The leg curl machine exercise is a single-joint movement that engages the muscles of the hamstrings. This exercise can be performed in various positions and provides a good amount of pressure to all parts of the hamstrings.
Leg Curl Machine
The leg curl machine is a separate exercise that targets the calf muscles (hamstrings and calf muscles). This exercise can be performed in various positions and is a great addition to most lower-body strength exercises.
Muscles Engaged in the Leg Curl Machine Exercise:
Primary muscles: Hamstrings
Assisting muscles: Glutes, calves
Anatomical Points in the Leg Curl Machine Exercise
The leg curl machine is a single-joint (isolated) movement that works the hamstring muscles individually. This makes it a very suitable exercise for pre-exhaustion techniques for the muscles involved. For example, you can push this exercise to failure, then immediately move to another hamstring movement like a leg press, and continue pushing to failure.
1. Foot Position in the Leg Curl Machine
If the toes are pointed straight and extended, all three hamstring muscles will be targeted.
If the toes point inward, the focus will shift to the inner hamstring muscles (semimembranosus and semitendinosus).
If the toes point outward, the movement will focus on the outer hamstring muscles (biceps femoris).
Keep the ankles bent at a 90-degree angle (dorsiflexion) to minimize calf involvement and better isolate the hamstrings.
If the toes point upward, the calf muscles will also participate in the movement.
2. Leg Distance in the Leg Curl Machine
The standard foot position is hip-width apart.
If the feet are wider apart, the inner hamstring muscles (semimembranosus and semitendinosus) will be more targeted.
If the feet are closer together, the focus will be on the outer hamstrings (biceps femoris). The tube-like pad of the machine will limit foot spacing.
3. Body Position in the Leg Curl Machine
The bench of most machines is inclined at the hip area, causing the upper body to lean slightly forward. This forward bend helps stretch the hamstrings and pelvis, aiding muscle isolation. Be sure to keep the spine straight and avoid arching the chest.
4. Range of Motion in the Leg Curl Machine
Bend your knee as much as possible while bringing the foot upward, and stop just before fully straightening the knee to maintain tension on the hamstrings and minimize knee joint stress.
5. Resistance in the Leg Curl Machine
The resistance during this movement is relatively uniform. However, in many modern machines, resistance is lower when the hamstrings are fully stretched (which is when they are most vulnerable to injury).
Benefits of the Leg Curl Machine Exercise
This exercise targets the hamstrings (biceps femoris, semitendinosus, and semimembranosus) and calf muscles (gastrocnemius and soleus). During the downward phase, the glutes, quadriceps, and tibialis anterior are also engaged.
Having strong, flexible hamstrings is important for overall strength, balance, and endurance. Research also links hamstring strength to better athletic performance, especially in high-speed movements.
Strong hamstrings are beneficial not just in the gym but in daily activities involving lower body movement, such as playing with children, doing household chores, and more. Hamstring strength and flexibility also help as the body ages, especially if you are prone to knee problems or joint and back pain.
Types of Leg Curl Movements
You can perform this movement in various ways to better match your skill level and fitness goals.
1. Standing Leg Curl
One of the benefits of the seated leg curl machine is that it improves balance and endurance. Beginners might want to try this movement standing, as it requires less hamstring engagement when performed without weights.
To perform this, stand with your feet hip-width apart. Shift your weight to one leg and bend the opposite knee, bringing that leg towards your glutes. Lower the foot and repeat on the other side.
2. Lying Leg Curl
Adjust the machine’s pad to your height and lie face down. Place your feet under the designated pads (they should be slightly below the calves). Tip: If possible, use a machine with an angled pad to better engage the hamstrings.
Position your body fully on the machine and ensure your legs are fully extended. Grasp the handles of the machine for better balance and control. The toes should be pointed straight.
On exhale, raise your legs with a controlled motion as much as possible, keeping your thighs in contact with the machine. Pause briefly at the peak contraction and slowly lower your legs back to the starting position.
You can use your toes to help target the hamstrings or calves. Curling your toes downward engages the hamstrings, while pointing them upwards isolates the calves.
3. Seated Leg Curl
You can also perform the leg curl while seated. This variation is useful if lying or leaning forward is uncomfortable or causes neck or back pain. Another advantage of this position is that the machine's design prevents your feet from rising while you perform the curl.
When seated, the pad should be positioned just above the knees, and the foot pads should be under the calves. Grasp the machine handles and press the foot pads downward, bringing them as close to your glutes as possible. Hold, then return to the starting position.
4. Nordic Hamstring Curl
For proper execution, start with lighter weights on the lying leg curl machine. What makes the Nordic Hamstring Curl different is that you keep the lower legs fixed while the rest of your body moves forward.
To perform this, kneel on the ground with your ankles secured under an immovable object (or by a partner), and lean forward at the knee. You need to control the movement as you lower your body forward, requiring more strength than other variations. Research has shown this movement is linked to a reduced risk of hamstring injuries.
Common Mistakes in the Lying Leg Curl Machine
Avoid these mistakes to make this exercise safer and more effective.
1. Too High of a Foot Pad
If the foot pad is set too high on the calves, it can stress the Achilles tendon and limit your range of motion. If you’re trying this exercise for the first time, consider asking a trainer to show you the correct positioning and adjust the roller if needed.
2. Using the Wrong Weight
For proper form, always start with lighter weights. You don’t want to overcompensate by raising your hips or arching your back. This will not engage the hamstrings properly and could lead to lower back injury.
Select a weight that allows you to perform 8-12 reps with reasonable effort and good form. If your goal is to build muscle mass, gradually increase the weight as your strength improves. However, remember that if your goal is strength and performance, you don’t want to lift excessively heavy weights.
