The ancient Greek engineers had invented a special device, called hysplex (ύσπληξ), which was placed at the starting line of any race in order to prevent the untimely start of the competing athletes. The study of this device is based on its unique representation on a Panathenaic amphora of 344/343 B.C., the architectural remains of three stadia located in the Northeastern Peloponnese (Isthmia, Epidaurus, Nemea) and on the race track of the Corinthian Agora as well as on the reference to an hysplex in two Hellenistic inscriptions from Delos. This evidence coupled with the assumption that the function mechanism of such a device might have been influenced by the advanced technology of the late-Classical catapults led to the reconstruction of hysplex. The hysplex consisted of two horizontal ropes stretched in front of the waist and knees of the runners. The ends of each rope was tied up at the top of vertical wooden posts which were firmed by mechanisms laid at both ends of the starting line and controlled by the starter of the race. At the appropriate moment he would let all the ropes to fall down, thus permitting all the athletes to start the race simultaneously. The reconstruction of a full-size hysplex model was made possible thanks to the financial support of the University of California (Berkeley). The function of this 2,300 years old device is successfully tested every four years at its original site, the ancient stadium of Nemea, during the modern conduct of the ancient Nemean Games.