Wales fitness coach Mark Bennett has been putting his squad through its paces since their return from tour in Australia, culminating in V02 testing at University of Glamorgan sports science labs on Wednesday.
The endurance test is designed to measure the amount of oxygen expired by a player when pushed to maximum performance.
Each member of the current 41-man Welsh squad has been put through the gruelling test which involves running on a treadmill at increasing speeds for a maximum amount of time.
'The test gives us a specific measurement of fitness and we are looking for all players to reach a minimum standard, which would give a score of around 50-60 mil (ml/kg/min of oxygen used by an individual)', said Bennett.
'Many of the players will be above that level, but we also donšt want them to score too highly.
'A cross country skier or a rower for example would expect a top score of around 90 mil, but a rugby player would have to lose power to score that highly which is not what we want.
'Footballers would score similarly to rugby players and the average man in the street would be down around the 30 or 40 mil mark, presuming he is reasonably fit.'
Professors Bruce Davies and Julian Baker of the University of Glamorgan run the tests on behalf of the Welsh team and Davies says he has been impressed by players giving their all.
'We have tested many sportsman over the years, from John Dawes' Welsh rugby team right through to the present day as well as the top rowers and athletes from many other sports,' said Professor Davies.
'This test is all about pushing yourself to the limit so we have to give the players lots of encouragement and make sure they go all the way to get the best results.
'But its been easy with this Wales team, they are all keen to see how far they can go and you can tell, just by looking at them when they've finished, that they've put everything in.'