The Long and Short of It

I get quite a few questions on run intervals. So I put together some information and principles around how I structure my interval workouts.

What intensity should Long Intervals be done at?

I focus my Long Interval sessions at a  “comfortably hard” intensity level. This is a range of paces from Marathon Pace to 60-minute pace that can be span tempo, steady-state, or threshold in different training systems. 

Given that we have an ingrained idea that hard work must equal better results the tendency is to push the pace too much in these types of sessions whereas the real goal of optimal stimulus is achieved by a hard but under-control workout that results in feeling invigorated and not torn down. 

The question isn’t how “hard” can I train, the key question is how “easy” can I train and still get the targeted stimulus leaving me fresh for the next session, consistency is king. Always warm up well and we strongly recommend that you incorporate running drills and high-intensity strides into your warm-up.

How about the Long Interval duration? 

For me, the target duration at intensity depends on the pace, with a rough guideline of Marathon pace 30 minutes, Half Marathon pace 25 minutes and 60-Minute pace 20 minutes. Then I have a progression of how the reps are split to hit this time at target intensity and the length of the recovery interval between them across the weeks. This duration at intensity is designed to give me sufficient stimulus whilst considering the overall volume and intensity of other sessions in my plan (as a swimrunner that includes swimming and strength work). 

You are of course welcome to lengthen the target duration at intensity (sometimes I do too)  but please note that around 35 minutes total time is the maximum you should be doing at the faster end of this range even if you are a very high-level runner. Remember the goal isn’t to see how “hard” can I train, it is how “easy” can I train and still get the targeted stimulus leaving me fresh for the next session

How are the Short Intervals structured?

My Short Intervals are typically prescribed at 1500m (neuromuscular power) or 3000m (speed endurance) pace. Therefore choose a surface where these paces can be targeted. To get optimal stimulus training at the “right speed” is more important than the “right distance” and therefore I prescribe these sessions in time duration (or adapt the distance to fit the target time). 

You’ll note that these paces are higher than the 5000m pace that is fairly typical in recreational training plans. I even incorporate very short all-out sprints in some of the workouts. These sessions focus on the development of base speed and running economy which is a foundation for maintaining a higher % of this speed in your races.  I have my thoughts on why this is important which I will explain in next week’s post, watch this space.

Contrary to what you might think, the workout stimulus occurs during the recovery interval, not the rep. This happens because your heart rate drops more quickly than at the rate at which previously pumped blood returns to your heart which stresses the heart chambers which in turn leads to an increase in stroke volume (take the recovery intervals as seriously as you take the work intervals!). 

The number of repetitions in a short interval session is prescribed as a recommendation. There is no magic in doing five or six or ten reps. What is important is causing an appropriate level of fatigue during the workout, as it is this fatigue that your body responds and adapts to. The number of reps at which I fatigue may change from week to week based on many factors (e.g. the training I did in the days before the workout, the amount of sleep, quality of nutrition, daily variation in performance, changes in fitness, etc.,). 

You may experience the same level of fatigue today after ten reps and next week after eight (or vice versa). You should always walk away from a session feeling like you are in control of the workout rather than feeling the workout is controlling you!

What About Rest/Recovery

When we think about recovery between repeats, what comes first to mind is how long it is and whether it is jogging or standing. As you might expect, we can go far beyond this simple dichotomy and look at many ways to vary recovery. Coaches then separate them into adjustments by length or style.

Adjustments to the length of the recovery should be self-explanatory, but most of the time people think of it only in terms of recovery between repeats. Instead, we can also vary the recovery by breaking the workout into sets and having a much longer recovery between the sets than we would have between reps. Having a long rest between sets, we can get the best of both worlds and challenge the athletes with shorter recovery, while ensuring that we can get an adequate volume of work done by inserting relatively longer breaks in the middle of the workout. Breaking workouts into sets is a great way to introduce a workout, with the goal over the next several weeks of being able to work down to doing the workout with no set breaks. For example, working down from three sets of 3 x 800 with 90 seconds rest with five minutes between sets towards 9 x 800 with 90 seconds rest by the end of the block.

According to coaching praxis, the way we vary the recovery impacts the workout demands and the subsequent adoption. If we shorten the recovery the aerobic demands of the workout increase. While this may seem counterintuitive, it occurs because there is no time for our anaerobic systems to recover between repeats. If instead, we had a longer recovery, we’d have time for our anaerobic system to recover and fire back up, as well as our phosphagen system. At the same time, especially if it was standing rest, our oxygen consumption and heart rate would drop, meaning that we’d need to spend the beginning of each repeat burning through our anaerobic system as we waited for our aerobic system to fully kick in gear. So recovery length manipulation not only matters in creating stress on the system but also determines what system is stressed. 

To start with the jogging versus standing question, the answer depends once again on what adoption we are seeking. As I mentioned above, the praxis is if we jog, we keep heart rate, blood flow, and oxygen consumption elevated. So it creates a situation where the aerobic system doesn’t go from fully engaged to resting as quickly, therefore making each subsequent interval more aerobic. Additionally, because they increase circulation, the body gets to work on the clearance and removal of fatigue byproducts during the rest. If we had standing rest, we’d create a situation where blood would pool more, so we’d accumulate more fatiguing products going into the next interval. So this might be a better option when we are looking at adapting to the accumulation of fatigue or from a physiological standpoint if we were looking at disrupting someone’s rhythm running ability. 

Inside the research community, there are some question marks on how important these differences in recovery interventions are. I’ll stay on the fence. Quite often experienced coaches see the impacts these factors have on their athletes even when what they believe to be the reason can’t be proven by the scientists based on the markers they are analyzing. Simply said, with style adjustments, we change how the recovery is done. The classic debate would be whether to stand or jog, but the reality is that there are a slew of speeds between jogging and very fast running, but still slower than repeat pace

We can take this a step further and look at making the speed of the recovery more defined. Instead of specifying that an athlete simply jog, we can look at faster speeds that may shift the emphasis to being able to recover while still working fairly hard. For instance, if running repeat 800s at LT2 pace, we might include a 400-meter recovery at a pace that is just a little slower. Now, during the recovery, the body would have to build up fatigue during the repeat and be barely slower than our lactate threshold. So, we’d be forcing our body to try and clear out the fatigue while it’s still working at a highly demanding aerobic speed. The fact is, for every subsequent repeat we have ever-increasing lactate levels being thrown into the body, and we wouldn’t be able to clear things out very much on the recovery, so we’d get used to dealing with ever-increasing fatigue. On the other hand, if he wanted to work on maximizing clearance, we might use a pace that is around marathon pace, so it’s slow enough that we aren’t at a steady state yet but fast enough that the aerobic system is fully revved up. The recovery run paces you can use are almost endless, from just slower to the repeat down to a sprinter shuffle/walk.

But if all that is just “too much” then perhaps the most important thing of all is to make it fun – make it a session you want to do. Micro adjustments will have no impact if you don’t get out there and do the work! 

We will take a break over the Easter weekend. The next post is on the 7th of April.