Duration versus Distance
As a coach, I often get asked why I prefer training using duration instead of distance as my preferred training method. It’s a very valid question, as all the gold standard in endurance training used to be distance based. There are still athletes and coaches who believe distance training trumps duration.
But times move on as does the research and science in our sport. The reason why athletes are performing near superhuman efforts has many contributing factors, from carbon plated shoes to better nutrition, although in my opinion, the big one is a rethink of training methods and practices.
So, why duration and not distance? Duration is a measure of how long the workout is based on time, not distance. We tend to think in terms of distance because our races are measured in distance. An athlete typically tries to determine how long it will take him or her to finish a race of a certain distance when training and preparing for the race. The point I want to make with you here is that it’s the race time, not the race distance, that is critical to success. So, you need to think in terms of duration, not distance in training.
Here’s the simple explanation:
With rare exceptions, all my workouts as an endurance coach are on duration, not distance. The reason is that the intensity of a workout is specific to its length in time, but not necessarily to its distance. Let’s explain that in a few examples:
If Runner A and Runner B both run a 10km race, with Runner A finishing in 30 minutes and Runner B in 60 minutes, with both runners running hard, their running intensity would not be the same.
Runner A is working at a much higher V02 max intensity.
If both Runner A and Runner B would now run hard for 30 minutes, they would likely be in the same intensity category. One runner would simply cover more ground than the other.
Here is another example:
Let’s say you’re going to run an ultra-distance road running event such as The Comrades Marathon. The route is undulating with a few bigger climbs scattered in-between. You have trained to do it at a given intensity with a specific time in mind. You’re fit and ready. But it just so happens that on race day it’s extremely hot. The race will now probably take an additional X number of minutes or hours to complete. What should you do about how intensely you will run? Should you keep it as planned or slow down? After all, the race is still 89 kilometres long. That hasn’t changed. Or should you reduce the intensity since the duration will be longer?
The answer is to reduce the intensity. The intensity is always directly related to duration, not distance. If you would keep the intensity the same despite the hot conditions, you will fade badly in the later stages of the race and have a terrible run as a result.
The bottom line here is that intensity is inversely related to time. This means that as one increases, the other decreases. As the time of a race or workout gets longer, the intensity at which you are working is reduced. It’s obvious. You can’t run a marathon at your 5-km pace. You run slower in the marathon because you must run for a longer time.
A 30-minute 10-km racer and a 60-minute 10-km racer are essentially not doing the same race, and thus they shouldn’t train the same way either. In the same way, if the Ultra marathon race will take longer due to the heat, then you must race at a slower pace.
Switching from tracking distance in training to duration places the focus on effort rather than how far you go. That is consistent with our understanding that the body does not know distance, but it does know stress, which is caused by intensity and the duration of the intensity.
This was a long way around of simply saying that the intensity of your workouts and races is more closely tied to their durations than to their distances. Workouts need to be thought of the same way. Train for duration, not distance.
