Which muscle groups are least activated when performing a standard plank?

When performing a standard plank, the primary focus is on engaging the core muscles, including the abdominals and obliques, along with stabilizing muscles in the shoulders, back, and glutes. While engaging these areas, the quadriceps are not significantly activated because they are not required for the stabilization of the body in the plank position.

The movement is isometric; therefore, it relies primarily on core stability without dynamic movement, which means that the quadriceps, primarily responsible for extending the knee, do not have a substantial role in this particular hold. Thus, the activation of the quadriceps is minimal compared to other muscle groups that play a more active role in maintaining proper plank form and stability.

In contrast, the shoulders and triceps, chest and back, as well as hip flexors, all play a part in holding the body in alignment and preventing sagging or arching of the spine, making them more actively engaged during the exercise.