Absolute rubbish,a dog needs conditioning before it ever enters a field or even runs hard.When the hard work is done,on the road,lane etc.[this is the part a lot of owners tend to skip because of the time and toil involved},then its time to fine tune the mutt in the field,the easy bit.To many take shortcuts to get a dog at its optimum condition,shortcuts risk injury to the mutt and a dog thats exercised that way rarely reaches the potential of a littermate that was conditioned in the best interest of the dog,not the owner.
if you take a top class greyhound on average it will get 2 20 minute r