Anaerobic Speed Reserve (ASR)

The Anaerobic Speed Reserve (ASR) has been used for many years in sports science and endurance coaching, specifically for running. As usual, it tends to be over-complicated and over-scientific, but the basic principle is one of the most important things that you need to understand as an endurance athlete. There’s a lot of information about ASR, which if you’re that way inclined, is only a google search away…

ASR in simple terms is the difference or the ‘gap’ between your ‘maximal aerobic speed’ and your ‘maximal speed’. Ok, so let’s define those 2 things:

Maximal aerobic speed is the speed at which you hit your VO2 max. If you went to the running track and ran as hard as you could for 6 minutes, the average speed would probably not be far off your maximal aerobic speed.

Maximal speed is quite simply the fastest speed you can run, so we’re talking about 50-100m in distance, flat out. That said, many people use 200m as a bench marker.

The ASR is quite simply the difference in speed between the 2 measurements above.

There is a bucket load of evidence which links the 2 things together. In elite distance runners, there is significant correlation between ‘maximal speed’ and ‘maximal aerobic speed’. In simple terms, the fastest 10k runners in the world, are faster over 100m than all the other 10k runners.

So, let’s look at some simple self analysis. If you’re aiming to run a fast 10k this winter, 2 questions you should ask yourself are:

  1. Can you run fast? Do you have the basic ability to move quickly over a very short distance?
  2. Can you keep it going? Is your aerobic fitness good enough to sustain you for 10k?

Can you run fast enough?

That’s question has got nothing to do with aerobic fitness. It’s about producing force with muscles and tendons, it’s about nerves sending signals so quickly that your legs can move at speed, it’s about how you land, store energy and push off and it’s about doing all of that, at speed, in a smooth, fluid and relaxed manner. It has absolutely nothing to do with blood, oxygen and aerobic energy. Running fast for 100m is NOT an AEROBIC activity.

Can you keep it going?

That has everything to do with aerobic fitness. Those hard workouts train your aerobic system to supply enough oxygen (and they train your muscles to need less, which is a bonus).

Give me some examples please!!

Of course… so there are lots of runners who are simply ‘not fast’. They are not able to run 100m at a quick pace. They may do lots of interval workouts and push themselves physically, but if they lack that basic ‘skill’ of running quickly, that will always be their limiter. It’s like having a car with a huge engine but the tyres are flat. Rather than trying to improve the engine, pump up the tyres instead. It’ll probably roll a lot better and for a lot less effort. Let’s call these people Type A.

By contrast, team sports players who take up running are often very quick over short distances, because that’s their background. Sustaining it for 10k however is another matter. If anyone is going to go off way too quickly in a race, it’s these guys, because the first few hundred metres feels so easy. However… the next 5.8 miles? Meh… not so easy. Let’s call these people ‘Type B’.

So, have a think about how you compare to your mates and fellow runners. Are you extreme Type A? Are you extreme Type B? Or are you somewhere in the middle? It is of course a sliding scale from one extreme to the other and you may be balanced in the middle. The first step to improving in any sport, is knowing what’s holding you back. It’s often very simple when pointed out.

Now… Anaerobic Speed Reserve sounds really technical, there are lots of sports science articles on the subject and it has been written about in recent years, but is it really anything new? No, not really… in the 1950s Arthur Lydiard would assess runners by completing a 200m time trial and a 1 mile trial, based on the results, he would determine whether they were middle or long distance specialists. But he was way ahead of his time in every aspect.

What is speed work?

This is perhaps one of the most misunderstood terms in distance running. Speed work should help you to develop your ‘maximal speed’ so being realistic, it should be distances from 50m, up to a maximum of 200m. Running 800m or 1 mile repetitions is not speed work. It could certainly be classed as ‘hard work’ but when running 1 mile repetitions, you are far from maximal speed. If you want to keep your training week simple, think about doing something fast, something hard and something long (and easy).

In summary…

The simple take away message from this article, is that if you can’t run fast for even 100m, it’s not going to happen for a full 10k. Basic speed over 100m is a fundamental of successful distance running, which is often overlooked because people feel they can only gain from going further and harder. Distance runners often don’t see how speed over 100m, has anything to do with 10k or marathon running.

Triathletes… You can also apply this exact same principle to swimming and cycling. If you’re a slow swimmer over the 25m distance, you won’t be fast for 1500m. In cycling, if you can’t produce a decent power output during a 10 second maximal sprint, you can’t do it for 40k (I wrote about that recently HERE).

I’d say that without the basic fundamental of speed / power over very short distances, your interval training will always be limited, as will your performances. The same though could be said about aerobic base work. So given that, your winter training sessions should either be long and easy (80-90% total training volume), or VERY short and VERY fast (10-20% total training volume). I believe they call that polarised training. Periodise your year correctly and then throw in some interval work 8-12 weeks before a race, and you’ll be flying. Easy as that.

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Marc Laithwaite is a level 3 qualified coach, who has been coaching endurance sports for the last 22 years. He is a former sports science lecturer of 12 years and spent 2 years with the British Cycling team as a bloods analyst. He has worked with British Triathlon Coach Education as a coach educator and spent 5 years as head coach of the NW Regional Triathlon Talent Squad. He’s also a former national age group triathlon champion, European duathlon champion and Ironman age group winner.

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