Wolves are now in a hectic schedule of pre-season matches and training programmes and they are in action again on Wednesday, when they take on Hereford United.
McCarthy is very happy with their condition and had heaped praise on fitness coach Tony Daley.
"They have come back fitter than I have ever seen any group of players", McCarthy told the Birmingham Mail.
"Levels have fitness have improved over the years but this lot are in tremendous shape. They were all given a programme to follow over the close-season and they stuck to it and, as a result, look great.
"Tony has been excellent. He has organised all the fitness regime while myself and Terry have been doing all the football."