Low cadence = Muscular failure during interval workouts?

I recently had an FTP bump form 252 to 268 this week, I was ecstatic about it; so much so that I did a 2X10 sweet spot workout immediately after the ramp test. The following day I did Dade +1 and had to dial down the intensity by 5% for half the intervals. Did a recovery ride yesterday. Today I did Thor -3 in lieu of Thor -1 and nearly failed the workout.

What I noticed with all the workouts this week is that I had to fight to keep my cadence above 85 rpm, even during the recovery valleys; my cadence is usually between 85-95 rpm without issue. Even on the recovery ride I had to focus to keep my cadence over 85 rpm. On Dade +1 and Thor -3, my cadence would fall to 70-80 by the end of the interval, totally felt like I was grinding.

My question is: Does the drop in cadence indicate muscular failure, and am I overreaching too much at this point? Last week I had three big outdoor rides involving my first ride up a local mountain in over a year, my first fast group ride and farthest I’ve ever ridden (51 miles), an endurance TR ride, and finally a solo outdoor ride at about tempo. The week prior to that was the midpoint of the short-power build low volume plan, so I basically substituted the endurance week with relatively hard outdoor rides +1 TR ride. Was I arrogant to think I could do those big outdoor rides and then go right into another build phase?




I was planning on doing a 1.5 hour endurance TR ride on Saturday, do you think I should skip that or just try and see?

Skip would be my vote.

Doing the endurance ride is going to pile on some more training stress and in case your RPE is higher than expected you are only going to batter your motivation.

Take a day off, rest is a vital part of getting faster and better at cycling.

And if you feel guilty about it, do something cycling related like cleaning your bike, reviewing your progress from the last couple of weeks, plan your next weeks of training, look at your eating plan etc.
All of them connected to your cycling training and progress but you are just not on the bike doing it.