Just a side note: I'm not in football or anything, just used it as an example.
Now that I think about it, a more appropriate example would've been, "I worked out my biceps/legs and spent all of yesterday helping someone move.. carrying large heavy boxes up and down stairs. Would that cause harm?"
But from the responses from the football example, and seeing as how it's more intense, I think it's just about answered
![Big Grin](/tfp/images/smilies/biggrin.gif)