“My sport is your sport’s punishment” is a popular T-shirt saying worn by many runners. When football players (for example) get into trouble, the coach often has them run laps as punishment. Many non-runners view running as torture.
 
“Our sport is your sport’s punishment” has been cited in print since at least September 2002 and it quickly became a popular saying with cross-country runners across the United States.
 
     
6 September 2002, Greensboro (NC) News & Record, “The desire and will to battle on” by Kate Hairopoulos, pg. C1:
Southeast is contemplating putting this phrase on its team T-shirts: “Our sport is your sport’s punishment.”
 
16 October 2002, The Virginian-Pilot (Norfolk, VA), “In sports’ popularity contest, cross country is a big loser” by Vicki L. Friedman, pg. C1:
A given at any high school cross country meet is the catchy slogans runners have on their running garb. Perhaps none is more fitting than this one: “Our sport is your sport’s punishment.”
     
Google Groups: rec.running 
Dan Stumpus 
Dec 26 2004
(...)
“Trample the weak, hurtle the dead”  (not that I’d do any such thing…)
“My sport is your sport’s punishment”
“Pride lasts longer than pain”
 
Google Books
Running—The Sacred Art:
Preparing to Practice
By Warren A. Kay
Woodstock, VT: SkyLight Paths Pub.
2007
Pg. 22:
This common dislike of running has prompted the now-famous message emblazoned on the T-shirts of cross-country runners across the nation: “My sport is your sport’s punishment!”
 
Google Books
Run!:
26.2 Stories of Blisters and Bliss
By Dean Karnazes
Emmaus, PA: Rodale Books
2011
Pg. 38:
The reality is, even most other athletes loathe running. As one runner once aptly noted, “My sport is your sport’s punishment.” Yet, based on my encounters, I’ve found runners to be a rather lighthearted bunch.
 
The Lawrentian (Lawrence University, Appleton, WI)
Why runners run
By Alex York
Published: Thursday, October 6, 2011
Updated: Friday, October 7, 2011 15:10
There’s a saying among cross-country runners that “Our sport is your sport’s punishment,” referring to how other sports use running as a disciplinary tool when a team hasn’t met their coach’s expectations. Fumbling the football, committing an error in baseball, shoddy defense on the court — all of these warrant a few humiliating laps, but what has the cross country runner done to deserve the Sisyphean toil of his or her laps? In other words, why — and how, for that matter — does the runner run?
   
RunnerSpace.com
My Sport Is Your Sport’s Punishment
Published by Benjamin.Bradley on Feb 20 2012, 11:43 AM
“My sport is your sport’s punishment” is a common slogan amongst Track & Field and Cross Country athletes alike. If you drop a pass at football practice what does your coach make you do? Run. If a player on your basketball team has a bad attitude to your coach what does the coach make that player do? Run. If a baseball team plays a game and loses because they clearly didn’t give their best effort what does the coach make them do? Run.