TRAINING: Lydiard Interval Training

I knew I’d be in the mood for a deep-diving training article today after a perfect weekend of training. So let’s discuss intervals.


My attention turned to the details of the upcoming interval training in April after Romain Denis, the UCD physiologist, had suggested my best pace for 400s was 73 seconds.

While this may be the speed where I am scientifically best stimulating the anaerobic energy system, it comes with a caveat: Can I run this repeatedly over the length of a meaningful session?

The answer is almost certainly “no”, you just need to look at my PBs. I am a 5:10 miler (3:13 pace) and 73 seconds is 3:03min/km pace – a full ten second faster – e.g. probably faster than my 800m pace!

In fairness to Romain, this was just an anecdotal comment while I await my full report, and I may well misinterpreted it. What’s important is that it had me think about intervals in detail and go to the Lydiard forum to discuss it with Nobby.

Gradual Pace Increase

One of the strengths of the Go2Lydiard training programs is the precise and controlled way they seek to increase your pace over the course of your full training program. This has nothing to do with what you can do as Romain said to me “of course you can run 3:55min/km pace fairly aerobically, because you have done so in your half-marathon, but if you did it every Saturday you’d probably wear down”. Nobby put it similarly:

You don't jump into running 78 seconds 400 just because you can do it. If you look at Master Run Coach, our pace is ALWAYS gradually picking up...either it's aerobic run or O&B or intervals or time trials. That's the way it should be; and it should come naturally; we are just showing the best possible educated guestimate.

So when you purchase your Go2Lydiard training program, you receive an interval pace chart which shows you the speeds of your workouts throughout the four weeks of anaerobic training. Pace of the intervals is determined by your previous performances as well as your racing speciality (middle-distance specialists do slightly different interval work than long distance runners) because they utilise a part of the anaerobic system termed the “glycolytic energy system” activated at around your 1 mile pace. Long distance runners do very little or no work at these paces as it can sabotage the aerobic enzyme system if done regularly (Livingstone 2009).

Pace Chart

As with everything in the Lydiard programs, you have pace ranges rather than targets because no one can predict for sure exactly your condition on any given day and the starting point is always to hit the right intensity (between 7 and 9 on the 10-increment RPE scale used in the program).


Nobby noted that this chart has been validated against the training times of some top runners such as the legendary Dick Beardsley. My 100m PB is 14.88 seconds, so very close to the prediction here. Just looking at the fastest efforts for the 100m times, they match very closely what I would experience as easier and harder efforts. The 1/4 effort of 19 seconds is fast but not overly so, 18 seconds obviously a bit harder and when we stray into 17 I really feel like I am moving.

On any given day, 20 seconds may feel as tough as 17 and some runners, regardless of their VO2 max, may have been blessed with less speed. There are undoubtedly 1:22 marathoners out there with less raw pace than me (perhaps because they are older) and 20 seconds may be very challenging for them for 100m.

So what pace?

To decide on your pace you simply need to understand the purpose of your intervals. For standard intervals you are conducting what Arthur called “tiring, exacting work”. Yet this work needs to be kept up long enough to lower the pH of the body and induce acidosis, as Nobby details:

Now, your 3:03 and 73sec 400 sounds pretty demanding to me... I guess my question is; so if you run 73 seconds 400, can you maintain that over 12 reps (with 400 recovery jog)? You can run one 400 all-out and you'll get into a heavy oxygen debt. But that's not the goal of interval training. You want gradually pull your pH level down and you'll need volume of intervals. In other words, doing 3 X 400 at 73 won't do for you.

The Lydiard intervals sessions have a total interval volume of between 4k and 7k depending on whether its the short repetition or long repetition sessions of the week as well as your target race distance.

Within these sessions, your recovery is generally a jog of the same length as the interval or the time it takes for your heart rate to return to between 120 and 130 beats while jogging (whatever comes first) but again the key is to understand what you are doing: “…to do enough prolonged hard work to get very tired, thus lowering the systemic pH as much as possible without it being so fast that the local acidosis in the leg muscles stopped the process too early.” 

Understanding intervals

My favourite example of an interval session comes from page 21 of “Running with Lydiard” when a group of pupils come to watch Arthur coaching Richard Tayler:

  • “What’s he doing”? one asked.
  • “Repetitions”, I explained
  • They knew all about those. “How many is he going to do?”
  • “I don’t know.”
  • “What times is he running?”
  • “I’m not timing him.”
  • They exchanged looks of disbelief. Was I supposed to be coaching one of New Zealand’s best runners?
  • Then I asked: “How far round is this track, anyway?”
  • They knew then I did not know what I was talking about.
  • When Dick finished and joined us, they asked him, “How many did you do?”
  • “I didn’t count them”, Dick said.
  • “What times were you running?”
  • “I didn’t time them.”
  • I decided then it was time to explain to these boys, before they ran off laughing, that times and numbers were unimportant. What was the effect on Tayler of what he was doing; and he knew better than I did what he wanted to do and when he had enough.

In essence, while it is useful today for us to measure our own progress by tracking our timing and pace, an experienced athlete who understand exactly what he/she is trying to achieve does not necessarily need this. If they knew the effort level required, how they should feel throughout and when they should stop, they could perform the whole session without a watch on a grass field and still be doing an ideal session.

Shorter intervals generally mean you can run them faster, this is about the hardest and fastest rule you can mention, but they are less race-specific so a combination is ideal and the Go2Lydiard programs have the long reps early in the week and the shorter faster reps later.

Interval design

Because of this it is less important whether you are doing 20x300m or 6x1000m or 12x400m or 6x800m with equal distance recovery jogs. The effects are more or less the same. The Lydiard program has a longer and a shorter interval session each week but what constitutes this depends on your target race and current ability (an elite miler might use 800s as his long reps and 300s as his short, an elite marathoner might use 2 miles as his long reps and 800s as his short whereas a novice marathoner might do 800s as his long and 400s as his short).

The permutations are endless but as long as you know what you are doing and put in the right level of effort you will stimulate the adaptations you are looking for. If you have the physical ability to withstand repetitions of a length that is increasingly similar to your race conditions, even better.

A 5000m runner, for instance, might get a lot of confidence out of doing a long rep session of 5-7 x  1000m early in the week. For this he’ll be approaching his race pace very quickly and despite the break, the session will feel reasonably similar to the actual race. The shorter session later in the week might have 12-14 x 400m where the pace will eventually be faster than the 5k race pace.

By doing just these two simple sessions over the four week period, the athlete would gain the anaerobic adaptations desired and learn a significant amount about their body’s ability to handle paces around the target pace as well as mentally equip them to be prepared for the level of discomfort associated with them.