Hill Intervals 51:00  5.5 mi (9:16 / mi)
TM 5 min easy then all at 830 3 sets of increasing incline 1% every two minutes to 5% each time then back to flat. No pain in back or other limitation during run. Felt good with no issues. I did stumble a bit once without falling and this did not cause any pain in my back. Felt good about this.