How to Tackle a Grandslam

Photo credit: Stuart March photography (

Contemplating the Centurion Grandslam of four 100 mile races in a year? Phil gives his tips….

Having finished a couple of 100 milers in 2015 and 2016 and vowing never again….. I found myself volunteering to help at a number of 100 mile races that comprise the Centurion Grandslam. There are four 100 mile races organised by Centurion Running – Thames Path, South Downs, North Downs and Autumn 100 between April and October each year.

And volunteering means a guaranteed place the following year…

But why was I doing this? Obviously I didn’t plan to run all four races because, that would be silly! But I persuaded myself that I’d like to have the option of picking and choosing which one I would do.

I don’t really know how this morphed into wanting to complete all of the four 100 mile races in one six month period. I can only think it was while I was daydreaming or distracted by cake that this notion entered my head. Or it might have had something to do with the amazing and huge belt buckle with each quarter of it signifying one of the four races, plus a coveted red Grandslam shirt.

I am a fairly ordinary runner but I genuinely believe that if you take your training semi-seriously, learn hard lessons from mistakes, and learn good self-management, then, with luck on your side, doing the Grandslam is not beyond the reach of most people who are excited enough and undaunted enough to enter (or else want the excuse to eat loads of cake).

I’m not going to pretend it’s easy.  I needed to find the motivation to want to complete all four races, even when I was so exhausted that I was throwing a total strop with my pacer (on NDW100 at about 80 miles).  Thankfully my wife was pacing me for that leg and knew me well enough to end the strop by telling me “to stop being a bloody baby”.  She knew that I wanted it more than I was able to contemplate at that moment.

There is the blow-by-blow account of all four races in my race reports (linked to below) but for this article I have set out some of the things I have learned that are specific to completing the Grandslam (and other ultras).  If you have any questions – please drop me a message.

The four races – a summary

I managed to finish the Slam in 102 hours, 5 minutes and 37 seconds in total. Here are the races, with my proudest achievement from each one:

  • Thames Path 100 (TP100) – my fastest one in 22h 26m 15s. Thames Path 100 race report
  • South Downs Way 100 (SDW100) – in exactly 1 day, 1 hour, 1 minute, 1 second (how did I make that happen?). South Downs Way 100 race report
  • North Downs Way 100 (NDW100) – managing to have a meltdown while my wife was pacing me and still being married at the end of it. North Downs Way 100 race report
  • Autumn 100 (A100) – going super well for the first half and then falling over at 68 miles and walking the remaining 32 miles without going completely nuts (I hate walking!).  Autumn 100 race report

What are my hard earned tips for you?

Photo credit: Stuart March photography (

1. Volunteer and give something back!

Volunteering on the Centurion Grandslam races is both a great way of getting a good understanding of each of the four races of the Grandslam (the “Slam” for short), and to appreciate the ways in which the races feel different.  It also helps to learn from the runners where the tricky bits are, and of course you get to give something back to those taking part in the races. Finally, you get to know the deal at each of the four (or more) checkpoints and meet other volunteers who may be considering joining you in the Slam.

I volunteered on TP100, SDW100, NDW100 in 2016 (I ran Autumn100 in 2016) so I bought my ticket for the Grandslam with three volunteering places plus a paid ticket for the Autumn 100. While Centurion races are not cheap, they are still good value for the amazing set up and the fantastic volunteers.  They are a race organisation that really understand ultrarunning. So, even more reason to get volunteering. I think if you just pay for the Slam then you are really missing out.

2. Recce the race routes

Each of the four races are very different in character, terrain, and feel. So take the time to find out about the races. Do sections of the route as you get close to the race day so that you can at least have one less thing to get worried about (getting lost) and you can concentrate on all the other things that could possibly go wrong.  Any sections you don’t recce, make sure you pore over them on the map.

I realised quickly that being prepared was especially relevant to the Grandslam, as mucking up one race could jeopardise the whole series.  I also found that recceing the race routes was useful to get me into the mood. It also meant that I had some prior intelligence on important decisions like race shoes rather than just following the herd in discussions on the forums in the week before the race.

3. Know when to train and when not to

Right, so training. Training actually works. There…. I said it. After years of just turning up to races and having a go, I actually trained and trained consistently before my Grandslam attempt. The fact is that the timing of the races leaves no room for catching up because there is something like 5 weeks in between the Thames Path and South Downs, 7 weeks from South Downs to North Downs, and then about 11 weeks until Autumn 100.

I found that I had to take 2 weeks off after a 100 mile race, and taper in the last week before the next race, which left in some cases, just a couple of weeks of any meaningful running. Don’t fret, the key thing is to turn up on the start line as rested as you can on SDW100, and then do some more hill training before NDW100, before having a good period of final training before the last 100 miler of the year.

Take it slow and pace yourself. Keeping injury free is hard and you have to be so careful, and of course there is an element of luck. You’ll get used to wrapping yourself in cotton wool and making absolutely sure that you are minimising all risks in your life as possible (kids on scooters on the pavement have never seemed so hazardous!).

4. Packing and kit

Really get to know your kit. Train with it. Run with it. Test it all out. Get to know what really works for you. Move things around. Get to know how you want to use it. Work out for the races where you want your collapsable cup. What you need, what you can do without, at what point you might need your headtorch. You really don’t want to be having a conversation with yourself about whether you should get a torch out. Cut that out and just have stuff available that you need.

During the Slam you will have the opportunity to tailor your kit choice to the style of racing on the centurion events. You’ll often want to carry two baselayers (one sealed in a dry bag, and one for using) – particularly overnight on the A100, and the TP100.

5. Know the aid stations and find out who is working them

It is a great idea to know the names of the aid stations and hang out regularly on the Centurion Running Community facebook page so that you can discover who is helping at each of the aid stations. It can be handy to know that there is a friendly hug waiting for you.

6. Get to know the other slammers

The chances are that you will know some of the runners, but if you don’t, get to know them. You’ll probably spend some miles with friends and other slammers during the races. You’ll also get plenty of encouragement from other runners during each race.

Keep an eye out during race briefings when the race director James Elson asks the Slammers to raise their hands. Have a scan around and you are likely to already recognise some of the others. Have a blast on the trails and of course because you are all in the same place you’ll each find each other a great source of support.

I enjoyed spending some miles with other Slammers. And I’m grateful to Georgina Townsend, who let me use her as a standing post while I had a cramp in my ankle.

7. Don’t obsess over the weather and shoe choice

You’ll stress yourself out in the week before each of the races because after perfect running weather you will find it rains heavily (and probably unseasonably) and then the perfect road shoes that you had chosen for their additional cushioning will no longer seem right for the race. You’ll stress and stress and stress…. and then you go on Centurion Running Community and stress each other out all the more.

If you have recced the route. You’ll know what will be the best compromise.

  • TP100: I wore road shoes (Pearl Izumi N3 road – It was dry and the Thames Path is hard on the feet, for some of it anyway. Right choice).
  • SDW100: It is chalky and flinty and grassy for much of it. It was dry. I used the same Pearl Izumi N3 road shoes. It rained a bit during the week before but the SDW drains fast.
  • NDW100: I wore the same road shoes. It was dryish, but had rained on and off. There was a rain storm forecast. I wore Pearl Izumi N3 Road shoes but came a cropper around 30 miles when it rained heavily and turned fields in to a chalky, muddy, claggy mess. I couldn’t be bothered to change my shoes and as a result I lost some time. Wrong choice.
  • Autumn 100: I checked the route over the previous weeks and I had friends local to the area too so there were lots of opinions. It was a finely balanced choice because it had been so wet. I decided to go for my Pearl Izumi N2 trail, which ended up being the perfect choice.

So, the weather will be the weather. Just get on with it and if you have checked out the routes and you know your body and how you run then you will be well placed to make the right choice.

8. Those little extras that make the Grandslam that little bit more comfortable.

  • Take some cash for ice creams and know where you can get them.
  • Crew Briefing. If you are lucky enough to have a crew and pacers, then really look after them.  If you have recced the route, you will know where you will benefit most from pacers. Also, take time to tell your crew how you want them to deal with you, and also just be really nice to them. Discuss in advance where you might want to see the crew – and know that it might not make sense at every possible crew point.
  • Practice eating and drinking regularly during training. Know when the aid stations are and what is available at each of the aid stations (as far as possible). Know what you want to take with you. Try it. Train with it. Practice. This reduces the chances of stomach issues, although they can still happen.

Above all, have fun….. Enjoy the training…. And bask in the loveliness of meeting like-minded runners and volunteers.

As the cherry on top of the cake I was over the moon to be awarded the David Simpson Memorial Trophy – awarded on an annual basis for achievement in hill and off road running, both of which were close to David’s heart. I didn’t know David personally but have heard from friends that he had a wicked sense of humour and loved being on the trails – so I am over the moon with such a great end to a pretty unreal year for me.

Phil Bradburn has been a Serpie member for a number of years and particularly enjoys running further than he really should and eating more cake than is sensible; which of course *absolutely* do not represent a causal relationship.