Dogsey

to SarahJade

If dogs hadn't evolved to do a lot of travel, some of it on hard surfaces, their nails wouldn't grow so fast

Risk it because you suspect that the balance of the evidence says exercise in moderation is good for young mammals. Would you keep your kids from doing sports until their growth plates were closed? Do wild canids keep their young in the den until they are fully grown? Heck no! A few miles a day at a moderate pace isn't a lot for a dog. I'd guess that their wild ancestors often did that distance just to get to the water to drink! You have to balance the risk of activity against the risk of inactivity . . . which is not zero. Poor musculature is not healthy.

As for hard vs. soft surfaces . . . again, no evidence. There IS evidence that jumping on hard surfaces is bad . . . but a slow trot on moderate grade? I think not. My dogs always have the option of moving a few feet to the side and running in the grassed margin of the bike path. They only do so if something over there smells good . . . and it's very convenient not to have to trim their nails.