The topic was aerobic and anaerobic metabolic contributions to performance and how athletes should train for their sport. The class was exercise physiology. High school wrestlers were used as the example to make a point.
A typical wrestling workout (at least at that time) was jogging for miles before or after practice.
The professor argued that because wrestling matches are short in duration and exchanges within those matches typically consist of short bursts, the sport is anaerobic in nature and aerobic training therefore had little to no impact on performance. Instead, sprint workouts or other high intensity interval training methods mimicking the time constraints of a wrestling match were more appropriate training methods (so it was said).
Weeks before then, however, we had learned that anaerobic metabolism kicks in only after the aerobic system has been “maxed out.” A fair comparison may be to a hybrid car: once the electric motor is tapped out and the car needs more juice, the gas motor kicks in.
Wouldn’t it make sense, then, that the bigger the electric motor, the less work the gas one has to do?
We had also recently discussed the concepts of oxygen debt and excess post-exercise oxygen consumption (EPOC). A bigger aerobic engine should, theoretically, make up that debt faster than a smaller one. Yet, there seemed to be something that made a certain amount of intuitive sense about the basic argument: how does jogging slowly help a wrestler in a two-minute bout?‘How does jogging slowly help a wrestler in a two-minute bout?’ asks @KD_KyleDavey. Click To Tweet
Indeed, the debate persists today. A prominent strength coach recently tweeted his position that a cardio base is overrated, and strength coach Twitter did what strength coach Twitter does and talked about it for a few days. In the wake, another prominent voice asked if walking counts as cardio, and the engagement was comical.
Which is it? Does “cardio” count? Should team sport athletes ditch aerobic training altogether, prioritize it, or somewhere in between?
In we go.
Transference: The Only Principle that Matters
The goal of training is simple: to improve sports performance. It is not to make athletes sweat, to become an elite technician in the weight room, or to mimic sport itself. These may very well be means to the end of improving sport performance, but let us not forget that they are indeed means to an end and not the end itself.The goal of training is simple: to improve sports performance. It is not to make athletes sweat, to become an elite technician in the weight room, or to mimic sport itself, says @KD_KyleDavey. Click To Tweet
Let us also move away from the notion that fitness testing and training must always resemble sport. Testing that does resemble sport may very well be warranted, but that does not mean fitness testing which does not resemble sport is always unnecessary.
The purpose of testing is to evaluate a particular quality; 1RM tests quantify maximum strength and aerobic tests assess the robustness of the aerobic system.
If we believe that maximum strength or aerobic health influence performance in a particular sport, periodically evaluating those qualities via testing is appropriate, even though standing up with a loaded bar across your traps isn’t an activity you’ll see on the field or court of play.
The degree of similarity between a training method and actual gameplay is not informative of how that training stimulus may impact gameplay. The fact that walking uphill on a treadmill at 140 beats per minute doesn’t remotely resemble a football game is not evidence that such activity will not improve player outcomes.The degree of similarity between a training method and actual gameplay is not informative of how that training stimulus may impact gameplay, says @KD_KyleDavey. Click To Tweet
It is also certainly not evidence that it will. The point is to think critically and reassess the eyeball test. While we’re on the topic—if long-duration isometrics are back in, are wall sits cool again?
Asking Better Questions
As mentioned earlier, when a prominent strength coach stated on Twitter that a cardio base is overrated, strength coaches went nuts. It is telling that some agreed with the statement while others vehemently disagreed. Perhaps this is the next frontier of fitness ideology.
Rather than scoff at the statement, I believe a better approach would be to ask oneself “what about this coach’s experience has led him to believe this is true?” Perhaps he has only worked with high level athletes who were gifted aerobically, and thus never saw a need to train it. Perhaps his training methods are so successful without incorporating cardio that he feels it unnecessary. Or perhaps he meant exactly what he said and nothing more: that he simply finds it “overrated,” which of course does not mean unimportant or irrelevant. Football players are not triathletes, after all.
How may aerobic training and adaptations impact team sports performance? Indeed, research has helped us answer this question, but let us not skip the thought experiment. In addition to research, let’s think.
My exercise physiology professor constantly challenged us to provide a “physiologic rationale” for our positions and thoughts. A physiologic rationale is a justification for why a thought could or could not be true based on physiology.
What might a physiologic rationale look like for the statement “aerobic fitness impacts anaerobic performance”?
Primary Aerobic Adaptations
To answer that question we must first understand basic physiology. The “big rock” adaptations to aerobic exercise are as follows, in no particular order:
- Increased capillary density
- Eccentric cardiac hypertrophy
- Increased mitochondrial density
- Increased aerobic enzymes
- Increased vagal tone
It is easy to see how each of these factors (outside of vagal tone, which has indirect implications) directly influence VO2 max and aerobic performance. With a little thought, we can also see how they benefit anaerobic performance.
Increased capillary density allows for more oxygen and glucose to be delivered to working tissue, and for more waste products to be removed. Although anaerobic metabolism by definition does not involve oxygen, glycolysis does require glucose. Further, as muscle tissues hypertrophy and become more physiologically demanding, delivery and removal demands would seem to increase as well.
Eccentric cardiac hypertrophy allows for an increase in stroke volume and greater cardiac output. More blood flow = more nutrients delivered. Couple this with increased capillary density, and blood flow delivery capacity significantly increases. Additionally, what I feel is often overlooked is that eccentric cardiac hypertrophy allows for a lower heart rate during submaximal work. In effect, it helps delay fatigue during fast but not all-out efforts that tap into anaerobic resources.Eccentric cardiac hypertrophy allows for a lower heart rate during submaximal work. In effect, it helps delay fatigue during fast but not all-out efforts that tap into anaerobic resources, says @KD_KyleDavey. Click To Tweet
Mitochondrial density essentially refers to how many mitochondria are in your muscle cells. Density is technically the absolute number of mitochondria in relation to the size of the cell (hypertrophy), but that’s somewhat of a technicality in this discussion as we’re really chasing greater absolute mitochondria numbers—we’re not seeking an increase in density via atrophy.
In any case, mitochondria are classically known as the “powerhouses of the cell.” More mitochondria allows for more ATP production via aerobic metabolism, resulting in greater ATP production capacity overall. Aerobic enzymes catalyze aerobic metabolism, so the more of those that are around, the more aerobic metabolism is available.
If more ATP is produced aerobically, less must be produced anaerobically to accomplish the same output, thus sparing anaerobic reserves. Consequently, metrics like maximal aerobic speed (MAS) are, to state the obvious, heavily influenced by these aerobic constituents.
Aerobic Contributions to Anaerobic Performance
MAS is fine, but how exactly does increased capillary and mitochondrial density help athletes jump higher, and why would eccentric cardiac hypertrophy improve a sprint time?
Well, I’ve contradicted myself, haven’t I?
Aerobic health does not directly improve maximal performance. Let me be clear: aerobic fitness will not directly improve your sprint speed or jump height.Let me be clear: aerobic fitness will not directly improve your sprint speed or jump height, says @KD_KyleDavey. Click To Tweet
If you had a genie in a bottle and were immediately granted a doubled aerobic capacity, your 40 time would not instantaneously drop, but the speed at which you run a fade nine plays into a two-minute drill would be significantly better than otherwise. You might actually look fast still, instead of looking at the sideline tapping your helmet, or pretending your route was a three step stop instead of a 50-yard sprint.
Indeed, research has shown us that aerobic health is highly related to repeat sprint ability (RSA), or the ability to run fast over and over with minimal decrements in speed.1-6 It is established that the presence of oxygen is required to resynthesize phosphocreatine (PCr) stores,7-8 which is likely one of the primary mechanisms by which aerobic adaptations support repeated efforts of high output.
Thus, although “cardio” won’t directly help your 40 time (more on that coming), it could be the difference between being fresh enough to make the play in the 4th quarter, or coming up a half yard short and giving up the game-winning touchdown.
For a non-football example: aerobic fitness could be the difference between performing at 95% of your maximum capacity instead of 88% in the final seconds of the game. That 7% difference could be the difference between winning and losing, and that effect compounded over a season or a career could make or break a multi-million dollar contract, scholarship opportunity, or simply a lifetime of good memories and the confidence that comes with them.Aerobic fitness could be the difference between performing at 95% of your maximum capacity instead of 88% in the final seconds of the game, says @KD_KyleDavey. Click To Tweet
What I’m saying is that aerobic fitness prevents fatigue from setting in, thus delaying fatigue-related performance drop-offs. And to again drive the point home: say an athlete runs 10 sprints with 30 seconds of rest between each; the more aerobically fit they are, the closer in time the first and last sprint will be. The less “in shape” they are, the slower and slower the sprints will get.
Training a Racehorse
This ability to repeat sprints is frequently considered as a fitness metric and performance outcome—and it most certainly is both—but put that principle into a training environment and we call it “work capacity.”
Certainly, volume drives results to an extent. I believe aerobic health plays a significant role in volume tolerance, and the ability to withstand high volumes of training is:
- Advantageous for driving adaptation; and
- Protective against injury.
I can’t point to a study to verify it, but something tells me that withstanding repeated bouts of high effort without breaking down mechanically or physiologically must contribute towards athlete health and injury prevention. Although not direct support for my previous claim, aerobic fitness has been shown to decrease injury risk during high‑speed running.9
Recovering between sets/plays is what allows athletes to maintain high levels of performance throughout, and indeed aerobic metabolism is what drives recovery.
When dealing with training constraints like time, recovery becomes a significant factor. For example, when accruing acceleration volume where an athlete may run up to 30 short sprints or more in a single session, recovery certainly becomes critical, as the goal is for all sprints to be at near maximal performance. Slow sprints are wasted ones.
Indeed, if one athlete tolerates just 10 short sprints before performance diminishes but another can conquer 30…do we not think this may play a role in athlete adaptation? If we can effectively deliver a powerful stimulus of 30 sprints vs. a relatively weak one of just 10, will that not deliver greater adaptation? I do understand this is nuanced, but rather than diving into the “it depends” scenario, in general, an increased work capacity is positive and allows for more intense training sessions to be positively received.
The minimal vs. maximally effective dose argument is at play here.
Beyond volume quality, however, is the ability to recover from a workout. Of course, adaptation (read: improvement) happens not during exercise, but afterwards, while recovering from the training session.Of course, adaptation (read: improvement) happens not during exercise, but afterwards, while recovering from the training session, says @KD_KyleDavey. Click To Tweet
Pat Davidson once posted that hanging out with people you like is probably one of the best forms of post-exercise recovery, and that post changed the way I thought. Optimal adaptation cannot occur while in fight or flight mode, so shifting away from a sympathetic state and upregulating parasympathetic activity is of paramount importance post-exercise. Laughing and breaking bread with people you like sets that stage.
Further, aerobic training both acutely and chronically upregulates vagal tone, making it easier to adapt to training.
Thus, aerobic fitness can not only increase the amount of high quality volume afforded to an athlete, it also makes it easier to adapt to that volume.
Greater dose + greater adaptability = greater outcome.
Going back to the genie in a bottle thought experiment: although doubling aerobic capacity won’t make you faster immediately, taking that new and improved work and adaptation capability into training over a year or a career may very well result in a faster you down the road.
Formula One Cars vs. Toyota Corollas
I believe this is also a Pat Davidson analogy. I noticed early in my training career that those with low training ages do not require as much rest between sets as those with higher training ages. Where a 21-year-old linebacker might very well need 3-5 minutes rest between sets, a 14-year-old in his first month of training might be fine with a fraction of that.
At first I was a bit perplexed by this. It did, after all, defy the guidelines I read in the CSCS textbook!
When a Formula One car guns it at full speed, it (and probably its driver!) are going to need a significant amount of maintenance and recovery before racing again. The car may need to go to the shop, the engine will need to cool, and the driver may need to re-collect himself as well.When a Formula One car guns it at full speed, it (and probably its driver!) are going to need a significant amount of maintenance and recovery before racing again, says @KD_Kyle Davey. Click To Tweet
But when you’re trying to beat the yellow light and you go pedal to the metal in a Corolla, there is very little consequence. Even if you hammered the gas for a solid 5-10 seconds on the freeway, the car and driver will be just fine.
So it is with training. Those with no engine can gun it and be ready to do so again very quickly. Those with big engines, however…
This basic premise provides two suggestions:
- As an athlete’s strength and power grow, so too should aerobic capacity.
- Aerobic capacity sets the stage for future development and success, and should be prioritized in youth athletes so the aerobic engine grows along with the anaerobic one.
Clean Up In Zone Two?
With aerobic robustness currently in the S&C spotlight, it’s not surprising that zone two training has seemingly re-emerged and is making the rounds.
Low intensity, steady-state training is not a novel concept. In fairness, I have not seen anyone claim it to be. Still, it is funny to see it making the rounds through the S&C circles when it is classically taught in physiology textbooks as one of the, well, textbook training methods for aerobic development.
I am happy the discussion is being had, but I do wonder if some will get lost in the weeds and go in too deep on aerobic training for power- and speed-based athletes. There is more to conditioning than low-intensity steady state exercise. Prescribing zone two training once or twice per week and hoping it will check all the aerobic boxes is wishful thinking. Tempo runs, training at and just above lactate threshold, and yes, even repeat sprints and oxidative work in the weight room all have a place on the curriculum. Guys like Joel Jamieson, Mark McLaughlin, and Alex Viada have excelled in this arena.
Beyond that, at the end of the day, field and court sports are indeed anaerobic by nature. Scoring well on an RSA assessment or a 30-15 intermittent fitness test does an athlete little good if he or she is simply not physically gifted enough to see the field or court in the first place.
For the sake of transparency, it is worth noting there is some research that shows little to no correlation between aerobic fitness and RSA,10-12 which partly begs the question: even if aerobic fitness does contribute to repeat sprint ability, by how much? That is a question I don’t believe is answerable at this point. I do believe it plays a significant role, but I can’t point to a percentage and say “aerobic fitness improves RSA by X%.”
As with all other training factors, balance and finding the lowest hanging fruit is key. Aerobic fitness deserves a seat at the table.
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1. Sanders, G. J., Turner, Z., Boos, B., Peacock, C. A., Peveler, W., & Lipping, A. (2017). Aerobic capacity is related to repeated sprint ability with sprint distances less than 40 meters. International journal of exercise science, 10(2), 197.
2. Aziz, A. R., Chia, M., & Teh, K. C. (2000). The relationship between maximal oxygen uptake and repeated sprint performance indices in field hockey and soccer players. Journal of sports medicine and physical fitness, 40(3), 195.
3. Bishop, D., & Spencer, M. (2004). Determinants of repeated-sprint ability in well-trained team-sport athletes and endurance-trained athletes. Journal of Sports Medicine and Physical Fitness, 44(1), 1.
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9. Malone, S., Owen, A., Mendes, B., Hughes, B., Collins, K., & Gabbett, T. J. (2018). High-speed running and sprinting as an injury risk factor in soccer: Can well-developed physical qualities reduce the risk? Journal of science and medicine in sport, 21(3), 257-262.
10. Castagna, C., Manzi, V., D’OTTAVIO, S. T. E. F. A. N. O., Annino, G., Padua, E., & Bishop, D. (2007). Relation between maximal aerobic power and the ability to repeat sprints in young basketball players. The Journal of Strength & Conditioning Research, 21(4), 1172-1176.
11. Aziz, A. R., Chia, M., & Teh, K. C. (2000). The relationship between maximal oxygen uptake and repeated sprint performance indices in field hockey and soccer players. Journal of sports medicine and physical fitness, 40(3), 195.
12. Rodríguez-Fernández, A., Sanchez-Sanchez, J., Ramirez-Campillo, R., Nakamura, F. Y., Rodríguez-Marroyo, J. A., & Villa-Vicente, J. G. (2019). Relationship between repeated sprint ability, aerobic capacity, intermittent endurance, and heart rate recovery in youth soccer players. The Journal of Strength & Conditioning Research, 33(12), 3406-3413.