Muscles don’t grow evenly—when you train your thigh, the top and middle parts of the front muscle grow more than the bottom, and the side muscle grows the same everywhere.

When performing resistance training, training to muscle failure may lead to slightly more growth in the vastus lateralis muscle, while training with 1-2 reps left in reserve may lead to slightly more growth in the rectus femoris muscle.

Muscles don’t grow evenly — some parts get bigger than others, and different muscles in the thigh respond differently to the same exercise.

When untrained men do a specific type of weight training called pre-exhaustion, some parts of their thigh muscles grow more than others—the lower front part grows 44% thicker and the upper outer part grows 32% thicker.

A specific type of weight training makes leg muscles grow unevenly, with some parts growing much more than others, because different parts of the muscle get worked harder during the exercise.

When you train your quads, the big front muscle (rectus femoris) grows more than the side muscles (vastii), even when you do the same total amount of work.