A punching bag is a heavy bag used for training in various combat sports, including boxing, kickboxing, and martial arts. It is typically filled with materials like sand, foam, or water to absorb impact and is designed to improve a fighter's strength, speed, and technique. Punching bags come in different shapes and sizes, including heavy bags, speed bags, and double-end bags, each serving a specific purpose in training. Punching bags can be hung from a ceiling or mounted on a stand, making them versatile for home or gym use. They are often made from durable materials like leather or synthetic fabrics to withstand repeated strikes. Using a punching bag can enhance cardiovascular fitness and coordination while providing an effective outlet for stress relief.