Blacks are faster than Whites in short distance running. Blacks dominate boxing but that doesn't mean they're stronger. They have stronger jaws so it's more difficult to knock them out. I'm talking about physical power. I guess wrestling would be the sport that most accurately reflects strength. Blacks are overrepresented in the American free style wrestling national team but Russia and eastern Europe dominate this sport. Recently many Eastern Europeans have been getting more dominant in boxing in the United States despite the strong jaw advantage of Blacks.
I don't think they are stronger at all. Not from my experience.
But, many have a slow metabolism and they overeat. They are getting lots of calories in and are not burning them off. All it takes is for them to lift weights - which is something alot of men like to do anyway - and then they burn those calories off and build muscle. There is a huge incentive to lift weights and they do. It's fun, it's an expression of masculinity and satisfying, it helps to lose weight if you are fat , it builds muscle and all men want muscle. The blacks that don't exercise are not stronger. And white people that eat well and exercise are as strong.
Black people do dominate quite alot in running and boxing.
But not weightlifting.. Not MMA. Maybe bodybuilding.
Some very large blacks are also very muscular.. Far exceeding any other athletes in their sport. Ronnie Coleman in bodybuilding. Bob Sapp in MMA.
Larger people can pack on more muscle. (i'm not sure that they are naturally stronger.. but they can hold more I suppose, so if they exercise maybe they have more potential). I must say, the strongest person in Britain's Strongest Man, was really short. He didn't win because some of the events required height. But for basic lifts he was way ahead!
So, I think it just boils down to that they have a propensity to get -really- big. That's most of the battle with building muscle, the other thing to do is lift weights, and that they enjoy, and it suits them.
Because of their natural ability to become huge, the average black has an advantage when it comes to benefits of lifting weights. But, there are of course alot of big white people too.
I'm not saying that being bigger means stronger. Just that it means you've won the harder part of the battle !! For them it's no struggle at all.. As is the case for many white people infact. But blacks have a culture that is more into lifting weights.
I guess I rambled a bit but anyhow..