The Bulgarian split squat is a single leg squat performed with the rear foot elevated on a bench behind you. It loads the quadriceps and glutes of the front leg hard while demanding balance, hip mobility and core control. Lifters use it to build leg strength one side at a time, fix left to right imbalances, and get squat like stimulus with only bodyweight or light loading.
The Bulgarian split squat is arguably the best single-leg builder in the gym, and it deserves a real slot in your program rather than a token set at the end. Run it for 3 to 4 sets of 8 to 12 reps per leg, once or twice a week, either as the second movement after squats or as the main lower body lift on days when your lower back needs a break from heavy bilateral work.
Load it with dumbbells at your sides until grip becomes the limit, then move to a barbell on the back or a single heavy dumbbell in the goblet position. Always start each set with your weaker leg and match the reps on the stronger side, since letting the strong leg do extra work quietly widens the imbalance you are trying to close. A rear foot placed on a bench around knee height works for most people.
One leg is handling most of the load through a long range of motion while also stabilizing, which produces a deep burn and notorious next-day soreness. That fades substantially after two to three weeks of consistent exposure.
Both are valid, they just shift the emphasis. An upright torso biases the quads of the front leg, while a moderate forward lean loads the glutes more. Pick the lean that matches your goal and keep it consistent.
For hypertrophy and general strength, yes, many lifters train productively for long stretches on split squat variations alone. If your goal includes a bigger barbell squat number, keep some bilateral squatting in the plan.
Log your bulgarian split squat sets in 1RM.fit and watch your estimated 1RM update automatically as you get stronger.