There really isn’t any secret on how to race the 400m. You hear about the 4 P’s (Push Pace Position Pray). But at the end, you need a good top end speed, and the ability to maintain that. As ironic as this may sound, you have to put MORE effort after 60m to get LESS speed as the race progresses. Especially at the 200m point where one can ‘fall asleep’ and really slow down!
A good read and 3 minute video can be found in Iwan Thomas & Michael Johnson: How to Race the 400m.
Wanda Diamond League Final 2023, Hayward Field, Eugene
Omega Timing does a good job producing splits with graphical analysis after major meets where Omega is used such as the Wanda Diamond League. They do all events (not just sprints), and they do all sports (i.e. bobsled, swimming, etc)
As you can see below in the 400m Finals, Kirani James (red line) does a good job at “picking up” speed at the 200m mark (It’s 200m from Lane 1 where the curve starts). Quincy Hall (green line) also has a similar pattern.
Take a close look at his split times & cumulative times (they call it Section times & Split Times). Look at Kirani James 200-250 where he actually speeds up.
As a side note, from the IAAF Biomechanical Analysis from Berlin 2009 splits, Renny Quow from Trinidad is the only sprinter in the group (and modern era) with near even splits. Otherwise, a differential between 1 and 3 seconds between 1st and 2nd halves are the norm.
If you haven’t seen or listened to this talk, I highly recommend this.
In the talk above, there was a recommended Podcast: Anaerobic Speed Reserve With Dr. Gareth Sandford found here: https://altis.world/podcast/podcast-anaerobic-speed-reserve-and-more-with-dr-gareth-sandford/
If you want to run a good 400m, you need to cover all aspects: speed, speed endurance, special endurance, speed reserve, relaxation, and supreme confidence with your race plan.