Race Preview: Les Allcorn Trail 10km

Race Preview: Les Allcorn Trail 10km

Coming out of my season opener at the NEMAA Open Relays I was forced to take a couple of unplanned rest days.

As I covered in my race report, I’d gone into the race with a sore throat and felt worse on waking the next day.

Although I don’t think it negatively impacted my performance, I didn’t feel well enough to train and took two days off.

This was a bit of a concern as I approach my next assignment at the Les Allcorn Trail 10km in Alnwick on Tuesday 9th May.

I’ve never tried this race before and, from what I can tell, it is a mixed terrain and hilly 10km. With that in mind I’m not necessarily looking to run a PB in this race (note: current 10km road PB is 34:49 from 2018).

A quick check on my power of 10 reminded me that I’ve only raced two 10kms on the road and two “Not Official Distance” (NAD). I suspect this race could be registered as NAD as well.

That’s fine as my main goal will be to get in a hard training run with one eye on following up with another 2 mile relay at the Gordon Smiths a day later!

But we will have to see if that plan is possible given how my body reacted to the 2 miler.

I’ll then look to use the data from all 3 races to create a short 6-7 week training plan taking me all of the way to the Great North 10km in early July where I will be aiming to set a new 10km personal best.

Race predictions and planning

Following the NEMAA Open Relay my Stryd running app is suggesting I can hold an average of 377 watts for 10km with a predicted finishing time of around 34 minutes +/- 41 seconds.

New Stryd race predictions

I’d managed to track down a Strava GPX file of the Les Allcorn course profile which can be uploaded to Stryd. If the race calculator is to be trusted the course shouldn’t present major issues, i.e. the uphills must be cancelled out by subsequent downhills.

From what I can see there is a decent portion of uphill at the start and end of the race and a decent downhill section in the middle portion.

The key therefore will be to maintain equal power output both uphill and downhill. That is harder than it sounds as you typically need to ease right off uphill and really push downhill – the exact opposite of what most runners do naturally. Most seek to maintain pace uphill by working harder and use gravity to help them downhill whilst trying to recover from the efforts expended uphill. Running hard downhill is a very specific skill not often practiced – it is inherently risky and can easily cause injury.

But as I said earlier, I’m looking for a hard training run so the rough plan will be to average around 360-370 watts in the first 5km, check the split, see how I feel and then decide whether to push on and average as close as possible to 377 watts in the second half.

The unknown will be the ground conditions. I’d found a race report from some years ago that mentioned muddy conditions early on. Given the recent wet weather that could make shoe selection tricky and it may be best to go with a pair of training shoes. I don’t think supershoes would be wise. Nor trail shoes.

With that plan in mind I was looking to complete one final training session on the Saturday before the race. I would usually long run on a Saturday but I felt like something around 15-16km easy with a 3km portion in the middle approaching something like 369-377 watts would suffice.

Overall volume for the week was going to be low (~50km/30mi) given the forced two days rest. That is well down on the 70km/44mi completed last week but in many ways I suspect that was a factor leading to my slight lethargy and sore throat this week as I’d (deliberately) spiked my training which I accepted as a risk worth taking for this set of “B” races.

But there’s not much I can do to move the fitness dial now, so this session was more designed to get a feeling for what something approaching 377 watts felt like in the legs more than anything else. Then tick over Sunday/Monday as I feel able.

I was still keeping an open mind to the possibility of pulling back the race plan even further, for example aiming for 355-365 watts overall for the race and a potential race finishing time of around 35:15 or even 36mins plus, i.e. still a very useful training run. For reference, I ran 77:46 at the Great North Run in 2021 averaging 355 watts on a challenging and energy sapping revised undulating course – the first 10km was done in 36:42.

Great North Run 2021 result

Alternatively, a target power average of ~369 watts (which is what I held for half marathon at Manchester in 2021 in a race time of 73:34, first 10km sub 34mins) and see where it lands time wise. Stryd is currently predicting a finishing time of sub 35 minutes at that effort level.

Final training…

Waking up on Saturday 6th May I felt a little better but still fatigued and snotty. I knew a hard long run was a terrible idea. And now even risking any portion of running at close to 10km intensity seemed potentially the wrong thing to do.

I’m a big believer in listening to the body and I’ve learnt the hard way that pushing a tired body too hard is counter productive. But I’ve also been using the Oura ring to track “readiness”, heart rate and Heart Rate Variability (HRV) since late 2019. Oura was much more positive than I felt within myself. Indeed Oura hadn’t really registered anything as being amiss all week, suggesting I could train as normal.

All things considered I decided to run at least 10km easy. First 5km keeping power below 245 watts and the second 5km around 270-275 watts. I’d then decide whether to stop the run there or add in some portions of faster running or strides.

In the end it didn’t take me too long to decide to keep the run really easy. I did an initial portion of 9km (5.6 miles) keeping average power around 250 watts which translated to 5:09/km (8:20/mi) pace. Average heart rate was 133bpm.

I then completed three 200m strides on a slight uphill gradient, just trying to visualise myself starting a 10km race. I was interested to see where that would land in terms of average power.

All three strides came out >380 watts and closer to the effort level at the NEMAA relay. I take this as a good sign as the strides felt very solid and controlled. I now just need to let my brain take over when it comes to the race on Tuesday. I know I can run quite comfortable, at least in the first half of the race, and still achieve my race aims.

Measuring Aerobic Efficiency: Beats per Mile

A useful metric I like to track is Beats per Mile (bpmi) which “does what it says on the tin”, i.e. calculates how many times your heart beats per mile on a run as an average. It’s very easy to calculate and once you have enough data it’s easy to spot trends in your training cycle and assess whether you are aerobically fit enough to start considering faster running.

So for this 9km easy run completed 3 days prior to Les Allcorn, my bpmi is average pace per mile multiplied by average heart rate, so 8.33 x 133 = 1,108bpmi.

To give some context, when I am detrained or something is not quite right my bpmi on easy aerobic runs could be 1,200+ whereas when I am pretty fit my bpmi can be <1,050,

I think this run felt about right and I am happy now to tick over with easy runs on Sunday and Monday.

Thanks a lot for reading and stay tuned for the race report!


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