The Best Leg Exercise:
The legs are the largest muscle group of the bunch and contain too many muscles to list individually. For the purpose of weight lifting we will focus on the two main sub groups most commonly hit by body builders, the hamstring and the quads.
Hamstring
The hamstring muscles are located on the back of each leg and help with the inward contraction (pulling) of the leg inward. This muscle is connected to your glutes and help in the growth of the entire back of your legs.
Quads
The Quads or quadricep muscles are located on the front of each leg and help with the outward contraction (pushing) of the leg outwards such as kicking. This muscle is connected to your knee joints and help in the growth of the entire front of the legs. This muscle is made up of four muscles hence the Quad- prefix found in the name.
While all muscle groups require a variety of exercises for optimal growth the single best leg exercise would have to be the Barbell squat.
This movement is by far the most popular leg exercise and for good reason. While primarily hitting the quads, the squat also puts adequate strain on the hamstrings as well resulting in an all around efficient exercise for muscle activation of both groups. As a barbell variation to the squat we can achieve the heaviest load while lifting. This is extremely important for leg growth because the legs involve so many smaller muscles that the only way to strain the legs as a whole is by overloading the lift as much as safely possible. This lift also partially hits the calf muscles which is valuable to consider when deciding the overall best exercise for the legs.