Sometimes you’re the Hammer. Sometimes you’re the Nail. Expect for the first two intervals, I was the Nail in Attacker this morning. I knew during the very first “Stand” in the warm-up that it wasn’t going to be my day. As soon as I came out of the saddle on that first “Stand” the legs felt tired and heavy and my HR shot up a lot higher than it should have. I knew then that I was in trouble. I was able to do the first two intervals at 100% but after just the second one, my HR was way to high, like I was in the fifth interval, and my breathing was labored so after the second one, I reduced the FTP to 80% for the third one to see if I could “smooth” things out for intervals 4 and 5. Nope. I kept it at 80% for interval 4 and upped it to 90% for interval 5. After interval 5 at 90% my HR was as high, maybe even higher, as it is when I do all 5 intervals at 100%. I was literally gritting my teeth just to make it through at 80% at 80rpms. Attacker is one of my favorites and I can usually crush it at 100% but today, for whatever reason, just wasn’t my day for it.
That’s an awsome SUF vid.
I definitely know that feeling of some days just not having “it”. Good decision to back off and do what you could. Sounds like you still properly suffered and shredded some chamois.
I think we should always keep in mind the rule of thirds:
If you say dat wit a French Canadian English accent it becomes “da rule of turds” 
See also Philly.
Sometimes the plan is in conflict with the body. The body usually wins. The problem with letting our ego get in the way (gotta do this workout) is the damage done (overtraining) hinders the ability to make performance gains. Rest, get in the nutrition, let the body recover for awhile and hit it again at a future date.
I hadn’t heard of this before, but after my last 2 SYSTM workouts, it certainly rings true. I did The Best Way is Blended (Mash-up) on Friday, and Blender (Mini Version) Sunday, and the Rule of Thirds describes the experience to a “T.”
The first several “intervals” of each workout had me feeling good, almost as if my 4DP setting was a bit too low and the workout would be a piece of cake.
Then the next couple or few made me think, “Hmm, no, maybe my 4DP is right on.” I’ll get through this about right. Maybe.
The last one or two intervals in each workout had me digging deep into the mental focus tricks and the physical demands were close but just barely not TOO much to handle.
I finished strong because I was determined to nail the targets, but the whispering in my ear was along the line of, “I sure am glad this is almost over!”
I’ll remember the Rule of Thirds now!
There are those days indeed. The key is adapting and your actions are a good example. More time and utimately completing the session is key on any given day, well done.
They idea is not to accumulate fatigue that does contribute to accomplishing the workout goal.
There is a blog post, and a reproduction of the old web page (another part of Sufferlandrian lore that has vanished) that discuss this problem in this thread: