Kiki,
I think most people would assume Samson had big muscles because muscles give strength. Do you know any weak body builders?
In the end Samson did not maintain his vow because a razor touched his head. Samson prayed to God for strength as you can see below:
Judges 13:5 For, lo, thou shalt conceive, and bear a son; and no razor shall come on his head: for the child shall be a Nazarite unto God from the womb: and he shall begin to deliver Israel out of the hand of the Philistines.
Judges 16:19 And she made him sleep upon her knees; and she called for a man, and she caused him to shave off the seven locks of his head; and she began to afflict him, and his strength went from him.
Judges 16:28 And Samson called unto the LORD, and said, O Lord God, remember me, I pray thee, and strengthen me, I pray thee, only this once, O God, that I may be at once avenged of the Philistines for my two eyes.
Val