How Often Should You Train Each Muscle Group?

How often should you train each muscle group? Twice a week beats once a week for most lifters, according to a 2019 meta-analysis pooling 25 studies and 836 participants. But the same analysis found that frequency itself barely matters once you equalize total weekly volume. The real driver is how many hard sets you accumulate, and frequency is mostly just a scheduling tool for fitting those sets in.

Here's what the research actually measured, and how to use frequency without overthinking it.

How often should you train each muscle group?

For most people chasing muscle growth, twice a week is a reasonable floor. Schoenfeld, Grgic, and Krieger's 2019 systematic review and meta-analysis, published in the Journal of Sports Sciences, pooled 25 studies covering 836 participants and training periods from 6 to 30 weeks. Training a muscle group 2 times a week produced significantly more hypertrophy than training it once a week. That's the headline result, and it's a reasonable default if you're building a split from scratch.

Does frequency matter once volume is equal?

Not much, and this is the part that gets left out of a lot of frequency advice. The same 2019 meta-analysis found that when weekly training volume, meaning total sets per muscle group, was equated between groups, the effect of frequency on hypertrophy was not significant. The advantage for higher frequency only showed up in studies where volume wasn't controlled for. In other words, twice a week usually wins in real life mostly because it makes it easier to fit in more total sets, not because hitting a muscle twice has some separate biological edge over hitting it once.

Why does 2x a week usually outperform 1x a week in practice?

Mostly because a single weekly session struggles to hold enough working sets without your performance falling apart partway through. If you're assigned 16 sets for a muscle group in a week, doing all 16 in one sitting means later sets are done fatigued, at lower quality, with less recovery time before the next session a week out. Splitting those same 16 sets across two sessions lets you train each set closer to full effort and recover between them. Hamarsland and colleagues' 2021 study in Frontiers in Physiology put this to a direct test: 34 resistance-trained men and women were randomized to a moderate-frequency group training 2 sessions a week or a high-frequency group training 4 sessions a week, with total volume matched at 32 weekly sets over 9 weeks. It found no significant difference in muscle or strength gains between the two groups. So once you're above roughly twice a week and volume is controlled, adding more sessions doesn't appear to buy you more growth.

How does this fit into an actual split?

It means you pick a frequency based on how you can realistically fit your weekly volume in, not because a specific number of sessions is magic. A push/pull/legs vs. full body comparison is really a frequency comparison in disguise: full body hits each muscle group more often per week at lower volume per session, while a PPL split hits it less often at higher volume per session. Both can work because progressive overload and total weekly sets are what's driving the adaptation, frequency is just the container.

So what should you actually do?

Pick a frequency, most commonly 2 sessions per muscle group a week, that lets you complete your target weekly volume with sets you can actually perform well, and that fits a schedule you'll stick to. Going higher than 2 isn't wrong, but the evidence doesn't show it's necessary once volume is matched. Going down to once a week works too. It just tends to require cramming in more sets per session than most people can execute at high quality.

Ori doesn't assign you a frequency in isolation. It builds your week around a volume target per muscle group and a schedule you tell it you can keep, then splits that volume across however many sessions actually fit your week.

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