Hysplex

Each racer stood behind his own hysplex and all of the strings were centrally connected behind the runners, held by a referee.

Therefore, the officials had to devise special mechanisms to ensure the fair start of the race.

[1][2] We know about the hysplex mechanism from depictions in surviving vases as well as from descriptions during the Hellenistic and Roman times.

According to those sources, the hysplex were two horizontal stretched ropes at the height of the knees and the chest of the runners correspondingly.

The official would trigger the mechanism, the ropes would fall to the ground and the runners would spring onto the track.