Lying Leg Curl

The leg curl is the only exercise in which you can train the hamstrings (and the weaker sartorius) in isolation from other muscle groups. The hamstrings perform the function of bending the knee and are assisted in this by the weaker sartorius muscle.

In this variation, a machine is used on which you can perform the exercise lying down.

Lying leg curl execution

Bring your heels toward your buttocks until you cannot go any farther. Prevent your thighs from lifting along with the movement by keeping them pressed against the lying pad.

Hold the tension briefly.

Return your feet backward and downward in a controlled manner, stopping when your legs are almost straight.

Lying leg curl setup

(also see the instructions on the machine)

Lie down at the correct height. Your knees should be aligned with the machine's pivot point.
Check the foot pad. It should be at ankle height or slightly higher. Stand up if necessary to adjust it.

Lying leg curl technique

Try to perform the exercise through the entire range of motion. Do not use too much resistance or weight so that only the final part of the exercise is possible.

The position of your feet can affect the relative involvement of the calves and which part of the hamstrings is loaded the most.

Foot position and hamstrings

Pointing your toes outward can place more emphasis on the outer hamstrings (biceps femoris). Pointing your toes inward places more emphasis on the two inner hamstring muscles (semimembranosus and semitendinosus).

This is due to their different attachment points (tibia and fibula).

Foot position and calves

The calf muscles consist of two different muscles, the gastrocnemius and soleus. The two heads of the gastrocnemius cross the knee joint and can therefore assist in bending the knee.

However, the position of the feet can affect the extent to which the gastrocnemius can assist. Just as an already lengthened muscle cannot produce maximum effort, an already shortened muscle cannot produce maximum effort either. If, during the leg curl, you point your toes toward your knees or push them downward, the gastrocnemius cannot exert itself fully. Keep your feet in a neutral position (as when standing upright) to engage it maximally.

Seated vs. Lying and Standing

Whether you perform leg curls lying, standing, or seated affects the involvement of the different muscles that make up the hamstrings. The hamstrings consist of three muscles, one of which has two heads. That makes three muscles with four heads. At the bottom (distally), all three muscles cross the knee joint. At the top (proximally), however, only three of the four heads cross the hip joint. The fourth head is connected to the thighbone, while the other three attach to the ischium. This means, among other things, that only this fourth head is not stretched when you, for example, lift your knee or try to touch your toes.

This fourth head is one of the two heads of the biceps femoris, the most laterally positioned muscle of the hamstrings (and its outer head).

What does this mean?

In the seated variation, the two inner hamstring muscles and the inner head of the biceps femoris are already slightly stretched. As a result, they cannot exert themselves fully (‘passive insufficiency’). The outer head of the biceps femoris is the only one that can do so because it is not affected by flexion at the hip.

In the lying and standing positions, this is not the case, and the workload is distributed more evenly across all heads.

At a glance