Proper punctuation for this sentence

[adrienne83]

Hi there, I'm wondering about the use of the comma after "strength" in this sentence:

Though his physical strength is obvious, the character exhibits another form of strength, an inner, emotional stability rarely seen in a boy his age.

It seems misplaced to me but I can't figure out why. Should the comma be replaced with a colon? An explanation with your opinion would be appreciated!

Thanks.

[MikeNewYork]

I would use the comma. The words following the comma explain "strength".