http://www.youtube.com/watch?v=0YiLlJdArec
The proper form: Leg extensions. Choose your weight. Legs under pads, position pads just above your feet. Make sure legs form a 90-degree angle between lower and upper leg. Using your quads, extend legs to maximum while you exhale. Lower your weight back to original position as you inhale. Repeat to your recommended sets and repetitions.
