Posted December 3rd, 2008
The winter season engenders a youthful spirit in all of us. Well, in the beginning of the season, anyway, before we get tired of the gym and other indoor workouts. If we are outside, the bright sunny winter days in Vermont can provide a much-needed dose of vitamin D. There is increased evidence that vitamin D is needed for good health and prevention of many chronic diseases. Go to the Vitamin D Council’s website at www.vitamindcouncil.org and read their newsletter. You’ll be surprised to find a growing list of diseases associated with vitamin D deficiency. At last count, I noted 17.
My column this month is about being outside in the wonderful Vermont winter, getting a great workout, and soaking up some vitamin D. Bright and sunny it may be, but also very cold. I want your exercise experiences to be safe, injury free, healthy, and fun.
PREVENTING COLD INJURIES
To compensate for the chilling effect of cold skin, you begin to shiver and your muscles become tight, stiff, and prone to injury. Preventing this type of injury, caused by becoming cold, is often a matter of thinking ahead, checking the thermometer before heading outdoors, and being prepared with the best protective gear. Temperatures do not have to be sub-zero to cause an adverse effect on the skin. Studies have shown that any temperature lower than 40 degrees, combined with wet conditions, can be harmful and cause skin injury.
Thermal injury often effects the feet first. Shoes or boots must offer protection from both wet and cold, and are the first line of defense for protection from hypothermic foot injury. Warm feet are as important as hats and gloves in any outdoor winter activity, and socks are as important as shoes. Always wear fabrics that wick wetness away from the skin. A single layer of thick acrylic has proven to work best, but of all the miracle fabrics produced today, it is still wool that will keep skin warm, even when it is cold and wet. I favor acrylic for running and cross-country skiing, but turn to wool for snowshoeing.
Maintaining core temperature is critical in the prevention of cold injury to your hands and your feet. Consider your hat and gloves as your thermostat. Heat flows from your core through your head. Wearing a hat will help prevent this escape of core warmth. In winter outdoor exercise, a hat can be used to help control body heat. When you’re feeling overheated, simply remove your hat and the cooling effect will be swift. Gloves work in a similar fashion. Cold fingers will ask for increased blood flow and this can effect your entire core.
Always be aware that tight footgear will restrict blood flow into the foot, increasing the risk of injury. Shoes should fit properly, neither too loose nor too tight. For runners, New Balance’s NB 921 and Asics’ Gel Artic are both winter running shoes with Gore Tex linings that offer some protection from wet running courses, and they also have a removable spike/cleat system that will help with the slippery spots on your training loop. Snowshoers and skiers must rely on good footwear as well, but in most instances the athletic shoes for these sports are appropriately designed.
At my clinic, we often see Achilles’ tendon injuries that are associated with outdoor sports. Usually the injury is caused by a slight slip at the propulsive phase of the gait. Just before the foot leaves the ground and the whole leg swings forward, a small, nearly insignificant slip happens. This slight slip can cause the calf muscles that conjoin to form the Achilles tendon to re-fire and momentarily contract to stabilize the leg and prevent a fall. This muscle contraction can put excess stress on the elasticity of the Achilles’ tendon and potentially result in small longitudinal tears in the mesothelium sheath in which this strong, yet vulnerable, tendon slides. The unfortunate end result is Achilles’ tendonitis and months of stiffness and pain. We often see this in runners, cross-country skiers, and snowshoers.
Similar to the Achilles injury, slipping can have an adverse effect on the muscle and tendons that stabilize the ankle. The peroneal brevis and longus tendons pass along the outside of the ankle and work in conjunction with the posterior tibial tendon to stabilize the ankle. On the inside of the ankle, the posterior tibial tendon offers medial side stability. Overuse caused from redundant slight slippage over an entire workout can eventually cause tendonitis. With the posterior tibial tendon, displacement from the peroneal groove on the heel bone can happen. This type of injury will result in long-term athletic disability.
Winter in Vermont is spectacular and should be enjoyed in a healthful and thoughtful manner. Using clothing and gear that is protective and sensible is helpful. Be proactive when making an exercise plan by checking local weather and temperatures. Enjoy our winter and get your vitamin D, too.