Fungal infections of the skin are common, especially among athletes and others -- kids or adults -- who work out regularly. Athlete's foot is just one example. Jock itch, ringworm, and yeast infections of the skin are others.
If you exercise at a school gym or field, health club, private gym, or tennis club, you're bound to be exposed to sweaty clothes, germ-ridden exercise equipment, or both. It can add up to an increased risk of these annoying, but typically not serious, skin infections.