HGH treatment for athletic enhancementhttp://en.wikipedia.org/wiki/HGH_treatment_for_athletic_enhancement
Lean body mass
The primary way HGH assists an athlete’s appearance is by reducing the amount of subcutaneous (meaning underneath the skin) fat an athlete has. One study found that taking HGH led to a significant increase in lean body mass, but the change was primarily for the short term. Although muscle is a primary component of lean body mass, in the instance of HGH, the spike is not muscular. The increase in lean body mass is attributed to a simultaneous decrease in fat related tissue higher fluid retention, and an increase of connective tissue as opposed to muscle hypertrophy. No increase in muscle strength was observed in laboratory testing. This makes an athlete’s muscles more visible but does not lead to an increase of the strength-producing contractile tissue and therefore HGH does not enhance muscular strength capabilities. As concluded by experiments performed at Washington University in St. Louis, HGH can increase the size of muscles, but not muscle strength. So while HGH can modify an athlete’s appearance, it will not boost his athletic capabilities.
 Muscle mass
Researchers are still debating whether the more noticeable muscles are larger in size as well. It should be clarified, though, that muscle mass is not the same as muscle strength. Some say that human growth hormone will build muscle mass through raised insulin-like growth factors levels leading to heightened protein synthesis without any side effects while other researchers argue that there have been no such findings on young healthy adults. The second argument is more supported by research discoveries that HGH effects muscle protein synthesis no differently than a placebo does.
 Injury Resistance
The biggest benefit an athlete gets from using HGH is its anabolic effects on the connective tissue within muscles. These effects “may promote resistance to injury or faster repair [but] would make the muscle no more capable of force generation”. While HGH can make an athlete better equipped to avoid or recover from a sports injury is an obvious advantage to professional athletes, it does not help them play better.
While human growth hormone is commonly used to achieve a higher level of physical capabilities, research has actually found HGH to lower athletic performance. Acromelagy patients, who suffer from natural growth hormone levels of up to 100 times higher than normal, have lower stamina towards physical activity than people with regular levels. When the patients are treated and their growth hormone levels decrease, their stamina improves. This knowledge is part of the evidence behind the new belief that athletes who use supplemental HGH to raise their levels far above average could actually decrease their exercise tolerance, and thus hurt their athletic performance. Further backing was provided in a study done by the Danish Institute of Sports Medicine. They found cyclists of good health and endurance “were unable to complete accustomed cycling tasks after administration of exogenous hGH” and concluded that HGH can inhibit recuperation from exercise. Participants have also been found to have lower stamina after HGH treatment along with higher rates of fatigue.