Work on your cardio, speed and accuracy with a punch bag that moves with you. Free-standing punch bags are popular for martial arts training because of their versatility. You can move them anywhere and they are perfect for boxing, punching or kicking. Boxers, kickboxers and mixed martial artists use them. Fitness trainers and home enthusiasts love them. Everyone can have a free-standing punch bag at home. Simply fill the base with water and sand and start slamming your way to fitness.