI-2D (all p < 0.038).

Conclusions: These observations indicate that older men and women display similar long-term RE outcomes. Additionally, regardless of frequency or intensity, the current prescriptions were effective for increasing strength, however these data suggest HI-2D > LI-2D and LI-3D > LI-2D but similar outcomes among HI-2D, HI-3D, and LI-3D. The variety of effective RE approaches provides flexibility among older adults for selecting a lifestyle intervention that would be most sustainable.

Keywords: Exercise; Intervention; Physical activity; Sarcopenia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon
  • Aged
  • Body Composition
  • Exercise
  • Female
  • Humans
  • Male
  • Muscle Strength
  • Muscle, Skeletal
  • Quadriceps Muscle
  • Resistance Training*