Exercise plays an important role in the management of both insulin-dependent diabetes (IDDM) and non-insulin-dependent diabetes (NIDDM). Regular exercise, especially aerobic exercise, strengthens the heart and circulatory system, thus reducing the chance of heart disease and stroke. It helps decrease blood cholesterol and increases the levels of the “good” high-density lipoprotein (HDL) in the blood. Exercise lowers blood glucose levels, both during exercise and for several hours afterward. Walking is probably the best, safest and least expensive form of exercise. It can fit into almost anyone’s schedule and can be integrated into other events and activities. The only investment needed is a comfortable pair of appropriate shoes. However, many people prefer to jog or run. This yields a more intense workout in less time. It also can be associated with organized competitive activities such as marathons and often results in a much greater feeling of accomplishment and self-satisfaction. Unfortunately, running can lead to many types of foot and leg injuries. When it comes to the average recreational runner who trains regularly and takes occasional long distance runs, the injury rate is somewhere between 37 and 56 percent. One must recognize the factors that contribute to these injuries, especially when you’re treating diabetic athletes who are at increased risk. Fifty to 75 percent of all running injuries are from overuse injuries, which usually result in muscle strains, such as plantar fasciitis and shin splints. Some of the biomechanical factors, which can lead to these overuse injuries, include leg length discrepancy, flexibility problems, muscle weakness or imbalance and laxity of ligaments. Training errors are the most common cause of overuse injuries. Training errors include excess mileage, a change in training patterns, improper footwear or troubles with the training surfaces. In addition to these problems, the presence of diabetes also appears to result in the increased prevalence of pedal fractures in the athlete. A study comparing the incidence of pedal fractures in 60 diabetic athletes with 60 non-diabetic athletes revealed a two-fold increase in the number of diabetics sustaining fractures with the most frequently fractured bones being the second, third and fifth metatarsals. The diabetic athlete group also sustained more multiple foot fractures. What You Should Look For During The Exam The development and use of a foot management plan for the diabetic athlete can be an important tool in preventing foot injuries and serious lower extremity medical complications such as infections, ulcers and amputations. A thorough lower extremity evaluation of the diabetic athlete is an essential part of establishing a foot management plan. The evaluation should include a medical and sports (athletic activity) history. One should also be on the lookout for peripheral neuropathy, circulation compromise and any biomechanical abnormalities. A history of prior infections or ulcerations of the foot has important predictive value with regard to the potential for future ulcerations and other pedal complications. Each patient visit should include a thorough evaluation for peripheral neuropathy since neuropathy is the major component of nearly all diabetic ulcers. Using the Semmes-Weinstein 10-gram monofilament wire, you should take measurements at the following 10 sites: the first, third and fifth digits plantarly; the first, third and fifth metatarsal heads plantarly; the plantar midfoot both medially and laterally; the plantar heel; and the dorsum of the midfoot. When the athlete loses normal sensation, he or she fails to be aware of excessive plantar pressure. When it comes to treating patients with sensory neuropathy, you should identify and protect areas of potential excessive plantar pressure, such as a plantarflexed metatarsal. One should also consider the increased potential for foot fractures when the diabetic athlete has an insensate foot. Consider obtaining X-rays after the patient participates in any strenuous sports activity such as a marathon. You should schedule a follow-up exam in two to three weeks given the possibility of a stress fracture, which might not be evident on the initial X-rays. A follow-up X-ray at that time is strongly recommended, especially if there are associated findings such as localized swelling and deformity. One should perform a vascular evaluation to detect claudication or rest pain, a prior history of lower extremity arterial bypass surgery, abnormal pedal pulses, capillary return time and dependent rubor or palor on elevation. You may use a Doppler to determine the ankle-arm index. Determining circulatory status is important given the increased incidence of atherosclerosis in individuals with diabetes. You must recognize and address structural pedal malalignments in the diabetic athlete, especially in the presence of sensory loss. Conditions such as hallux valgus, hammertoes and plantarflexed metatarsals create areas of increased pressure and potential tissue breakdown. Advising Patients About Increases And Timing Of Activity When it comes to increasing exercise activity, diabetic patients with the aforementioned conditions should do so in small increments. The goal of limiting the increase in activity time is to avoid the accumulation of the localized inflammatory effects in the areas of bony prominences. The athlete should check these areas of the foot after every exercise activity for increases in temperature. If he or she notes any “hot spot” area at night that is still present in the morning, this is an area of risk for the athlete. Normal hyperemia from exercise should resolve within 30 minutes. For this reason, jogging workouts are often best divided into two intervals during the day, and performed every other day. Key Pointers On Evaluating The Footwear Of Diabetic Athletes It’s also important to evaluate the diabetic patient’s athletic gear. Obviously, size is not the only consideration for proper shoe fit as a specific size shoe can come in many different last patterns. One should measure the foot with a dependable measuring device. Shoes should fit properly while the patient is weightbearing. The widest part of the shoe should accommodate the metatarsophalangeal joints. There should be three-eighths to one-half of an inch between the longest toe and the tip of the toe box, and adequate space around the heel. The athletic footwear should also have adequate “breathability” in order to avoid the buildup of thermal energy within the soft tissues of the foot, which can lead to tissue damage. When they are used properly and have a proper fit, running shoes have been shown to be a valuable aid in reducing plantar foot pressure. In one study, running shoes reduced the tendency for plantar foot callus and decreased forefoot pressure by 30 percent, with pressure reduction of 44 percent under the second metatarsal head. Since foot orthoses and inserts comprise common treatment modalities for sports related problems, you need to evaluate these as well for appropriateness and condition. About 90 percent of runners continue to use their orthotics after their condition has improved, with an average duration of 23 months. An orthotic device that may have been helpful at one point may be inappropriate or even detrimental two or three years later, and thus must be discontinued or changed. Final Notes Patient education is the most important part of managing the diabetic athlete. The education should be designed to meet the needs of each patient, considering his or her athletic activity and diabetic foot status. Obviously, a strategy of prevention is preferable to treatment in terms of cost to the patient and discomfort. The injured athlete should complete a program of rehabilitation in order to successfully return to full activity and continue his or her exercise regimen. If the athlete has healed from a foot ulcer, the goal is to prevent re-ulceration. Preventing injuries involves proper selection of clothing, shoes and the surface to be trained on, as well as good training techniques and proper preparation. Knowledge of the causes of foot infection, ulcerations and injuries by the athlete is an essential part of the prevention process. Dr. Caselli (pictured) is Vice President of the greater New York Regional Chapter of the American College of Sports Medicine and is a Professor in the Department of Orthopedic Sciences at the New York College of Podiatric Medicine. Editor’s Note: For a related article, see “A Comprehensive Review Of Pediatric Orthoses” in the October 2002 issue or check out the archives at www.podiatrytoday.com .
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