The medicine ball Russian twist is a weighted version of a popular abdominal training exercise. It targets the oblique muscles, as well as the deep muscles of the core and the rectus abdominis or "six pack" muscles. It can be done for reps or time in the ab-focused portion of any workout.
Allows you to train in lower rep ranges when bodyweight twists get too easy
Weighted ab training can help the core muscles grow and look more defined
Trains the core in different planes of motion than crunches or sit-ups