Overview

The leg curl is a machine-based isolation exercise primarily targeting the hamstrings through knee flexion. Available in seated or lying variations, it builds hamstring strength, size, and endurance while complementing quad-dominant movements for balanced leg development and injury prevention.

Target Muscle Groups

• Primary: Hamstrings (biceps femoris, semitendinosus, semimembranosus)

• Secondary: Gastrocnemius (calves), Popliteus​

How to Perform Leg Curl (Seated Variation)

Setup

1. Sit on seated leg curl machine with back against pad.

2. Adjust thigh pad above knees, ankle pad against lower calves/Achilles.

3. Legs fully extended, toes neutral, grip handles for stability.​

Execution Steps

1. Inhale, flex knees to curl pad toward glutes until ~90° flexion.

2. Squeeze hamstrings at peak contraction (1-2 sec hold).

3. Exhale, slowly extend legs (2-3 sec eccentric) without locking knees.

4. Repeat controlled reps, keeping hips/upper body stationary.​

Tips for Proper Form

• Use full range: full extension to contraction.

• Brace core to prevent hip lift.

• Slow eccentric maximizes growth.

• Higher reps (12-20) for hamstring pump.

• Single-leg for imbalances.​

Common Mistakes to Avoid

• Using momentum or swinging.

• Lifting hips off seat.

• Incomplete range of motion.

• Arching lower back.

• Locking knees at extension.​

Benefits

• Isolates hamstrings without quad dominance.

• Improves posterior chain strength.

• Balances quad training to prevent injury.

• Enhances knee stability and flexion power.

• Versatile for hypertrophy/finisher sets.