To keep your body healthy and at correct weight
100 m sprint and sprint events when the athletes do not breathe.
balance boards. stability ball.. 1 legged squats (one foot behind you on a chair!). ballet Gymnastics. . . .
The muscles that are used on and elliptical are the pectorals, triceps, and biceps when pushing or maneuvering the handles and your gluteus maximus, hamstrings, and quadriceps when moving your legs...
no,you use muscle