In the cycling world, any larger-than-average male rider. Most likely labeled so because they are bigger, usually slower and sometimes stronger than others (just like the horse). As it is with most men, this label is taken neutrally (neither a compliment or an insult). However the same can not be said for the females' version of this word: Athena.
Why don't you get a carbon fiber bike?
I'm a Clydesdale! I'll crack the frame!
In the cycling world, a larger-than-average female rider is often referred to as an "Athena." Most likely called so because the greek goddess being referenced was often portrayed as a strong, larger than life kind of woman. Some women see it as an insult, others take it as a compliment. The jury is still out on its connotation.
That Athena passed me on the climb like I was standing still!