Bulgarian Split Squat on Box

The bulgarian split squat rests the top of the rear foot on a box and works almost entirely on the front leg. That distribution is its great virtue: you achieve a very high load on one side with a moderate total weight, so the spine carries far less than an equivalent bilateral squat would demand. The quadriceps and glute of the supporting leg do the work, and the hip of the trailing leg is stretched on every repetition. The distance between the feet decides the emphasis: the further forward you place the front foot, the more the glute contributes, and the closer it sits, the more the work falls on the quadriceps. The back foot provides balance only and should never push. If you notice yourself driving off it, reduce the load and check the setup again.