Seated Leg Curl

The seated leg curl is one of the most reliable ways to isolate and build the hamstrings. You sit upright in the machine with your thighs locked under a pad and a roller across the back of your lower shins, then curl your heels down and under by bending the knees. Because your hips stay flexed and fixed, the machine takes your glutes and lower back out of the equation, forcing the hamstrings to do nearly all the work. The seated position also keeps the hamstrings under a stretch at the top, which makes this variation especially effective for building knee-flexion strength and hamstring size. It is beginner-friendly, easy to load progressively, and a smart accessory to pair with squats and deadlifts.

How to do the seated leg curl

1. Adjust the seat so the rotating knee axis of the machine lines up with the center of your knee joint, and set the back pad so your thighs rest fully along the seat.
2. Position the thigh pad snugly across your lower quads, just above the knees, then lock it down so your legs cannot lift off the seat.
3. Set the ankle roller so it sits against the back of your lower shins, just above your heels and Achilles, with your legs nearly straight at the start.
4. Grab the handles, sit tall against the back pad, and brace your core so your torso stays still throughout the set.
5. Curl your heels down and under by flexing your knees, driving the roller toward the seat until your hamstrings are fully contracted.
6. Pause briefly at the bottom and squeeze the hamstrings hard, keeping your thighs pinned and hips down.
7. Return the weight slowly under control until your knees are almost fully extended, resisting the roller the entire way, then repeat.

Muscles worked

The primary muscle worked in the seated leg curl is the hamstrings — the muscle group on the back of your thigh made up of the biceps femoris, semitendinosus, and semimembranosus. Their main job here is knee flexion, which is exactly what the curling motion trains, and the seated position holds the hips flexed so the hamstrings work from a lengthened, stretched position for greater tension. The calves, specifically the gastrocnemius, assist slightly as a secondary knee flexor, and the deep hip and core muscles act as stabilizers to keep your torso fixed against the back pad. Because the machine isolates knee flexion, this is true hamstring isolation rather than a compound leg movement.

Benefits

• Isolates the hamstrings directly, making it ideal for adding size and addressing weak points squats and deadlifts miss.
• The seated, hip-flexed position keeps the hamstrings under stretch, often producing greater growth than lying or standing curls.
• Beginner-friendly and low-skill: the machine guides the path so you can focus purely on contracting the muscle.
• Strengthens knee flexion, which supports sprinting, jumping, and healthier knee mechanics.
• Easy to load and progress with small weight jumps, and gentle on the lower back compared to free-weight hamstring work.

Common mistakes

• Using momentum: control the weight instead of swinging your torso or yanking the roller to start each rep.
• Letting your hips and thighs lift off the pad: keep the thigh pad locked tight so only your knees move.
• Misaligning the machine: if the knee axis does not match your knee joint, you lose tension and stress the joint.
• Cutting the range short: curl all the way down and under, then return until your knees are nearly straight.
• Rushing the lowering phase: resist the roller on the way back up to keep the hamstrings under load.
• Setting the ankle pad too high on the calf: place it just above the heels for the best leverage and comfort.

Form tips

• Sit tall and press your back into the pad so your torso stays anchored and the hamstrings, not your hips, do the work.
• Drive your heels down and under, thinking about pulling them toward your glutes for a deeper contraction.
• Pause and squeeze for a count at the bottom of every rep where the hamstrings are most contracted.
• Keep your toes relaxed or slightly pulled toward your shins to bias the hamstrings over the calves.
• Lower under control over two to three seconds, never letting the stack slam or the legs snap straight.

Sets & reps

For most lifters, the seed scheme of 3 sets of 10–15 reps with about 75 seconds of rest is an excellent default, since the hamstrings respond well to moderate, controlled volume. For hypertrophy, aim for 3–4 sets of 10–15 reps taken within a rep or two of failure, emphasizing the stretch and squeeze. For strength-oriented work, you can drop to 6–8 reps with heavier loads and slightly longer rest. For muscular endurance or as a finisher, push to 15–20 reps. Beginners should start light, master the controlled tempo, and add small increments weekly. Two to three sessions per week pairs well with compound leg training.

Frequently asked questions