The marathon is the only "common" distance, where our elites don't or rarely run farther during training. The only ppl who go farther are the ultra ppl who never had elite 26.2 & 10K talent. How many fades in the race's last 25% are needed to see this?
Judging from all the 18-20 mile strong pace tempos & lower distance accomplishments of many US 26.2 elites- this has to be the problem. If a 10K'er falls apart at 7-8K, a half guy comes unglued at 10 miles... or a miler fades at 1200M, most advice on here would correctly say increase the strength. Sometimes, it can be due to a huge pace. But it seems to happen whether 2:06 or 2:11 pace.
And I can't believe anyone will say that consistent late race fades in the last 25% (big chunk) doesn't demand more strength... or that more strength shouldn't be attempted, because it'd be "hard". Injuries are the only reason- but besides Ritz, can't pro runners & pro coaches ease up slowly? Even a dam.n'd 1 mpw every month? Same problem every race. Maybe Meb doesn't suffer from it. But 1 exception doesn't mean for everyone else to repeat same pit falls.