The Dumbbell Leg Extension is a good free weight version of the regular Leg Extension and is actually less stressful to the knees. You will be amazed at the intensity of the contraction you can get in your quads when you have to physically support the weight in the air as well as lift it.
This exercise works the quads at the hip (the rectus femoris muscle of the quads is a hip flexor) because you have to support your leg in the air. It also works the quads at the knee, like a regular leg extension. This combined action gives you a greater contraction in the quadriceps than you get with a machine leg extension.
How to incorporate this exercise into your workouts:
The dumbbell leg extension can be used either as a finishing movement, due to the intense contraction you get from it, or as a pre-exhaust movement for another leg exercise such as the leg press.
1. Not squeezing at the top
The value of this exercise lies in the contraction at the top of the movement. If you don’t pause and squeeze, you are missing out on an incredible contraction.
2. Setting the dumbbell improperly
Be sure you angle the dumbbell properly on your foot (at about 15 degrees). The handle should run right along the line of where your toes start. Remember to curl your toes up to cradle the dumbbell and keep it from moving.
1. Unbalanced leg extensions
As you get better with this exercise and your balance improves. Try doing this exercise freestanding (without hanging onto anything for balance). This will increase the instability of the exercise and help increase muscle fiber activation.
2. Counterbalance yourself
You may wish to hold a dumbbell behind you with one hand to counterbalance the weight in front of you. This is especially useful when you start using heavier weights.
