[1][2] Rühl began training at the age of 18 following a doctor's recommendation to build some muscles in his legs after sustaining an injury in his left knee while playing football.

Despite his lanky frame at a bodyweight of 54.5 kg (120 lb), Rühl began training hard six days a week because he loved to go to the gym and to be a bit bigger than his friends.

At 2000 Mr. Olympia he placed 7th behind Ronnie Coleman, Kevin Levrone, Flex Wheeler, Shawn Ray, Nasser El Sonbaty and Lee Priest.

In 2002 Night of Champions, Rühl brought up his best physique ever weighing a staggering 129.5 kg (285 lb) on-stage, massive and ripped to easily win the competition.

[5] Numerous critiques and fans rate this version of Rühl to be one of the freakiest and best bodybuilding physiques of all-time.