I need help picking my 3rd ride of the week? I usually ride a fast Tuesday outside (30+ miles, 22mph avg) and a long weekend ride (~60 miles, 17-19mph), everything rolling hills or climbing. I stick to the TR plans for a solid 20 weeks over the winter, but just head outside when it warms up and when its not raining.
What sort of Thursday ride should I do indoors? VO2 Max? Sweet spot? Threshold?