Leg Curl
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Leg Curl Strength Standards (kg)
| Body Weight | Beginner | Novice | Intermediate | Advanced | Elite |
|---|---|---|---|---|---|
| 120 kg | 45 | 65 | 90 | 120 | 155 |
| 130 kg | 45 | 65 | 95 | 125 | 160 |
| 140 kg | 50 | 70 | 95 | 130 | 165 |
| 150 kg | 50 | 70 | 100 | 135 | 170 |
| 160 kg | 50 | 75 | 105 | 140 | 180 |
| 170 kg | 55 | 75 | 105 | 140 | 185 |
| 180 kg | 55 | 80 | 110 | 145 | 190 |
| 190 kg | 55 | 80 | 115 | 150 | 195 |
| 200 kg | 60 | 85 | 115 | 155 | 200 |
| 210 kg | 60 | 85 | 120 | 160 | 205 |
| 220 kg | 60 | 90 | 120 | 165 | 210 |
How to Perform the Leg Curl
Lie face down on a leg curl machine with the pad positioned just above your heels and your knees aligned with the machine's pivot point. Grip the handles for stability. Curl the weight up by bending your knees and bringing your heels toward your glutes. Squeeze the hamstrings at the top of the movement, then lower the weight slowly under control to the starting position without letting the weight stack rest between reps.
Muscle Activation
The leg curl isolates the hamstring muscles through knee flexion. The biceps femoris, semimembranosus, and semitendinosus are all heavily activated. The gastrocnemius (calf muscle) also crosses the knee joint and contributes to the curling motion. Unlike hip-hinge exercises that train the hamstrings through hip extension, the leg curl targets the knee flexion function of the hamstrings, making it a valuable complement to exercises like Romanian deadlifts.
Common Mistakes
- Lifting the hips off the pad during the curl, which uses momentum and reduces hamstring isolation.
- Using too much weight and performing partial reps instead of achieving a full range of motion.
- Letting the weight drop on the eccentric instead of controlling the descent.
- Not aligning the knee joint with the machine's axis of rotation, which can cause knee discomfort.
Variations
Seated leg curls place the hamstrings in a stretched position at the hip, which may provide a different training stimulus. Single-leg curls address imbalances. Nordic hamstring curls are a bodyweight alternative that eccentrically loads the hamstrings with extreme intensity. Stability ball hamstring curls can be done at home.
Programming Tips
Perform 3-4 sets of 10-15 reps, 2-3 times per week. The hamstrings respond well to both heavy loads and higher reps. Include both a hip-hinge movement like the Romanian deadlift and a leg curl variation for complete hamstring development across both functions of the muscle.