The average adult man has 41 percent more non-fat body mass (blood, bones, muscles and so on) than the average woman, 50 percent more muscle mass in his legs and 75 percent more in his arms. His legs are 65 percent stronger, and his upper body is 90 percent stronger. The overwhelming upper-body advantage is nowhere near accounted for by differences in size – as can be seen in weightlifting competitions, where competitors are banded by weight, and the male world champion in each category lifts around 30 percent more than the female one.
