This paper aims to define sports engineering through the use of historical and contemporary examples. The historical development of the technology in the sprint and in the javelin are discussed, from their introduction to the Olympics over two and a half thousand years ago to the current day. The rules pertaining to tennis racquets are described and the ways in which manufacturers and researchers attempt to maximize performance using technology are examined. Two models for a tennis racquet are shown, one in which the racquet is modelled as a rigid body and one in which it is modelled as a flexible beam. Use of the models shows that further advances in racquet technology using stiffer and lighter materials are unlikely to speed the game up. It was concluded that technology can be used by athletes and manufacturers to enhance performance. Equally, the ruling bodies of sport can also use technology to limit performance, leading to a delicate balance between technology and tradition.