The 20-yard shuttle is designed to test lateral speed and coordination. The player starts in a three-point stance. When the whistle blows, the players run five yards to one side, touching the yard line. They then sprints 10 yards in the other direction and again touch the yard line, at which point they sprint back to the yard line they started from.
"What we're looking for from players is to drop their weight and accelerate quickly," Philadelphia Eagles college scout Matt Russell said.
However, athletes are always looking for ways to knock even fractions of a second off their times.
"Players are always trying to get away with stuff," Russell said. "(In the cone drills) guys will try to run over the top of the cone."