1:25:57 - Oxford Half Marathon Training Diary - Week 10

Posted on: 15 October 2024

This post is part of a 10-part series charting my training block for the Oxford Half Marathon 2024.

7th - 13th October

  • Total volume: 60km
  • Longest run: 21.1km
  • Average resting & max HR: 39 / 147
  • Average bed time: 22:47
  • Easy / hard split: 53/47
  • Tanda marathon race predictor: 3:10:23 (đź”˝ 00:00:10)
  • Training VDOT: 53.8

Oxford week 10 plan

Monday - Saturday

The start of the taper began as Mondays typically do: 7km easy during the day and football in the evening. The run felt OK and I held back a little in the football. Happy with the effort though. Tuesday was 8km in the drizzle and wind. Easy pace, just ticking by until Sunday. Wednesday I took off in an attempt to bring my recovery down on my watch. I did do a 25 minute strength and mobility session which felt really good though. Low weight, just keeping the body nimble.

Thursday was my last workout before the race. A chance to test goal pace. This was quick; I was feeling fresh. 3.5km warmup at 4:35/km pace, followed by 15 minutes at 4:04/km and 5 minutes at 3:57/km (a bit faster than threshold pace). Finished off 12.5km with a 4km cooldown at 4:35/km pace. A great final session to improve confidence for Sunday.

Friday I took off.

Saturday was a travel day up to Oxford and a bit of a course recce. Managed to get 5k in around some of the route and to shake the legs out for the race.

Sunday (race day)

Wow. What a day. I'll break down the race in roughly 5k splits.

NOTE: I reference both my Garmin/Strava splits below as well as the official splits at 5k, 10k, 15k and finish from the timing mats. I have a suspicion the 10k mat might have been placed short (more on this later). GPS splits will of course be a little out from reality (I ran 21.3km according to GPS), so take them with a pinch of salt. But they’re enough in the ballpark to use for breakdown analysis.

Pre-race

It was all very rushed from wake-up to leaving the Airbnb we were staying in. I woke at 6:00, and I was leaving at 7.15, and Charlotte & the kids at 8.15. We had to get everything tidied up and cleaned to check out of the rental. My race routine from home is usually pretty chilled and dialed-in. But being outside of my home environment, there seemed to be friction at every turn.

The next challenge was the Park & Ride, which suffered under the strain of such a big event. But it was still probably the most practical way to get into the city if you weren’t local. Buses were regular, but queues were long. Consequently Charlotte ended up missing the start of the race and seeing me at miles 1 and 2. Buses dropped off a 20 minute walk to the race village, which was fine. It wasn't awful, but we queued all the way back to the Park and Ride in the afternoon, and queued again to get out of the car park.

The walk to the race village on a crisp Autumn morning was picturesque, and the race village was very well equipped. Big open space, tonnes of toilets, an efficient bag drop and refreshments available. I made the mistake of taking on too much liquid before the race and had an uncomfortably brisk walk from the bus to the toilets. Then I managed to lose Andy, my running partner, and we didn’t reconvene until we got to the pen.

I quickly dropped off my bag, pinned my bib onto my vest, did another toilet stop, then started my next journey: to the pens! This was around a 15 minute walk, and one they recommended you start an hour before the race begun!

Feeling a bit flustered, I made it to pen B with half an hour to spare. Right in the middle of Oxford City centre, the start was a real vibe. Space to warm up was minimal though, and there were no toilets outside of the race village. Bringing an outer layer to dump was a good call, as it was a chilly Autumn morning. The atmosphere was palpable as we prepared to set off. Andy and I exchanged words of encouragement. This was a goal race for both of us. Talk of a strict 9:30am start was exaggerated, but at around 9:35 we were away!

First 5k

I had strict plans to stick to my goal pace (4:07/km) for the first 5k. I know the tendency in any race is to shoot off and enjoy the crowds and the freshness in the legs. But I really wanted to negative split this one.

It takes some discipline because it seems like everyone is overtaking you in the first 5km. It was perhaps naive of me to expect there to be packs forming at this level in a Half Marathon race. Outside of the pacer groups, there weren't any at all. Maybe I've been watching too many sub-elite marathoners on YouTube recently. I’d run alongside someone for 20-30 seconds, then they’d move on. This was the pattern of play for the first 5km.

Crowds were amazing, Oxford was looking lovely. I was happy to see the kilometres ticking by close enough to goal pace, and feeling very strong. It never ceases to amaze me in a race how good race pace feels compared to most of those training sessions. But this is what it’s all about. Train hard so race day feels easy.

I averaged 4:05/km for the first 5k. Kilometre 2 registered a 4:02/km, but it didn’t feel any faster. This was my first indication GPS might be a little out so not to take my watch splits as gospel.

The crowds were big in this part of the race, and although I’d run some of this the day before, the route was twisty and I lost my bearings. But we ended the 5th kilometre back onto the long, straight section of Banbury Road.

My timings indicated I was a few seconds faster than planned on my first 5k split - 20:27. However the 5k timing mat, which I didn't notice passing over, clocked me at 20:39, 12s slower, which is perhaps closer to reality. 4:05/km average was likely more a 4:08/km. I was right on track and hadn’t overcooked the first quarter.

6-10k

The 6th kilometre marked the start of a long a straight section. It was this 5k block up to 10k where I’d planned to gently squeeze up to 4:05/km pace. However I thought I was pretty much already there pace-wise, so mostly just kept things steady at this point.

This was a really good part of the race that allowed me to lock into my pace and take stock of how things were feeling. Fortunately, I still felt great. There was less movement of runners around me, but still no sizeable packs to speak of. 7km was the first water station, and marked the turnaround point to head back southwards.

I ran with a small group for a few minutes, 2 women and a male pacer relaying instructions. I later found out this was Runna head coach Ben Parker, pacing 2 other Runna coaches to a sub-90. I overheard they were ahead of pace and on for an 88-minute finish. I soon began to slowly pull away from them.

I took on my first gel and noticed my pace and HR both spike. This often happens as I’m taking on water/nutrition due to my body overcompensating for the change in action.

Kilometres 8-10 were really good. I was settled into a good rhythm, enjoying the benefits of the Nootropics gel I’d taken at 7km. My splits were very even around here, 4:04/km was feeling really manageable. I was trying to work out how ahead of my 10k target of 41 minutes I was going to be.

This section of the course was lovely. Minimal crowds, but another long, flat, straight (or gently curving) road with minimal distraction. Scenery got a bit more rural and it was a nice change of pace from the busting centre we’d just left.

I was still feeling great, enjoying some of the pockets of support and getting some high fives. The people around me were fairly consistent now, but we were all running our own race. My watch beeped a 40:54, 6s ahead of plan. Exactly the same duration as the first 5k (20:27). Metronomic. I don't recall passing over the 10k timing mat. It clocked a 41:03, meaning a 20:15 split for 6-10km, 24s faster than the first 5k, and 12s faster than the GPS. This is what leads me to believe the 10k mat might’ve been placed short.

11-15k

Kilometres 11, 12 and 13 was a loop around the small village of Marston. This was my favourite section on the course. We had some energy drink at the start of this, and the locals were really supporting.

I’d had plans at this point to squeeze my pace again, to 4:03/km depending how I was feeling. I was feeling really positive, and it was at this point I spoke to a guy next to me. I asked him what his target was, he said sub-1:25. I said I was shooting for a 1:26, to which he replied that I was well ahead of pace. This was the cue for him to up the pace, and gestured for me to follow. I said I was going for a gradual increase and that maybe I’d see him later in the race!

It was nice to exchange a few words with a fellow runner. I wish I’d done more of this. The conversation had boosted my confidence, and physically I was still feeling great. Unintentionally, I was stating to crank out 4:01 KMs and barely noticing. Something in me wanted to keep eyes on the white-vested, sub-85 guy out in front. I had a target to follow.

I think I knew at this point it was going to be a good day.

Honestly it’s hard to know how accurate the 4:01/km splits were, but GPS had all 5 Ks between 11-15km between 4:01-4:02.

It was on the approach to 15k though, that I noticed my heart rate was beginning to rise. Until now I’d managed to keep it to high-160s, and I knew in my training that the low-to-mid 170s was heading into the danger zone when things would start to get hard.

I was mindful that I’d designated mile 10 / kilometre 16 as the point I was allowed to unleash and try to dip under 4-minute Ks. I attempted to steady my breathing and slowed my pace down ever so slightly. I was surprised to see this did the job, and managed to get my HR back into the high-160s/low 170s.

On the turn back onto the main street, I spotted Jess from the Running Channel and shouted her name. She reciprocated by shouting my name, written on my bib, and it was a really nice boost. I popped my 2nd gel and noticed my HR momentarily spike at 180. I deliberately tried to slow down now, not wanting to exceed my anaerobic threshold with over 6k still to go.

Strava had this 5k split at 20:09, 18s quicker than the last. This felt about right based on how fast I felt I was going during this portion of the race. Oddly though, the 15k timing mat (which, again, I failed to notice) clocked a 1:01:30. This equates to a 5k split of 20:27, 18s slower than my GPS-tracked time.

Obviously there will be some extra distance logged for navigating water stations, etc. but I did minimal weaving and tried to stick as closely to the racing line as possible. This slower recorded 11-15km split supports my theory the 10km mat was placed short.

16k-finish

At 16k I knew I probably had a faster 5k left in me. The exertion was starting to take its toll, but I seemed to be doing better than most around me. The 16th kilometre was a winding one that I’d done the day before. There were some great cheer points on the road which were much needed.

The 17th was more of the same, and honestly I remember very little of the race at this point. I could feel I was running consistently faster than I had been for the race so far. I knew my HR was high 170s and low 180s at this point, which in training would mean close to exhaustion, but in race conditions, this is what we live for.

Support was incredible in these last few KM, especially during a tricky kilometre through the University Parks on a loose, narrow dirt path. Trees and crowds lined the path and I tried to keep my focus. All I could think about was whether I’d started to push too early. I was very aware I still had nearly 3km to go.

It was around here that I caught up with the guy I'd spoken to earlier. I think we exchanged some brief words and he encouraged me on. He was lagging, but ended up coming in only a few seconds behind me.

16-18km was an average pace of 3:57/km, but I’m skeptical of this, because it certainly didn’t feel like I was going that fast. GPS inaccuracy probably to blame here.

Kilometres 20 and 21 were very tough. I wasn’t familiar with the course here, and every corner felt like a false dawn to the finish. The course gets very twisty again here, in the old part of town. The cobblestones in one section had been covered up by some temporary plastic flooring. This didn’t feel very sturdy underfoot and wasn’t very appreciated! The crowds, though, were fantastic, lining each side of the street.

At some point in the 21st K, I remember thinking to myself, “I’ve done the hard work, I’ve put in a monumental effort and am going to smash my target”. “I can ease off now and enjoy cruising over the line”. “There’s nothing left to beat now”. But there’s something in you at the end of a race that refuses to listen to that voice. I couldn’t slow down if I wanted to.

My 21st kilometre was my fastest at 3:50/km. I was pushing, but whether to that extent I don’t know. When my watch ticked over to the 22nd kilometre and I couldn’t see the finish line, I knew the GPS was going to measure a fair bit long.

Up until this point, I was tracking for a mid-85 minute half marathon. An inconceivable time at the start of the race. With the course registering long, in reality it was going to be closer to 86 minutes. I was far too close to the red line to even compute this at the time though, and as I rounded the final corner and could see the finish line 200m into the distance, I kicked.

The roar of the crowd was inspiring and seeing my family at the 13 mile marker was special. I thundered it as fast as my legs would go towards the finish, unaware what time I was on for.

It was just as well I kicked; I ended up coming in 3s under 1:26. 86-and-change still would’ve been incredible, but sub-86 sounded sweeter.

There was no 20k timing mat, but the finish mat clocked a 24:27 split from 15km, which is an average of 4:00/km for those final 6.1k. I felt I was going a little faster than that, but who knows. I don’t have the exact figures with no halfway time, but it felt like a perfect negative split race.

Things I learned

Find a way to accurately measure your pace, or don’t put too much emphasis on it

If mile markers are reliable, and you don’t mind splitting manually (and dealing with the imperial measurement), this is probably the most accurate way to pace the race. But you will need to have written down target times for each mile for this to work. And in my experience, mile markers aren’t always placed accurately.

Similarly, you can manually split on 5/10/15/etc. timing mats for larger races to keep track. These should be more accurate, but as I alluded to, I have my doubts for this particular race.

Failing that, just rely on your watch auto-lapping, and if you’re aiming for a specific time, go 1-2s/km faster than your target pace to account for running over the distance.

Don’t drink too much before, especially on cooler days

This will be personal depending on your bladder tolerance, but I always tend to have a sensitive, nervous bladder pre-race. I think I also overestimate how much fluid I need to take on pre-race. I wasn’t thirsty during the race at all, and only needed a sip or 2 at each water station. Bringing 600ml of electrolytes pre-race was not necessary, and made for an uncomfortable dash to the toilets on arrival. Keeping hydrated in the days leading up to the race will probably have a greater impact.

Leave way more time than you think

Providing you’ve brought some warm layers with you, get to the race village as early as you can. Wake up as early as you can. Especially if you have to factor in travel scenarios outside of your control. Rushing about is not a good start to any race.

Bring a disposable upper layer you can discard

Buy something from a charity shop or wear something old you had planned to throw out anyway. You can be in the starting pen for a while, and starting a race cold isn’t much fun. I was shivering in the start pen at Brighton Half earlier this year after a delayed start. All clothes left at the start line for Oxford Half are donated to charity, and I suspect most races have the same policy.

Negative split = positive experience

I am so glad I stuck with my plan to start relatively conservatively and aim to negative split. Inspired by Eric Floberg and Mack Dewar’s recent half marathon efforts. There’s no greater feeling in a race still feeling strong past halfway and beginning to overtake people.

Leave the family at home

This one sounds a bit heartless, but bear with me. Seeing my family at mile 13 was amazing, and filled me with pride to cross the finish line. But it was a fleeting matter of seconds, alongside hours of fighting through crowds and waiting in the cold. Races are wonderful events, but not very fun for young kids (and the adults that care for them).

I loved seeing my family at the end, but the stress of planning a small break around the race, travel logistics, snacks, managing tiredness, etc. all made me realise it wasn’t a fair sacrifice for them to make. I won’t be dragging them to my marathon next year.

Closing thoughts

I’m thrilled with the result of this race. Oxford Half has been on my calendar for months, and I always targeted it as a goal race to finally go sub-90. From the beginning of the 10-week training block, however, I knew I was already likely in shape to beat the 90-minute barrier. It was a question of by how much.

1:25:57 is a strong indicator that what I’m doing in training is working. Increasing volume, adding strength training, showing up consistently all contributed this year to this 6 minute PB (previous was 1:32:00 in Barns Green, September 2023).

10 week training plan for Oxford Half

Perhaps my only gripe with how I ran it would be that I slightly lost my discipline at 10km and got carried away a little too early. But it’s hard to be too critical when I was still able to finish strong and still achieve a negative split.

My new VDOT score based on my HM time is actually 0.1 points down from where my current 5k PB has me (set 8 weeks before). This suggests my 5k performance is stronger than my longer distance. This doesn't surprise me, as I practice the 5k distance a lot more than the Half Marathon. It's a win for VDOT as a means of performance prediction that I got within 7 seconds of its HM estimate for me.

Honestly the most exciting thing about my time and this race is it has me so pumped for what’s to come. I know I can improve my fitness more; I know I can get a stronger body. I know I can get under under 4:00/km average over the half marathon.

But the big question on my mind now is what is in store for the marathon distance?

I’m running Manchester Marathon in April 2025. It’ll be my second marathon, but my first in 13 years. I am super excited for the build and a chance to show what I can do over 42.2km. It’s going to be a lot of mileage, a lot of strength improvement, and a lot of consistency required. I’m not expecting to be in sub-3 hour shape, but I want to use this race as a springboard to get to that goal. It feels nearer than it ever has.

Tags: running race achievements