PROBLEM: Your riding partner skidded on wet leaves in a curve and fell hard. She cracked her helmet and felt dizzy and disoriented. This scared you because you didn't know what to do.

SOLUTION: When you or a friend suffers a concussion, it's vital to determine the seriousness and act quickly. For recommendations, we asked Fred's brother, Mike Matheny. He's a cyclist and head of the Athletic Training Department at Ithaca College in upstate NY.

Head trauma can be frightening, says Mike, because symptoms may change rapidly. Look for any of the following indicators of a serious injury:

blood or cerebro-spinal fluid (it's straw-colored) coming from the nose or ears

uneven pupil size

nausea and/or vomiting

loss of consciousness

If any of these are present, immediately call for medical help. Use your cell phone, run to a nearby house or flag down a motorist. Keep your friend quiet and warm as best you can. Don't move an unconscious person because there's also the chance of neck or spinal injury.

Sometimes symptoms are less pronounced but they can be just as serious. These include inability to maintain balance, a severe or worsening headache, and confused or inappropriate responses to what's happening at the scene.

Even if none of these conditions are initially present, keep an eye on the person for several hours after the fall. If it was you who got conked, tell someone at home what happened in case you start having a problem.