How many times a week should I train each muscle group?

The question looks like it is about a schedule, but the research keeps pointing back to something else: your total volume across the week. In 2016 Schoenfeld and colleagues pooled ten studies and found that training a muscle twice a week produced more growth than once a week. The conclusion spread quickly as "more often is better". But in most of those studies the higher frequency also carried more volume, so the two could not be separated.

When the same group reran the analysis in 2019 across twenty-five studies, this time holding volume equal between groups, the difference disappeared. Frequency did not meaningfully affect growth once the number of sets was the same. Their conclusion was that you can pick a frequency to suit your week.

For strength, Ralston and colleagues point the same way. Across twelve studies there was a weak trend favouring higher frequency, but it was not statistically reliable, and once volume was equated the strength gain was essentially identical regardless of frequency. What looked like a frequency effect was really just more training.

The takeaway is calm and usable. First decide how many hard sets per muscle you want across a week. Then split them over as many sessions as fit your life. Twice a week per muscle group is a practical rule of thumb, mostly because it makes the volume easier to gather without any single session running absurdly long, not because the muscle counts the days.

The idea that more often is always better survives on how the first headline sounded. The 2016 conclusion, train twice a week, was correct, but it got read as if frequency itself were the engine long before the volume-controlled follow-up arrived. More sessions also feel like more devotion, and devotion feels like results. Then come the incentives. A program of six short sessions a week sells more plans and fills more calendar slots than "do two sessions and count your sets". Split schedules where each muscle gets its own day also carry a long gym tradition that makes them hard to question.

Count sets per muscle across the whole week instead of chasing a set number of sessions. Land on a volume you can actually recover from, often around ten hard sets per muscle group, and spread them over two sessions or more. If you train full body, two or three sessions a week works well; if you run a split, each muscle still gets trained a couple of times. Choose what you will actually keep doing over months. And remember that muscles only build what you feed them, so enough daily protein belongs alongside the volume.