StrideCoach Race debrief Race Debrief · USD 19
You ran the first 5K of your half marathon 41 seconds per km too fast
One race, split by split, and what it means for the next training cycle.
You missed your target by nine minutes and you did not miss it because of fitness. Your training says 1:55 was realistic. You lost the race in the first twenty minutes and then spent ninety minutes paying for it, which is the most common and most fixable way to miss a target.
First 5K at 5:12 per km against a target pace of 5:27. That 41 second per kilometre surplus over the opening banked about 75 seconds and cost you roughly nine minutes across the last 8 km. The fitness was there.
Splits
What the race did
| Actual | If you had run even | Difference | |
|---|---|---|---|
| 0 to 5 km | 26:00 | 27:15 | You banked 75 s |
| 5 to 10 km | 26:55 | 27:15 | You banked 20 s |
| 10 to 15 km | 29:35 | 27:15 | You lost 140 s |
| 15 to 20 km | 33:25 | 27:15 | You lost 370 s |
| Final 1.1 km | 6:53 | 6:00 | You lost 53 s |
| Total | 2:04:18 | 1:55:00 | 9:18 lost |
You banked 95 seconds in the first half and gave back 563 in the second. That exchange rate is roughly six to one, which is why going out fast is the worst trade available in a half marathon.
Why
Three things that made the opening too fast
| Factor | What happened | Fixable? |
|---|---|---|
| Start pen position | You started in a pen with faster runners and ran with the crowd | Yes, easily |
| No pace check until 5 km | Your watch was on total time, not current pace | Yes, in one setting |
| Downhill first 3 km | Course profile. Effort felt right, pace was not | Yes, with awareness |
| Taper legs | You felt excellent. That is what a taper is for and it is a trap | Partly |
| Fuelling | First gel at 10 km | Yes. Too late |
| Training volume | Peak week 52 km, consistent for 14 weeks | Not a problem |
Five of six are execution and one is training, and the training one is fine. That is why this debrief is about race day rather than about a new training block.
Next
The next cycle, and the next race
- This week
Nothing. Rest properly
Two full days off, then easy running only for a week. Debriefing a race in week one is useful; training in week one is not.
- Next cycle
Add two race pace long runs
Last 8 km of a long run at 5:27. Not faster. Learning what target pace feels like when tired is the single training change that addresses this.
- Next cycle
Practise fuelling from 6 km
In training, not on race day. Your first gel at 10 km is too late and you will not find that out at 10 km.
- Race day
Change the watch screen to current pace
One setting. You cannot correct a pace you cannot see.
- Race day
Start in the correct pen and let people go
Roughly 400 runners will pass you in the first 3 km. Every one of them going out too fast. You will pass most of them after 15 km, which is a genuinely enjoyable experience and the best argument for even pacing there is.
- Two days completely off
- Watch set to current pace before the next race
- Two race pace long runs per cycle
- First fuel at 6 km, practised
- Next race chosen with a flatter first 5 km if possible
- Target for the next one agreed after four weeks of training, not now
Over to you
Two questions
- At 3 km, did you know you were going too fast? Most runners do. What made it hard to slow down?
- You finished the last kilometre faster than the two before it. What was left at the end, and what would it take to spend that at 15 km instead of 21?
Nine minutes is a large miss and it is entirely made of one decision in the first twenty minutes. That is a much better problem than being nine minutes short of fitness, because fitness takes a season and pacing takes one race.
Coach note