1) Bodybuilder, often 2) Juicer 3) Lifting regular 4) Long-term trainee 5) Perpetual exerciser 6) Workout junkie 7) Workout obsessive 
One of many usually colorful terms for persons who, perhaps with some swagger, believe they know climbing because they climb in rock gyms. When rock and mountain climbing they become frightened because they neither understand nor trust the anchors and protection. One of many often colorful terms for persons who, with swagger, assert they know climbing because they climb in rock gyms. When rock and mountain climbing, they often become frightened because they are nubs (aspiring newbies) regarding anchors and protection.
Gym rat is American slang for someone who spends too much time in a gym.