Leg Extensions

The muscles worked in the leg extension are,
  • Quadriceps (Rectus Femoris, Vastus Lateralis, Vastus Medialis, and Vastus Intermedius.)
The leg extension is a great exercise to isolate the quads. It's the best exercise to grow the rectus femoris, which is one of the heads of the quads, which isn’t hit hard with squats or squat-like movements.
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Quads-Leg Extensions

How to do Leg Extensions

  • Adjust the seat so that the knees are directly in line with the axis of the machine, and so you’re leaning back slightly. Don’t have the seat set so you’re sitting completely upright.
  • Pull yourself with the handles into the seat. You should feel stable, and your hips shouldn’t rise at all during the set.
  • Aim for a full range of motion. Extend your knee as high as you can, and all the way back. If you’re only going halfway up, reduce the weight so you can achieve the full range of motion. The only exception is if you find that you get knee pain at the end range of motion. If this is the case, you should limit the range of motion a bit.
  • Lower under control. Aim for at least two seconds on the eccentric portion of the lift.
  • Don’t bounce the reps! Tension should be on the quads through the lift.