Single-Leg Seated Leg Curl
The single-leg seated leg curl is a one-legged knee flexion that isolates the hamstrings with the hip flexed, the position that stretches them most, and is used to even out strength between legs.
HAMSTRINGS · LOWER BODY
How it is executed
- Sit in the seated leg curl machine with your back against the pad and one leg hooked over the roller, the thigh pad locked snugly over your legs.
- Keep your hips and torso still as you curl one heel down and under, flexing at the knee against the resistance.
- Squeeze the hamstring firmly at the bottom of the contraction.
- Return under control until your leg is nearly extended, keeping tension on the muscle.
- Working unilaterally lets you match strength between legs and focus the contraction.
- Muscles worked
- Hamstrings
- Primary muscle
- Hamstrings
- Equipment
- Leg curl machine
- Movement pattern
- Lower body
- Difficulty
- Intermediate
- What it is for
- Hypertrophy
- Also known as
- Single leg seated hamstring curlUnilateral seated leg curl
Common mistakes
- Lifting the glute off the seat as you curl. Tilting the pelvis buys you inches that do not come from the knee. Keep both glutes down and end the rep where the knee stops flexing.
- Leaving the thigh pad loose. If the thigh rises with the weight, part of the range is done by the hip. Cinch it down before the first rep and check it again when you switch legs.
- Letting the return snap back. Working one leg makes the relative load high, and the eccentric is the hardest part to control. Come back over two or three seconds with the leg still under tension.
Frequently asked questions
- Which muscles does the single-leg seated leg curl work?
- It works the hamstrings: biceps femoris, semitendinosus and semimembranosus, which flex the knee against the resistance. The calves assist as secondary muscles because they also cross the knee. Being seated, the hip stays flexed and the hamstrings start from a more stretched position than when lying down, which increases the tension at the top of the range.
- What is the difference between the seated and the lying leg curl?
- Seated, the hip is flexed and the hamstrings work at a longer length throughout the set, which many coaches prefer for hypertrophy. Lying face down, the hip is extended and the muscle works shorter, with a more intense end contraction and less tension in the stretch. If only one machine is available, either works; if both are, alternating them covers the full range.
- Why do the seated leg curl one leg at a time?
- With both legs at once, the stronger one does more of the work without anyone noticing. With one leg, each side moves exactly its own load, and a strength difference shows up in the rep count. Always start with the weaker leg and match its reps with the other, even if it has more in the tank. Within a few weeks the gap closes.
- How many reps and how much weight for the single-leg seated leg curl?
- As a reference, many coaches program 10 to 15 reps per leg, with a load around half of what you use with both legs together. The rule for choosing it is simple: both glutes must stay on the seat for the whole set and the return must take two to three seconds. If either fails, drop the weight.
