When he was at Southampton, Pochettino trained his players to raise their game as the season went on, making them among the strongest finishers in the division. Now he is attempting to do the same at Tottenham, and the seeds of their endurance were sown many months ago. Pochettino’s aim during pre-season is to break his players so thoroughly that they grow back stronger as a result. The hot-coals exercise at Southampton was one example. Another was getting his players to smash arrows over their collarbones as a test of physical and mental strength.