Pre-race nerves, combined with the taper in your training, can play havoc with the stomach.
"First-race nerves," Mark DeRose said of his varsity lightweights' initial race of the regatta.
That's another £35,000 in the hod for the champion trainer, Paul Nicholls, who admitted to some pre-race nerves.
It started to go wrong on Friday: pre-race nerves and hypochondria started to give way to definite temperature and chesty cough.
Tall for a jockey, at a fraction over six feet, O'Brien junior sounds wise beyond his years when asked about big-race nerves.
So when Tyson Gay, Greene's heir as US 100m record-holder, tells the world's media that he deals with his pre-race nerves by calling his mother, the initial reaction is one of shock.
The former track runner, who struggles to see well in bright lights, says having someone alongside her on the start line takes away some of the pre-race nerves and provides extra motivation in the run.
However, it turned out to be a revelatory experience for Bolt as he vowed never again to let himself be affected by pre-race nerves.
To stifle pre-race nerves, Kent met up with Hartman and Opell in a hotel lobby near Boston Common just after 7 a.m.
Consider this; its nighttime, your eyes are hazy, your adrenaline is pumping, heart racing, nerves are shot... do you really need the added pressure of making a 20 feet (6.1 m) shot at a melon sized target?
