Pair-up with someone around the same speed. Elect who will start as the attacker (A) and defender (B). Pairs start on the baseline all facing coach (C) stands on one sideline at centre court
(B) stands one arms length behind (A). A whistle or 'go!' from (C) signals everyone to sprint down the court, (B) attempts to touch (A).
Continue sprinting regardless of whether a tag happens
A second whistle / 'stop!' tells players to quickly - but safely - stop and return to an arms length from their opponent and wait for the next 'go!' signal.
Repeat the ('go!' / 'stop') sprint and tag attempts up the court several times.
Vary the length of the sprints - Start/stop as many times as you want each lap of the court.