Peak Power Output and Muscle Metabolism in Sprinters

For more, See my new post on Usain Bolt SMASHING the world record in Berlin!

Usain Bolt, the enigmatic 21 year old sprinter from Jamaica, has taken Olympic track and field by storm being the first person in 24 years to win gold in both the 100 meter and the 200 meter sprints. His successes in both were definitive. He broke the 100 meter world record with a 9.69 (seconds). And his 200 meter was another world record at 19.30. In both races he was able to sprint at top speed for nearly the entire race, only losing a bit of speed near the end of the 200 meters.

In contrast to Bolt, Sonya Richards, the American favorite in the women’s 400 meters, ended up barely getting the bronze. She started out strong, way ahead in the first 200 meters sprinting at top speed. She still had a solid lead at the beginning of the last 100 meter stretch. But, then, suddenly, and dramatically, she ran “out of gas”. She struggled just to stay in third place. She didn’t have the energy to keep up, and she lost her chance at a gold medal.

It is rare for a runner to run out of gas at the end of a 100 or 200 meter dash. But, it happens a lot in the 400. Why the discrepancy? What does it say about the limits of human sprinting ability? And how long can a person, even an elite athlete, maintain maximal speed?

At the elite level, a 100 meter dash lasts about 10 seconds; a 200 meter lasts about 20 seconds; and the 400 takes about 1 minute. It is interesting to note that the 200 meter time is about double that of the 100 meter time, but the 400 meter is six times the 100 meter.

Insight into why it is that after about the 200 meter mark, or after about 20 seconds, the human body can’t keep up its maximal speed can be found at the cellular level: it comes down to ATP (the body’s preferred fuel source) production and the ATP turnover rate (Katz, 1986). The ATP turnover rate refers to your body’s speed-ability to produce ATP. But, to use ATP, the body first has to make it. There are three primary sources of ATP production. The fastest is the phosphocreatine (PCr) system that relies on creatine phosphate. This is used primarily for the shortest bouts of energy, like lifting a maximum weight for one repetition or a 20 meter dash. The second fastest is glycolysis that relies on sugar metabolism used for repetitions at a maximum power output, such as sprinting up to 200 meters. And the slowest is aerobic metabolism that relies on oxygen, primarily used at sub-maximal thresholds. Marathon runners rely primarily on aerobic metabolism.

According to a study by Bogdanis (1996), PCr is highly important to maximum power output for the first 10 seconds of sprinting, but declines rapidly thereafter. Peak power output, the highest level of power that a sprinter can produce, occurs at approximately 3 seconds (Bogdanis, 1998).

It has become widely accepted that PCr provides up to 25-30% of ATP production in a 30 second sprint, the rest coming primarily from glycolysis. In another study, also by Bognanis (1998), PCr stores were found to drop by nearly 60% after the first 10 seconds of sprinting. And after 20 total seconds of sprinting PCr levels have dropped to as low as 25% of the resting value. This means that in a sprint lasting longer than 10 seconds, there just isn’t enough PCr to do the job. But, power output doesn’t slow to a crawl.

Glycolysis generally works right along side the PCr system. Glycolysis uses glucose to form ATP. The glucose is stored in both the liver and in the muscle cells themselves. Glycolysis can operate in an anoxic (without oxygen) environment which makes it ideal for sustained maximal power output situations like a 100 to 200 meter dash because at that speed, the aerobic (oxygen) pathway can’t keep up. But, it has its drawbacks. The primary drawback of glycolysis is that when it is performing without oxygen the system backs up and produces an excess flood of lactic acid (Klapcinska) that builds up to high levels fairly quickly after the first 200 meters.

Aerobic metabolism is the way that our bodies generate ATP while we’re simply waking around, watching TV, or reading papers about metabolic reactions. It is slow, but it creates a large abundance of ATP. The trouble is that at top speed the aerobic pathway just isn’t fast enough to keep up. But, aerobic metabolism isn’t completely out to lunch in an all-out sprint. Remember that Usain Bolt and his competitors all ran the 200 meter sprint at close to full speed throughout the race, and it took most of them about 20 seconds to do it. They slowed down a bit near the end, but not much. If their PCr stores were used up, and their glycogen levels were down one would suspect that their speed would drop considerably as their ability to maintain maximum power output would be severely compromised. But, while their speed did drop near the end, it didn’t drop that dramatically (barely noticeable in fact). There must be some help coming from a different source. Bognanis (1998 ) found that some of that help may be coming from aerobic pathways, though more study is needed to examine why and how this happens.

But the aerobic pathway is too slow to help out for too long. For Sonya Richards, her all out effort for the first 200 meters of her 400 meter sprint left her completely lacking in power by the end of the race. She’d used up all her PCr, she’d depleted her glycogen, and the aerobic pathways just weren’t sufficient to replenish the amount of ATP she needed to win the gold. Her competitors, however, relied more on a combination of their aerobic pathways and glycolytic pathways in the first part of the race and saved their maximal power output for the end where they were able to overtake her.

Human beings are able to do amazing things when they train hard for them. Usain Bolt is a shining example of that. But there are limits to what our species can accomplish. After 10 to 20 seconds, it becomes exponentially harder to maintain the same average power output that one was able to achieve up to that point in an all out sprint. It just so happens that the fastest people in the world sprint the 200 meters in almost exactly 20 seconds, and the 100 meters in under 10 seconds. But, for 400 meter runners, an all out maximal sprint is not a good strategy. The body simply can’t maintain that pace for long. A lesson Sonya Richards will likely never forget.

References:

1. Bogdanis, G (1996). “Contribution of phosphocreatine and aerobic metabolism to energy supply during repeated sprint exercise”. Journal of applied physiology (1985) (8750-7587), 80 (3), p. 876.

2. Bogdanis, G (1998). “Power output and muscle metabolism during and following recovery from 10 and 20 s of maximal sprint exercise in humans”. Acta physiologica Scandinavica (0001-6772), 163 (3), p. 261.

3. Gaitanos, G (1993). “Human muscle metabolism during intermittent maximal exercise”. Journal of applied physiology (1985) (8750-7587), 75 (2), p. 712.

4. Katz, A (1986). “Muscle ATP turnover rate during isometric contraction in humans”. Journal of applied physiology (1985) (8750-7587), 60 (6), p. 1839.

5. Klapcinska, B (2001). “The effects of sprint (300 m) running on plasma lactate, uric acid, creatine kinase and lactate dehydrogenase in competitive hurdlers and untrained men”. Journal of sports medicine and physical fitness (0022-4707), 41 (3), p. 306.

Myths of Womens Weightlifting, Part 1

(See Part 2 Here)

We humans are an animal that has Survived, in part, because of our ability to learn from others, and apply that knowledge to our own lives. From fire to the Wheel, we’ve built on the knowledge of one another, and taken our species to ever grander heights. Unfortuanately, in our effort to not reinvent the wheel, we rely on eachother to be honest, and correct, in the information they relay to us.

Whether I’m training men or Women, there is always an initial stage of Re-education. I can’t call it education, because that would imply a clean slate. And My clients have rarely if ever come to me from that preferred vantage point. Instead, they come with preconceived notions about what constitutes good eating, good training, and good living.

And they believe this because they’ve been taught it from people they trust. The trouble is that the information is wrong. If it were supposed to be a wheel, it’d look like a square.

Now don’t get me wrong. I’m not so naive as to believe that all preconceived notions are inherently false or bad (I’m naive for other reasons). But, some of the ideas swimming in the minds of many of you out there with regards to weight training, and what effects it has on you, and in what way, are patently vile.

The Myths seem to also come with a gender bias. Women are faced with a wholly different set of concerns than are men (in MOST cases, this isn’t meant to be an exhaustive statement). As such, the information they seek out, and get, is of a different nature. (of course, there is overlap).

I’m going to go out on a limb, and say that the BULK of the training knowledge being spouted off by people in the gym is at best only ½ the story, and at worst TOTALLY false.

Of course, you can’t blame them. The magazines dedicated to the gym-culture are nearly all crap. And at the top of the heap of crap is FLEX magazine. The one with all the huge Pro Bodybuilders on it.

If you could do one great thing for your body and life, it would be to look at one of the proposed routines in FLEX, take their advice to heart, then do the exact OPPOSITE.

In truth, there is little or no science behind any of their advice. It’s made up. Period.

But, the culture of bodybuilding (and the fiction associated with it) has become so ingratiated into the new gym culture, that there is now no separating out fact from fiction.

To complicate matters, there was a time in our not too distant Past when even the medical community was convinced that training with weights was BAD for you. They were sure that it would give you a heart attack, make you “muscle bound”, slow you down, etc (more on this later).

Thankfully, now-a-days, the world of science, through diligent testing, and research is realizing in fact that weight training is among the most important parts of any successful health building routine, and down right essential for changing body composition.

But the Myths remain. In this series I’ll examine some myths I often hear from Women. (I’ll eventually do one about the men, who’s myths are often even more wild and outlandish).

MYTH 1—Lifting Weights makes you Bulky and look like a Man!

This is by far the most commonly heard myth given when a woman is worried about starting a weight training routine. It is saturated in the minds of the female public. And it is often crippling. Women are so worried about weight gain, and looking “big” and “Manly”, that they avoid the one thing that will help them the most to look “Small” and “Feminine”.

Bad Bad move!

To Debunk this myth, we need to break it down.

The main argument is that their muscle size will increase and therefore increase the size of their overall “look”. There is some truth to this. But it misses the point. Of course, if you increase the size of your muscles, and everything else (fat mass) stays the same, then you’ll get bigger.

But, this isn’t how it works. In the real world. When you increase muscle size, you increase your metabolism, which aids in burning fat off of your body. You get leaner and less fat.

The second argument, is that it will make you weigh more. Also partly true. Muscle weighs more than fat. But muscle is Denser than Fat. Which means, that 2lb’s of muscle is smaller than 2lb’s of fat.

Of course, the weight gain is part of it. When you lift weights, your bone density increases. That is, your bones get stronger, a lot stronger. You can’t see it, but it’s happened. You are at less risk for osteoporosis, fractures, breaks, etc. And, yes, this makes them (and you) weigh more. But, is that a bad thing when you LOOK better? Get off the scale, it says nothing about how you LOOK.

The most important reason for lifting weights is not even the muscle gain, but the act of lifting itself. When you do a form of High Intensity Training (like weight training), you actually raise your metabolism for up to 24 hours! That’s right, for 24 hours you are burning more calories than you would have had you not trained with weights.

None of that “heart-zone” cardio shit you’ve been doing will give you that benefit. When you do high intensity exercises like weight training (and intervals, hill running, sprinting, etc), you end up causing more general fatigue to your body. It also breaks down slightly your muscles, which in turn requires your body to repair them (takes energy, calories). You body must replenish ATP stores, remove acid and other metabolic by-products. And restore Glycogen (the fuel you body uses to exercise).

All of this is energy intensive, and keeps your calorie burning furnace going long after you leave the gym

In the end, that means you will NOT look bulky, you will look lean, and fit.

And the last one is the most ridiculous and related to the first. You WILL NOT look like a man unless you take steroids. It isn’t possible. The average man has up to 10 times as much Testosterone running through his body than you, and he doesn’t even look like much of a man. To get truly huge, bulky muscles requires years of dedication, a solid workout routine, perfect diet, and gobs of Testosterone.

You can and should build muscle. But, you’ll never look like a man without hormone therapy. Sorry.

You will, however, look more feminine.

So, lets just remind ourselves of a short list of benefits of weight training:

1. Increased strength and ability to get around

2. Increased bone density, decreased risk of osteoporosis

3. Reduce arthritis pain

4. Reduce Back and shoulder pain

5. Increased metabolism

6. Lowered body fat percentage

There are many, many more.

MYTH 2—Women should use machines, not Free weights

TRUTH: No-one other than the decrepit, and severely injured should ever bother at all with machines. I make exceptions for cables, and a few others, but by and large, your entire routine should consist of free weight movements.

You are human. Being a Man or a woman is not going to change that much how you physiologically respond to a given stimulus. There are differences of course: The higher Testosterone levels of Men means that they have a higher plateau point generally, and sometimes means they can recover faster than women. But, the Stimulus used is very close to the same.

In fact, because of the fact that women have less stable joint cavities than men, free weight training is even more imperative, because it builds balance strength. It trains the little stabilizer muscles that don’t get worked on a machine.

Research has shown that machines cause MORE injury than free weights, because they force your body to conform to the movement pattern of the machine, rather than your own. No machine is one size fits all. We are all shaped slightly different. Free weights allow our bodies to move in their natural pattern, without mechanical hindrance.

MYTH 3—Cardio is better for your Health

Wrong. At least not steady State cardio. (for an Article on the kind of Cardio you should be doing, check out this Article by Keith Scott).

A Harvard Allumni Health study, followed 17,000 men for 4-years, and found that only VIGOROUS—NOT moderate—exercise reduced risk of death. There is very good reason to believe this study would apply to women, as the cardio vascular systems of both sexes are nearly identical.

Hard and Heavy weight training that includes circuits, and super sets will be far better for your health than slow paced heart-zone cardio. Add in Sprints, and intervals, and you’re golden.

There you have (my rather long) first installment. I will debunk more myths in Part 2. Until then, lift heavy!