Recently retired Australian cricketer Ricky Ponting says critics of the controversial rotation policy "have no idea".
The policy has come under the spotlight this week with in-form quick Mitchell Starc left "shattered" by his exclusion from the Boxing Day Test due to a high workload.
The call to rest Starc followed similar decisions to omit Ben Hilfenhaus and Peter Siddle from the third and deciding test of the South Africa series, in which Australia were humiliated by 309 runs.
Former Test quicks, led by Damien Fleming and Dennis Lillee, have panned the idea of rotating fast bowlers, saying they had the potential to jeopardise a player's development and confidence.
But Ponting says the modern game had an increased workload, hinting at the additional one-day and Twenty20 cricket which is played as a reason behind the need for extra rest.
He says "a lot of people talking about it, past bowlers in particular, have got no idea of the workload of some of the guys."