Couch to 5K
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Speed versus aerobic endurance --

what is holding me back??.

I subscribe to a number of things on the Internet - and this morning this below popped up in my email. It could not have been at a better or more appropriate time as I am intending to change my training methods very soon. Basically it is telling me that I already have enough "speed" to run faster than a 30 minute 5K - I just don't have the aerobic endurance to do so!!!

""Hi Barry

I started working with Brad back in 2012. Brad was a a pretty experienced runner looking to improve his 5k time. He wanted to break 20 minutes.

In our first conversation, I asked Brad what he thought his weaknesses were.

The first step to improving is almost always identifying your strengths and weaknesses since this allows you to dedicate your time to the activities and training that will provide the most value.

"Speed, definitely speed" Brad said. "I really need to work on my speed to crack 20 minutes. I am just not fast enough yet."

So, I asked Brad what he could run a mile in.

"I ran 5:45 last summer at one of those road mile festivals" he replied

Ok. So I asked Brad what was the fastest 400 meters he had run in a workout previously.

"Right about 1:20 (5:20 pace)" he answered.

I scratched my chin (that's what I usually do when I am thinking - I notice it all the time when I record interviews)

It seams Brad was making one of the classic mistakes when it came to training...

Focusing on the wrong weakness.

You see, Brad had plenty of speed to run a 5k under 20 minutes. To illustrate:

Brad wants to run a 5k in 20 minutes. That is 6:25 pace per mile.

But Brad can already run a mile in 6:25. In fact, he can run one in 5:45. He can also run 400 in 5:20 pace.

Thus, the problem isn’t that Brad doesn't have enough speed to run a 20-minute 5k, it’s that he lacks the endurance to run three 6:25 miles without stopping.

In fact, from a training standpoint, speed is rarely the limiting factor in how fast you can race, even for a distance as “short” as the 5k.

Therefore, when you’re examining your training and identifying your strengths and weaknesses, the most obvious areas of improvement are going to come from improving your aerobic endurance and lactate threshold.

If you can already run faster than your goal race pace, the problem isn’t your speed.

Aerobic capacity and lactate threshold, what running coaches refer to as “strength” work, are the backbone of your ability to sustain a fast pace for a long period of time.

In short, the higher your aerobic capacity, the longer you can run near your maximum speed.

But what about speed during the end of a race?

Speed during the end of a race

All runners want to open up the stride and close hard the last 400 meters of race.

Not only does it feel great to pass droves of competitors, but finishing strong helps motivate you for the next race.

However, actual speed has little to do with how fast a runner can finish the last 400 or 800 meters of race.

As discussed above, most runners already have the absolute speed necessary to fly through the finishing shoot.

A 30-minute 5k runner is probably already doing multiple 400 meter repeats at about 8:20 pace.

However, finishing the last 400 meters of a 5k at 8:20 pace is probably next to impossible for that same runner.

Again, the ability to kick and finish fast is not limited by absolute speed. Rather, the limiting factors are the ability to run fast when tired or to hit the last 800 meters in a less oxygen deprived state.

Therefore, if you’re a runner who is trying to improve your finishing speed or you tend to fade during the last mile, your training time would be better spent improving your aerobic capacity, not necessarily your absolute speed.

Tempo runs and threshold intervals are going to address your late race “speed” weaknesses better than a steady diet of 400 meter repeats.

What role does speed play?

Certainly, speed is a component of a well balanced training plan and it’s important to include speed workouts to improve your running efficiency and V02max. If you completely neglect speed all together, or any energy system for that matter, your performance will suffer.

Perhaps the biggest role speed plays is that it helps improve your running economy and efficiency.

In unscientific terms, speedwork helps you run goal race pace with less effort.

However, there is a limit to how much you can develop your absolute speed. At some point, your body approaches its natural talent point and working to improve speed provides diminishing returns.

Luckily, improving your aerobic capacity is virtually limitless.

Therefore, once you’re able to run about 20-30 seconds faster than your goal 5k pace for a full mile, you’ve probably developed enough speed to comfortably race your goal pace.

The focus in your training should then be turned to improving your aerobic capacity and lactate threshold, which will help you develop the physiological fitness to race faster and maintain a top end speed for longer.

How this works in your training

This training philosophy that favors strength (aerobic endurance) over speed is the backbone of your training at RunnersConnect.

Whether you’re being personally coached by a member of our staff or you’re using one of our custom plans, we design all our training with this principle in mind.

So, the next time you’re looking for a training plan, take a look at the workouts and see if their attacking your strengths and weaknesses.

Likewise, when you’re analyzing your training and looking to identify the areas you need to improve the most, you can ask yourself whether it’s really your speed that is holding you back or if you actually need to get stronger aerobically.

Now that we've talked a bit about workouts and paces I think it's time to talk about pacing. In next week's article, I am going to teach you exactly how to stop staring at your Garmin (yes, I know you do it) and why it's important."

4 Replies

That's very interesting...but seems rather complicated too. My son says the best way to get faster is intervals. It seems to work as he does them about twice a week and his 5k time has gone from 26 minutes to 22.10 in the last few months!!!!


That means that he is running 5K at an average 4:26 mins per k. Ask him what pace he can do when running only 1K?? According to the article, this would mean that he should be able to do 5 k in a time that is that pace times 5 - IF he has sufficient endurance to run at that pace for 5K :)


This seems sensible to me. It's not how fast you can go along, but how long you can go fast that makes the difference, as they say.

I can say I don't stare at my Garmin though. TBH I find it difficult to focus on it while running. I listen for the km marker beeps and read teh data after the run and that's it.


Yes- to me too! :) I currently run 5K at my fastest 32:30. I would like to be able to some day break that 30 minutes. I know that I can run faster than 6 mins per k - but not for 5 straight klms !! :( I've got to figure out how to do that in a manner suitable to me. Firstly I am going to start doing longer distances at an easy pace - not just as a means to be able to run any particular distance non-stop ( ie this is what I did to get to 10K) , but to add total volume to my weekly running. I will do this for some time and THEN I will start to try to run at 6 mins per k for 1K then 1.5k, then 2K, etc and see where it leads me :)


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