Seated Leg Curl vs. Lying Down Leg Curl

Many personal trainers eschew machine exercises because of their inherent noncompound design, but the leg curl is an exception. The leg curl is an effective, basic compound exercise suitable for exercisers ranging from novices to bodybuilders. But some exercisers may be confused as to which of two common leg curl machines -- the lying leg curl machine and the seated leg curl machine -- is more appropriate for their workout routine. These two exercises are similar but have a handful of differences.

Seated Leg Curl

The seated leg curl machine requires you to sit with your legs extended, resting on the leg curl pads. From this position, bend your knees until your feet are under the chair upon which you are sitting. Return your legs to the start position. The resistance of the leg curl machine’s weight will be applied mainly to your hamstrings.

Lying Leg Curl

The lying leg curl machine requires you to lie, face down, with your hips at the highest point on the machine’s bench. Grab the handles at the base of the machine, directly below your head, for support. Position your ankles under the leg curl pads. From here, bend your knees so that your feet move toward your buttocks. A full movement will have the pads touching your behind. Return your legs to the start position.

Benefits of the Seated Leg Curl

The seated leg curl is a more natural position for many exercisers, as the bench of the lying leg curl is not flat but angled. It may then be easier for an exerciser to concentrate specifically on the movement of the legs. Unlike the lying leg curl, the seated leg curl does not place any pressure on your torso or chest, making it much easier for steady, natural breathing. If your leg curls use heavy weights, this can be important, as how you breathe can affect your performance.

Benefits of the Lying Leg Curl

The lying leg curl has one arguable benefit: It works one more muscle than does the seated leg curl. Because of your body's position on a bench, the movement of your leg during a lying leg curl is slightly different and recruits the rectus femoris muscle, a muscle at the front of your thigh. How much this muscle works depends on the angle of the bench, with steeper angles requiring less of this thigh muscle.