Exercise for Guinea pigs

Don't buy the runner balls or runner wheels, because they have a very delicate spine and legs, their back is not flexible and these toys are not suitable for them. the best form of exercise is a guinea pig run, they provide exercise and extra nuitrients when placed on grass, which should be done.  put a ball or some toys in there too, so they can play and eat grass, they mainly eat, or you could let them off in the house being aware of cables, and furniture, always keepe the guinea pig in supervision while doing this.