MariposasTraining Split
A training split is the way you divide your workouts across the week, deciding which muscle groups or movement patterns get trained on which days. The logic behind it is recovery: muscles need time to repair before you hit them hard again, so spreading the work out lets you train with more total volume and intensity than if you tried to do everything in one session. A full-body split trains everything every session, an upper/lower split separates pressing and pulling movements from squatting and hinging, and a body-part split (sometimes called a 'bro split') dedicates each day to one or two muscle groups. The most common mistake people make is choosing a split based on what looks cool in a program rather than what fits how many days per week they can actually train consistently. A four-day upper/lower split done faithfully beats a six-day push/pull/legs split that falls apart by Wednesday. The 'best' split is the one that matches your schedule, recovery capacity, and the specific goals you're training toward.
Example
A lifter who can train four days per week runs an upper/lower split: Monday and Thursday are upper body (chest, back, shoulders, arms), while Tuesday and Friday are lower body (quads, hamstrings, glutes, calves). Each muscle group gets hit twice per week with roughly 48 to 72 hours of rest in between sessions, which tends to suit intermediate lifters chasing size or strength. Swap that same person to a one-day-per-week chest day and the total weekly volume for that muscle drops sharply, usually slowing progress.