Alternatively, Pike isn't exactly bulging with muscle, but he's still a pretty large guy, with all the strength his size implies.
Pike's family was determined to raise him a scholar, and he probably would've been The Smart Guy had he not inherited his gladiator great-grandfather's height and build.
Pike was born seeming naturally ultra-masculine: Tall, muscled, very strong, possibly other traits that suggest more rash and impulsiveness, such as visible veins. Deciding to break people's first assumption, Pike becomes very scholarly, but still makes good use of his natural advantage by becoming a very strong combatant.
Pike went through a brutal and complex form of Training from Hell where he built up his physical strength and combat skills while also educating him on various fields of more intellentual skills (such as military tactics or mechanics), to go with it. (Truth in Television for a Military Academy.)
Pike was an average-build Mad Scientist who invented a super-steroid and tried it on himself. It made him grow enormous muscles without affecting his scientific knowledge.
Alternatively: Pike has his talents, but he's neither very smart nor particularly strong.
"We need a Smart Guy and a Big Guy, but we only want four team members, instead of dropping one, let's put the two together!"
"We want our villain to be a credible threat, so he should be tough and cunning."
Lampshaded: Pike keeps tossing his opponent through walls, then stops. "Next one's about where I'd put a load-bearing wall if I built this place. You wanna give up, or you want me to bring the house down?"
Invoked: Naturally big and tough, Pike never had to exercise much to stay in shape, so he decided to hit the books so he'd have brains and brawn going for him.
Exploited: Pike has used his immense brainpower to figure out that Dracone is The Mole, but Dracone counters, "Are you really gonna listen to a big meathead like that?"
Defied: Pike realizes his immense strength and stature can be intimidating to many, so he downplays his physique and emphasizes his intelligence whenever people need his help.
Discussed: Pike: "I hit him in the liver because I noted his jaundiced sclera."
Conversed: "Pike's pretty smart for a giant wall of muscle..."
A doctor's license can be seen in Pike's training area.
Pike is never actually seen in a fight, but he has a strong build and has no trouble moving heavy lab equipment unassisted.
Deconstructed: Pike spends so much time training his mind and body that he has no friends and is too busy to really aid the heroes or affect the plot.