Is One Strength-Training Session a Week Enough to Stay Strong as You Age?

Short answer: in two small trials of healthy adults 65 to 79, one hard session a week built as much strength as two or three. But the picture changes fast. In older adults who were already active, only twice-weekly heavy training clearly beat doing no resistance training, and across the reviews, gains in muscle size were smaller and less consistent than gains in strength. It depends on who you are and what you are measuring.

The “once a week is enough” claim is real, for strength, in small trials. The anchor study is Taaffe (1999), a randomized trial of 46 healthy adults 65 to 79 who trained one, two or three times a week for 24 weeks, three sets of eight reps at 80% of their one-repetition maximum. Strength rose in every training group, with no difference among the three frequencies: 37.0%, 41.9% and 39.7%, versus 3.9% for the control group (Taaffe 1999). A timed chair-rise test, a marker of everyday function, improved in the exercise groups. A smaller 2007 randomized trial (DiFrancisco-Donoghue 2007; 18 adults 65 to 79, 9 weeks, one set to fatigue) found the same thing: once a week matched twice a week on one-rep-max strength. For a healthy older adult, a single hard session a week is clearly not a waste.

But “stronger” is not the same as “bigger.” Grgic (2020), a meta-analysis of 22 randomized trials in people 75 and older, found significant strength gains, including in those 80 and over (effect size 1.28). Whole-muscle size also increased, but the effect was small (0.30), and there was no significant difference from controls in handgrip strength (p=0.064) or muscle-fiber growth (p=0.266). Two newer reviews in older adults with sarcopenia point the same way. Ran et al. (2025) found moderate gains in grip strength and physical function but no significant change in muscle-mass index, and Tan et al. (2026) found a strength effect of 0.71 against a lean-mass effect of 0.22. A once-a-week randomized trial in 25 breast-cancer survivors (Santos 2019) improved bench- and leg-press strength over 8 weeks but detected no body-composition change. So the honest claim is this: resistance training reliably builds strength. Gains in muscle size are smaller and less consistent.

For people who are already active, once a week can under-deliver. Richardson (2019) randomized 54 moderately to highly active but resistance-untrained adults 60 to 79 (50 analyzed) to once- or twice-weekly training at a high load (7 reps at 80% of one-rep max) or a low load (14 reps at 40%) for 10 weeks, or to a no-exercise control group. Only twice-weekly high-load training beat the control group on chair-stand, arm curl and grip; once-weekly high-load and twice-weekly low-load each beat it on just two of eight lifts (Richardson 2019). The authors put this down to effort: sessions need enough intensity and volume.

How much is actually enough? The dose-response reviews point to two or three sessions a week. Rhea (2003), a meta-analysis of 140 studies not limited to older adults, put the peak for untrained people at 60% of a one-rep max, three times a week, and for trained people at 80%, two times a week, with four sets per muscle group best for both. Borde (2015), reviewing 25 randomized trials in healthy older adults, found the largest strength gains at two sessions a week, two to three sets, seven to nine reps and 70 to 79% of a one-rep max, with the important caveat that trial quality was poor (mean quality score 4.6) and heterogeneity high (I-squared 80%). Tan et al. (2026) estimated that about 1,043 cumulative minutes of training were associated with maximal strength gains in sarcopenic adults, a figure the authors call exploratory. Lan et al. (2026) found that in eccentric-overload training, more than two sessions a week was more effective for lower-limb strength, while two or fewer appeared better for explosive power.

It depends on who you are. The big-picture reviews (Liu 2009, a Cochrane review of 121 trials and 6,700 people; Grgic 2020; Ran 2025) show that resistance training helps strength and function in older adults. In a network meta-analysis of 47 studies, the largest grip and timed-up-and-go gains came from multicomponent exercise combined with nutritional support, followed by resistance training plus nutritional support (López-González 2026). For one measure of thinking, the once-versus-twice gap was small: in a 12-month trial of 155 women 65 to 75, Stroop-test performance improved 12.6% with once-weekly and 10.9% with twice-weekly training, versus a 0.5% decline in controls (Liu-Ambrose 2010). The sarcopenia and cancer-survivor trials are context here; they are not a prescription for a healthy 45-year-old who wants to maintain strength.