Photographing people in the middle of the day is a daunting task at the best of times. Your choice of shooting angles can be limited, especially when you're covering a sporting event.
When photographing golf tournaments, I had only seconds to get a portrait shot of the players as they were coming off the greens. The aid of an assistant and a professional grade flash gun was my only viable option for capturing quality professional portraits.
To shoot tight portraits (head to waist) I would have my assistant hold a large white patio umbrella angled to diffuse the direct sunlight. I would bracket my shots and use fill flash to cancel out any harsh shadows.
When shooting wider portraits, I'd lose the umbrella and bump up my flash output to compensate for the strong sunlight and have my assistant bounce light from a white or silver/gold reflector disk back onto the subjects.
It takes a bit of practice to get the right amount of flash and reflector disk bounce light, but after a few tries, you'll be shooting like a pro.To process the images I use Nikon's Nik Software plugin for Photoshop to correct the white balance.