New VO2MAX Test Further Highlights Difference Between Trail and Road Running

New VO2MAX Test Further Highlights Difference Between Trail and Road Running

Last post I discussed the factors affecting trail running race performance and how they differ to road running performance greatly. Today I’m going to present some more information about how trail running and road running are different to one another using the example of a series of VO2MAX tests done by Scheer, Ramme, Reinsberger and Heitkamp (2018) on 13 highly trained trail runners.

 

If you’ve been paying attention up until now then you’ll know that VO2MAX means maximal oxygen consumption or the maximum amount of oxygen one can utilize to create energy during intense exercise. You’ll also know that VO2MAX makes up the one third of the classic endurance model which, in road running at least, is one of the key performance indicators of running performance. Research into VO2MAX spans back almost 100 years now – starting with work done by a physiologist (A.V. Hill) back in the 1920s. Since then, research on VO2MAX and evolution in practice has lead us to the treadmill VO2MAX test (using either the step or ramp protocol) which is/are the gold standard method(s) for measuring VO2MAX. Gold standard means that there is no better way to measure VO2MAX – and if you ever come up with another method of measuring (or attempting to measure) VO2MAX, you would have to compare your results to those of this gold standard. So this is where it gets interesting – what if the current gold standard method of measuring VO2MAX fails in it’s assumption? What if there was a better way of measuring VO2MAX? Is that even possible?

 

Currently there are two standard ways of performing a VO2MAX test, both of which are done in a laboratory, on a treadmill. The two VO2MAX test methods are the step and ramp protocols respectively. The step protocol starts with athletes running at 8.0km/h and every 3 minutes that treadmill speed is increased by 2.0km/h with a 30 seconds pause between each ‘step’ to measure blood lactate. The ramp protocol starts athletes off at 10km/h and then continuously increases treadmill speed by 1.0km/h every minute. Both the step and the ramp protocol take place at a 1 degree incline to better simulate over ground running conditions (bloody lab tests I tell you). That being said, let’s get back to the question I asked earlier – what if there was a better way of measuring VO2MAX? Let’s see what the latest research is telling us…

 

Scheer et al. (2018) subjected 13 highly trained trail runners (average weekly mileage 80 ± 27km/week) to both the step and ramp protocol VO2MAX tests with one week’s rest in-between. Thereafter, they designed and subjected these runners to a third (new) VO2MAX test which started at 10.0km/h and continuously increased speed (0.5km/h) and incline (1 degree) per minute with incline starting at 0.5 degrees. They called this VO2MAX test the trail running protocol. To make sure that training effect didn’t bias the results (i.e. I get better results in my 3rd VO2MAX test because in the two weeks prior I ran two other VO2MAX test which made me fitter), the runners were randomly assigned the order that they would complete the three tests (split by one week for three consecutive weeks). Here’s what they found:

 

  • On average, the trail runners achieved a significantly higher VO2MAX value on the trail test (62.5 ± 5.9ml-kg-min) compared to the ramp (59.7 ± 5.5ml-kg-min) and step protocols (60.1 ± 5.3ml-kg-min).
  • On average, the trail runners’ circulating blood lactate was significantly higher 3 minutes after the trail test (9.6 ± 2.2mmol-L) compared to the ramp (8.4 ± 2.2mmol-L) and step protocols (8.8 ± 2.3mmol-L).
  • On average, the trail runners took a significantly quicker/shorter time to reach exhaustion (one of the requirements of a VO2MAX test is that you reach exhaustion) (557 ± 73sec) compared to the ramp (605 ± 95sec) and step protocols (1378 ± 152).

 

Importantly, the only variable in which the ramp and step protocols differed significantly as well was in the time to exhaustion variable.

 

So here’s the crux of the matter. We assumed that the VO2MAX test in its current format (ramp or step) was the gold standard test for measuring VO2MAX amongst runners – but these results clearly show that it isn’t. Once again, we are limited by our inherent bias that we have which is towards road runners and road running performance. This series of tests has shown that for trail runners – who are specifically adapted to trail running requirements – there is a better method of determining VO2MAX. As such, if you compare a trail runner to a road runner based on a step or ramp protocol – you are setting yourself up to failure because of design bias. Scheer et al. (2018) suggest that adding the factor of increasing incline to the VO2MAX test would make the test more specific to trail runners, because of the sample trail runners’ specific neuromuscular, biomechanical, and physiological adaptations that they have accrued through many miles of mountain running. They were right. To explain this further Scheer et al. (2018) highlight that while road runners require repeated, consistent muscular contractions, trail runners have much more variation in gait, including prolonged and intense muscle contractions when going down and uphill. These trail runners have become adapted to the large peaks in ground reaction forces when pushing off while running uphill, as well as to the repeated braking forces required when running downhill.

 

It’s really no surprise why the trail running protocol took the quickest time to exhaustion amongst the groups either (the ramp takes quicker than a step because you start at a faster pace and there is no pause for rest), because glycogen depletion (yes that’s the stuff that provides us with energy when we run) is much higher when running uphill than in level running. Additionally, our glutes, quads and calves are recruited to a greater extent when we move ourselves uphill. Both of these factors culminate in an accelerated time to exhaustion when completing the trail running protocol. While no information was offered by Scheer et al. (2018) for the significantly higher level of blood lactate within 3 minutes after the completion of the trail running VO2MAX test (this is also measured to ensure that that each VO2MAX test is in fact maximal), I hypothesize that the greater activation of these large muscle groups might have a factor to play here.

 

In closing, referring back to the question in my title, “Trail Running vs Road Running: What’s The Difference?” I hope that I have provided some more evidence to you about the difference between the two sports. No longer can we assume that what is right and true for a road runner will be right and true for a trail runner. Runners adapt mechanically and metabolically to the type of running that they do most often. If you trail run more often than you road run, you are likely to develop specific trail running adaptations and as such, I should not test you and measure you on the yardstick of a roadrunner. Scheer et al. (2018) showed us that we should never rest on our laurels, and assume that just because something has been done the same way for a very long time, that it is the best and most accurate way to measure a given variable. If VO2MAX is an important factor in running performance (regardless of surface), it’s important that we measure it accurately – and trail runners should be encouraged to perform the trail running VO2MAX test to get the most accurate reflection of their oxidative capacity.

 

References:

 

Scheer, V., Ramme, K., Reinsberger, C., and Heitkamp HC., (2018). VO2MAX testing in trail runners: Is there a specific exercise test protocol? International Journal of Sports Medicine. 39 pg 456-461.

 

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