Are the main differences between Int Tempo and special endurance training the recovery times and the speed?
Are there any circumstances in which one could use intensive tempo for 400m training instead of SPec End?
Go through the Lactate training thread in the archives and there’s a TON of valuable info on the use of all types of work for the 400!
And you’ll probably find that depending on your focus at any given time, more options are available to you! 
When I wrote this, I was still having trouble making sense of that thread. This was my solution:
Printed most or all of KK’s posts that were at least a full-bodied paragraph
Hi-lited certain phrases that encapsulated what is methods and philosophies were and studied that. This is helping a ton now.
It helped to categorize or get a better visual on his approach. He seemd to be the backbone of that thread. I have never used his approach in its entirety because of time and fear. Now I have a group of girls who want the state record in the 4x400 and are willing to work on it through the season.
They all have the speed for the most part in place but they can improve so much more. I am using CFTS for that approach. What I notice as I look at foootage is they have poor come-home speeds in the 400. IF the last 100 is strong then their first 200 was turtlish (31-33 seconds). I have some work to do but thanks. I will keep everyone posted on the progress on this.
Also Charlie, could you peak at my other record undertaking? Its in the 100m section. THanks in advance
Women tend to have slower 2nd 200 splits then men. Even at compareable talent levels.
I agree but I am only speaking about the females. THis is not a comparison to the males at all. Their come home speeds are only stronger when the first 200 is 31-33 sec. That is too slow. I am working on their speed more this year because they are starting to train earlier.