This is because 'cramp' has several definitions. 'Cramped' is the past tense, though. I'll give you some examples of the meaning of cramp: 1. My leg cramped really badly while I running last night. This is a medical definition of cramp, which describes a muscle that suddenly tightens and becomes painful. 2. That elevator is too cramped for me. This can mean that the elevator is too small, or that there are too many people on it. Either way, it is uncomfortable because the space is too small. 3. That dude totally cramped my style at the party last night. This is slang, and it means to ruin someone's fun. 'Rained on my parade." is another similar expression.