I've tried to add running back in for cross-training purposes, but it seems to result in injury. In the 90s, I used to run half- and full marathons until Piriformis Syndrome kicked in. I can now manage the PFS with stretching and not overtraining, but overpronation now is the problem. Doesn't seem to cause knee problems -- hits me in the ankles.

For crosstraining, I am back to rowing. I also walk/hike and occasionally, do some kickboxing (Powerstrike).