A hang clean is an explosive exercise for the legs. Load a barbell and hold it down infront of you with your knuckles out (underhand). Bend at the knees as if you are doing a squat but do not go down quite as far. Then explosively push up with your legs and move your arms slightly enough to direct the barbell upwards. By the time your feet are flat on the ground again, your arms should be bent at the elbows with your hands right up against your shoulders holding the barbell. Bend at the knees right as you "catch" the barbell to reduce the impact and stand back up. Move your arms forward and lower the barbell to starting position.
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