Or in other words more readily understood, "hard". I'm not much of a science guy so I tend to avoid big words like "anaerobic alactic". Similar to my car, I don't understand even a little bit about the AFR sensor in my Honda but I do know how to press my gas pedal to make the round rubber turny things go and get to my destination in the desired amount of time. Today's workout was 3 X 150 meters which still is not a true "speed" workout. Terminology is important and we tend to use the term "speed work" often and also incorrectly. Anyway, 3 X 150 meters (on 5:00 rest) was on my schedule with the goal of hitting 19"-20" on each. It felt like forever since I've done a track workout so I wasn't positive I could hit those splits. That's roughly 13" at the 100 then 6.5" for the last 50. Not exactly MAF.
#1- 19.4". Not 100% warmed up. Legs felt tight.
#2- 18.9". Better.
#3- 19.2". Felt the strain a bit on this.
Then I took some liberties and decided to do 2 X 100. 12.85 on the first and then 13.3 on the second which is sort of a sign that I was done. That much of a drop off in speed, and I was pushing to max, was my body letting me know that it was done from a CNS perspective.
Back to terminology. Technically an anaerobic alactic session would need the recovery to be long enough to recover the creatine phosphate used in the interval which takes roughly eight minutes. Today's workout called for five minutes of recovery which blurs the lines of the definition. Not exactly sure what the implications are in this regard. I personally don't believe that at my own level of ability it matters that much. A truly elite runner however may lose some benefits of the sessions.
I liken the spectrum of runners to a blade. At the very beginner end you have butter knives, or their fitness is very dull. If you hone the butter knife on anything it will be easy to make it sharper than it was. With the runner they can generally do ANY workout and it will make them better to some degree. Then at the elite level you have razor blades. Even the tiniest stroke against a stone will dull it and in order to get the edge back to 100% you must very carefully and skillfully hone it on precisely the right stone. The elite runner needs to train very precisely and specifically and the tiniest details matter. I'd put myself somewhere in old pocket knife range. It's pretty dull from years of use and abuse but it has potential.