Can someone with a 12.5s 100m PB run a sub-50 400m?

No

Farah only ran 12.9 from blocks, FAT in the British superstars show. Now conditions weren't great, and hey may or may not have been going all out (tho it seemed as if he were to me ) but it suggests that it may we be possible, as some distance guys are so "damaged" by FAT and block start they lose tremendous time.

Now if that 12.5 is a running type start...then I think no way. Maybe 55 or something.

NO!

Agree would expect to be at least under 12

This is what you can expect.

12.5 100m

25.0 200m

54.0 400m

Fat Boy is pretty accurate, although the 400 time can certainly be worse than that if one doesn't train the 400 distance.

BTW, I re-iterate that Mo's 12.98, wasn't--it was at best a 13.1, probably a 13.2

And YES, someone with a 13-second FAT 100m from the blocks CAN run a flying-start 50.89 400m. Obviously. As long as the timing of the 50.89 was accurate, that is.

I think it would be close to possible. I was pretty good 5000 runner with no acceleration. I never ran a "real" 100m, but I ran lots of 200m reps with good rest and flying starts. In all my years of training, I only dipped under 25 twice (24.7 and 24.9), running all-out. Given the flying start, I think this is pretty good evidence that my best 100 would have been much slower than 12.5. From a standing start, I think it's very unlikely I could have broken 13.

I seldom ran all-out 400s, but I ran indoor relays a couple of times on flat 200m tracks, and ran 50.4 and 50.5. That's with a running start, obviously (with terrible hand-offs!), but the tight turns offset that a bit.

So if I had to guess my potential times from standing starts, I'd guess ~13.0 -> 51.0. Of course, I was a no-speed, poor-acceleration distance runner.

'And YES, someone with a 13-second FAT 100m from the blocks CAN run a flying-start 50.89 400m. Obviously. As long as the timing of the 50.89 was accurate, that is.'

Every runner who can run a lying start 50.89 must be able to run faster than 13 seconds

Say worst case 51.89. If you 100m best is 13 your 200m is 26. If your pr for 200m is 26 no effing way can you keep that speed to 400m

Reality is taking wind and tiredness into account he must be capable of around 50 flat for a 400m and you need 12 flat speed minimum for that. Something does not add up!

12.5x4=50. No one can sprint the entire thing, so more like 54 like the other guy said. Although, I know two guys who run around 12.2. One has ran 56, the other 60. They are pretty bad.

coach: "Every runner who can run a lying start 50.89 must be able to run faster than 13 seconds"

Here we go again.

That is not the corollary of "someone with a 13-second FAT 100m from the blocks CAN run a flying-start 50.89 400m"

Especially when that somebody is Mo, with superior aerobic endurance and a concomitantly weaker start and acceleration.

Had I used your type of logic, my statement would have been something like "every runner who can run a 13-second FAT 100m from the blocks can run a flying-start 50.89 400m"

Which would have been clearly incorrect.

Coach, EVEN IF your statement was accepted as true, and if it was believed that Mo did actually go 12.98 and not slower, as was the case, you would have been proven correct to only a .02 level, since Mo ran 12.98

YOU MUST GET OVER THIS.

Answer me this question: what would Mo's 50.89 have been, had he started from the blocks instead, and had it been FAT? You can consider that he would run it fresh, if you wish.

Only if the 12.5 doesn't represent how fast they can actually go in the 100. And they should be a distance runner. I say this because 200 PRs are basically 2x100 PRs. For 400 you gotta slow down.

From personal experience I would think this was possible if not very close. I concur with the distance runner (5k guy) that with that type of middle endurance you can go high 24 and low 50.

My age 15 pbs were 11.9, 24.0, 57.5, 2:27 (age 14) - tanking in the 8, still won despite lack of endurance. So I had got ok sprint endurance to get 24.0 without blocks and a lack of drive phase but then for 400 endurance you need a little more aerobic? and Type IIa strength starts to come in? But mainly the energy systems curves. My 400 was a one-off as well at the end of an event where we were all tired and I was the only one who could bother to do a 400. The winner was a guy who trained and got say 55 or under, and probably was around 12.5 for the 100. So with better training to max out the endurance for 2-4 like MJ, as I got for 1-2 just by doing the event a couple of times that summer, I always wondered if I could get to low 50s and by extension break 2:20 to near 2:15.

But I've got no illusions that I could match a guy in the year above who did nationals at that time and regularly did 53 sec and 2 min. He trained on Snowdonia, was tall and strong and his 8s looked like a flat out sprint (one of our teachers was a fell runner). He got a collapsed lung in sixth form (17-18) but did break towards 1:55s and 52-under towards 50. He could probably have gotten 12.5 in the 100 towards 12, and is similar in this respect I feel to the 5k guy, from what I can make out. To be honest I think he might actually have done this if he continued, or I lost contact, and he wasn't winning nationals in the UK - so I would imagine elites can do this, considering they are another rung up above. Farah could definitely train a minimal amount and do both fresh if serious.

In order to run a sub-50 400 they would have to break their PB of 12.5 en route. It is impossible mathematically.

Maybe if you had artificial legs that made it impossible to get a good start but allows you a top end speed over 25 mph.

Then you may only be able to hit 12.5 for a 100 from the blocks, accelerate to 24 flat at the 200m split and hold on to close in 25 to get that sub 50.