Hamstrings: Single-leg bodyweight deadlift
Deadlifts offer a killer hamstring workout, but they're hard to perform without dumbbells or a barbell. The single-leg deadlift unilaterally targets each hamstring while using your bodyweight as resistance. Focus on using your working hamstring to control your movements, not your low back.
Stand with your feet hip-distance apart, your knees slightly bent. Shift your weight to your left foot, keeping your weight in your heel. Lift your right foot from the ground and extend it behind you, your toes touching the ground lightly.
Tighten your core, and keeping your torso completely straight from your hips to your head, press your hips backward as you tilt your torso forward toward the floor, using your left hamstring to control and support the action. You can leave your right toes on the ground for balance, or to make the exercise harder, allow your right foot to lift from the ground, extending behind you as your torso tilts forward. The goal is to get your torso to a parallel position with the ground, but if your hamstrings are tight, only lower as far as you comfortably can. From the lowest point, tighten your left hamstring and glute and use it to "pull" your torso back to the starting position. Perform 10 to 15 repetitions before switching sides.