Alternating Single-Leg Curl 101 Video Tutorial
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Exercise Synopsis
Target Muscle Group
Hamstrings
Secondary Targets
Execution
Isolation
Force Type
Pull
Required Equipment
Lying Leg Curl Machine
Fitness Level
Intermediate
Variations
None
Alternatives
Timer
Hour
Minute
Second
Stopwatch
00:00:00:00
Overview
Alternating Single-Leg Curl is a machine-based lower-body isolation exercise that focuses on strengthening and developing the hamstrings by curling one leg at a time on a lying leg curl machine, allowing for unilateral control, improved muscle balance, and greater mind–muscle connection. The alternating execution helps identify and correct strength imbalances between legs while reducing compensation, and the calves assist as secondary stabilizers during knee flexion, making the movement effective for targeted hamstring development with controlled resistance.
How to Perform
Adjust the lying leg curl machine so the pad rests just above your ankles and lie face down with your hips pressed firmly into the bench.
Grip the handles or bench edges to stabilize your upper body and keep your torso and hips flat throughout the movement.
Extend both legs fully at the start, keeping your toes neutral and knees aligned with the machine’s pivot point.
Curl one leg upward by bending the knee, driving the pad toward your glutes while keeping the opposite leg fully extended and relaxed.
Squeeze the hamstring at the top of the movement while maintaining control and avoiding hip lift or lower-back arching.
Slowly lower the working leg back to the starting position under control until it is fully extended.
Alternate to the opposite leg and repeat the same curling motion with identical range of motion and tempo.
Continue alternating legs for the desired number of repetitions, maintaining consistent tension and controlled breathing throughout.
★ Bonus: For exercises that involve external weights (such as dumbbells, barbells, or machines), the One Rep Max (1RM) calculator can help you estimate your maximum lifting capacity. Use it to track your strength progress and adjust your training for optimal results.
Tips
Keep your hips pressed firmly into the bench to prevent lower-back involvement and maintain hamstring isolation.
Use a controlled tempo, especially during the lowering phase, to maximize hamstring tension and activation.
Match the range of motion and speed on both legs to avoid reinforcing strength imbalances.
Avoid pointing or excessively flexing the toes to prevent the calves from taking over the movement.
Focus on squeezing the hamstring at the top of each repetition rather than lifting the weight higher.
Keep the non-working leg relaxed and fully extended to maintain unilateral emphasis.
Select a load that allows strict control without jerking or momentum.
Maintain steady breathing and avoid holding your breath during the curl.
How Not to Perform
Do not lift your hips or arch your lower back to move the weight, as this shifts tension away from the hamstrings.
Do not use momentum or swing the leg upward, which reduces muscle engagement and increases injury risk.
Do not rush the lowering phase or let the weight drop, as this wastes tension and control.
Do not excessively point or flex the toes, which can cause the calves to dominate the movement.
Do not shorten the range of motion by stopping the curl early or failing to fully extend the leg.
Do not allow the non-working leg to assist or push against the pad during the movement.
Do not twist the hips or rotate the pelvis while alternating legs, as this compromises alignment.
Do not use a load that forces compensations or loss of strict form.
Variations
Variations of fitness exercises refer to different ways of performing a specific exercise or movement to target various muscle groups, intensities, or goals. These variations aim to challenge the body differently, prevent plateaus, and cater to individuals with varying fitness levels.
Alternatives
Alternative exercises in fitness refer to different movements or activities that target similar muscle groups or serve the same training purpose as the primary exercise. These alternative exercises can be used as substitutes when the original exercise is unavailable or challenging to perform due to various reasons such as equipment limitations, injuries, or personal preferences.
