Instructions
Position a barbell on the floor just behind your legs legs. Place a foam roller behind your lower back. With a narrow stance and your feet flat on the floor, squat down, allowing the roller to roll up your back, and grasp the barbell from behind with an overhand grip.
Whilst keeping yourself against the roller, lift the bar by straightening your legs. Squat down by bending your hips back and bending your knees forward. Descend until your thighs are at or below parallel to floor. Repeat for the desired number of repetitions.