Based on the discussion in the pod today. I had to give up running five years ago because of my knees. What my knees will tolerate to burn 1000 calories in an hour is this. 20 Minutes on elliptical, 20 rowing, 20 uphill walking on a treadmill. Oocasionally mix in 20 on a stationary bike but that knocks the calorie burn down a little. Been doing it 4 days a week for years with little knee problem. The other days I do an hour in the off the main trail routes at Whirlpool Trails. Something about the uneven terrain helps. If I walk a half hour on streets or concrete the knees will bark but seldom in the woods
