This answer will surprise you.
A mediocre 100m sprinter (like me) could theoretically break the open WR for 400m.
How can a guy who’s PB is 11.54 sec for the 100 meters run a world record in the 400m of 43.18? In theory, it’s possible.
11.54 is about 10.54 on the fly if you take in account 1 full sec for acceleration* out of the blocks. This translates to an average speed of 9.48m/s, or about 42.18 sec for 400m. Add 1 second back for acceleration out of the blocks, and voila, you have 43.18!
[*Some argue you should use 1.17 seconds, as the 1.00 seconds is taken from a world class athlete – Valery Borzov to be exact!]
So the answer is… a 10 m/s average speed for 400 meters would give you a new World Record.
Speed Endurance (Physiology, not the Blog)
Everyone slows down after reaching maximum velocity, approximately 7 seconds or 60 meters in men, in a 100m, 200m, and of course the 400m. The rest is speed endurance. I’ll talk about negative splits or even splits in a future article on 400m race strategy.
You’ve heard the expression: In a 100m race, the person who slows down the least wins the race. It may appear the sprinter is speeding up, but in reality, the others are slowing down.
I love numbers, math, conversions, fantasy sports, and being the armchair Quarterback. Here are some accepted conversion factors to calculate potential for the 200m and 400m:
- 100m to 200m: double 100m time +/- 0.2 seconds
- 200m to 400m: double 200m time +3.5 to 4.0 seconds
Frankie Fredericks

Most seasoned 200m sprinters slow down about 0.5 sec between the first and second 100m when you take in account 1 sec for acceleration out of the blocks.
Take for example Namibia’s Frankie Frederick’s 100m PB of 9.86. This translates to a potential of 19.52 – 19.92 and his PB for 200m is 19.68. Even if he ran the first 100m in 10.1, well within his means, his second 100 with a running start would be 9.58. Thus:
19.68 = (1 + 9.1) + 9.58 = a slowdown of 0.48
Now children, you can’t take a 100m time and double it to determine the worlds fastest man compared to a 200m sprinter, because the 2nd 100m has a running start. Memories if the 1997 Skydome match race between Donovan Bailey/Michael Johnson come to mind.
Michael Johnson
Speaking of Michael, here is the greatest example of someone running the perfect race with minimal slowdown with his 200m WR of 19.32 seconds at the 1996 Atlanta Olympics.
His 100/200m splits was recorded at 10.12/19.32. If you factor in 1 sec for acceleration out of the blocks, we get:
19.32 = (1 + 9.12) + 9.20 = a slowdown of 0.08 between his first and second 100m.
Absolutely incredible speed endurance!
[Tweet “MJ 19.32 200M = (1 + 9.12) + 9.20 = a slowdown of 0.08 between 1st + 2nd half”]
Since his PB for the 100m is 10.09, I truly believe he ran within his human potential limit for a 200m. I shiver and wonder if he didn’t hurt his hamstring in that 200m, what would he have run in Zurich for the 400m 10 days later? 19.32 doubled plus 4 equals… 19.32 doubled plus 3.5 equals…
Yes, I believe MJ would have (should have) run 42 point for that race!
43.18 is still the WR today.
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