The run-walk method is nothing new to running, and a lot of its notoriety can be credited to legendary running coach Jeff Galloway. However, I struggled to find not only the scientific reasoning behind the run-walk method but also any data on runners going under 3 hours using this method. Personally, I have successfully used the run-walk method to run a 2:55 marathon the day after riding 190km as part of my build-up for Ironman. After that experience, the seed was planted for this experiment.
What is Run-Walk?
The method works as the name suggests, you run for a period then walk for a short period to recover and delay the onset of fatigue. The theory suggests that you’ll be able to run faster at the end of the race and thus have a faster overall finishing time than if you had tried to run the whole time and were forced to slow down at the end due to fatigue.
The Science of Run-Walk
Running requires the brain to send neurological impulses to the muscles that are needed to propel you forward in a running motion. Both these neurological signals and the muscles they activate can become fatigued if they are used continuously for extended periods, as they are in a marathon. Therefore, if we can break-up this continuous recruitment pattern by interspersing our marathon run with short walking breaks, we should be able to maintain our pace for longer due to delaying the onset of fatigue.
Our cardiovascular system can also become limiting because as we fatigue we require more muscles and more oxygen to do the same amount of work. Our cardiovascular system can then reach an upper limit to transport enough blood to the working muscles to supply enough oxygen and nutrients. Not only that, if we are in a hot environment, then we lose a lot of fluid (sweat) and reduce the volume of blood we have. As a result, our heart rate must go even higher, and our body is strained even more. In this regard, walking will not only help us maintain our core temperature and reduce the loss of fluid through sweat, but it may also give the cardiorespiratory system time to catch-up to the ever-increasing demands of the working muscles. All these physiological systems play into the power and benefits of the run-walk method. Think of it as a marginal gains approach, every little bit helps.
What’s the Catch?
You need to run faster to make up for the walking breaks. This becomes more and more important the faster you run and is the main reason you won’t see a lot of fast runners using this method. If you’re aiming for a 4-hour marathon, your average pace is 5:41min/km (9:08min/mile). If you were to run 14min and walk 1min, you’d need to be running 5:29min/km (8:50min/mile). In speed terms that’s not a big jump. However, I want to run at least a 2:39 which is an average of 3:46min/km (6:03min/mile). If I’m to run 14min and walk 1min I’ll need to be running 3:36 (5:48min/mile) and at that speed that is a big jump! Especially for 42.2km. This is where the mathematics of how long to have each run-walk block become very important. Galloway has suggested 6min and 30sec for those who want to average 4:20min/km (7min/mile). However, I’m not convinced that is enough time to reduce the load on all physiological and biomechanical systems in play. This why I’ve come up with the table below;
At a run-walk ratio of 19-1, I believe there is adequate opportunity to get all the benefits of the run-walk method as well as still being able to run fast. I’m going to put my money where my mouth is and compare the run-walk method to a non-stop run in two of my upcoming marathons. In the first race, the Hawkes Bay Marathon (13th May), I’ll use the run-walk method and in the second race five weeks later, the Wellington Marathon (18th June), I’ll run non-stop. Both courses are similar in elevation but differ in terrain and weather. To try account for these variations, I’ll use a stryd running power meter which will be able to give me an independent measure of output rather than just finishing time.
there are points where it will be quicker for faster runners to abandon the 19-1 run-walk for a faster time; 1. Headwind and the opportunity to run in a pack. Because of the speeds, faster runners are travelling the impact of wind resistance is far greater so getting to draft behind other runners will be more beneficial. 2. The last quarter to? of the race. By this stage, you have done as much work as possible to delay fatigue, and the process of transferring momentum from run-walk-run may be more costly than pushing through until the end. 3. Downhills. If there is a large downhill in the race that falls during your walking break, it’s better to continue the momentum and walk at a later stage. 4. Aid Stations. If the aid stations are within 2-3min of 19min, then it’d be better to walk through those rather than run through spill all your nutrition and walk a minute later.