This exercise is a variation of barbell squats that will help to strengthen the hip flexors. This exercise can be helpful to lifters that have trouble at the bottom of the squat.
Begin by placing a bench or box behind you so that you squat down in front of it. Next, place a barbell onto a rack that is slightly lower than shoulder height. Step under the bar and place across your back, like a normal squat. Use your legs to lift the bar out of the rack and step back into your squatting stance. Begin the movement by pushing your hips back and bending through your knees. Continue to bend through the knees and sit back until your glutes touch the bench. Do not place all of the weight onto the bench, keep your back tight and make sure that your knees have not gone past your toes. Next, push through your heels and raise the bar back to the starting position. Repeat this movement until you have completed your set.
Make sure to keep your upper back tight as well as your core muscles. Try to pull your elbows together and drive your traps into the bar.
Do not allow your body to fall onto the box; slowly lower your body until you touch the bench. Slamming your body onto the bench will cause lower back injuries.