Well said. And very accurate.

Any time a dog will run with effort on the ground it is better than the mill. There is something to carrying your own body weight and propelling that weight forward against gravity.

The same goes with people who run. I think it is pretty much accepted that running on a treadmill is not the same as running out doors. The terrain plays a factor, the changing grade, however slight, it plays a factor.

Your biking is exceptional. Especially if the dog will respond well to changing speeds and changing terrains. It really can't get much better than that.

The only thing that may be better is the dog exploding into a sprint paying fetch. A dog can some what sprint/run fast on the bike but you can't go from zero to max on the bike the same.

If some explosive type sprint work is couple with the bike work you describer, that is a really hard combination to beat.

EWO