From my TT Members' forum TT Transformation Challenge thread...
Today (Sept 23) I did my 1st intervals in 4 months. When I quit, I was up to 12MPH on the work phase for 30-40 seconds. I knew going in to today that I wouldn't hit that so I did 6 sets, rest @ 3.5 MPH - work @ 9.5 MPH. It was difficult, but not killer. That said, I'll bump it up to 10 MPH for my next session.
Immediately after the interval session I jumped on the stationary bike and did 25 minutes at about a 15 MPH pace. The HRM said I was at ~160 BPM which puts me up in the 90% territory, but it didn't feel like it.
After reading some recommendations, I may just stick with interval training and when I reach a plateau, I'll follow this type of routine. It's called the Stubborn Fat Protocol for anyone else interested.

