Machine • Legs Exercise

Leg Curl

Exercise demonstration

The leg curl is the premier isolation exercise for hamstring development. By focusing purely on knee flexion, this machine exercise allows you to build powerful hamstrings, improve knee health, and create balanced leg development to complement your quad-dominant movements.

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Muscles Worked

Primary Muscles

  • Biceps Femoris
  • Semitendinosus
  • Semimembranosus

Secondary Muscles

  • Gastrocnemius (Calves)
  • Gracilis
  • Sartorius

How to Perform

  1. 1

    Setup: Lie face down on the leg curl machine and adjust the leg pad so it rests just above your heels on your lower calves. Align your knees with the machine's pivot point. Grip the handles and keep your hips pressed firmly against the bench throughout.

  2. 2

    Starting Position: Begin with your legs fully extended but not locked. Point your toes straight or slightly down to minimize calf involvement. Engage your core and keep your body flat against the bench. Take a breath and prepare to curl.

  3. 3

    Curl Up: Exhale and contract your hamstrings to curl the pad up toward your glutes. Drive your heels toward your butt, focusing on squeezing your hamstrings hard. Curl until your knees reach approximately 90 degrees or your hamstrings are fully contracted.

  4. 4

    Peak Contraction: Hold the fully curled position for a one-second squeeze, maximizing hamstring engagement. Keep your hips pressed down—don't let them lift off the bench. This is where the magic happens for hamstring growth.

  5. 5

    Lower Controlled: Inhale and slowly lower the weight back to the starting position over 2-3 seconds. Resist the weight on the eccentric—don't let it drop. Return to full extension while maintaining tension, then immediately begin the next rep.

Common Mistakes

  • Lifting Hips Off Bench

    Arching your back and lifting your hips reduces hamstring isolation and can cause lower back strain. Keep your entire body pressed flat against the bench throughout the entire movement.

  • Using Momentum

    Swinging the weight up with explosive jerky motions reduces time under tension and increases injury risk. Use smooth, controlled movements and squeeze at the top for maximum hamstring activation.

  • Incomplete Range of Motion

    Only curling halfway limits hamstring development. Curl all the way up until your hamstrings are fully shortened, and extend all the way back down to full extension for complete muscle engagement.

  • Dropping the Weight

    Letting the weight fall quickly on the eccentric wastes the growth potential of the negative portion. Control the descent for 2-3 seconds to maximize muscle damage and hypertrophy stimulus.

Pro Tips

  • Toe Position Matters

    Point your toes straight or slightly down to minimize calf involvement and maximize hamstring activation. Flexing your feet dorsiflexion brings calves into play, which can reduce hamstring isolation.

  • Single-Leg Training

    Perform single-leg curls to identify and correct strength imbalances. Most people have one hamstring stronger than the other. Training unilaterally ensures balanced development and reduces injury risk during compound movements.

  • Perfect for Drop Sets

    Hamstrings respond incredibly well to high-volume training. Try drop sets by reducing weight 25-30% and repping to failure. The pump and growth stimulus is exceptional with this technique on leg curls.

  • Balance Your Leg Training

    For every quad-focused exercise, include hamstring work. A 2:3 hamstring-to-quad strength ratio is ideal for knee health and injury prevention. Strong hamstrings protect your ACL and improve athletic performance.

Variations

Lying Leg Curl

Traditional prone position isolates hamstrings with consistent resistance throughout range of motion.

Seated Leg Curl

Seated position with hips flexed emphasizes lower hamstrings and provides deeper stretch at start.

Single-Leg Curl

Unilateral version identifies and corrects strength imbalances between legs.

Toes-Pointed Curl

Plantar flexed ankles shift emphasis to upper hamstrings and gastrocnemius.

Alternatives

Romanian Deadlift

Compound hip-hinge movement that builds hamstrings with functional strength carryover.

Good Morning

Barbell hip-hinge that hammers hamstrings and builds posterior chain stability.

Nordic Hamstring Curl

Bodyweight eccentric exercise that builds hamstring strength and prevents injury.

Glute-Ham Raise

Specialized bench exercise for full hamstring and glute development with minimal lower back stress.

Related Leg Exercises

Romanian Deadlift Good Morning Hip Thrust Glute Bridge Back Squat Leg Extension Walking Lunge Calf Raise
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