Planks engage the transverse abdominis, rectus abdominis, obliques, and glutes. This is important because each muscle group serves a different purpose, and together they protect your body from injury.
The transverse abdominis increases abdominal pressure so you can lift more weight, which is needed to increase your strength. The rectus abdominis improves performance in sports that require jumping, while the obliques are responsible for side-bending and waist-twisting moves. The glutes take pressure off the back and reduces risk of injury (looking at you, folks with lower-back pain). Any type of plank will boost energy and improve productivity—and in this quick workout, I give you four different plank variations to try.