How many times a week should you train a muscle to grow?

What is training frequency?

Frequency can mean how many sessions you do a week or, what matters here, how many times a week the same muscle is trained (Schoenfeld et al., 2016). Three sessions a week can still train your hamstrings only once.

How long does one session keep your muscle building?

After a session, your muscle builds more of the proteins that make it grow. After a heavy session, this building rises fast and is more than double 24 hours later. In 6 young men who had done 12 sets of elbow flexion with one arm, it was almost back to the other arm’s level 36 hours later: a day and a half (MacDougall et al., 1995).

The more hard sets in the session, the higher and longer it goes. In 8 trained men, on one-leg extensions to exhaustion, three sets pushed it to 3.1 times rest 5 hours later, versus 2.3 times with one; 29 hours later, it was still at 2.3 times with three sets, back to rest with one (Burd et al., 2010).

One big session or three small ones?

In 20 students who hadn’t lifted for at least a year, the same 12 sets of leg extensions a week, at 67% of max: 6 sets of 12 in one session, or 2 sets of 12 three times. Eleven weeks later, quad thickness and thigh girth had grown just as much in both groups. But six sets in one go felt much harder to them: perceived effort of 7.3 to 8.3 out of 10, versus 4.3 to 5.3 with two (Ochi et al., 2018).

Across 25 studies, with equal sets, frequency doesn’t change growth, trained lifters included, upper or lower body (Schoenfeld et al., 2019). In 23 men training for 7 years on average, each muscle once or five times a week with the same sets: the same lean mass gained in 8 weeks (Gomes et al., 2019). In 27 trained men, three or six sessions a week at equal volume: comparable muscle thickness in 6 weeks (Saric et al., 2019). Across 67 studies, the effect of frequency on muscle size remains compatible with a negligible effect (Pelland et al., 2026).

Should you train each muscle at least twice a week?

The advice comes from an analysis of 10 studies: two sessions per muscle a week did better than one there, hence “at least twice a week” (Schoenfeld et al., 2016). The same researchers, with 25 studies in 2019, no longer find a difference with equal sets; only studies where coming more often meant more sets favor higher frequency, and modestly (Schoenfeld et al., 2019). So coming more often only helps if it makes you do more sets.

What about lifting heavier?

For strength, doing an exercise more often may help a little. Across 67 studies, strength rises with frequency, but less and less (Pelland et al., 2026). An older analysis of 22 studies found no clear effect at equal volume: the edge came mostly from the extra sets (Grgic et al., 2018). In the student study, strength measured with the leg held still rose 65% with three sessions versus 44% with one, while estimated max improved in both groups (Ochi et al., 2018).