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The Chasers Pace Calculator

Posted on March 11th, 2018 by

We have a pace calculator on our website which you can use to figure out what you might be able to achieve in a race and also what sort of pace to run in training.

It’s pretty straightforward to use except when it comes to figuring out your marathon pace, but it gives you a range of three possible marathon times.

The reason for this is that the marathon is a pretty extreme event, so it is hard to predict a marathon time based on shorter distances. So rather than give you a single figure I think it is better to show you a range.

The “Optimistic” time is based on a formula devised by Peter Riegel in 1977. This is the formula used for all other distances and it is pretty accurate for short distances. It predicts a marathon time only a few runners actually achieve (though some do achieve it, for example it predicts my times very well).

Ian Williams of Fetcheveryone had a look at the data for his runners and wrote an article about it that you can read here. I’ve used this article to come up with our “Conservative” time, though I actually used a different formula which should improve on it (see Geek’s corner below).

I call this time “Conservative” because it attempts to work out how the average runner will perform. But this average includes all the idiots who haven’t trained properly, who have set off too fast, or are running dressed as a chicken. I think you should be able to achieve the Conservative estimate if you train and race sensibly.

Finally with have the “Pessimistic” time. This is also based on the Fetcheveryone data but assumes that you will be roughly in one of the bottom 95% given your half marathon time. I think it is helpful to show the full range of marathon times, but I’d recommend you try to achieve a better time than this. I mean, you’re planning to train well and race sensibly aren’t you?

I’d recommend that when racing a marathon you should target something between the optimistic and conservative times. If you have raced a marathon before, you will have some idea of which of the predictions works better for you. If you haven’t raced a marathon you might want to err on the side of caution to make sure you enjoy the race.

When you use our calculators or schedules you can choose whether to go for the optimistic, conservative or pessimistic estimates by saying whether you or biased towards longer or shorter distances.

Geek’s Corner

The Riegel formula is:


What Ian Williams of Fetch everyone asked is whether the power 1.06 in this formula is the best choice. He studied how half marathon times predicted marathon times and found that the best power varies quite considerably from runner to runner, but a value of 1.15 would work for the median runner.

In his article he also drew the following graph showing how the best choice of power varies according to the half marathon time.


The correct power for the Riegel formula (the Riegel number) by half marathon pace. The graph comes from the article by Ian Williams linked to above.

The red line in the graph shows what value you should use instead of 1.06 to predict how the median runner will perform given their half marathon time. What this shows is that the basic shape of the Riegel formula doesn’t work so well since no single power works for all times. Since the red line in the graph looks roughly straight, I decided to let the power used in the formula vary linearly from 1.10 for an 80 minute half marathon runner to 1.20 for a 2 hour marathon runner. I also decided that for runners faster than 80 minutes I’d cap the power from below at 1.08. This is how I calculate the “Conservative estimate”.

For my pessimistic estimate I just made sure that the conservative estimate was half way between the optimistic and pessimistic estimates. The graph suggests this is a fairly reasonable thing to do.

Of course, one could try to produce a more accurate calculator by examining the data closely and taking more factors into account. If you are a computer scientist looking for a project, why not train a neural net or similar to predict people’s times? In practice, I think these formulae are accurate enough. They give a decent impression of the range of possible times you might achieve and are a useful reminder that we are all different.



Time to cut the crap

Posted on March 6th, 2018 by

Nobody wants their marathon time ruined by a loo break. If that’s a concern for you, now is the time to decide what you are going to do about it. Ultimately its a matter of experiment to find what works for you. Start experimenting now rather than leaving it to race day. Here are some thoughts…

1. Come up with a nutrition plan now, write it down and see if it works.

2. What time will you get up on race day? You will probably want to mirror this in your trial runs. You may want to get up early for a few days before race day to shift your body clock.

3. What time will you have your evening meal before the race? You might want to eat early, say 6pm.

4. Does cutting down on fibre and fat for a couple of days before the race help?

5. Try a hot drink in the morning. Does caffeine help or hinder you?

6. Try taking an imodium before a long run. If it helps you could do this on race day.

7. If you are travelling to your race, should you prepare your own food in advance (or  take ingredients if you are self-catering). Unfamiliar restaurant foods are a terrible idea. If it’s a big problem for you, maybe do your big PB target races close to home and not race abroad for the holiday and the experience rather than the time.

8. Know where the loo stops will be on your race, so you can find them if you need them.

9. When you’ve got to go, you’ve got to go. Get it over with quickly and you’ll spend more of the race running comfortably and a little lighter.

10. If you insist, keep a food and bowel movement diary. But please, don’t blog about it.






The Road to Nowhere

Posted on March 1st, 2018 by

If you get a chance, go for a trail run in the snow. It’s safer and more fun to run through fresh snow than on icy paths. If you wear your cross country spikes they will miraculously clean themselves. A double win.

If you are racing the 10k this weekend, I’d probably just have some enjoyable snowy runs and forgo a speed session. But those of us doing the marathon schedule have had a couple of light Thursday sessions recently and so might consider a treadmill session instead.

Here’s what you need to know about treadmill running:

  • Most treadmills measure speed in km/h. You can use our pace calculator to find the right treadmill setting.
  • There is no air resistance on a treadmill so you should set the gradient to 1-2% to compensate for this.
  • It’s easy to overheat on a treadmill, so take unseasonal clothes like a vest. Bring water too so you can practice drinking and running.
  • Stop staring at the screen. If you can’t resist, put a towel over the screen. I consciously ask myself what focal point I will stare at for the session and fixate on that rather than the screen.
  • It’s psychologically tougher on the treadmill, so try to practice your mind games. I find focussing on my form helps. As the session gets tough, I found counting slowly in my head helps me stay focussed and also helps me stop looking at the screen.
  • Wear headphones. If Talking Heads don’t do it for you, try PJ Harvey. She feels your pain.


Race Day: National Cross Country

Posted on February 24th, 2018 by

It’s a gorgeous day for smashing out a fantastic performance in the National Cross Country championships.

In case you didn’t notice, our schedules got you doing a long run on Tuesday, so you’re all set up for a guilt free rest day tomorrow. That means you can really push it. Also on Thursday we did a light sprint session, so you should be going to the start line with fresh legs and a taste for speed. It’s almost like we planned it.

Today is definitely a race, so let’s talk race tactics. There are two kinds of running tactics, PB pacing tactics and beating your enemy tactics. Times mean nothing today, so let’s focus on the latter. Here are some fun tips:

  • When you overtake do so with a burst of speed so it is hard for them to follow.
  • If someone is just behind you, put on a burst of speed as you go round a corner. The sudden inexplicable gap will break their morale.
  • Overtake wide. Buy the time you’re in their field of vision you’re already ahead.
  • Control your breathing. You can fake not being tired as you pass and that will break their heart.
  • Pre-empt their attack. If you think you can guess their plans don’t wait to counter attack, attack first.
  • Attack on the flat or a downhill. It’s hard to make substantial gains on an uphill and it is demoralizing if you lose all your gains instantly on the downhill. When a downhill levels off is a time many runners drop their guard, so that might be a good time to attack.

As usual, warm up well and don’t set off too fast. The race is crowded so you probably do need to push it a little at the start to not get stuck, but you shouldn’t kill yourself. When the going gets tough, focus on your form, relax and then deploy the ultimate psychological weapon: smile.


Life after London

Posted on February 15th, 2018 by

Our current training schedules all end after the London Marathon. What will happen for the rest of the year?

I thought I’d let you know the key events we will base our training around once marathon/half-marathon season ends.

What do you need to do now to prepare?

  • Go to our calendar and ask it to email all the events to your calendar. Sure you might not do them all, but its good to pencil them in.
  • Enter Cabbage Patch 10.
  • Be poised to enter St Neots.


In the summer we focus on shorter distances, from 5k to 10k. I hope we’ll also organise some middle distance and perhaps even sprint training too.

Our main club racing focus in the summer is 10k and 5 mile races for Summer League. This is a super friendly race series for absolutely all abilities and includes kids races, relays a picnic and (new this year) a bake-off. You simply enter on the day.

A second summer strand is track amd field with Southern athletics. If you have an inner sprinter or middle-distance runner you want to unleash, this should be your summer focus. Entry is free, but you will need to sign up in advance so the officials know who is running. You’ll be able to sign up using our calendar nearer the time.

If you fancy triathlon, the Crystal Palace Triathlon is our club championships. Contact triathlon@chaser.me.uk for info on how to enter.


Our club training will switch to a half marathon focus in the autumn.

The big races are the St Neots Half Marathon in November and our club championship the Cabbage Patch 10 mile. Both races sell out.

St Neots can sell out within hours so sign up as soon as entries open. If you’ve never entered before you could try liking them on Facebook and asking to be put on their mailing list. We will mention it in our Facebook group, but you don’t want to miss it.

You can already sign up for Cabbage Patch, so do.

The other autumn races we know we’ll be doing are the Essex Way Relay and the usual cross country races. Essex Way is a relay through some lovely countryside with legs for all abilities. Its brilliant. Its free to enter, but we will need to decide on teams in advance so will take names nearer the time.

Finally, if you plan to run an autumn marathon, Dublin and Abingdon are good choices that attract a lot of Chasers. Abingdon sells out fast, so be poised ready to enter.

Even More?

Hopefully we’ll also organise a trip to the countryside for some trail running, probably in May. We may also book the track for the day so we can all finish the summer with PBs (and I can show Lauren Longhurst how to win at the wheelbarrow race).

Watch this space.


February Training

Posted on February 5th, 2018 by

For those following our online marathon and half marathon schedules, we’re now one month into training. I hope you can look back on the last month and see the progress you have already made. (Yes! If you did the Kenyan Hills last Tuesday, you really can run up twice the number of Primrose Hills you could at the beginning of the month).

February marks the beginning of a divergence between the marathon and half marathon schedules.

For marathoners this month is all about the Sunday long run. For half marathoners, you should let the marathoners go off on their own. You want to keep fresh with a shorter Sunday session so you can really nail the Thursdays.

Whichever distance you are targeting, we’ve got three races coming up to keep you focused.

  • This Saturday there is a Met League cross country fixture in Trent Park. You’ve done the Kenyan Hills, now test out your hill running skills for real. This race is definitely one of the best Met League races and possibly the best. I have to say this partly because it is organized by Chaser Rob Scott (also of Barnet and District AC, the host club) and also partly because it is true. Just turn up with your spikes and your Chasers vest on the day. Spikes are essential this late in the cross country season. Expect mud.
  • On Sat 24 Feb we have the National Cross Country Championship taking place on Parliament Hill. This is THE cross country race of the season (see the photo of the women’s race below to get a hint of the scale). If you haven’t signed up already, you’re too late I’m afraid. Just remember to sign up next year (it will be the southern champs next year not the nationals, but the southerns are even better).
  • On Sun 4 March we have the Mornington Chasers 10K club championship taking place at Regent’s Park. You should already be able to claim free entry from the marshalling you did earlier in the series, right? If you want to race it and haven’t marshaled, there are still spaces available via the usual online entry.

Marathon runners can’t afford to take both the National Cross Country Championship and the 10K club championship seriously. The fact is your weekend focus needs to be long runs and you shouldn’t take two weeks in a row off long running. Our schedules recommend that marathon runners race the National Cross Country properly and then chill out the next day. The next week the schedule suggests you build the 10K race into a long run rather than racing it full on. However, if you haven’t got a place in the national cross country championship, I’d recommend swapping the two weekends around doing a long run the first weekend and then racing the 10K properly.

Half marathoners can do both, but personally I’d suggesting holding back a little in the cross country to try and keep something in the tank for the 10K.

I hope you’ve enjoyed your first month of training. Have a fabulous February.






Marathon Pace Practice

Posted on January 30th, 2018 by

This Sunday, Marathoners following our schedules will want to do the final chunk of their run at target Marathon pace.

I recommend getting up early, doing the easy bit of your run and then doing the Marathon pace section on the Regent’s Park 10K course.

Regent's Park 10K

The advantage of this is that you’ll be replicating race day as close as possible on a flat traffic-free route with water stations. This means you can really learn what marathon pace is meant to feel like and you can practice things like taking gels and drinking on the run. You could even drop off a water bottle or some Lucozade sport with a friendly marshal so you can replicate race day more exactly.

If you have marshaled (or just signed up to marshal) one of the 10K’s, you get free race entry to the rest of the series. So if you fancy running the 10K this weekend, you could sign up to marshal in March. You sign up to marshal via our calendar and then log in to our website and select “Enter 10K”. Do this (or pay in the usual way) before midday on the Friday before the race.

We don’t run at target Marathon pace every Sunday because it is very tiring. You need time to recover before trying this kind of session again. There will be a few runs with sections at target marathon pace throughout the schedule and they are a great way of monitoring progress. Don’t worry if you find them tiring and find yourself wondering how on earth you will ever manage to do the whole race at your target pace. They are meant to be hard work and you will be going into race day feeling fresh and with considerably more training under your belt.


Race Day Nutrition

Posted on January 24th, 2018 by

For those of us who are marathon training, our Sunday runs are starting to get seriously long. Once you are running for over 2 hours, you should think seriously about nutrition.

On marathon day, nutrition is crucial. Your body’s ability to store fuel is often the limiting factor on marathon ability. Your body’s main fuel reserve for running is called glycogen. This is the main way carbohydrates are stored in the human body for use by your muscles. Your body can also use fat reserves when you are running, but this is a much less effective source of energy on race day. Many runners will run out of glycogen at about mile 18 or 20. This is often called “hitting the wall” for self-explanatory reasons.

This is why on race day you should definitely be taking on board fuel as you run. There are many options: you can carry energy gels and/or eat the various energy gels, sweets and drinks they hand out at most big marathons. Personally, I eat 3 jelly babies every 5k during a marathon until I can’t stand them any more plus one energy gel at the start and a caffeinated gel towards the end. I also make sure I know where the water stations are so I get a drink immediately after eating anything.

What works for  me may not work for you. But you should start trying to figure out what you intend to do on race day. How much can you take on without getting a stomach upset? Does Lucozade agree with you etc? We all respond quite differently.

Start experimenting on your long runs with nutrition to find out what works. If you practice taking on fuel, your body will learn how to make the most of it. There is some debate about how much fuel you should take on during training.  Personally, I think you should do all or almost all of your long runs (>2hrs) taking on a reasonable amount of food to stop your training runs being too exhausting and to aid recovery. You should certainly do a few dry runs where you try out your race day strategy as close as you can.

There is some (in my view slightly unconvincing) evidence that doing some training runs where you allow yourself to run on low glycogen can help you develop the ability to use fat as a fuel on race day. So some people do recommend running occasional “glycogen depletion” runs. The reason I find the evidence is unconvincing is that although in the experiments they were able to show athletes who had experienced glycogen depletion training had better fat metabolism, they didn’t actually have better times. You might wonder about the effect of glycogen depletion on weight loss, surprisingly the evidence suggests that glycogen depletion runs don’t help with weight loss (having said that, anyone who drinks sports drinks when they are not doing sport is on a fast-track to weight gain, we’re talking about moderate carb consumption as part of a greater than 2hr run here).

Despite the pretty clear evidence that you need to eat to get the most out of your marathon, I know that a lot of people worry about doing so. One obstacle that I know stops some people trying gels etc is that they taste pretty revolting. Also I know a lot of you don’t like eating rubbish processed food. And it’s absolutely true that eaten when you’re not running, gels are just the kind of pure sugary junk you should avoid. But so long as you eat a balanced diet when you’re not choking down your High 5’s, you shouldn’t worry about taking them when you run.  The fact is that on race day, the flavour and the lack of fibre are not important considerations. On the other hand, be warned that failing to take on energy during the race will cost you dear.

Geek’s Corner

Here are two links to some science. I’m not claiming to have read the articles in full, but I think I’ve managed to extract the gist of both.

The first paper Metabolic Factors Limiting Performance in Marathon Runners has a number of references to back up the basic claim that you need to eat while you run to achieve your best performance. They also develop a mathematical model that can supposedly be used as a marathon pace/energy calculator. I’d be very skeptical about their calculator as they don’t really seem to have tested it much.

The second paper is Training in the fasted state facilitates re-activation of eEF2 activity during recovery from endurance exercise. This title says it all: namely that they study the effect of glycogen depletion exercise not on performance but on some rather technical aspect of how your cells function. One might conjecture this cellular change could make you run faster but in the time trials they conducted they didn’t observe a difference.


Run a Better Half with Betterave

Posted on January 20th, 2018 by

There is a tremendous amount of rubbish printed about sports nutrition. One thing that sounds like total rubbish is the claim that consuming beetroot shots can boost your race results by 1-2%. That equates to about a minute off a half marathon, which is a huge claim.

And yet the evidence is pretty good. A paper in the Journal of Applied Physiology by Prof Andy Jones of the University of Exeter is the main one cited in the many newspaper and magazine stories on the subject. You can find a readable account in this article from Runner’s World.

On a practical level, the bottom line is that you should probably try 2 shots of Beet It concentrated beetroot about 2-3 hours before you want to hit peak beetroot. So for a ten mile race probably take it 2 hours before the start. Weirdly you mustn’t brush your teeth since the interaction of mouth bacteria is an important part of the chemistry behind it. The optimal dose varies from person to person so you might experiment.

Should you get Beet It, Beet It Sport or Beet It Pro Elite, or some other brand? It really depends how much you want to pay as there doesn’t seem to be any meaningful difference between the products. The research was done using the cheapest option.

Whether it is true or total rubbish, its pretty harmless. The flavour is a bit disgusting, but that is part of the fun. Like everything, however, you shouldn’t try it for the first time on marathon day. So if you’re racing this weekend, why not give it a go?




Posted on January 11th, 2018 by

If you are following our marathon and half marathon schedules, you will see that we’ve got a lot of long Sunday runs coming up. For marathons in particular, the long Sunday run is the key session of the week.

One mistake a lot of people who are new to marathon running make is to try to do the long Sunday runs too fast or to go too far too often.

The fact is that running for two hours or longer is tiring, and running it fast is utterly exhausting. It is OK to be exhausted occasionally during training, but not every week. You will see that in our schedule there are a few sessions where you run a long way fast, but they are spread out throughout the schedule to give you time to recover.

What happens if you do not take time to recover? You are very likely to fall ill (perhaps getting a cold that never seems to go or simply feeling tired all the time) or get injured (too many miles can take a real toll). There is absolutely nothing worse for your training than being ill or injured. It is better not to be training at all than to be making yourself sick.

I think there are two reasons people make the mistake of over-training.

  • Firstly, it’s easy to believe that more is more. If you increase your mileage a little, your race times will probably improve so you find yourself reasoning that if you run 100 miles a week you will probably become an elite athlete. In reality if you run 100 miles a week you are for more likely to become someone with a chronic injury who cannot run at all without discomfort. Yes, there are the occasional biologically blessed individuals who can cope with tremendous training loads, but for every elite athlete there are a thousand talented athletes nursing injuries.
  • Secondly, it’s impossible to believe that on race day you will be able to run 26.2 miles with all of those miles run faster than the longest run you did in training. Especially when that longest run was only 20 miles (for most athletes 20 miles should be the furthest they run, some faster runners may do as much as 22 miles or even 24 miles). When I’m training I find it impossible to believe that I can do it too, and yet I have done it time and time again, and athletes I have trained have done it too! It takes a bit of nerve to believe that moderation will pay off, but experience says that it does. That’s why experienced athletes don’t push their Sunday runs too hard. If you are new to marathons you have a choice: the hard way is to learn from your own experience; the easy way is to learn from other people’s.

How fast should you do your Sunday runs? Our schedule will tell you.

Our schedule mostly says “easy” or “steady” and gives you a rough idea of what pace that might be. For easy runs, you shouldn’t be too much of a stickler about the precise pace you run them. Apart from anything else you should sometimes be running on hilly routes or off road and inevitably you should run slower on tougher terrain. An easy run is a conversational pace but not a complete plod. A steady run is a brisk conversational pace.

Occasionally our schedule says that you should run some of the session at race pace. These are key sessions in the training programme. This gives you practice running at your target marathon pace and I recommend finding a flat fast route to give you a fighting chance of achieving this. You will find these sessions are seriously tough. They will make you question your ability to run 26.2 miles at your target pace. But they should do the opposite, if you can do these sessions you’re on track. Come race day it is astonishing what you will achieve.

How far should you go on your Sunday runs? Our schedule will tell you.

If you are doing an off-road route, I recommend judging your run by time rather than by distance. Don’t run 20 miles over mountains, that will exhaust you.

Where should you do your Sunday runs? From Talacre at 9 am using one of the routes on our website!

We’ve got 30 routes for you to choose between and you can easily follow them using a smartphone if you don’t yet know the way.

We encourage everyone to post on Facebook what they are doing for their Sunday runs so we can train together. Fairly obviously if you plan on running 18 miles at 7:30 minutes per mile, you can’t really expect to have company unless you’ve arranged to meet up in advance. Sometimes a solitary 3 hour run can clear your head, but most of the time it is a good idea to do these big runs with other people. I strongly recommend trying to get to Talacre as often as possible over the next few weeks so you can find the running buddies who are going to get you through the long runs ahead.