Its been tested etc. Blacks are designed to run faster. I read that Blacks' lower legs are thinner and their calf muscles are smaller than Whites. Thats an advantage Blacks have for running but for strength its a disadvantage. That's true, blacks and muds have skinny legs the calfs specially are quite small, white legs are more muscular...    I've seen that in the gym even negros with lots of training still have skinny calfs, actually they get impressed by a white amateur lifting the same or more they do on calf exercises and overall leg exercises....