As already mentioned, this has always been a very popular theme. In literature, real life and smut, the classic Greek elements of athletic pursuit for personal perfection, nudity in locker rooms and sexual energy amongst men has played out for generations. Please note that a different gay smut film by the name Track Meet was theatrically released in 1976.
Track Meat works so well because of the production values. It features old-school style jock straps, baggy gray sweat pants, and a locker room that looks like more than a few years' worth of young men have passed through its cement block walls. It provides a perfect setting to showcase the physique adoration by both the athlete and his coach. The action in the movie is also up to NOVA's high standards. The viewer is treated to watching this track runner as he begs for a second fucking from coach Mark. Interestingly, Clay was identified as Clay Hughes for the original VHS cover artwork.
In terms of ages and physical appearances, both Clay and Mark were perfectly cast for their roles. Track Meat also generated a high quality smut magazine. Photographs of Clay from this magazine are probably how most people surfing the Internet first discover Clay, as they remain quite popular and easy to find.