When Sir Bradley Wiggins describes his next challenge as a "horrible experience" you tend to sit up and take notice.
This is a man after all who has won multiple Olympic gold medals on track and road and ?conquered the Tour de France.
On Sunday night in Stratford he'll try and break what's known as the Hour Record - racing laps of the velodrome for 60 minutes to try and beat the current best distance of 52.94km set by Alex Dowsett.
I meet Wiggins after a midweek training session at a deserted Lee Valley VeloPark. "These are the moments I relish the most and look forward to", he told me.
But it won't be quiet on Sunday. The 6,000 tickets sold out in seven minutes. So how can the spectators help him out?
It's an incredible physical challenge but clearly mentally draining too. Wiggins breaks down the hour into five 12 minute chunks.
Yet he remains remarkably pragmatic about what his body is about to go through.
But if he gets beyond the magical 53km on Sunday (and he's aiming for 55km) - I'm not sure Wiggins, or the thousands packed into the velodrome, will actually want the end to come.