Leg Extension 

A leg extension is an exercise done in a leg extension machine. Leg extension curl machines are a great way to incorporate strength training into your home. Strength training helps with rounding out your fitness, preventing injury, and handling everyday physical tasks better.

Leg extension machines work primarily on your quadriceps. Your quadriceps are responsible for proper knee extension and knee straightening. Leg curl machines work primarily on your hamstrings. Your hamstrings help bend your knee joint and help position your hips when bending.