It’s not an exact science and should never be regarded as such, but that advocacy has to come from those who experience the symptoms. Slogans like ‘when in doubt, sit them out’ push the right policy, but the players have to play a part.

With two key forwards out, the tourists had a mountain to climb, but after their remarkable second Test comeback, anything was possible. They had plenty of time to rest and reassess as play was suspended for 40 minutes due to lightning, with less than three minutes of the second half played.