You finish your bench-press sets and look at the week ahead: two gym visits fit, but a four-day split looks more serious. A trial in women new to regular lifting tested that choice. The extra visits produced no clear advantage when both schedules kept the weekly exercises, sets and repetitions the same.
A training split describes how you distribute exercises across the week. To compare it fairly with a full-body routine, count the work each muscle receives, rather than treating every gym visit as another session for every muscle.
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Two longer sessions, four shorter ones
In the 12-week trial published in 2022, researchers in Norway randomized 50 young adult women who had not trained regularly in the previous six months. Forty-four completed the study.
One group performed all 10 exercises in each of two full-body sessions. The other split them into six upper-body exercises on two days and four lower-body exercises on two other days. Both groups trained each muscle group twice weekly.
Both improved their bench-press, lat-pulldown and leg-press strength, with no statistically significant differences between schedules. This was a study of beginners over 12 weeks; the result does not establish that every possible two-day and four-day routine is equivalent.
The same weekly work has to go somewhere
The American Council on Exercise’s programming guidance explains why weekly volume matters when comparing schedules. One way to count it is sets multiplied by repetitions. Another also includes the weight lifted.
Consider a simple bench-press example: three working sets on Monday and three on Thursday gives six sets that week. Those six sets remain six whether the sessions also include legs or sit inside an upper/lower split. Four gym visits do not automatically double the chest work.
Nearly all completed sessions were supervised, and the weights progressed during the intervention. The trial tested two ways to organize a structured program, with each group following the same exercise and repetition plan throughout the week.
A 2024 review of 14 studies involving 392 participants also reported no significant strength or muscle-growth advantage for split versus full-body routines when training volume was equated. That condition matters: it does not compare a high-volume split with a much smaller full-body program.
Compare the plan beyond its name
“Split” covers several arrangements. A bro split typically assigns individual body parts to different days. The Norwegian trial used an upper/lower split, so its four-day schedule should not be mistaken for a five-day body-part routine.
Before replacing a full-body plan with a split, compare what each muscle will actually do across the week: the exercises, working sets, repetitions and loads. Check where that work lands, too. Two plans with different numbers of gym visits can still train a muscle on the same number of days.
A split may be useful when you want to distribute more work across shorter visits. A full-body arrangement may fit a week with fewer available days. Choose between those practical demands after comparing the training itself, rather than using the number of gym visits as a score for the program.