What is the leg curl?
The leg curl is an isolation exercise for the lower body using a machine. The exerciser sits in the seat and lifts the weight by bending the knee, while the rest of the body remains still.
It is also possible to perform leg curls from a lying position. For this exercise, you lie on your front on the machine bench and lift the weight by bending your knee.
The leg curl machine works in the opposite way to the leg extension. When you perform leg curls, you bend the leg as opposed to straightening.
What muscles does the leg curl use?
The leg curl uses the muscle at the back of the thigh (hamstring). To a lesser extent, leg curls also work the calf muscle (gastrocnemius). This curl exercise is still described commonly as an isolation exercise as the focus is most strongly on the hamstrings.
The hamstring muscle works in a pair with the quadricep muscle, working to flex and extend the leg. When you bend your leg you work the hamstring and when you straighten your leg you work the quadricep.
It is a good idea to use both leg curls and leg extensions in your lower body workout in order to develop a balanced physique and develop the muscles on both sides of your legs equally.
The best leg workouts incorporate all the different exercises so that each muscle is developed at the same rate.
Leg curl position
Proper leg curl technique will help you get the best out of this simple exercise. The first thing to think about is positioning, whether you choose the seated or the lying version of the lift.
Before performing seated leg curls, you need to adjust the seat so that you are in the correct position for the lift. Move the back rest so that the centre of your knee is aligned with the centre of the pivot joint on the machine.
Next, adjust the ankle pad so that the pad rests just above your Achilles tendon and at the bottom of your calf (gastrocnemius).
Your feet should be placed a hip distance apart on the pad. Tuck your legs under the thigh pad to create a firm hold, so that your upper leg does not move. You need this positioning in order to achieve a good curl technique for the duration of the exercise.
Types of leg curl
There are a few types of leg curl. The main types are the seated leg curl, the lying leg curl and the cable leg curl or hamstring curl. These variations of curl work the same main muscle, the hamstring, but each exercise requires a slightly different technique due to the position.
Cable leg curl
The cable curl for the hamstring is a standing exercise whereby you pull a cable back using your hamstring muscle. This is an exercise that can be performed easily at home using a resistance band or cable attached to an immovable object.
Cable machines in the gym can also be used for this exercise.
Seated leg curl
To perform seated leg curls, pull your heels down, towards your buttocks to lift the weight off the stack. The ankle, knees and hips should remain aligned throughout the movement with toes facing forwards and pointing upwards.
At the base of the lift, pause and raise your legs back up, extending the leg fully without locking out the knees. Chest should be high and out, with abdominals engaged to help create a neutral spine.
To improve your leg curl technique, take it slowly and keep a controlled motion, paying attention to your body position. After performing your last rep, gently return the weight to the stack, always maintaining a slow and steady motion.
Lying leg curl
The exercise can also be performed as a lying leg curl. The motion is the same for the lying leg curl as for the seated version except that your position is lying face down on a workout bench.
When performing the lying leg curl, move your feet into position with the pad resting just above your Achilles tendon. Grasp the handles under the bench and with abdominals braced, lift the weight by bending your knee fully.
Once fully flexed, pause then lower the weight slowly, by extending the leg fully without locking out. Your toes should face forwards throughout the movement, with knees, ankles and hips aligned.
It is important to keep a strong core by bracing your abs throughout the movement.
Leg curl technique
Using these steps, you should be able to achieve a good leg curl technique and see some impressive strengthening and stability in your hamstring muscles.
The technique is slightly different for each type of curl because the angle of the exercise is different.
Although you are still focusing on the hamstring, you need to be more aware of your abs and arms in the lying leg curl as you need to brace yourself using the handles in order to perform the lift with steady control.
Read about the leg extension, the perfect complement to the leg curl for balanced muscle development.