Miraclecello/Cecil, one of my regular visitors, asked me to write about the merits of using a cycling shorts or a regular running shorts in a road race. I tried my best to make a research on this one on published articles and running references but I haven’t seen any resources that deal on this topic. So, this a new thing to tread on and I’ll try my best to give my opinion on this one from my personal experiences and observations.
In my observation in past sports events and athletics events as seen on TV, Sports Magazines, and actual events, the cycling shorts or tight-fitiing shorts which has a leg length of at least six inches from the groin area or the length goes up to few inches above the knees, are used in shorter distance runs in oval tracks (i.e. 100-meter dash to 10,000-meter runs). Seldom you could see elite marathon/ultra-marathon runners using these tight fitting cycling shorts. I can surmised that this kind of shorts impedes ventilation to the groin area and upper legs, thus, this is not preferred to be used in longer distance runs like marathon and ultra-marathon races. The regular running shorts are used to these kind of races.
Most of the triathletes use the cycling shorts because they can use it in swimming to cycling then to running without removing from their body, thus, minimizing their spent time in the transition phase in between events
In my experience, using the regular running shorts in 10K, 20K, half-marathon and marathon races produces “chaffing” or skin rashes on the inside portions of the upper legs as the wet seams of these shorts stick to the skin and rubs the skin as the legs move during running. The cycling shorts don’t produce any “chaffing” or skin rashes as the upper leg portion is covered due to the longer length of the inseams. However, “chaffing” is prevented with the application of baby oil, body lotion, or petroleum jelly on the inner portion of the upper legs.
In last Sunday’s Mizuno Infinity 15K run, my New Balance running shorts produced some “rashes/chaffing” on the inner side of my upper leg due to the wet seams of my short that tend to stick to the skin. The body oil and lotion that I applied on my upper legs were not enough to prevent the “skin rashes”.
Also, in my experience, the cycling shorts absorbs more perspiration/sweat coming from the upper body, thus, preventing the sweat to flow towards the legs and your running socks. As compared to using the regular running shorts where most of my perspiration flows towards my running socks making my feet wet, creating a hard rubbing between my wet socks and my feet. This creates some blisters to my feet in longer distances. Petroleum jelly applied to the feet before wearing your socks would prevent any blisters to the feet.
Using tight cycling shorts could be aerodynamically more advantageous to elite athletes in shorter races or dash runs in the oval tracks and they don’t restrict natural leg movements while running. The regular running shorts could create restrictions in the leg actions while running and could produce more air resistance due to its loose appearance.
Lastly, using the tight cycling shorts need a “bold face” from the user as it invites others to look what and how big your “boil” in between your legs. If you don’t want to create suspicious faces from people when they look at your tight cycling shorts, better use the regular running shorts.
Bottomline? I highly recommend using the regular running shorts in longer distance runs (half-marathon to ultra-marathon) and using the tight cycling shorts in shorter distance runs.