I'm an avid runner. I usually do my long runs and most 5-Ks, etc. I go to are on Sundays.
As long as I attend Mass, is there a problem? I'm still unsure about Roman Catholic teaching on the Sabbath.
The following link should answer your question about observing the Sabbath. If you have any further questions, please contact Catholic Answers directly.
What can I do on Sundays?