Why the full distance is the hardest to judge
Over 112 miles a small overbike does not announce itself. Ten watts too many feels fine for four hours and then costs you the back half of the marathon, long after the bike is over. By the time the run comes apart the cause is hours behind you, which is exactly why memory is such an unreliable witness here.
The advice is the usual: what percentage of FTP, did power fade, was it smooth. All correct, all leaving you to interpret it tired and disappointed. And a high intensity factor on its own does not prove you overcooked it — over a full distance the honest test is whether you rode above a level you have genuinely held for that long before.
What The Debrief actually checks
- Whether your bike power sat above a level you have demonstrably sustained, judged against full-distance targets, not a 70.3 ceiling or an estimated FTP you never touched.
- How your power held across the four to six hours, since on the full distance the fade often creeps in late rather than in a clean second-half split.
- Whether your marathon decayed in the pattern that follows a bike that was too hard, versus fuelling, heat, or a run that went out too quick.
- How your heart rate tracked your power across the day, since decoupling over a long ride is one of the clearer tells that you were spending more than you had.
If the file cannot support the verdict, it will say so. On the full distance especially, an overbike and a fuelling shortfall look almost identical by the time you are walking — the read stays inside what your data can actually prove rather than picking one to sound confident.
What you get back
A debrief written the way a coach would talk you through it. Not a wall of charts to interpret yourself after the longest day of your season, and not a confident verdict pulled out of thin air. Just what the file shows about how you executed, in plain language, on screen, right after you upload.