Its might be a bit old fashioned going out at 5 am dress like an eskimo to sweat everything off for 6 miles. Running is more scientific now . I have noticed that Mark Tibbs takes his guys out in large parks with hills slopes and trails . The soft surface reduces the traditional injurys related to roadwork but this method is now right across traing for all sports The morning slog after the alarm goes off has also been replaced with track work . 400 meters / 1500 meters 2.5k track sessions with bursts of fast speed That sort of stuff
None of that is really new, if you read about what fighters were doing all along. The real purpose behind getting up at 4 am to go out to run is to teach yourself discipline, to train yourself to do things you don't want to do.
You can always swim if you don't like running, but most boxers do road work. The only boxer I know doesn't run mile is Deontay Wilder.
