Being strong is so much more than just "muscles" and is the reason why there are world class freaks who are clean whereas in bodybuilding it is almost always possible to spot someone who is "on".
I know a clean, sub 80kg guy, who screws around with his training, looks more like a Men's Health model, who can deadlift 315kg without even a belt. when he was 19yrs old he apparently lifted a barbell for the first time (dead) and pulled 210kg.