To many, Jon Jones is a prospect that represents the state of the art in terms of technical and physiological potential.

(Photo: nbcsportsmedia4.msnbc.com)

Because so many factors define a fighter’s efficacy in battle, it's forgivable that we settle for terms like "good cardio" and "bad cardio" to describe an athlete's fitness.  Nevertheless, when one is truly seeking to cast a thoughful appraisal, a term like "cardio" simply falls short of capturing the various nuances of human output.  Given the trend toward fighters with increasingly elite athletic pedigrees, we trainers, fighters, and fans would do well to move past the term "cardio" and become more familiar with the fundamentals of human physiology as defined by sports science.

Admittedly, this article is at best an overview of fight physiology.  Additionally, your author is more construction worker than sports scientist, therefore, please don’t expect this piece to be more than a jumping-off point for your own study. 

Nevertheless, in the spirit of expanding our collective physiological vocabulary; let's take a peek beneath the tattoos and see how the flying knees are made.

Since it’s bones that do the hurting, and since muscles move the bones, our review of fight physiology begins with the composition of skeletal muscle itself.

The bulges of meat that we think of as muscles must be subdivided several times before reaching the actual mechanism of muscle contraction.  From muscle groups, such as biceps, deltoids, and hamstrings etc, are individual muscles, which are attached to bones by tendons. 

The next subdivision of muscles—the muscle fascicles—are still visible to the naked eye.   You have probably enjoyed the tasty texture of muscle fascicles in say…a pulled pork sandwich. 

If we go down to the microscopic level in our magic school bus we’ll see that each muscle fascicle contains yet another bundle of individual strands known as muscle fibers. 

Although we will describe muscle contraction as a function of muscle fibers, it’s important to note that the actual mechanics of contraction happen at an even smaller level in yet another bundle of microscopic filaments called myofibrils. 

A review from large to microscopic: muscle groups, individual muscles, muscle fascicles (here called muscle bundles), muscle fibers, myofibrils.

(Diagram: www.bio.miami.edu/~cmallery/150/neuro/muscle.htm)

The smooth operation of a well toned athlete’s body belies the frenetic contraction of individual muscle fibers, which individually contract in mere thousandths of a second.  It’s actually the accumulation of these individual, microscopic contractions that lead to the smooth movements of muscles, muscle groups, and humans themselves.

Muscle Memory=Muscular Efficiency

Interestingly, the number of individual muscle fibers recruited for a task is an active function of our cerebellum and only seems automatic to the extent that we have trained for that particular task.

If you’ve ever attempted to heft an entire gallon of milk out of the refrigerator only to find that the gallon was nearly empty, and you almost threw the jug into your ceiling, then you understand the power of the neuromuscular connection.  If your brain thinks the jug is full it recruits more fibers than if it thinks the jug is empty.  In other words, an athlete who is well practiced in his craft will recruit a more appropriate number of fibers for the necessary movements than a less experienced practitioner of the same craft.

This is often called muscle memory, but muscle memory is also used to describe repetition as it relates to getting good at something-like a golf swing.  In terms of our discussion, muscle memory can also be thought of as the ability to recruit the optimum amount of contraction at the right moment for the right task. While the purpose of training is also to build skill and fitness, we should also consider the power of repetition as it relates to building muscular efficiency.

Consider this: We marvel at Randy Couture's fitness in spite of his age, but perhaps it is his age, or more specifically the decades he’s spent refining his "natural" clinch game that give him a physiological advantage over less experienced fighters. 

Randy Couture forcing yet another young buck to use more muscle than he.

(Photo: Sherdog)

Aerobic (with Oxygen) Respiration vs. Anaerobic (without Oxygen) Glycolysis

Depending on the availability of oxygen, and the horsepower demanded for a given situation, one of two reactions can occur in the muscle fiber to create a contraction.

In the presence of oxygen, aerobic respiration creates around 30 ATPs (1 ATP is sort of like one cylinder's worth of gasoline in an engine) for each molecule of glucose.  Aerobic respiration is very sustainable and describes the bulk of our corporeal animation during the course of a day. Eating, standing in line at the bank, running from Nate Quarry, and turning laps around your local Wal-mart, are all aerobic activities.

In the absence of oxygen, anaerobic glycolysis yields only 2 ATPs per molecule of glucose—roughly the difference between commuting to work in a front-end-loader to aerobic respiration’s Honda Civic. Since ATP’s are the energy packets that cause muscle contraction, the body strives to use them as efficiently as possible,  and yet sometimes the body must create power faster than aerobic respiration can do the job.  Escaping cougar attacks, getting above the rim, and shooting a double-leg takedown are all classic anaerobic movements.

Before going on, let’s take a moment to appreciate the dynamic interplay between aerobic and anaerobic efforts during the course of a fight.  MMA isn’t simply "harder" than other sports; but it does more violently and less predictably cover the entire spectrum of human output.  While this may be MMA’s brilliance from a tactical perspective, it’s also why conditioning for the sport will always be a major challenge including many compromises and trade offs.

Regardless of an athlete's conditioning, a full anaerobic effort is still only sustainable for a handful of seconds, whereas even heavy aerobic efforts should be sustainable well beyond the five 5 minute rounds of a championship bout. 

Melvin Manhoef vs. Evengelista "Cyborg" Santos is one of the epic battles and epic gas-outs of all time.  The reason that particular fight is so entertaining and the gas-out so complete is that both fighters ignore the unwritten agreement to return to aerobic rest (circling, feinting, throwing light jabs, etc.) between anaerobic efforts.   The irony is that when we say "cardio" we’re more accurately describing the physiological requirements of your mom’s Zumba class than we are those of a gladiatorial battle for supremacy.

Slow Twitch vs. Fast Twitch Muscle Fibers

As we’ve discussed aerobic efforts are very efficient but anaerobic efforts are very powerful. Since both aerobic and anaerobic activities are inevitable in our lives, we're all born with distinct amounts and proportions of these muscle fibers based on nature's best guess of our physiological needs. 

Since an athlete’s unique cocktail of fast and slow twitch fibers will drastically affect his potential physiological output, it is something we should keep a keen eye out for in MMA.  Short of a muscle biopsy or genetic sequencing, knowing the exact composition of an athlete’s musculature is largely a matter of conjecture; however, understanding the nature of the fibers themselves gives us some clues as to who is packing what.

Because aerobic function is the basis of most human movement, much of the human body is made up of muscle fibers that optimize sustainable, efficient energy. This muscle type is known as oxidative, red muscle,  and most commonly: slow-twitchmuscle. Slow-twitch muscle fibers are thinner in diameter than fast-twitch fibers so the reduced surface area combined with an increased presence of myoglobin (which facilitates the transfer of oxygen) makes slow-twitch fibers much more efficient at creating aerobic power.

Conversely, the fibers optimized for anaerobic function are known as glycotic muscle, white muscle, and the aforementioned: fast-twitch muscle. 

Since force equals mass times acceleration, fast-twitch fibers--which contract 2-3 times faster than slow-twitch fibers--also create more force! Do you think world class sprinters, strongmen, shot putters, and slam dunk champions didn’t become the best just because they trained harder? Of course increasing one's mass can improve muscular acceleration, but the pound for pound king of big power is always going to be a high preponderance of fast-twitch fibers. 

Kevin Randleman demonstrates the hallmark of the fast-twitch freak--the vertical leap. 

(Photo: Sherdog)

Aside from the thought of simply creating more power is the fact that a fast twitcher can create the same amount of power as a slow twitcher but by recruiting fewer individual fibers. Because fast twitchers can create anaerobic power ease, and because slow twitchers can more easily work an aerobic game, we shouldn’t be surprised to see fighters build fight plans off of their strengths.   Armed with this informed perspective, it should be intriguing and rewarding--not boring—to watch the likes of Kevin Randleman, Antonio McKee, Brock Lesnar, and Jake Shields stick to their game plan of bench pressing their opponent’s faces into the canvas for the entire fight.

While abundantly endowed fast twitchers are usually the first picked on the playground (as well as the NFL draft), it’s important to recognize the technical and physiological trade offs of different body types before rubber-stamping any single genetic blueprint as "Ideal for MMA".  Perhaps the true ideal is to understand each athlete's personal strengths and vulnerabilities and train to maximize and mitigate them respectively.

VO2 max

Another genetically predetermined slap-in-the face, but one that favors slow twitchers, is total aerobic capacity also known as VO2 max (Maximum absorbable Volume of Oxygen).

Because aerobic capacity largely depends on muscle composition, lung capacity, and cardiac strength, there is a limited amount of improvement one can hope to gain through training.  While aerobic conditioning, altitude training, blood doping and weight loss can all increase one’s effective aerobic output per kilogram of weight, none of these efforts can turn your average athlete into an elite-level endurance machine.  Now please don’t misconstrue that statement, humans have an immense capacity to adapt from sloth to fit relative to their own fitness, but on the grand stage of elite competition only the genetically peculiar will ever run a sub 4 minute mile or a 2:30 marathon.

Since so much of MMA is anaerobic, can an off-the-charts VO2 max athlete use that as an asset in a fight? As a case study, let’s pretend 7 time Tour de France winner and aerobic capacity superfreak Lance Armstrong decided to throw his hat in the ring (cage).  He probably wouldn’t want to get into a power struggle with the likes of a Sean Sherk, but as long as he patiently relied on continuous movement and threw a high volume of pitter-patter punches he might just do pretty well.  Sound like a fighter we know?

Nick Diaz in 2007 on his way to finishing a 1.2 mile swim, 56mile bike, and 13.1 mile run in 5 hours 53 minutes.

(Photo: http://www.auburntriathlon.com/2007/2007eventphotos.shtml)

While Nick Diaz’s VO2 max values are not public record, his triathlon times are, and they are actually quite respectable.  We can therefore deduce that his VO2 max, if not elite, is at least very good.  So you can watch Diaz fight and say "oh he'll never get tired, he's got great cardio from all that swimming", but perhaps the more intriguing notion is that his game plan matches his unique physiology, and not the other way around.

Anaerobic/Lactate Threshold

Now let’s see what happens when we push the pace past the "max" part of VO2 max.  As the heart reaches its upper limits, let’s say 80-90% of its maximum beats per minute, the body exceeds its VO2 max and has to supplement the struggling cardiovascular system with a little help from its anaerobic friends.  The point at which anaerobic glycolysis kicks in to supply power is known as the anaerobic threshold or lactate threshold. 

Whether by intelligent design, natural selection, or a combination of both; anaerobic glycolysis instantly produces lactic acid as a byproduct.  Although lactic acid burns and degrades muscle function, it also serves as an early warning that we’ve crossed our anaerobic/lactate threshold and need to return to aerobic respiration before reaching complete muscle failure.

Interval Training

The actual point in the continuum of effort that triggers anaerobic glycolysis and the speed at which lactic acid is cleared out of the muscles may be two of the most important fitness factors to the mixed martial artist.  The good news for the genetically average is that these traits are highly critical and highly trainable.

Most sports train to build their aptitude at and above the anaerobic/lactate threshold through one form or another of interval training. Interval training aims at taking the body to full exertion and then back to an active aerobic recovery to clear the accumulated lactic acid out of the blood stream.  Intervals are often comprised of 30-120 seconds of maximal effort with 1-5 minutes of rest.  Remember the point is to push well beyond a sustainable pace, and then train the body to quickly recover from the deleterious effects of such effort.

One thing that interval training is not: hour long barf-o-matic sparring sessions against fresh opponents with no rest.  While the effect of this type of training might have benefits in various facets of combat readiness, it is not interval training and is probably a common cause of overtraining in the sport.

Overtraining

Overtraining, incidentally, is not just an excuse invented by Brazilians who lose, but is rather a condition where an athlete’s body is forced into a state of rest because adequate recovery periods were not respected during training.  One of the great miracles of our bodies is its ability to adapt to the stresses of training, but care should be taken not to push the stress/reward/rest relationship too far.

If an athlete maintains a good balance of intensity and rest, he or she will see a gradual increase in output at known levels of heart rate.  If an athlete begins to see a decrease in output over time at the same given heart rates, then it’s time for a rest.  If a fighter is training in a "more pain=more gain" culture that doesn’t respect the realities of overtraining, they might just find themselves getting a dose of forced rest via unresponsive muscles on fight night.

Genetically-Tailored Game Plan

As the fight game continues to evolve and fighters become more equally matched in terms of technical skills, the genetic physiological gifts and liabilities of a fighter will more frequently and unabashedly reveal the truth of a given matchup.

We saw the quintessential application of this reality in the case of Georges St. Pierre and Greg Jackson, who were seen as interplanetary soothsayers after they revealed that their strategy against BJ Penn included avoiding Penn’s genetic strengths (letting Penn snap punches at range-aerobic) and exploiting his genetic limitations (forcing him to push back on St. Pierre’s body-anaerobic). In such a compelling stylistic matchup, victory through the exploitation of the opponent’s physiological weaknesses seemed shockingly straightforward.

Kenny Florian attempts to repeat St. Pierre's game plan against Penn but without St. Pierre's off-the-charts fast-twitch physiology.

(Photo: Sherdog)

If we believe there is a positive correlation between money and genetic elitism in a given sport, then we are just now reaching the era where elite athletes are actually choosing MMA over other pro sports.  While we pray that athletic ability and conditioning never completely supplant technical superiority or the fighting spirit, it’s hard to argue against elite-level athletes being the future of top-tier mixed martial arts.

So there you go; even given the volume of the preceding content we've failed to address nutrition, strength training, muscle deterioration with age, effects of dehydration, heart rate and heart-rate monitors, supplementation (both legal and illicit), sleep deprivation, stretching, flexibility, bipolar disorder, the legendary pitfalls of the pre-fight sexual congress, or even the fact that some dudes simply hold their breath the moment the cage door shuts!  So don't quit now, cruise over to your library, bookstore, or even Wikipedia and be the first one on your block to ditch the term "cardio".