Both workout routines made people lift the same total amount of weight over time, so if one built more muscle than the other, it wasn’t because they did more volume — something else must be going on.

We analyzed the available evidence and found that differences in muscle growth can occur even when training volume stays the same. One study showed that two different workout routines led to different amounts of muscle gain, even though both routines involved lifting the exact same total weight over time [1]. This suggests that factors beyond how much weight is lifted — such as how the sets are structured, rest times, movement speed, or muscle activation patterns — might play a role in how muscles respond. What we’ve found so far points to training volume alone not being the only variable that influences muscle growth. When volume is held constant, other elements of the workout may still create different outcomes. This doesn’t mean volume doesn’t matter — it just means that when volume is equal, something else appears to be making a difference. We don’t know exactly what those other factors are from this single assertion, and we haven’t reviewed enough studies to say whether this pattern holds across different people, training levels, or exercises. But the evidence we’ve reviewed so far leans toward the idea that muscle growth isn’t only about total weight lifted. It could also be shaped by how the training is performed — the rhythm, the tension, the way muscles are challenged within each set. For someone trying to build muscle, this means that if you’re not seeing the results you expect, changing your routine — even without adding more sets or weight — might still help. Small adjustments in how you lift could matter just as much as how much you lift.