Target the four muscles on the front of the thigh, known as the quadriceps, with the leg extension exercise. The quads are mainly responsible for extending, or straightening, the knee.
The leg extension, a single-joint exercise, typically requires a leg extension machine; however, if you don't have access to one, you can use free weights to replicate the exercise at home.
Be Smart, Use a Dumbbell
All you need to do the leg extension exercise is a dumbbell and a chair.
HOW TO DO IT: Sit on the front edge of the chair and grab the sides of the seat. Hold the dumbbell vertically between your feet so the top end of the dumbbell rests against the top of your feet.
Lean back slightly, but keep your back straight. Lift your feet so the dumbbell isn't touching floor. Your lower legs should be perpendicular to the floor. Extend your legs by straightening your knees until your legs are about parallel to the floor. Pause before slowly lowering back to the starting position.
Although an effective quadriceps-strengthening exercise, the dumbbell leg extension exercise has limitations. It can only be done with both legs simultaneously, so you cannot work each leg independently like you would with a machine.
As your legs become stronger, you will need to use heavier dumbbells to progressively overload the muscles. However, it can be challenging to hold a large, heavy dumbbell between your feet.
Alternative: Resistance Bands
With the resistance band leg extension exercise, you can work one leg at a time. To do the exercise, attach the band to an anchor point behind the chair and attach the other end of the band around your ankle. If available, use a band with an ankle cuff.
Perform the exercise in the same manner as the dumbbell extension, but work one leg at a time. Place the chair far enough away from the anchor so the band is taut and provides resistance.
Working the Whole Leg
The leg extension exercise doesn't work the hamstrings, the muscles on the back of the thigh. Other leg exercises, such as squats and lunges, work both the quadriceps and the hamstrings.
However, quadriceps are more active and dominate these movements. This overemphasis on pushing exercises leaves the hamstrings weaker and undertrained compared to the quadriceps, negatively impacting sports performance and increasing your risk of muscle tears. When developing a leg routine, create balanced workouts that train all the muscles of the legs.