Main article: History of strength training and resistance Antigua charged with a dumbbell bar Russian soil. Hippocrates first explained that it was weight training when he wrote “that uses this unfolds, and who do not use this wasting their time.” The progressive resistance training minimally dating of ancient Greece, legendary characters as the wrestler Milo of Croton trained carrying a newborn calf on his back every day until it grew. Another Greek physician Galen, described strength training using haleteres, an ancient form of dumbbells during the second century C. Another year old instrument was the Indian club, which was created in ancient Persia. Later, around the nineteenth century these elements became popular in England and America. The barbell itself joined the bar in the late nineteenth century.The first bar had hollow globes that could be filled with sand or lead, but before the twentieth century were replaced by the current records. Strength training using isometric exercises was popularized by Charles Atlas in the 30s. Later in the sixties began to implement the exercise machine at the gym. Strength training has increased its popularity in the 1980s, due in part to the bodybuilding film Pumping Iron and the subsequent popularity of Arnold Schwarzenegger. Since the nineties the number of women increased weight training, influenced by programs like Body for Life training: currently one in five women (USA) trained with weights.