Since the UFC’s prestigious first event on Fox, I have had a number of training partners and clients asking me questions as to how professional fighters can perform to their optimum standard when suffering from injury. The main event of UFC on Fox: Velasquez vs. Dos Santos has generated lots of discussion as to whether both Dos Santos and Velasquez fought at 100% health.

Certainly Brazilian Junior Dos Santos and his camp have stated that a torn meniscus in his knee meant he was on elbow crutches ten days prior to the match up. He will now undergo arthroscopic knee surgery and subsequent rehabilitation before he makes his first heavyweight defence later in 2012.

What is less publicised but has been announced by UFC colour commentator Joe Rogan is that the former heavyweight champion Cain Velasquez also reportedly suffered a knee injury and required a corticosteroid and local anaesthetic injection prior to the bout.

The answer I give anyone who questions how these athletes can perform at such a high level despite injury is that the body has an amazing ability to alter and adapt in response to painful stimuli, especially when it is facing great challenge. This is the topic which we will be discussing further in this article; how is it that MMA athletes can fight through injury and why are they not stopped where a “lesser” man may be incapacitated?

A Warrior's Heart

A commonly uttered compliment to MMA fighters is that despite any physical damage or injury they suffer, if they continue to fight then they are demonstrating great heart or a warrior’s mentality. This is a common belief in sport due to a potent combination of self-imposed pressure and societal expectation which creates the principle that “real men” or “great athletes” play through the pain.

The truth is that the reason pain takes a lesser toll on these individuals is partly psychological, partly physiological and partly environmental. The answer may lie to some extent in what is usually described as the fighter’s adrenaline rush in the cage.

(See the previous All Powers article “The Autonomic Fighter” for further details on the role of the autonomic nervous system in MMA fighters’ performance and the “adrenaline dump”)

Junior’s Pain

UFC on Fox: Velasquez vs. Dos Santos, November 12th 2011- Anaheim, California

We will take the example of Junior Dos Santos in Anaheim, California during his UFC heavyweight title fight with Velasquez and examine further.

Dos Santos was suffering from a meniscal tear which, if now requiring surgical intervention, is likely to be a significant injury.

(See the previous All Powers article “WTD? Meniscal locking mania” for greater details on this injury)

Now take the picture above of Dos Santos performing an end of range knee flexion with all his weight beared through the knee joint. This is the exact position which would fully load this particular tissue and would definitely be painful for a torn meniscus.

In a normal situation (e.g. Dos Santos bending down to pick something up from the floor at home) then it is likely that this stimulus would have been interpreted as a nociceptive (painful) action. The body’s adaptation to the mechanism of injury (meniscal compression and damage) is what prevents Dos Santos from feeling the pain sensation.

In the normal situation compression of a torn meniscus tissue would cause an increased pressure and biochemical reaction which stimulates a variety of sensory receptors which are present in all tissues. These receptors are all stimulated in varying degrees with any degree of knee bend and include pressure receptors, chemical receptors, movement receptors, temperature receptors and of course pain receptors.

All these receptors send signals of varying strength to the dorsal horn of the spinal cord and then the brain. The pattern of signals sent to the brain is similar to how an orchestra is a variety of musical instruments, but in different pieces of music you will hear the woodwind section more than the strings section. The brain’s interpretation of these signals and the output created by the brain is like the orchestra’s piece of music - it is the final accumulation of all the smaller inputs.

So when the knee is injured and Dos Santos bends down at home a large number and type of receptors are stimulated. If a critical threshold of pain receptors is reached then the pain signal to the brain is amplified and the output of the brain is more likely to be 'PAIN!' This would cause Dos Santos to react and move to prevent himself causing more damage to his knee.

Descending Inhibition

The mechanism which the body uses to prevent it reacting to every small and insignificant stimulation of its pain receptors helps define the critical threshold we have described.

Descending inhibition is a modulatory pathway from the brain to the body which involves the stimulation of certain areas of the brain and the release of specific chemicals and neurotransmitters in order to inhibit pain stimuli reaching the brain.

This is an automatic and natural phenomenon which affects all stimuli from the body to the brain. For example, if you wear a watch, initially as your body gets used to it being there the sensation of the weight, feel and temperature of the watch will cause you to feel it. However, eventually your body recognises that that sensation is not important and the descending inhibition system works to stop that signal reaching the brain. It does this in regards to pain by releasing key chemicals such as serotonin and endorphins, which cause a natural analgesic opioid response.

Back to the Honda Center

Now the question remains about what is different about fight night than any other day, and the normal response is adrenalin. The adrenalin rush is commonly touted as the key mechanism which causes MMA fighters to exceed superhuman levels of ability in the face of adversity. However, this is even more amplified in the example we have set of Dos Santos and his UFC championship fight.

The noise of the crowd, the pressure, the expectation, the anxiety, the fear, the excitement, the hope, the happiness, the TV cameras, the millions of viewers on National TV, the waiting eyes of the bosses… All these elements are feeding into the psychology and physiology of both Dos Santos and Velasquez before they lock horns.

As previously mentioned adrenaline release is normally the explanation as to why fighters carry on through the pain barrier but this may not be a true reflection of what is occurring in the body of Dos Santos to allow him to perform to his best.

Falsely Blaming Adrenaline

Adrenaline is also known as epinephrine or its psychoactive counterpart norepinephrine (noradrenaline). When secreted into the blood stream it prepares the body for action as part of the 'fight or flight' reaction. It boosts the supply of oxygen and glucose to the brain and muscles as part of a sympathetic nervous system reaction by increasing heart rate and stroke volume, dilating pupils and arterioles in skeletal muscles, elevating blood sugar by increasing catabolism of glycogen to glucose in the liver, and at the same time begins the breakdown of lipids in fat cells.

However, the normal response of epinephrine/ norepinephrine on acute pain stimuli, is to increase the sensation by further excitation of the sympathetic nervous system. This is because an acute pain stimulus acts as a warning to reduce provocative or potentially damaging activity.

It is true that some medications are utilised which increase norepinephrine with the aim to reduce pain. For example, tricyclic antidepressants (at a low dose) or serotonin-norepinephrine reuptake inhibitors are commonly prescribed for individuals with pain. However, this is due to the effect of norepinephrine as a neurotransmitter in the spinal cord and its effect on neuropathic pain (rather than acute pain). It is unlikely that an acute injury would involve this type of pain response.

JDS & SIA

Now obviously the presence of adrenaline in the fighters we are discussing is not being debated, but if this does not come with a natural increase in pain response, then it must be due to some other explanation.

The answer may lie in something which is called stress-induced analgesia (SIA). Sah et al (2007) published an article in the journal Neurone which discussed and examined this topic.

Their studies looked at a part of the brain which is the emotion-processing and mediation region; the amygdala. It is well established that this area is controlled by the brain stem and regulated by norepinephrine. Sah and his team sought to see how this chemical influenced transfer of pain impulses into the brain.

They found that norepinephrine worked to suppress electrical impulses along the pain pathway from the brain stem to the amygdala and prevented a number of sites from launching nociceptive signals. Therefore, the stress reaction in the amygdala of adrenaline release causes an analgesic effect.

Pain in the Brain

Other studies (Ossipov at el 2010) examined the effect of electrical stimulation of other areas of the brain such as the periaquaductal gray and rostral ventromedial medulla to the pain response. Their work demonstrated that stimulation of these brain sites caused a cascade of reactions, including communication to other brain areas which resulted in a norepinephrine level increase in the cerebrospinal fluid and greater direct descending input to pain transmission neurones, ultimately causing more descending inhibition of pain.

Summary

So before and during the fight at the Honda Centre, both Dos Santos and Velasquez would have had a number of biochemical changes to how pain was being transferred around their body and interpreted in their brain. Whilst adrenaline should have caused an increased pain response, what actually occurs is that the stress reaction to the environment causes the brain to provide greater natural analgesia through descending inhibition.

The pain signals for Dos Santos’ knee are still being sent to the brain, but they are being blocked due to his body’s reaction to the environment and situation he is feeling them in. This is why he is able to perform to his best despite the underlying issue which 10 days previous had put him on crutches. His body subconsciously defeated the pain.

Brazilian Bravery?

A final interesting point to make regarding this topic and this fight particularly is regarding genetic predisposition to pain management.

Professor Irene Tracey who works at the Oxford Centre for Functional Magnetic Resonance Imaging of the Brain examines real-time brain scans to examine how individuals cope with pain. She has found (recently reported in the PNAS journal) that an individual’s personality is key in their dealing with a pain experience.

Higher levels of anxiety and worry may leave people more susceptible to feeling pain. When a person has a more laid back and relaxed personality (like is well known and common within the Brazilian Jiu Jitsu community) they demonstrate greater connection between the brain stem and other key brain areas, and as such have a better coping reaction to pain subconsciously.

Now I have been lucky enough to meet the new UFC heavyweight champion and, like the majority of the Brazilian athletes I work with and know, Dos Santos was a very laid back, kind and well mannered man. I wonder if the Brazilian attitude has something to do with why the UFC currently has 3 Brazilian champions.

Stay healthy and keep fighting,

All Powers

Follow @AllPowersPhysio on Twitter and head over to the All Powers Physio blog for more articles on MMA.