Now that's a segue!
Sounds like one heck of a regime for all of you. When the time comes, roller blades. Winter time skijoring? All that pounding on the pavement may eventually come along later on as arthritis. That it's showing up now as heal spurs and shin splints and such in a warning I think, don't you?
The running is good over all for all of you but I would want to change that impact issue. There is no better way of burning off that excess energy in a dog them a good long run. There is also a mental aspect to excersizing a dog too. Obsticles are great and problem solving aswell. Finding a dogs motivation is key. Once you do it's only a matter of designing the excersize to use the motivation.
I was unsure of that before I started but once done, the dog is tired. It's hard work to figure things out and it's that focus that does it. Like the way your dogs work together in hunting. It's the thinking it through that provides the challenge and the reward when it works the way they anticipate.
The protection training you have incorporated is geared to that mental excersize nicely. I would if you don't already aspects like searching by sight, smell and sound, the obsticles to the apprehencion can be set so that only using a specific skill or set of skills depending on level of ability in the dog.
There is an old barn out in Oakville that I used for training in pitch black and using planks and crates to build levels that have to be traversed that in part go away from the target. So my dog has to understand that it's finding the route to the target is the activity rather than jumping and barking.
How are they at regular day to day obedience?