# Another exercise question

**URL:** <https://boards.straightdope.com/t/another-exercise-question/389365>\
**Category:** Factual Questions\
**Created:** [January 25, 2007, 2:52am UTC](https://boards.straightdope.com/t/another-exercise-question/389365 "2007-01-25T02:52:41Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![cmosdes](https://avatars.discourse-cdn.com/v4/letter/c/a587f6/32.png) [@cmosdes](https://boards.straightdope.com/u/cmosdes)\
**Post date:** [January 25, 2007, 2:52am UTC](https://boards.straightdope.com/t/another-exercise-question/389365/1 "2007-01-25T02:52:41Z")

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Some days I can do my run and come back and feel like I could run it all over again. Other days I run and feel like it is a struggle to get through.

Am I burning more calories on the days the runs don’t feel as fluid than on the days I’m feeling strong?

How about lifting weights? Some days I can do my reps without too much trouble, other days I can’t get through all the reps. Am I building more muscle on the days I do fewer reps but work my muscles to fatigue?