Sports Fitness Training

Body movements in physical activities such as running, swimming, and bicycling are highly repetitive, so participants are susceptible to overuse injuries. In fitness activities, the joints of the lower extremities(foot, ankle, knee, and hip) tend to be injured more frequently than the upper-extremity joints(shoulder, elbow, wrist, and hand). Three of the most common injuries from repetitive overuse during exercise are plantar fasciitis, “shin splints,” and “runner’s knee.”

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Plantar Fasciitis Plantar fasciitis is an inflammation of the plantar fascia, a broad band of dense, inelastic tissue (fascia) that runs from the heel to the toe on the bottom of your foot. The main function of the plantar fascia is to protect the nerves, blood vessels, and muscles of the foot from injury. The repetitive, weight-bearing fitness activities such as walking and running, the plantar fascia may become inflamed Common symptoms of this condition are pain and tenderness under the ball of the foot, at the heel, or at both locations. The pain of plantar fasciitis is particularly noticeable during your first steps out of bed in the morning. If not treated properly, this injury may progress in severity to the point that weight-bearing exercise is too painful to endure. Uphill running is not advised for anyone suffering from this condition, since each uphill stride stretches(and thus irritates) the already inflamed plantar fascia. This injury can often be prevented by regularly stretching the plantar fascia prior to exercise and by athletic shoes with good arch support and shock absorbency.
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Shin Splints A general term for any pain that occurs below the knee and above the ankle is shin splints. More than 20 different medical conditions have been identified within the broad description of shin splints. Problems range from stress fractures of the tibia(shinbone) to severe int1ammation in the muscular compartments of the lower leg, which can imerrupt the t10w of blood and nerve supply to the foot. The most common type of shin splints occurs along the inner side of the tibia and is usu ­ ally a combination of a muscle irritation and irritation of the tissues that attach tIle muscles to the bone in this region. Typically, there is pain and swelling along the middle one-third of the posteromedial tibia in the soft tissues, not the bone.

Sedentary people who start a new weight-bearing exercise program are at the greatest risk for shin splints, though well­ conditioned aerobic exercisers who rapidly increase their distance or pace may also develop shin splints. Running is the most frequent cause of shin splints, but those who do a great deal of walking(e.g., mail carriers, waitresses) may also develop this injury.

To help prevent shin splints, wear athletic shoes that have good arch support and shock absorbency. If the severity of this lower-leg condition increases to the point that you cannot comfortably complete your desired fitness activity, see your physician.

Runner’s Knee An overuse condition known as runner’s knee describes a series of problems involving the muscles, tendons, and ligaments about the knee. The most common problem identified as runner’s knee is abnormal movement of the patella(kneecap). Women are more commonly affected by this condition than are men because their wider pelvis makes abnormal lateral pull on the patella by the muscles that act at the knee more likely. In women(and some men). this causes irritation to the cartilage on the back side of the patella as well as to the nearby tendons and ligaments.

The main symptom of this kind of runner’s knee is the pain experienced when downward pressure is applied to the patella after the knee is straightened fully. Additional symptoms may include swelling, redness, and tenderness around the patella, and a dull, aching pain felt in the center of the knee. If you have these symptoms in your knee, your physician will probably recommend that you stop running for a few weeks and reduce daily activities that put compressive forces on the patella until you no longer have any pain around your kneecap.

Yohimbe is an herbal or natural supplement extracted from the bark of the African tree pausinystalia yohimbe, which contains yohimbine, the active ingredient. In most dietary supplements, yohimbe is standardized to 3% yohimbine. Yohimbine is an alpha2-antagonist Human fat cells possess both alpha- and beta-adrenergic receptors. Catecholamines are able to stimulate lipolysis through beta-receptors, whereas they inhibit lipolysis through alpha2-receptors. The balance between these receptors controls the rate of lipolysis. Therefore, an increase in thermogenesis for fat-loss purposes could be achieved by either stimulating beta­receptors or by blocking alpha2-receptors. Because yohimbine has alphaTantagonistic properties, this supplement could be used during fat-loss procedures to further increase the rate of lipolysis. This discussion will focus on the lipolytic effect of yohimbine. However, it should be noted that yohimbine is a prescription drug. No specific studies have been done on yohimbe.

Animal Studies

Oral or intravenous administration of yohimbine in dogs has resulted in a significant elevation in plasma free fatty acids and an increase in sympathetic nervous system activity. Norepinephrine was significantly elevated following yohimbine administration. Furthermore, chronic oral administration resulted in a reduction in body weight and in food intake, suggesting that alpha2­antagonists may influence satiety. The lipolytic effect of yohimbine may result either from a direct action of yohimbine or from an activation of the sympathetic nervous system.

Human Studies

The interplay of beta-receptors and alphaTreceptors regulates the lipolytic response of adipose tissue to the catecholamines. A supplement which would inhibit the alpha2-receptors would theoretically increase the action of catecholamines on lipolysis. Yohimbine has been shown to effectively increase lipolysis.

An abundance of studies have been done investigating the lipolytic action of yohimbine in humans. In vitro studies using human adipocytes have indicated stimulatory effects of yohimbine on lipolysis when catecholamines are present.

Oral administration of yohimbine to humans has been shown to significantly elevate plasma glycerol and free­fatty acids. Furthermore, the effect of yohimbine was further enhanced during physical exercise when the levels of catecholamines are further elevated. Yohimbine also appears to stimulate norepinephrine levels by increasing sympathetic nerve activity.

When yohimbine was administered during a low­energy diet, patients lost significantly more weight than patients receiving a placebo Energy expenditure did not decline in the patients consuming yohimbine, while the placebo group experienced a 15% reduction in energy expenditure.

Safety and Toxicity

Alpharreceptors are present in a number of tissues including heart, arteries, lung, and adipose tissue. Therefore, yohimbine could react with any of these receptors and influence those tissues. However, both animal and human studies indicate that cardiovascular changes are either nonexistent or minimal following yohimbine administration.

Some side effects associated with yohimbine include feelings of panic, clumsiness, and confusion. There have also been reports of chills, nausea, and tremors. The prescription form of yohimbine is normally prescribed for impotence problems; therefore, individuals may experience heightened sexual arousal. Furthermore, there have been reports of mood disturbances and anxiety.

Another concern regarding yohimbe is the purity of the dietary supplement. Yohimbine is the major alkaloid of the plant and the active ingredient. The bark of the tree has been reported to contain 6% total alkaloids, 10-15% of which are yohimbine. Most dietary supplements have been standardized to 3% yohimbine. Therefore, a 100-mg dose of yohimbe will contain only 3 mg of yohimbine. In research studies, yohimbine is usually administered at a dose of about 0.2 mg/kg of body weight.