Resistance band side lunges for Son of the Beast strengthen the hamstrings, core, and glutes. This exercise will target the glutes much more than forward or reverse lunges. They are also easier on the joints than forward or reverse lunges. This exercise is great for hip mobility and injury prevention. Learn more about properly executing this exercise with the video above.
Regression
Make this exercise easier by moving farther away from the achor, placing more tension on the band and providing more assistance through the range of motion. Alternatively, you can substitute for a lunge.