Exercises: core
The bridge targets the glutes, hamstrings, abdominal muscles and lower back muscles. Great for rehabilitation exercise for lower back pain and core stability.
The bicycle crunch for advanced users hits the rectus abdominal muscle hard. The result can be a six-pack, something that many athletes strive for.
The cross-body crunch is a little more challenging because the movement is larger. The exercise mainly focuses on the oblique abdominal muscles.