Well, I planned to give an ENworld exp point to whoever guessed the most useful support skill but what the hell, this is almost over.
The olympic tip referred to rowing. In a crew of 8, there is always a coxswain who keeps the pace and motivates the crew. I could also have given a clue referring to a staff sergeant keeping his men on target pace during forced march.
The support skill is either using diplomacy or intimidate (depending on your style) to motivate the crew into keeping pace.
It has to be done by someone who is keeping pace (someone who has successfully done his endurance check). It's not very serious for a struggling runner to urge his companions to go faster...
At this point Dagran, Garrick and Barrion can do it.
It grants +2 to endurance to everyone (trained or not).