Stair Climbers: What are they?
Stair climbers have foot platforms on each side and there is a handle at the top. As you press own on each side with your feet its like climbing steps. The problem is that it's bad for your knees. You should not let your weight make the platforms go down. You should push them down with your feet. They build the muscles in your legs.
Exercise balls: What are they?
An exercise ball is a large inflated ball usually made of plastic. It is used for stretching and strengthening . You lie on the ball with your back and stretch. Then for strength instead of stretching when you are lying down you do sit ups. They aren't used for bouncing.