One-legged Bosu squat
Setup: Stand on the dome of a Bosu and lift one foot. Extend your arms to the side and focus on a spot on the floor several feet in front of you. Tighten your abs and square your hips. Move: Slowly bend your knee and squat down as low as you can, keeping your chest lifted and your shoulders back. Feel free to move your arms forward or to the side to help balance, as shown. Extend your leg to return to the start. Do all reps on one side before switching. Tip: Your ankle will work double time here to keep you steady on an unstable surface. Split your sets into smaller groups of reps to prevent burnout of those tiny muscles.