How to Leg Extensions

About the Leg Extensions

The quadriceps is the name given to the group of four muscles located to the front of the upper leg which are responsible for the extension of the knee. By supplying resistance to the extension of the knee, the leg extension machine successfully targets all four quadriceps muscles.

Many athletes believe that by changing the direction the toes are pointing during the leg extension we can shift emphasis onto either the inner (mainly the vastus medialis), or the outer (vastus lateralis) quadriceps. To what extent this is true, if at all, is unknown to us at present, although it is a fairly wide spread belief.

Being an isolation movement, the leg extension is probably best viewed as a supplementary lower body exercise, with multi-joint movements such as the squat and deadlift considered the staple. A great use of the leg extension by bodybuilders is just prior to squats, enabling the bodybuilder to pre-exhaust the quadriceps before the squat to make the exercise more challenging for the target muscle.

The leg extension can also play a critical role for those who are rehabbing from a knee injury, allowing the athlete to slowly build up the quadriceps strength and muscle hypertrophy.

How to perform


  1. Set the pin to the correct resistance on the weight stack and adjust any settings on the machine so that you feel comfortable and supported when seated
  2. Sit on the seat, placing your feet under the pads, and grasping the support handles down by your sides


  1. Whilst keeping torso and hips stationary, extend at the knee to raise your lower legs up
  2. Once you have reached peak contraction, slowly lower the lever back to the starting position
  3. To keep constant tension on your quadriceps do not allow the weight stack to rest at the end of the movement
  4. Repeat for the desired number of repetitions

Other Leg Exercises