I'm writing this as a follow on from my last article, published here recently. This raised a few eyebrows and some great discussion surrounding the exclusion of aerobic training, or continuous/long slow distance (LSD) training in particular, from military physical training programs. Many were sceptical of this and argued the need for aerobic training or even the primacy of it.

This has been discussed in the office over the last few weeks and there was finally enough momentum generated for me to venture forth my opinion again (and sacrifice some lazing around time) when an esteemed colleague of mine highlighted a symposium review paper by MacInnis and Gibala (2017) which covers the topics of physiological adaptation to differing exercise intensities. So while my position is not to dismiss aerobic training altogether, I thought I would take the time to discuss in more detail my argument for interval based training – primarily in the anaerobic intensity spectrum over traditional aerobic and LSD training which is so prevalent in our Army today.

What peaked my interest in this paper was that both High Intensity Interval Training (HIIT) and Sprint Interval Training (SIT) once again trumped continuous training at its own game – aerobic adaptation.

HIIT and SIT are both methodologies involving repeated bouts of high effort intervals interspersed with recovery times; with HIIT generally conducted at 85- 95% of maximal heart rate, and SIT at 'all out' or supra maximal efforts. This can be periodised, progressed and tailored through modification of work vs. rest times, number of efforts in a session, and frequency of sessions in a week.

The studies reviewed focused on the impact of training on VO2 max and muscle mitochondrial content. VO2 max is the maximum rate at which you can consume and use oxygen during exercise (the most common measure of aerobic ability) and mitochondrial are the engine cells of muscles, responsible for the recycling of the fuel used for energy production.

When compared to continuous training, the findings were that:

  • Both VO2 max and mitochondrial content are increased more by HIIT for the same training volume
  • Both VO2 max and mitochondrial content are equally improved by SIT for less training volume

As I expect from all you astute military readers, you are now asking: so what? Well, for the same of less amount of time on feet you can achieve better aerobic fitness adaptations with interval training; and it provides a whole slew of additional benefits, not specific to aerobic fitness, for instance:

  • Increased anaerobic fitness - the ability to recover quickly from repeated bouts of hard work, for example fire and movement during an attack.
  • Beneficial crossover to concurrent strength training - continuous or endurance training tends to impede strength gains.
  • Easily measurable and individually programmable - meaning less chance of overuse injury and stagnation.
  • Provides excellent baseline fitness specific to sport - improved conditioning will reduce injury risk in sport which is a large part of the ADF health burden.

Finally, this would be performed in conjunction with external load carriage training which will provide the specific stimulus needed for loaded marches and fill in any low intensity long duration fitness gaps. As always I welcome robust debate as I am passionate about the continuous improvement and professional development of strength and conditioning for the military.