from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Having inelastic, overdeveloped muscles, usually as the result of excessive exercise.
- adj. Hindered by or as if by overdeveloped muscles.
- adj. Characterized by inflexibility; rigid.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having pronounced muscle development through weightlifting, bodybuilding, or other physical exercise.
- adj. Having excessive muscle.
- adj. Ungainly as a result of muscle over-development.
From muscle + bound "held" (Wiktionary)