In patients who are resistant to first-line physical therapy such as eccentric loading, ABI or PRP injections are useful second-line therapies to improve clinical outcomes. In this study, up to seven out of 10 additional patients in this difficult to treat cohort benefit from a surgery-sparing intervention.

In recent years there have been rapid developments in the use of growth factors for accelerated healing of injury. Growth factors have been used in maxillo-facial and plastic surgery with success and the technology is now being developed for orthopaedics and sports medicine applications. Growth factors mediate the biological processes necessary for repair of soft tissues such as muscle, tendon and ligament following acute traumatic or overuse injury, and animal studies have demonstrated clear benefits in terms of accelerated healing. There are various ways of delivering higher doses of growth factors to injured tissue, but each has in common a reliance on release of growth factors from blood platelets. Platelets contain growth factors in their alpha-granules (insulin-like growth factor-1, basic fibroblast growth factor, platelet-derived growth factor, epidermal growth factor, vascular endothelial growth factor, transforming growth factor-beta(1)) and these are released upon injection at the site of an injury. Three commonly utilised techniques are known as platelet-rich plasma, autologous blood injections and autologous conditioned serum. Each of these techniques has been studied clinically in humans to a very limited degree so far, but results are promising in terms of earlier return to play following muscle and particularly tendon injury. The use of growth factors in sports medicine is restricted under the terms of the World Anti-Doping Agency (WADA) anti-doping code, particularly because of concerns regarding the insulin-like growth factor-1 content of such preparations, and the potential for abuse as performance-enhancing agents. The basic science and clinical trials related to the technology are reviewed, and the use of such agents in relation to the WADA code is discussed.

Stories about illegal doping in sport are a regular occurrence. Julian Savulescu argues that rather than banning performance enhancing drugs we should regulate their use, but Leon Creaney and Anna Vondy say this would lead to escalating use and call for tougher enforcement

Ն40), and grades 2 and 3 obesity (BMI of Ն35) among adults over the survey periods covered by our article. There were no statistically significant increases over the period 1999 through 2008 in the prevalences of grade 2 or grade 3 obesity in sex-specific logistic regression models adjusted for age group and race/ethnic group.According to the report of an expert committee convened by the World Health Organization, there are no generally accepted standards for defining obesity in terms of percentage of body fat 1(pp312,420) ; thus, it cannot be definitely stated what proportion of the population has excess body fat. Information on the distribution of percentage of body fat from the NHANES data and its relationship to BMI has been published elsewhere. 2