Improvements can be made to chairs by evaluating the chair and athlete separately or in performance conditions together. Prosthetic devices come in a variety of designs suited to different athletic purposes. Prosthetic legs may be designed for rock climbing, running, or jumping. The technology is designed to attain goals, such as greater gait efficiency when running. The technology is constantly improving to meet the demands of athletes who set ever-higher sports challenges for themselves. In 2008, the International Association of Athletics Federations (IAAF) began a worldwide debate when they established Rule 144.2(e), prohibiting the use of technical devices that offer a competitive advantage. South African athlete Oscar Pistorius, using energy-storing prosthetic legs, fought for the right to run against able-bodied athletes in the 2008 Olympic and Paralympic Games, and won the right to compete, although he did not meet the qualifying time required for the traditional able-bodied competitions. Functional classification systems are used to evaluate and categorize athletes in elite sports. The classification determines the type and extent of assistive technology use by the athlete. Organizations and associations at the national and international level support the development of adaptive sport and recreation, often through the use of assistive technology for players. These organizations are "growing in number and scope". Assistive technology has made sports accessible to many athletes who would have otherwise not been able to play. However, it has its downfalls. This technology is expensive, so many people will never have access to it. It can be subject to abuse, as some people use the technology when they don't actually need it. There have been rulings that athletes who use assistive technology have an advantage over "able-bodied" athletes.