Cross-body bicycles strengthen your side abs and balance. "Stand with feet hip-width apart, knees slightly bent, and hands behind your head.
Dumbbell halos strengthen shoulders and tighten the core.
Reverse twist lunges work your quads, glutes, and obliques, making them a powerful lower body motion.
This pelvic stability-boosting lower ab workout keeps you fit and tight.
Murdock says this workout strengthens your core and lower back.