Push pull legs vs upper lower for size

Before comparing the two splits, it helps to name what actually grows muscle. It is not the label on your training day. It is three things: enough hard weekly volume for each muscle, enough frequency to spread that volume across the week, and steady progressive overload so the work gets harder over time. A split is just how you arrange those ingredients across your calendar.

Once you see it that way, the question push pull legs or upper lower stops being a battle of philosophies. Both are perfectly good arrangements. The one that grows more muscle is the one that lets you hit your target volume, at a good frequency, on the number of days you can actually keep showing up for.

Upper lower divides the body in half. Upper days cover chest, back, shoulders, and arms. Lower days cover quads, hamstrings, glutes, and calves. You alternate between the two.

The reason it is such a strong size split at 4 days a week is that the twice-a-week frequency is baked in. Upper, lower, rest, upper, lower, then two days off, and every major muscle group gets two sessions. That structure spreads your volume across two exposures instead of cramming it into one, which tends to grow more muscle for the same total sets.

Push pull legs groups muscles by their job in a movement. Push day is the pressing muscles: chest, shoulders, and triceps. Pull day is the pulling muscles: back and biceps. Legs day is everything below the waist.

For size, the appeal of PPL shows up on 6 days a week. Run the three days once and you have a 3-day week where each muscle is trained once. Run the cycle twice and you have six sessions, each muscle trained twice, with room for a lot of focused volume per muscle group. That is where PPL earns its reputation as a bodybuilding split.

Strip away the names and both splits are really about the same two levers: how much weekly volume each muscle gets, and how many sessions that volume is spread across. Here is how the two compare as you add days.

A meta-analysis by Schoenfeld and colleagues found that, when total weekly sets were matched, training a muscle at least twice a week tended to produce more growth than training it once. A separate review from the same group found that muscle growth keeps climbing as weekly sets per muscle rise, at least into the range of about ten or more hard sets. Put those together and the pattern is clear: get your volume in, and spread it over two or more days.

Forget which split is theoretically superior. Start from the number of days you can commit to, then let that decide.

1. Training 3 days? Honestly, neither is the ideal size split here. A full-body plan usually grows more because it hits everything multiple times a week. If you insist on one of these two, PPL run once works, but accept the once-a-week frequency.
2. Training 4 days? Upper lower is the stronger size pick. Twice-a-week frequency, sensible session length, and it survives a missed day. This is its home turf.
3. Training 5 days? Either flexes to fit. An upper lower with an added arm or weak-point day, or a PPL with a rest slotted in, both work well for growth.
4. Training 6 days? Push pull legs, run twice through. Two focused sessions per muscle with plenty of volume is exactly what this split does best.
5. Whatever you pick, be honest about consistency. A 4-day plan you actually finish beats a 6-day plan you abandon by Thursday. The split you keep grows more muscle than the split you admire.