Thursday, October 02, 2008

*** Brain Training for Runners by Matt Fitzgerald

As a life long, avid runner, who has logged enough mileage to circumscribe the globe (at the equator mind you!), I thought there can't be too much more to learn about the subject of running. Well, I was very wrong it seems. The thing I liked about this book, it that it brings up the evolutionary history and the biology of running, and buttresses that with studies (science rules!), to create convincing arguments to at least try what is being proposed here. I am in the middle of altering my stride by following the precepts of this book (since I have became an overstrider in my 20s for my marathons, but when I was young and running track in High School, I was not). I have not yet raced with these insights, but I plan to determine if they indeed can boost my performance, and reduce my pain and injury suffering. For all runners a great read!

The wall is not solid
When you hit the wall, you don’t actually run out of glycogen or ATP. Exercise depletion of ATP has never been shown to exceed 50%. Fatigue in prolonged exercise is supposed to be caused by glycogen depletion, but in reality there’s always glycogen left over in the working muscles of exhausted. If total glycogen depletion ever did occur, ATP depletion would soon follow because glycogen is a source of ATP replenishment. And if ATP depletion ever did occur, the result would be muscle rigor – that is the working muscles would become locked in a state of contraction or paralysis. I doubt you’ve ever seen this happen. P47

Runners routinely begin to experience fatigue and slow down in the latter stages of a race, only to find the wherewithal to sprint the final straightaway. According to the catastrophe theory of fatigue (hitting the wall), this phenomenon is impossible. P49

The average adult stores 500g of glycogen (400g in the muscles and 100g in the liver), as compared to 12 to 18kg of fat. Glycogen supply becomes a performance limiter when runners try to maintain a fairly aggressive pace for an extended period, this is because glycogen supplies energy faster than fat, so the higher the intensity, the more the muscle have to rely on glycogen. P54

Over 80 means that it is too hot for your best time
Only 25% of the energy that the muscles release during running is used for muscle contractions. The other 75% is lost as heat… When air temperature exceeds 78F, heat accumulates in the muscles and contributes to fatigue. P55

And it can be dangerous
Hot weather racing is the only circumstance in which the brain’s self protective fatigue mechanisms sometimes fail to prevent runners from seriously harming themselves… Elevated core temperatures accelerate nerve impulse transmission, potentially causing the protective inhibition of muscle activation to lag behind motor signals ordering continued work at the same intensity. P56

Spring in your step
Few runners realize just how much energy they are able to reuse thanks to the spring effect in their joints and muscles. Research has shown that runners consume oxygen at a rate that is sufficient to produce only about ½ of the energy needed to run at any given speed. The other ½ is provided by the spring effect. P86

Think short and quick
The best runners tend to make shorter strides and hence have a higher stride rate at any given speed than average runners. P87

Unstable at any speed
When the foot lands in front of the body (overstriding) there is a lack of stability. To understand why, perform the following test. Stand normally, and then lift one foot off the ground. Is it difficult to balance? Not terribly. Now stand in a split stance with one foot half a pace in front of the other. Lift your rear foot off the floor. Can you balance in this position? Impossible. Your point of support is not aligned with your center of gravity. P87

A brake in the action
When your forward leg is reaching ahead on footstrike (overstriding common in heel strikring), the impact forces that travel up your leg move backward against your direction of travel. By contrast, when your foot lands underneath your hips, the impact forces travel up more your leg more or less straight, neutral to your direction of travel. To minimize the braking effect of overstriding, runners unconsciously try to land softly. Unfortunately, the softer you land, the more ‘free’ elastic spring energy you waste, because it dissipates before you can use it. P88

Changing your stride:
Ballistic Action
Many distance runners believe that the ideal pattern of muscle action is sustained and gentle. The idea is to use energy evenly throughout the stride, landing softly, staying relaxed, and avoiding wasteful peaks and valleys in muscle work. In reality, the best runners have a ballistic style of running. They contract their muscles extremely forcefully – much more than avg runners – during a small slice of the overall stride that begins in the moment of bracing for impact, continues through a brief ground contact phase, and terminates at push off. This anticipatory tensing is a major factor in creating the stiffness that enables the capturing of elastic spring energy. The best runners then relax their muscle as they float in the air between footstrikes and they spend more time floating between footstrikes because they are faster. P88

½ the energy we use to run goes toward simply preventing our joints from collapsing to the ground each time our feet make contact with it… If you watch avg runners you will see that they tend to bend the knee of their support leg more on impact and also that the hip of the unsupported – swing – leg dips toward the ground while support foot is planted, and you’ll notice that pelvis tips forward on impact. These excessive joint movements waste a lot of energy and put extra strain on the joints leading to pain and injury… Overstriding is a major cause of joint collapse. When your foot lands in front of your body, your muscles are not in a good position to absorb the impact. By the time your body has caught up to your foot, these forces will have had time to pull you toward the ground at your most susceptible points: knees, pelvis, and hips. P89

One of the most problematic asymmetries is long axis rotation or twisting of the spine. This tends to develop in runners who are not able to begin the thrusting (pushing off) phase of the stride until late in the stance phase, when the body has already passed ahead of the foot. To make up for the inability of the muscles to develop adequate force, the runner must keep the foot in contact with the ground for an extra last moment push off. And to keep the foot on the ground, the runner must rotate the pelvis in the direction of the trailing leg, making this leg longer. To compensate for this movement, the runner must through the opposite shoulder forward, twisting the lower – lumbar – spine in one direction, and the upper – thoracic – in the opposite… Top runners run with their hips and shoulders more square to the direction of travel. They are able to keep their pelvis fairly neutral by generating thrust early, when the foot is still underneath the body. P90

Cues to help change your stride
Falling forward
Tilt your whole body slightly forward as you run. Don’t bend at the waist. Tilt from the ankles… This cue will help you correct overstriding because while leaning forward your feet will naturally land closer to your center of gravity. P92

Navel to Spine
This cue will activate the deep ab muscles that stabilize your pelvis and lower spine, by pulling your bellybutton inward toward your spine.

Running on water
Imagine running on water without falling in. To do this you must apply maximum force to the water in minimum contact time. Run quickly, lightly, yet forcefully. This will stiffen your stride, minimize ground contact, and begin the thrust phase earlier.

Pulling the road
Imagine running on a huge rug, and you are pulling the rug behind you with your feet as you thrust forward.

Think about thrusting your body forward not upward. Imagine running underneath a ceiling that is only 2 inches above your head. This cue reduces vertical impact forces.

Pound the Ground
Running speed is almost entirely a function of how forcefully you hit the ground. The typical overstriding runner lets his foot fall passively to the ground with each stride. Instead drive your foot into the ground. If you are a heel striker, work on landing flat footed before attempting this.
Drive the thigh
Drive the thigh of your swing leg forward more forcefully than normal. This will create a counterbalancing backward-downward action in your opposite leg.

Floppy Feet
The foot contains 27 bones and dozens of muscles and ligaments. This complex structure allows the foot to deform in an intricate wavelike pattern while it is in contact with the ground. Unfortunately shoes greatly restrict this natural movement. To overcome this, concentrate on running with relaxed – floppy – feet. Continue to strike the ground forcefully, but use the muscles of your upper leg to generate this force while keeping the foot relaxed. P94

Butt Squeeze
The instant before your foot makes contact contract the muscles in the hip on that side of your body and keep them engaged through contact with the ground. This will minimize long axis rotation.

Feeling Symmetric
Compare the feeling of your arm and leg swing on your left side with that of your right side. If there is a discrepancy, adjust your stride to eliminate or reduce it.

Axle Knees
Imagine an axle or dowel pushing your knees about a ½ inch apart than normal. This engages your hip flexors and external hip rotators preventing the thigh to twist the knee – a common cause of injury.

Running against a wall
Imagine a wall in front of your nose. Your knees and feet will knock into this wall unless you shorten your stride and place your feet under your hips. Leaning forward at the ankles will create more room to drive your thighs forward as well. P95

Technique Drills
Running with no arms
Lace your fingers together and make a big circle at shoulder level like a basketball hoop. Run 100 yards at moderate speed with your arms out in that position (looking like a dork!). This will activate your deep ab muscles to maintain upright posture and teach you how to feel and activate those while running.

Steep Hill Sprints (my favorite!)
Run ballistically and fast up the steepest hill you can find.

One leg hop
Run as fast as you can on 1 leg for 20 seconds. This increases your forward push off power, and enhances hip, pelvis, spine, knee stability by forcing these joints to stabilize extreme impact forces for a short period.

High Knees
Run with an extremely exaggerated knee lift for 30 seconds. This drives your thigh forward, and strike the ground with greater force.

Run with long, leaping strides for 30 seconds. This enhances push off power and retracting your lead leg before impact. Bounding teaches you to reduce the braking effect from overstriding.

Stiff Legs
Run for 20 seconds with your knees locked. This helps your feel your buttocks and decreases your hamstrings for forward movement, improving stiffness. P97

Where or where are my deep abs?
The deepest muscles of the abdominal wall (transverse abdominis and internal obliques) are vital to proper stabilization of the pelvis during running. Yet the vast majority of runners, including elite runners, are unable to activate these muscles to maintain pelvic stability. This results in energy waste, and increased risk of overuse injury. Weakness is not the issue. It only takes 10% contraction of deep abs to do the job. Rather it is a problem of neuromuscular communication. Our brains literally cannot find these muscles, probably because of the absurd amount of time we spend slouching in chairs. P101

Why we get sore
Most of us associate inflammation (swelling) with acute injuries such as an ankle sprain. But a much milder inflammation response occurs after normal workouts in which we do not suffer any serious injuries. Every workout causes microscopic damage to muscle fibers, which are repaired with the aid of inflammation during the following recovery period. The main cause of muscle damage are lengthening contractions such as the lowering phase of a bicep curl when gravity is pulling the weight down, but the contracted muscle is resisting. In running a similar thing happens during the footstrike, when the quadriceps are forced to lengthen by impact forces but contract to absorb these forces and prevent joint collapse. P141

And why it hurts worst 2 days later!
Inflammation from muscle exercise produces chemical signals which begin 2 hours after a workout and last about 48 hours… Inflammation promotes satellite cell proliferation, a step in developing bigger, stronger muscle fibers, and it protects (even after 1 workout!) muscles from further exercise induced damage. P142

There is a negative side to inflammation, it also causes secondary muscle damage between workouts from the release of free radicals. Secondary muscle damage is the main reason you feel sorer the morning after, and why you sometimes feel sorest 2 days after a workout. This soreness does impact your performance, in trained runners, it reduced running economy by 3% (which is significant because a lifetime of training may only boost your economy by 10%). P142

Science behind recovery runs
It is widely assumed that the purpose of recovery runs (slow runs undertaken 4 to 24 hours after a hard run) is to facilitate recovery from the preceding hard training. You hear coaches talk about how these runs increase blood flow to the legs, clearing away lactic acid, and so forth. The truth is that lactic acid returns to normal within 1 hour even after the most brutal workouts, nor does this acid cause fatigue in the first place, nor is there any evidence that light activity promotes muscle repair, glycogen replenishment or any other physiological response pertinent to muscle recovery. Why then are recovery runs then universally practices by top runners, and what are the real benefits? There’s a cytokine Interleukin 6 (IL6) that is released into the bloodstream by the muscles during exercise and travel to organs throughout the body, including the brain. Increasing levels of IL6 in the brain cause fatigue. In an experiment, runners injected with IL6 run a full minute slower than those given a placebo. IL6 is believed to facilitate many of the body’s adaptations to exercise training, ranging from increased fat burning to greater resistance to muscle damage, to improved cognition. The primary trigger for IL6 release during exercise is glycogen depletion… Thus training in a glycogen depleted state will tend to produce more IL6 than a non-depleted state. Research backs this hypothesis: Subjects exercised one leg daily, and the other twice every other day. The total amount of training was equal for both legs. After several weeks, the twice trained leg increased its endurance by 90% more than the once daily leg. P150

The release of IL6 is probably not the only mechanism by which recover runs enhance fitness… The brain also tries to avoid worn out muscle fibers and instead involves fresher fibers precisely because they are less preferred under normal conditions. When your brain is forced out of its normal pattern, it find neuromuscular shortcuts that enable you to run more efficiently. Another benefit is that seldom used fibers now become conditioned to prolonged running. They adapt to these demands by producing more mitochondria, capillaries, and aerobic enzymes, so they can be more helpful when called upon again. P151

Sitting is your enemy
The average office worker spend 9.5 hours sitting per day… A study showed that folks who spend more than 7 hours sitting/day are nearly 70% more likely to be overweight than those who spend less than 5 hours sitting. P173

The deep abdominal muscles wrap like a corset around the midsection of your body, to help you maintain upright trunk posture and stabilize the pelvis and lumbar spine during activities. When you sit, you don’t use these muscles, consequently they become weak. Instead it is the hip flexors, muscles that cross the hip joint in front of the body, do the job of keeping the trunk upright while sitting. As a result of using our hip flexors for hours each day, they become really tight because the brain spends so much time providing low level activation of these muscles that it loses the ability to fully relax them. Tight hip flexors create problems for body alignment by causing a forward tilt of the pelvis, this causes your center of mass to shift forward too, so the body compensates by tilting the pelvis forward and arching the lower back. This compensation puts a tremendous strain on the hamstrings, which become active in pulling the pelvis down on the rear side to correct the forward tilt. As a result, the hamstrings become tight. And finally, sitting requires that you relax the buttocks and outer hips, so these muscles become weakened. All of these imbalances can lead to running inefficiencies and injuries. If you have tight hip flexors you are unable to fully extend your hips at push off (you should achieve a 10 degree backward extension of the hip). If you can’t do this, then you can’t completely use your strong extensor muscles – your buttocks and hamstrings – to generate thrust. In addition, tendonitis of the hip flexors is common. And weak quads are commonly implicated in runner’s knee – the most common running injury. .. Finally, excessive forward pelvic tilt contributes to lower back pain. P175

The overstriding epidemic
80% of runners overstride and land heel first (I’m one of them!), but when barefoot, exactly 0% of runners overstride. Why does this happen? The heel of the foot contains nerves that transmit information regarding the hardness of the surface and force of impact. This helps the brain decide whether to adopt the walking or running gait. A slower pace with less forceful impacts will help the brain determine a walking gait is appropriate. Cushioned running shoes produce a softer impact at any speed, so the brain develops a hybrid walk-run gait with a heel strike. This is somewhat speculative. The rigidity of the shoes also prevent the foot from deforming upon ground contact in a natural wavelike pattern compared to bare feet. As a result impact forces are sent shooting up the leg, concentrating in the knee, hip, pelvis and lower spine. P182

Rinse, repeat
In one cycling time trial of 1 hour duration, subjects rinsed their mouths with water (no swallowing) every 7-8 minutes. The same subjects repeated the time trail after some time. This time they rinsed with a sports drink. They completed the trial almost 2 minutes faster with the sports drink. Somehow the carbohydrate in the drink affected the performance without ever reaching the bloodstream. How did this happen? There are carbohydrate (sugar) receptors in the mouth that communicate with the brain, which stimulated the brains ability to recruit muscles by fooling the brain into believing an source of energy was available, making it safe to work a little harder. P189

It's all in your head
Older studies have show that when endurance athletes are given a carb drink at the start of the race, they go faster from the very start when compared to be given water. This flies in the face of conventional exercise wisdom, which holds that consuming carb drinks enhances performance by delaying muscle glycogen depletion… If this were true, then athletes would not go faster from the very beginning, they would merely continue longer. The fact that they go faster suggests a brain mediated factor is at work. P190

Obey your thirst
There is a prevailing belief among nutritionists in and out of sports that the thirst mechanism is unreliable, and that we should drink water at regular intervals to avoid dehydration. This is because the typical voluntary drinking rate during vigorous exercise is only 70% of the rate of body fluid loss. On the basis of this observation and the presumption (not proven) that any amount of dehydration is detrimental to performance and health, scientists decided that you should drink ahead of your thirst. As it turns out, an abundance of recent research has demonstrated that the negative performance and health consequences of dehydration during exercise have been greatly overblown. In fact, the negative consequences of drinking too much appear to be greater. P191

Dehydration seldom causes runners to overheat. Instead it is overexertion in a hot environment. In hot (especially humid weather), excess body heat doesn’t dissipate well, and it accumulates in the body… Interestingly, hot weather racing is the only circumstance where the brain’s self protective fatigue mechanisms fail to prevent serious harm. Elevated core temperatures accelerate nervous impulses, potentially causing the protective inhibition of muscle activation to lag behind motor signals ordering continued work at the same intensity. P192

Runners who attempt to hydrate as fast as they lose fluid encounter gastrointestinal distress, due to the jostling of the gut, and the slower rate of gastric absorption during exercise. P193

During running urine production decreases by as much as 60% due to increased blood flow to the muscles. This traps excess water in the tissues… Drinking too much during prolonged exercise causes blood sodium levels to drop. This will cause your tissues to absorb more water in an effort to restore the sodium level, and thus lower your blood volume (just as dehydration). So overhydrating while exercising is not good strategy. P194

The typical elite marathoner drinks only ½ a liter per hour while sweating 2 liters per hour, and the higher the finisher the more dehydrated and the higher their core temperature on average… The lesson we need to take from the top runners is simple. It’s better to trust your thirst and drink only as much as you can tolerate while running as fast as you can than it is to slow down to drink more or risk GI distress. P195

It’s important to bear in mind that our ancestors had no way to drink on the run while chasing prey (or being chased!). They had to run for long stretches without stopping to drink, and when they did drink, they had to stop. So while there was a strong pressure toward the ability to continue running despite heavy fluid losses, there was little or no selection pressure toward being able to drink effectively while running… It is interesting to note that training has no effect on the rate at which the stomach and small intestine absorb fluid during exercise. The digestive system is one of the only parts of the human body that does NOT adapt to exercise training. P197

A little protein goes a long way
15 cyclists rode stationary bikes to exhaustion twice on 2 separate days while drinking either Gatorade or a protein laden sports drink. The cyclists were able to ride 29% longer in the 1st ride and 40% longer in the 2nd ride when drinking the protein drink. They also found that the protein drink reduced muscle damage by 83%... This study has not been successfully duplicated, however, drinking protein drinks has equaled or bettered endurance performance in every study when compared to a carb only sports drink (ie. Gatorade), and the reduced muscle damage claim has been confirmed in every study designed to measure this variable. P198

Researchers are still trying to figure out how protein consumption reduces muscle damage during exercise. The simplest is that protein provides an extra source of direct energy that substitutes for muscle protein, because scientists now recognize that the body relies far more heavily on protein for energy during intense and prolonged exercise than was previously thought… Another possibility is that elevated blood amino acid levels that occur when protein is consumed during exercise act as a brain signal that reduces muscle breakdown. P199

What to drink?
Given the established performance boosting effect of carb drinks, you might assume it would be a good idea to use a sports drink during every run (I never use them and would prefer to indulge in getting my calories in another, more pleasurable form). New research suggests that intentionally underfueling the body during workouts may trigger a more pronounced fitness boosting adaptive response. The rationale centers on IL6… The primary trigger for IL6 is glycogen depletion, so it follows that training in a glycogen deleted state will tend to produce stronger training adaptations (remember recovery runs?). Studies have shown that muscles produce much less IL6 when carbs are consumed during exercise… Given this, it’s reasonable to ask if whether runners should underfuel themselves in every workout… Studies have shown that athletes who consume carbs during workouts are able to handle higher training loads than those who don’t, and are able to perform at a higher intensity. Consequently, the best training recipe is probably a mixture of fully fueled and underfueled workouts. P201


zhurnaly said...

many tnx, Ben --- excellent review/notes on what sounds like an excellent book! --- ^z

Unknown said...
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Unknown said...

Thanks for sharing your idea and information its really help.

Brain Training | Improve Memory

math therapy said...

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Unknown said...

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