EATING RIGHT FOR WINTER SPORTS

Whether you're an Olympic athlete or a weekend warrior, winter sports require that you pay special attention to food and water, cautions UC Davis nutritionist Liz Applegate, an expert on nutrition and fitness. "Particularly for sports like snowshoeing or downhill and cross-country skiing, where you're out for several hours, you need to make sure that you take plenty of food with you," she says. "If your blood sugar gets low, you're more likely to become confused and run the risk of getting lost." Plus, running out of "fuel" results in poor performance and makes it hard to stay warm. She suggests tucking a half-cup of dried fruit and an energy bar -- about 200 calories -- into your pocket before taking off for a half-day in the snow and perhaps something extra in case of an emergency. For all cold-weather exercising, Applegate stresses that a high-carbohydrate food, perhaps hot cereal and a banana, should be eaten a couple of hours before your workout. "You'll find that you exercise harder and longer, and actually burn more calories than if you started your workout on an empty stomach," she says. And even though it's cold, you need to make sure you're drinking plenty of water because cold air is drier than warm air and draws out more body moisture. She also urges winter athletes to dress in layers, rather than in one heavy coat, so that they can peel off one layer as they warm up without risking a sudden drop in body temperature. Applegate is one of the nutritionists made available by the International Olympic Committee to advise Olympic athletes. A former award-winning triathlete, she is the author of several books including "Eat Smart, Play Hard."

Media contacts: Liz Applegate, Nutrition, (530) 752-6682, eaapplegate@ucdavis.edu; Patricia Bailey, News Service, (530) 752-9843, pjbailey@ucdavis.edu.


AVOIDING SKI INJURIES

For recreational skiers, setting bindings a little lower can help avoid knee injuries, according to Maury Hull, a biomechanical engineer at the University of California, Davis. Hull has studied leg injuries related to skiing and snowboarding for over 20 years. With orthopedic surgeon Steve Howell of Sacramento's Methodist Hospital, he directs the UC Davis "knee lab" investigating injuries in skiers and boarders. Rigid plastic ski boots mean fewer ankle injuries but more knee injuries, Hull said. Injuries generally happen because the ski acts as a lever that can put considerable force on the nearest available joint -- the knee.

One aspect of Hull's work has been to develop ski bindings that are better at sensing the forces on the ski and that release under the right conditions. Published release adjustment standards (DIN settings) are too conservative for most skiers, Hull said. He recommends that skiers treat the standards as an upper limit and set their bindings a few points below, then adjust upwards as required. In contrast, competitive skiers will keep their bindings as tight as possible to avoid losing a ski. Common sense and a knowledge of how injuries occur are also important for safety, Hull said. For example, many skiing injuries occur when someone tries to recover and ski out of a fall.

Media contacts: Maury Hull, Mechanical and Aeronautical Engineering, (530) 752-6220, mlhull@ucdavis.edu; Andy Fell, News Service, (530) 752-4533, ahfell@ucdavis.edu.


WHAT MAKES ICE SLIPPERY

Most skiers assume that pressure or friction melts snow under the ski to make a slippery layer of water. But there just isn't enough pressure on skis to do that, according to University of California, Davis, chemist Timothy C. Donnelly. In fact, the problem of why ice is slippery at all was only solved in the 1990's, he said. Just how skis run over snow is a long-standing interest for Donnelly, a keen skier. He developed ski waxes that work in all types of snow conditions. On cold snow, hard ski waxes smooth the ski base and make it slick. On warmer, wet snow, softer waxes act more like lubricants to make the skis slide faster. Donnelly's waxes included a surfactant, or soap-like molecule. On cold snow, the surfactant stays inside: as conditions warm up, the surfactant is released and adapts the waxing to the conditions. Donnelly's research on ski waxes led to commercial products used by medal winners at the 1988 and 1994 Winter Games.

In 1996, UC Berkeley chemist Gabor Somorjai discovered that oxygen atoms at the surface of ice crystals are vibrating much faster than those inside. This creates an outer layer that acts like a liquid, although the ice crystal is solid, and that's what makes ice slippery. Skis, snowboards and ice hockey pucks all swim on this semi-liquid layer. For ice skates, there's enough pressure to cause some melting as well, Donnelly said.

Donnelly is currently developing an environmentally friendly liquid deicer for uses as diverse as dog sled runners, fishing boats, light aircraft and microwave towers.

Media contacts: Timothy C. Donnelly, Chemistry, (530) 752-0964, (707) 452-8920 (fax), donnelly@chem.ucdavis.edu; Andy Fell, News Service, (530) 752-4533, ahfell@ucdavis.edu.