April 2023 - mhhealthandfitness

Lessons from my first negative split marathon

This is written as a follow on to my last guest blog post, how not to run a marathon (which I wrote after my ill-prepared but ultimately fun attempt at Brighton). I went into London this year, 3 weeks after Brighton, without huge expectations – I’ve been on and off with injury since January, had only just run a marathon, and in the 12 marathons I’d run so far, I had faded (usually quite badly) in the second half.

Most of us know that feeling… where your legs get fatigued, your mind won’t fight and you end up slowing down or even walking. Well, for the first time ever for me, that didn’t happen. Whilst London wasn’t a PB, I do consider it my most successful marathon. I felt strong, and ran my first ever negative split, with the second half over a minute faster than the first – according to London marathon chip timing, each of my 5k splits were within 3 seconds of each other, whereas at Manchester in 2022, I ended up over a minute per mile slower. This has raised a few questions in my mind, biggest of which is what made this happen, and can I replicate it to get a PB.

Quite a few things were different this time, so it is quite hard to isolate what had the most impact. And of course, this is a study of one, so what worked for me this time may not work for me next time, and may not work at all for you. That said, there are a few things I will definitely be doing again, playing with and improving:

Training and pre marathon:

More cutback weeks / recovery time
Because I have had on and off injury issues this spring, I have run lower mileage overall – 600 miles in the run up to London this year, compared to 960 in the run up to Manchester last year (I did replace some of the mileage with cross training, but no more than another 100 miles equivalent). On top of that I did fewer 20 mile + runs (4 compared to 6) and less speedwork this time round because I couldn’t risk it with a dodgy achilles.
In summary, more cutback weeks and a better balance between mileage and speedwork meant I built aerobic fitness but was able to recover properly. I have no secret answer for the magic balance, but be aware of the signs of under recovering – poor sleep; getting irritated; unable to hit paces etc. and don’t be afraid to drop a session to run easy, or an easy run to rest.
Build a strong base – run miles, strength train and do the prehab
I was able to maintain fitness through my injuries, and keep going for longer because I have been consistent and diligent in building base mileage and doing strength work prior to this training cycle. It is what you do consistently for months and years that holds you in good stead for a marathon, rather than just one training cycle. Don’t neglect the non-running stuff!
The controversial one – running the distance (or over the distance) in training.
Please take this one with due caution. I felt running Brighton Marathon three weeks before London really helped me. I walked sections of Brighton, so it wasn’t done as a hard effort, but it did give me confidence and the full distance miles in my legs. I felt this helped and I would do it again. However, I know that other experienced runners and coaches disagree, and I bow to their expertise. Martin suggests that whilst a time on feet easy run (where you run for your intended target time for the marathon but at a much slower, easier pace) is very useful, running the full distance is risky and produces too much fatigue.

Lessons for the marathon itself:

Pacing – get it right. Hold back in the first half, hold on in the second.
This is one I often get wrong, going out too fast, and then struggling after half way (at which point my mind gets to me and says you still have so far to go, just slow down / walk). A key learning point for me is that going out too fast doesn’t just mean faster than your proposed marathon pace, it also means listening to your body. Is your proposed marathon pace right for that day, those conditions, that training cycle? Too often I’ve focused on the end goal time I want, and not listened to my body. As, for London, I had a soft target for me, I could afford to pay more attention to what my body was asking.
GPS in London this year seemed worse than usual, so I had to rely more on effort and heart rate than usual. My target pace was 8.40-8.50, but I couldn’t always tell what I was running at using my watch, so whilst I did use average pace as a rough guide, I also had heart rate visible, and kept it below 150 for the first 12 miles where I could (about 5-10bpm lower than I have done for a marathon in the past), and focused on my breathing. If I felt it rise too much, I pulled back. I did a lot of holding back in those first few miles. My splits reflect the fact that London is downhill for the first 3 miles, but after that I just sort of found a rhythm and went with it.
Fuelling – fuel lots, often and practise it in training. Find what works for you.
I don’t like taking gels. I often skip one or two. This race I didn’t – 40g carbs from a sports drink on the start line then a 20g carb gel every three miles. In addition, I decided to play with timing of caffeine in London. I love coffee, and have normally had at least three strong cups by midday. My first coffee is always the most impactful and gives me a productivity boost, so I decided to not have any caffeine in London until after mile 12. I was flagging by that time, but after a 70mg caffeine gel after Tower Bridge, I felt great. Not buzzy, but bouncy and full of energy. Every gel taken after mile 13 had caffeine in. Please note – I have practised this a lot and am comfortable with taking a lot of gels, including with caffeine. Don’t try this for the first time on race day!
Mindset – break down your run into small chunks. Running ten miles on tired legs is hard. Running just one more mile until you get to [insert target here] is a lot easier on your poor tired brain!
One thing I realised at Brighton Marathon 3 weeks ago, is that I wasn’t breaking my run down enough. At mile 16 of Brighton, I was overwhelmed by the thought of 10 miles to go (I was still poorly so not really a surprise) but instead of saying just one mile and then I’ll see, I let it overwhelm me and started walking. This time, I took the pressure off in my head a little bit more and broke it down into cutty sark (6 miles), Tower Bridge (12), half way… and then focused on each kilometre, and each 5km chip timing mat. I visualised the people tracking me seeing even splits and no fading, just for that one 5k “parkrun equivalent” section. When I hit 22 and started to get more tired, I aimed for the 40km mark, and then the MH Runners cheer squad at 25.5 miles and by then I was nearly home… different ways of chunking work for different people but this is the first time I’ve actually got it right. For me, the key was really believing I could back off if I want, but would try just one more kilometre first. Find what works for you.

Finally, I have been asked a couple of times if the fact I didn’t fade means it wasn’t hard. No, it was – all marathons are hard , it’s a long way and every time I do one I remember just how far it is! (you would think I would have learned by now, but if you’ve run a marathon, you’ll know what I mean!). But because I managed to keep a consistent pace for longer, when it did get hard, I had the confidence behind me to try and carry on. That hasn’t happened before, but I do hope it will again – it was a whole lot more enjoyable than going out hard and fading. I would trade that feeling for a PB if I had to, but hopefully, with these lessons under my belt, I can aim for both next time.

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Reality check here – this isn’t really how not to run a marathon. Yes, there are a lot of things I could have done better in the run up to Brighton Marathon 2023, but on the other hand, I ran it, I loved it and I got a sub 4. So I’m not going to be super critical. But despite having run 12 marathons, 6 of them under 4 hours, I still have some very familiar lessons to learn!

So let’s start with the good stuff. What worked?

Carb loading. I did carb load properly for Brighton. It was slightly different to previous times and I found it much more manageable. I went by Martin’s rule of 7g/kg body weight on Thurs, 9-10g/kg on Fri and 7g/kg on Sat (finishing earlier to allow for digestion), but this time I took in 200g of those carbs in the form of drinks. In past years, I’ve changed my diet to accommodate more carbs as meals or snacks, but this time, I just cut back a little on fat and protein and made sure I drank orange juice (breakfast and mid morning) and sports drink in the afternoon. Part of this was because I was ill over the carb load and lost my appetite, and partly because I was travelling and having drinks with me was very convenient. I diluted the orange juice with water and the energy drink I used was OTE super carbs which has 80g carbs in 500ml, so I stayed hydrated and got a LOT of carbs in. It meant I didn’t have to obsessively count or worry, just make sure I set out my drinks in the morning and consumed them during the day. OTE duo bars are also a bit of a saviour here – very light, easy to carry and eat but 40g of carbs. I also made sure not to have any sugary snacks after 7.30pm and that really helped my sleep. On which note…
Getting lots of sleep! This wasn’t deliberate, but it worked. Normally I’m working in the run up to a marathon. The week before Brighton I got a cold that went to my chest. I ended up working 1.5 days out of 5 that week, having 3 days off sick and sleeping for most of them. I wouldn’t have made it otherwise. But it really made me appreciate the value of sleep (and not running much) in that final week. Not sure 14 hours a day is necessary, but use the time you don’t need to run to sleep. It really does help.
Science says 60g+ carbs an hour during the race. I can’t claim I hit that but I did have a regular gels throughout, ended up having 5 x 30g gels over the course of the marathon. And two things I note from that. More would still be good and have a positive impact, I will aim for 6-7 next marathon; training with the gels has meant I tolerate them well and all but 1 were caffeine gels. It’s a process of trial and error and I know caffeine really works for me, but I think I’ll save the caffeine ones for second half of the race and see if it gives me an extra boost.
Know your priorities and modify your plan if needed. After an injury ridden build up, I wasn’t expecting a PB, but I was hoping for around 3.45. After getting a cold literally the week before the race, and it going to my chest, I wasn’t sure I’d even be able to run. So I had to go by feel on the day. I went out slightly too fast in retrospect but it felt comfortable. I started to tire at mile 13 which wasn’t a surprise given my hit-and-miss training, but I then had a choice. Push on through with a tight chest, and coughing, or modify. It was time to assess my priorities. Was my priority a GFA time or to enjoy the race? I chose to turn off my watch and walk a bit at each mile marker, and just enjoy. Somehow walking in a marathon can feel like a failure – but its really not. I don’t regret taking the time to enjoy the last 10 miles instead of suffering through. It really did show me the power of knowing your why though. My desire for a GFA time just wasn’t strong. So if you want to go for a time, you need to really want it and know why its important to you.

And what didn’t I get right

Not respecting the taper.
Due to injury, my training was hit and miss. I lost over 2 weeks in peak mileage time, and ended up doing a 20 miler 16 days out from the marathon. I did too many miles in the penultimate week compared to the rest of my training, and didn’t focus on refuelling well. The final week was only a proper taper because of illness, and probably saved the day. The taper is a tricky time to get right. Too much running and you don’t recover, too little and you feel sluggish. This is truly a time to listen to your body and your coach.
Not listening to my body (running when ill). This was the worst of all my sins in the run up. I felt headachy and unwell on Saturday night a week before Brighton, so pulled out of my 10 mile race the next day. I decided on a gentle test run instead. That didn’t go well – I pulled out after less than 3 miles easy because I felt weak and shakey. A sensible person would have gone to bed, but I was determined to do what was originally planned before I got ill. So I rested and then went back out for 7 more miles, 6 at marathon pace. If I’m honest. my recovery from my cold would have been a lot quicker without this and it may be why the cold went to my chest. Moral of the story – please adapt and listen to your body or your coach. Going back out again on Sunday was foolish. I did listen to my body the rest of the week and was able to recover for the marathon, but it was touch and go. And that run on Sunday is probably why.
Not practicing race pace. If you’re rested and your legs feel good it is SO hard to do short runs at race pace during the taper weeks. But a few seconds a mile does make a difference, it is well worth sticking rigidly pace to in the final couple of weeks and ignoring the desire to run faster. Running faster adds no extra benefits so close to the race, and hitting the pace trains you both to recognise the place and to be disciplined. I didn’t do a single run at my proposed race pace (all were slightly faster) and of course that meant…
Setting off too fast. The first half of the race at Brighton I ran faster than my original proposed race pace before I got ill. So it was probably inevitable that the second half was going to involve fading… This is a lesson I have never got right, but one day I will, and won’t bomb the second half of a marathon! Top tip – stick a pace band on your wrist and use it to guide you. I may even try and follow a pacer for my next one!

All in all, I was lucky. I got to do an amazing race on a beautiful day, I ran my revised sub 4 goal and was able to slow down and enjoy the moment. I may still have lessons to learn, but I’ll re-read this before my next marathon, and hope that I’ll make some new mistakes instead!

The distance never fails to humble me. Good luck, marathon runners, and above all, enjoy. Don’t forget, we do this for fun!