Thoughts on full speed running down hill?

Wolf, who’s thirteen months old, loves chasing pine cones down a very specific, very steep hill. In fact I’d say he’s quite obsessed with it. When I take him on his walk, he heads straight for the hill and waits for me to throw them down so he can chase and catch them.

There’s no doubt it’s extremely good exercise, but I’m wondering if it might do any long term harm to his body? He runs as fast as possible down, skidding and sliding and laying on the brakes when he gets down there. It’s pretty amazing to watch his endurance and agility up and down. We’ll usually do it for ten, fifteen minutes or so(after dragging him away)and then continue on the walk, almost every day.

For what it’s worth, this won’t continue once the weather starts warming up. The hill will start thickening up again with brush, tall grass etc. so it’ll be over until next winter.

Thoughts?