I just watched coverage of the Olympic marathon on TV this morning and caught the end where these incredible athletes turn on the burners to cross the finish line and give their coaches a wet biohazard hug.
It made me think that I should start up a marathon coaching business on the side. The overhead is minimal: 1) waterproof track suit; 2) headband/wristbands; 3) Hover-Round with 3 hour battery life and 20mph speed limit; 4) silver whistle; 5) stopwatch; 6) clipboard; 7) case of those little bags of trail mix (just enough for me); 8) a thermos to keep my coffee warm, and 9) a bullhorn.
I would recruit only the fastest runners around but I could even coach-up average marathon runners by positioning my Hover-Round about 5 paces in front of those average runners and instructing the runners to keep up with me through verbal instructions issued through my bullhorn. I would let them know their time after I jotted it down on my clipboard and would tell them that it was ok, but tomorrow you’ll need to go faster. I would also be a coach who discouraged hugs at the end of a race but if one of my runners lost their mind because they were drunk on endorphins, I’d have my waterproof track suit on which would protect me from any sweat-borne communicable diseases. 
If any of you are really good at running or know of a really good runner who might be in need of a really good coach, please contact me.