Standard lunge and split squat form doesn't hit your glutes and hams much, and it can cause knee issues. The fix? Lean forward with a straight back.
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Hinge at your hips and lean your torso slightly forward at roughly a 45-degree angle while keeping your back straight. Do this for reverse lunges, walking lunges, or Bulgarian split-squats. At the bottom of each rep, the dumbbells should be on each side of your front foot instead of by your hips, which is where they'd be if you were performing this exercise in the normal manner with an upright torso.
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Leaning your torso forward increases the recruitment of the glutes and hamstrings. Doing this places less force on your knee joint and therefore demands less activation of the quadriceps. (If you're targeting the quads, then skip this variation. Include both torso positions in your lower-body training.) Doing these exercises with a forward torso lean can be especially helpful to females since women are more quad-dominant than men, tend to have weaker hamstrings, and may be more prone to knee injury.