I began doing the stairs again last night. It was much cooler than it's been recently, and I felt pretty well rested. It ended badly.

I made 17 trips up and down the two flights, two steps at a time. Hamstring was doing fine, knees not complaining too much. Then I got a pebble stuck in the bottom of one shoe, and it was a bit aggravating due to the reduced traction and the clicking. So I put the bottom of the shoe on the edge of one of the steps and pulled my foot backward to dislodge the pebble.

Holy cow! It felt like someone stabbed me in the hamstring. Of course the pebble had to be on the side I'd injured earlier... I hobbled around the rest of the night. It's still really sore. I'll be eating aspirin for a while longer.

17 trips
10 minutes
131 heart rate. Terminated due to injury.