IVE RAN THEM FOR 5miles A DAY ALONGSIDE ME WHEN I DONE A LOT OF RUNNING, IVE TROTTED THEM ALONGSIDE BIKES/CARS. WALKED THEM FOR MILES EVEN SWAM THEM. HAVING 2 DOGS THAT WILL RUN AROUND WITH EACH OTHER ON GRASS HELPS AS WELL. . HOWEVER THESE THINGS ONLY HELP PREPARE YOUR DOG OR KEEP THEM TICKING OVER.. AS THEY SAY"something is better than nothing". HOWEVER in my opinion!!! NOTHING GETS A DOG TRULY FIT OTHER THAN RUNNING IT. GEARING UP ITS BODY FOR THE CHASE, NOT JUST EXERCISE,,, YOU NOT ONLY HAVE TO GET ITS BODY FIT BUT ITS MIND FIT ALSO FOR SUCCESS. DOGS" ran from their beds"SHOWS BAD STOCKMAN