Would the high humidity prevent me hitting my 4:00 min/km target in this 5 mile race around Norfolk?
Last Friday evening (July 28th), I ran the Worstead 5. As per my pre-race article, this was a 5 mile road race, the 11th event of the 2023 Sportlink Grand Pix, and organised by North Norfolk Beach Runners.
During the day, whilst working, I kept checking the weather forecast as I felt this would be a deciding factor in how close to my predicted 32:15 time I could manage. The forecast remained ‘sunny intervals with a moderate breeze, with a temperature of 21° C, and humidity approaching 70%’. This last aspect would no doubt be the biggest issue to contend with.
My plan was scuppered by my son unexpectedly arriving home with some new fish
I planned to leave home at 5pm, to give plenty of time for the drive to Worstead. However, my plan was scuppered by my son unexpectedly arriving home with some new fish for our pond just as I was about to depart. Once the fish were settled, I set off. I still had a good amount of time to get to Worstead itself, however, the village is very small and so the congestion meant a long queue to get to the event parking.
Once parked (with the car reading the forecast 21° C), it was a case of rapidly getting into my racing gear, a quick last-minute toilet stop, and jogging straight to the start-line. Arriving with only a minute before the race was started.
My Race
Twice I almost fell from having my heels clipped
The start-line was on the edge of the village market square, at the start of a very narrow road between two rows of houses. This, along with starting further back in the corral than I would have liked (due to my tardy arrival), resulting in an initial race like my parking experience – congested. Twice I almost fell from having my heels clipped. Fortunately, I managed to save myself on both occasions and it was not too long before spaces began to open up and I could get into my running stride. This was helped by a gentle down hill until around the 500 metre mark. Where upon it was a relatively flat run to the first kilometre point.
I completed this first kilometre in a time of 4:04. Given the rocky start, I was pleased. The second kilometre was an uneventful flat that took me 3 minutes and 56 seconds. I was now bang on my 4:00 min/km average pace, and whilst I could feel the humidity, I was feeling in good shape. The third kilometre, despite being slightly uphill was covered in a time of 3:58 – I was now 2 seconds ahead of schedule and still feeling good.
I knew the second half of the race was going to get tougher
However despite being flat, kilometre four is where the humidity suddenly hit me. For me, the first sign is that my hands begin to throb – and they sure did. By the time I reached the 4 km point (and just under halfway) I knew the second half of the race was going to get tougher. I ran kilometres four and five in times of 4:07 and 4:05 respectively. By this time, I was really beginning to overheat and my head was throbbing in unison with my hands.
I kept telling myself “only 3 kms to go – less than a 3.2 km assessment!” and forced my legs to keep moving. This worked for k’ 6, helped by a slight downhill gradient, which I covered in a time of 3:58. However, the penultimate kilometre had an incline that got the better of me, and slowed me down for a 4:09 split.
Just 1 kilometer and a bit to go! I did all I could to just keep running as fast as possible, knowing it would all soon be over. As I left the roads for a final twisty section to the finish, I managed to put on a fresh burst of speed. Unfortunately, this was short-lived, and as I turned the final corner, with 50 metres to go, my legs were spent and my speed dropped back again. I crossed the line, my head pounding from that final effort. And unusually for me, I had to go the side and fall on the ground to recover.
Official race time, 32:29.
Analysis
That was a hot one. Or more precisely, a humid one!
I was 14 seconds (0.7 %) slower than my target, but given the conditions, I am extremely happy with my performance. I don’t think I could have pushed myself any harder.
This is exemplified by my Garmin heart rate stats: I ran over 30 minutes (94 %) of the race in heart rate zone 5, running the whole race at an average of 94% of my maximum heart rate.
And speaking of Garmin stats, below is the Stamina chart for my race. Can someone explain why, if it takes 1.55 km for my Stamina to basically reach zero, that I can continue to run at around the same pace for another 6.5 km!? Have I completely misunderstood what this metric is meant to be telling me, or is it just erroneous?
Below is a table illustrating the various predictions for my race, along with their error from my actual performance.
| Algorithm | Predicted Pace (min/km) | Predicted Time (mm:ss) | Error (seconds) | Error (percent) |
| Riegel (6 min Assessment) | 4:33 | 36:42 | + 253 | + 13.0 % |
| Riegel (3.2 km Assessment) | 4:17 | 34:30 | + 121 | + 6.2 % |
| Running Watch | 4:07 | 33:07 | + 38 | + 1.9 % |
| Athlete Data Analysis Platform | 4:05 | 32:51 | + 22 | + 1.1 % |
| TrainAsONE | 4:00 | 32:15 | – 14 | – 0.7 % |
| Riegel (5 km Race) | 3:59 | 32:07 | – 22 | – 1.1 % |
As expected, the Riegel estimates based upon my assessment runs were not accurate, predicting much slower finishing times than performed. Too inaccurate to be of any real use.
All the other predictions were within 2.0% – a first for both Running Watch and Athlete Data Analysis Platform. This was helped by the hot and humid conditions.
Under ideal race conditions, TrainAsONE calculates an adjusted time of 31:55. This keeps the TrainAsONE and Riegel (5 km Race) predictions still within 1.0 % error, but widens that of Running Watch and Athlete Data Analysis Platform to 4 % and 3 % respectively. Which is still not too bad.
Finishing Up
Despite the conditions making that a really tough race, it was still fun. Looking at the overall race results, in comparison to a number of runners that I keep tabs on, I performed relatively better, and so it was certainly a ‘good day at the office’. I’m almost looking forward to having another go at this atypical distance again next year…
As ever, a big thank you to the race organisers, volunteers and all those involved. A great race. Thank you.
Till next time.
