The hamstrings are the primary muscles worked during a power clean, but other muscles worked include the shoulders, forearms, calves, lower back and triceps. The exercise uses a pulling movement.
A power clean begins with the lifter standing over a barbell, with his feet about hip-width apart and the balls of the feet underneath the barbell. He squats down to grab the barbell with an overhand grip and the hands a bit more than shoulder-width apart. The back is kept arched.
The hips and knees are extended to pull the bar off the floor to the lifter's knees. He raises his shoulders to lift the barbell further. The barbell is kept near the thighs as it rises before touching them towards the top. Once his legs are fully extended, he stands on his toes and shrugs his shoulders while exhaling to lift the barbell. He pulls his body under the bar and turns his elbows.
The legs can bend as he lifts the barbell, but the knees shouldn't be lower than 90 degrees. After he catches the barbell on his shoulders, he stands up completely.
To lower the barbell, he bends his knees slightly while lowering the barbell from his shoulders to his thighs. He then lowers it to the ground by squatting. Another method is unloading, where the barbell is dropped from the top position. This is typically done by advanced athletes, but rubber weight plates and a sturdy floor are necessary.