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The Case for Abandoning Continuous Aerobic Training

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
Click on the image to access the article ‘Physiological adaptations to interval training and the role of exercise intensity’ by MacInnis and Gibala, 2017

(See the image above for all the glorious detail)

As I expect from all you astute military readers, you are now asking: so what? Well, for the same or 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.


About the author: Calen Thomas has a both a bachelor of Physiotherapy and of Applied Science (Human Movement Studies) with honours, majoring in Exercise Science. Before joining Army in 2015, he worked in a strength and conditioning role with the QLD Reds and Australian Rugby Union Academy as well as in a sports trainer role with South’s Rugby Union, Brisbane. Calen is a keen advocate of rehabilitation and return to high performance activity and the modernisation of Army Physical Training.

10 thoughts on “The Case for Abandoning Continuous Aerobic Training

  1. Question: How can one increase aerobic capacity if one doesn’t train in the Aerobic level?

    – Humans have adapted to conduct sustained aerobic activity in order to hunt/gather with the ability to conduct sustained activity over long periods of time working within the aerobic energy system (walking and jogging).
    – Humans have adapted to conduct short high intensity bursts require for hunting and combat utilising an anaerobic energy system where lactic acid is a consequence for sustained bouts of working at high intensity without oxygen (sprinting/fighting).

    Combat conditioning requires the tactical athlete to be able to do both. The tactical athlete must be able to conduct extended aerobic activity as a means of getting to the target objective to then conduct periods of high intensity activity for a brief period of time, to then return to sustained aerobic active to move off the target. Through training we make these tasks possible. If we neglect to train within aerobic zones we ultimately leave ourselves unable to conduct the required tasks being sustained aerobic activity. Ultimately it doesn’t matter how fast your can run if you need to continually stop to recover (even if the recovery time is short) and clear lactic acid build up when you need to move on or off the target.

    The tactical athlete MUST not be concerned over numbers such as their VO2 max but must be concerned about their ability to perform required tasks. The ultimate solution is to modify the current ADF thought process of physical activity to adopt the science which is already there giving training the greatest bang for buck. This means more individualised approach to fitness, training with the use heart rate monitors to ensure we are working within the targeted zone being conditioned, and ensuring activity being trained meets the end requirement i.e. long infils, periods of manual labor, periods of rapid high intensity movement (under fire) and significant high strength tasks (moving heavy large objects). This is not being achieved through interval sessions on the oval clean skin, or 40 minute circuits in clean skin.

    1. Heart rate monitors are not necessary.
      Given the ample evidence available that suggests that anaerobic conditioning can improve both anaerobic and aerobic systems, wouldn’t improving the system we don’t train be of more benefit?
      You’re suggesting we should get more bang for our buck and that, as the studies show, is clearly anaerobic training.

      Yes, training in full kit would be great, but the injury risk is not worth the benefit to switch to an entirely kitted training model.

      The Army needs to find a way to train strength and power within the confines of large group exercise, yes, but running long distances daily won’t ever help that.

      The paradigm needs to change, we can’t be a big bench, long run army if we want to be an elite, well conditioned fighting force.

    2. Hi Patrick, thanks for the questions, here are some of my thoughts:

      Training above the anaerobic threshold does in fact result in aerobic adaptation as no system works in isolation and the anaerobic system supplies energy above and beyond the max output of the aerobic system. The research consistently backs this up (See the systematic review linked in the body of the text above).

      However interval training doesn’t only have to occur in anaerobic exercise intervals and in fact Maximal Aerobic Speed (MAS) interval training and even the Tabata method (applied correctly) is a fantastic way to develop this aspect of fitness, and is more efficacious than continuous training for conditioned athletes (see Dan Bakers paper below).

      https://simplifaster.com/articles/implementing-high-intensity-aerobic-energy-system-conditioning-field-sports/

      This is not an argument against all aerobic fitness, just a thought on how we can achieve superior, more efficient and safer outcomes. That is why I don’t argue against the need for a level of aerobic fitness for a soldier, but rather that it is not specific or efficient to achieve this through continuous aerobic training. But the aerobic and muscular endurance needs for in-fil/ex-fil and pack marching can much better addressed with…pack marching, which should absolutely be included in the programming as discussed in my last article. Nothing except load carriage can optimally prepare someone for load carriage. But clean skin conditioning and gym based strength training will absolutely transfer through to combat specific demands.

      A key factor in all of this is load management for our soldiers, and conducting all running/conditioning sessions in patrol order will increase risk rates of overuse injury due to the total load increases, periodisation is a fundamental principle of strength and conditioning and so high demand activities can be programmed to peak and taper when required.

    3. Patrick – your post is worth more discussion, however, over the years we have not been patient enough to follow this through. The PT Manager at ADFA going back several years now had a program based around HR based training and working in conjunction with Dr Rob Orr had the one of the lowest injury rates in a long time coupled with superior fitness……..the problem, it is not sexy and people power won out at the expense of a very good program and PTI. We currently use HR training in the WII space with very good results and I have used it to train individuals for a wide variety of roles over the past 25 years. I still run faster than 95% of soldiers 20 years younger with 85% of my training aerobic – I say this not due to ego, but as a point that for longevity, we do not need to be red-lining every day. I rate Calen’s articles and they have some very good points – what it is doing is raising discussion on one of the most important aspects of our craft. Cheers.

  2. No doubt that heart rate monitors and even tools such as gps monitoring of running loads offer fantastic insight to pro teams. However I can’t see them realistically implemented or funded within Army.

    Who would collect the data? Who is qualified to interperate it and individualise it? What would be the ongoing funding liability? Would it add significant value when there is research to suggest that subjective reporting methods such as session Rating of Percived Exertion (RPE) can provide good insight into intensity and load management at a fraction of the cost.

    More to follow in future articles on tracking work loads with session RPEs and balancing chronic vs acute work ratios to reduce injury risk and maximise performance.

    1. All valid points. When a knee reconstruction costs 30-80k (est including work days lost), a few thousand for some HR monitors is minimal. The PTIs that I trained and worked with were more than qualified to interpret the data. Get them doing what they were trained to do working in conjunction with trained health professionals (physics). Agreed that RPE is effective and HR monitors are not required…..all of the time. They are a tool that is very useful for the detrained or injured member who does not know their fitness well. Also a great reality check when I put one on someone who thinks they are super fit and can’t run 20mins at less than 160bpm.

  3. Morning Simon,

    Acknowledged on the cost of injury, that’s one reason I advocate for the need to make changes to training as we can have a huge impact there; but as the vast majority of injuries resulting in the need for Knee reconstruction generally result from twisting/change of direction/jumping activities I’m not sure what value HR monitors would add in preventing those. They are far more suited to managing training loads rather than acute injury risk reduction, and as discussed this can be done through tools such as RPE.

    WRT PTIs monitoring the data, that is a great option at training institutions or SRCs where you have the funding/manning and training environment to do so, but I don’t think it could be as easily done for every Battalion in FORCOMD, noting that almost none of them have PTIs directly attached to them, and that PTIs are responsible for monitoring a number of Battalions, with the day to day work conducted by CFLs (I’m sure you are well aware of that but I note it for the benefit of other readers).

  4. PT in the army needs to change, we can all agree to this. My thoughts on this are a multi angled approach.

    1. PTIs need to grow with the times. We all witness PTIs stuck in old school methods of training. We all can bare witness to having done the exact same PT session over the years and we have all read and seen evidence demonstrate that what we were doing 10 years ago isn’t what we should be necessarily doing now. Some PTIs have adopted their sessions but many have a long way to go. The old ‘smash’ sessions are generally the cause of the most injury, and as we all know, every soldier is not at the same fitness standard, so individuals will have different outputs at their own 60, 70, 80, 90 and 100%. This is where the use of heart rate monitoring is one device capable of assisting members identify this level (not the only, but a very simple method).

    2. Education of soldiers on fitness needs to be dramatically increased. Rather than having PTIs and CFLs as the only people ‘qualified’ to be educated on fitness and run training and develop programming, we need to see further education to the individual soldier improve. If soldiers were able to understand fundamentals of fitness they too would be able to take control of their own conditioning. This would ultimately pass on responsibility to the soldier (and probably be a morale boost).

    3. Increase the time available for soldiers to conduct training. Currently most support staff in various support units are only able to get 3 days a week of scheduled PT. Soldiers who have family commitments, are currently studying and have significant commute times to and from work are generally unable and to conduct PT in their own time and frankly not motivated to do so. For us to create a ready, healthy and physically superior army we need to have DAILY PT.

    4. PT programming needs to be based around the task at hand, and not individual goals. This means PT must be based around development of the combat machine. This can be broken down into a few key areas:
    – The combat chassis – Strong core, this ultimately protects the body from injury in the dynamic environment. This translates to the ability to safely move awkward loads, to protect the spine from compression during high impact activities such as parachuting, etc.
    – The well developed motor – A heart that is strong, solid aerobic and anaerobic capacity to conduct long patrol movements, along with the ability to rapidly bound during fire and movement.
    – The ability to produce powerful actions – To move heavy objects quickly and efficiently, to fight.
    – The ability to provide continuous manual work – Work parties, how many times have we seen individuals fall out from doing manual laborious task? To dig pits, to move stores, to fight, etc etc.
    These are what the modern soldier needs to be able to do, not play competitive sports, not rack the highest 1RM, not perform on the stage in budgee smugglers. Programming must be created around the missions required with emphasis of what that soldiers job required. For an infantryman (and support staff embedded within a platoon), this ultimately will mean being able to walk a long way, with a lot of weight, conduct a period of heightened activity, followed by manual labour and finishing with a lengthy walk out with equipment. For a clerk, well this might just be maintaining a base level of fitness.

    I could write for hours on this topic however I think my point has been made. Education, technology, individualisation, increased time doing pt and specification will ultimately lead to the super soldier. But to end this point as stated before, this is something that will take time, and cannot be rushed. Soldiers MUST be given the time to develop this level of fitness and by expecting too much too soon and going too hard out at the start WILL lead to injury.

  5. Patrick, you raise some good points surrounding the need to bring both PTIs and soldiers up to date with current research as well as conducting specific training based on their required duties. However, I think that these points can be summarised better.

    Current research – What it really comes down to is: What is the best way to gain an accurate assessment of external load (the activity or exercise performed) and internal load (how the body responds to said exercise). HR zones are one way to see internal load, however it is quite individual and does not accurately portray intensity. A better internal load is RPE (yes, this has it’s weaknesses as well, but can be tracked over time to identify abnormalities).

    Specificity – heavy resistance training (racking the highest 1RM) is actually a fantastic way to adapt the soldier for what they need to perform in your list: strong core (high levels of EMG activity through lumbar multifidus with both back squat and deadlift), well developed motor (see Calen’s other articles for references to increases in running economy with strength training), the ability to produce powerful actions (self explanatory) and provide continuous manual work (higher strength levels means that a given activity is performed at a lower relative capacity and therefore less fatiguing). Combining this with HIIT and SIT when periodised appropriately (i.e. modulated load) results in a greater ability to generate aerobic power, anaerobic power, muscular strength and muscular power…all the things that a solider needs. Performing continuous aerobic training results in reduced muscular strength and an increase in type I muscle fibres, which is detrimental to performing manual work and heavy load carriage. I agree that performing on the stage in budgees does not translate well to performance, but bodybuilding is a sport and should not be confused with weightlifting and developing high levels of strength.

  6. As a soldier of over 34 years service, I have been indoctrinated into aerobic training. Now you can quote all the science you like. The graphs look great. It doesn’t change the fact that as a 51 year old soldier I can still meet the performance standards of a 25 year old and often finish ahead of soldiers half my age. Why, because through out my career, I have trained aerobically. Sure, there is a place for high intensity interval training, (we called it circuit training back in the day!), but to suggest that aerobic training is somehow old fashioned or of reduced value is to deny the performance of older soldiers who have used it. Or younger soldiers, whose fitness is often not at the standards we expect.

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