Stand with one foot flat on the ground and the other leg extended behind you, with only your toes and the ball of your foot on the ground. Place the resistance band under your front foot, and hold the end up by your shoulders, palms facing in and elbows tucked to your sides.
Slowly drop your back knee, keeping your hips stable as your front knee bends with it. Stop when both knees are at a 90-degree angle and there's a straight line from your neck to your hips and down to your back knee.
Press through your front heel as you return to starting position.