What the seated leg curl does
The seated leg curl is a machine exercise where you sit with your thighs supported and curl your lower legs back and under the seat against resistance. It trains knee flexion, which is one of the two main jobs of the hamstrings (the other being hip extension).
Main benefits
It isolates the hamstrings
Because the machine supports your body, you do not need to balance or brace as much as in a deadlift. This makes it easier to push the hamstrings hard without being limited by your lower back, grip or balance.
The hips are bent, which suits the hamstrings
In the seated position, the hips are flexed, which places the hamstrings in a lengthened position at the start of the movement. Some research suggests that training muscles at longer lengths may be favorable for muscle growth, and a study comparing seated and lying leg curls reported greater hamstring growth with the seated version. The evidence is still limited, so treat it as a reasonable reason to include seated curls rather than proof that they are always better.
Easy to load and progress
The weight stack lets you add small increments, which is useful for beginners and for steady progressive overload. It is also simple to do drop sets or slower repetitions.
Beginner-friendly and low skill
The movement is simple to learn, which makes it a good way to start training the hamstrings if hinges feel intimidating.
Useful for rehab and strength balance
A physiotherapist may use leg curls as a controlled way to rebuild knee flexor strength. If you are recovering from an injury, follow professional guidance rather than loading heavily on your own.
Supports balanced leg training
Many lifters have strong quads and relatively less hamstring work. Including curls alongside hinges and squats helps balance the thigh muscles.
Do leg curls work the glutes?
Not much. The glutes are mainly hip extensors, and the seated curl has the hips fixed, so the glutes are not the target. For glute and hamstring hip-extension work, add movements such as bridges or Romanian deadlifts. See our guide to exercises for stronger hamstrings.
Seated or lying: which is harder?
Difficulty depends on the machine, your strength and your leverage, so neither is universally harder. Seated curls often feel different because of the lengthened hip position, and some people find them tougher on the hamstrings for that reason. Lying curls place the hips more open. Many programs use one or the other, or rotate between them.
How to do a seated leg curl
- Adjust the seat so your knees line up with the machine’s pivot point.
- Set the thigh pad snugly on top of your thighs and the ankle pad just above your heels.
- Sit tall and hold the handles.
- Curl your heels down and back, pausing briefly at the end.
- Return slowly, taking about 2 to 3 seconds, without letting the stack slam.
How much weight should you use?
There is no universal number. A good guide is a load that lets you complete 8 to 15 controlled reps with the last couple feeling hard but not sloppy. Start lighter than you think, learn the movement for a couple of weeks, then add weight in small steps. Machines differ, so compare by effort and form rather than the number on the stack.
Sample set and rep ideas
- Muscle growth or general strength: 2 to 4 sets of 8 to 15 reps
- Technique focus: 2 sets of 10 to 12 with a slow lowering phase
Rest about 1 to 2 minutes between sets. Pair with a hinge such as a Romanian deadlift, much like the compound-then-isolation order in post exhaustion training. Our dumbbell stiff leg deadlift article shows one option.
Common mistakes
- Swinging or lifting the hips off the seat
- Cutting the range of motion short
- Letting the weight drop on the return
- Setting the machine so the knee does not align with the pivot
- Pushing through sharp pain behind the knee
Who should be careful
If you have knee pain, a recent hamstring injury or a medical condition affecting your legs, check with a healthcare professional first. Reduce the load or stop if the exercise causes sharp pain.
Seated leg curls versus other hamstring exercises
Leg curls do not replace hinges. They are best used alongside them. Runners may also like Nordic curls, covered in our hamstring exercises for runners guide.