1) Cowboys were/are lean and tough
2) They usually were/are very saddle sore at the end of their days on horseback.
Don’t forget, horseback riding is fun and relaxing as well...the fact that you are having fun takes away some of the muscle ache. Being crammed in between Jaba the Hut and some mom and her three year old who has had too much candy and OPPS it’s nap time is neither fun nor relaxing.