Weight training is a form of strength training that develops the size of skeletal muscles. For this purpose it utilizes the force of gravity as an opponent to the power generated by muscles through eccentric or concentric contraction. A variety of specified equipment is used as a way of targeting specific muscle groups as well as types of movement. Weight training is central in sports such as weightlifting, bodybuilding, strongman, power-lifting, shot-put, discus throw, highland games and javelin throw. To understand the concept of weight training appropriately, it is important to analyze its purpose and history.