You've gotta shake your head in awe and wonder when you realize what muscles do, either when going about the regular tasks of daily life or exercising at your limits.
Truly one of the great miracles of life is how chemical energy, stored in our bodies as glucose or fat, is converted into power and motion - lifting, running, catching, kicking, throwing, etc. To accomplish these, our bodies have multiple energy systems at work, often simultaneously.
To move, muscles must contract, which requires what is called adenosine triphosphate (ATP). When a single phosphate molecule breaks away from an adenosine molecule in the muscle cell, energy is released that causes a muscle to contract. Each time this happens, another phosphate molecule must replace the previous one for the muscle to contract again. That phosphate must come from delivered from outside the cell. The harder and longer we exercise, the more ATP is needed. When you run out of ATP, you stop moving.
Depending on whether you are jogging slowly or sprinting hard, a different energy system will perform the job of providing the phosphate to form ATP. If you're jogging slowly (aerobic), you use oxygen with glucose or fat. If you are doing high intensity exercise (anaerobic), you will use creatine phosphate for a few seconds, then switch to pure glucose, which won't last much longer than a few minutes.
Few of us, even in our most intense workouts, ever discover the limits of our energy systems because if we push our muscles hard enough, our willpower surrenders to the the burning sensation caused by the buildup of lactic acid and we slow down or lower the barbell. On rare occasions, such as shown in the video below, we reach our chemical boundaries, sometimes in ways that are admirable and comic at the same time. You can also learn a lot about how muscles work by watching someone, like these triathlon competitors, enter the twilight zone of muscle failure.
What you just saw was somenne who can no longer deliver phosphate to the ATP in their muscle cells. The commentator is wrong that the person has run out of calories. The energy is present in the body, but in forms that can no longer be delivered and converted fast enough. Actually these women were probably starting to produce glycogen by metabolizing their own muscle tissue through a slower process called gluconeogenesis, a last ditch effort by the body to respond to signals from the brain to get fuel to the muscle cells. But it's too little, too late. The people who finished ahead of them, through a combination of genetics and training, were able to keep their energy flowing.
What's also interesting to watch is how the body naturally recruits other muscles to accomplish a task that muscles usually used in the task can no longer perform. If you are trying to open the tight lid on a bottle of ketchup, sometimes you cannot do it just with an easy twist of your fingers, but must enlist your hardest grip and the action of your forearm muscles. Often when you watch the finish of a running race, you'll see people running in abnormal or awkward ways, throwing their arms side to side or lifting their hips to pull their legs forward. When one set of muscles fail, another set will come forward to try to get the goal accomplished. In the case of the video, these womens' leg muscles were depleted of ATP, but they were still able to recruit their fueled upper bodies, still rich with ATP, and crawl to the finish.
Shakespeare was right: we are such stuff as dreams are made of.
Showing posts with label muscles. Show all posts
Showing posts with label muscles. Show all posts
Over-Carbed and Under-Exercised
Months ago I talked about Doug McGuff, MD, and John Little's book entitled "Body by Science."
It's one of the most informative books on the relationship of muscles, strength and metabolism I've run across.
I recently ran across a video of a lecture by McGuff that's worth watching because he does an excellent job describing the dynamic relationship between muscles, glucose, and metabolic syndrome, the plague of civilization and underlying cause of the obesity epidemic.
Body By Science from Pinpoint Multimedia on Vimeo.
While I don't subscribe to his narrow view of exercise (he dismisses aerobic exercises like running and biking in favor of high intensity torture on weight machines), he has a deep understanding of the role of muscle in health, especially people who are trying to lose weight.
We tend to think of diet and exercise as separate topics, but after watching McGuff you'll see why it's critical to have muscle and exercise all three types of your muscle fibers hard, not just the slow twitch ones.
It's one of the most informative books on the relationship of muscles, strength and metabolism I've run across.
I recently ran across a video of a lecture by McGuff that's worth watching because he does an excellent job describing the dynamic relationship between muscles, glucose, and metabolic syndrome, the plague of civilization and underlying cause of the obesity epidemic.
Body By Science from Pinpoint Multimedia on Vimeo.
While I don't subscribe to his narrow view of exercise (he dismisses aerobic exercises like running and biking in favor of high intensity torture on weight machines), he has a deep understanding of the role of muscle in health, especially people who are trying to lose weight.
We tend to think of diet and exercise as separate topics, but after watching McGuff you'll see why it's critical to have muscle and exercise all three types of your muscle fibers hard, not just the slow twitch ones.
In Praise of Exercised Muscles
There's more to exercised muscle than meets the eye. What I mean by that is in our body-image obsessed culture, some tend to focus on the superficial aspects of it, like looking buff and strong. But there are many more compelling health reasons to build muscle with strength training than how it looks under our skin.
Consider the obvious, and not so obvious, benefits:
Mobility - No muscle, no movement. That we can walk, dance, run, lift, pump, jump, kick is a miracle. The most advanced robot can only crudely mimic the incredible array of movements made possible by the interplay of our muscles and bones.
Protection - Muscles are our shock abosorber system. Whether your're an NFL football player or snow boarder or an old TOJ, the muscles buffer your bones and internal organs by dissipating the shock of a fall or blow. Muscles keep you from falling. The stronger and more resilient your muscles, the more protection you have.
Stability and Balance - We know where we are, and whether we're right side up, by a combination of the brain, nerves and muscles called proprioception. The muscles do the heavy lifting to keep us erect and in line with the forces of gravity, as well as the subtle adjustments to enable us to navigate uneven terrain, like rocky trails.
Bone and joint health - Muscle contractions move, and place force on the bones, which in turn strengthens them as they respond to the stress. The movement of the muscle also spreads the synovial fluid, a lubricant between bones in a joint, to help the bone surfaces work smoothly and painlessly.
Metabolism - The most over-looked function of muscle is its role in reducing inflammation, which has been associated with the killers like cancer, diabetes, and cardiovascular disease. A major cause of inflammation is insulin resistance, a condition in which the glucose in our blood (there from eating or drinking carbohydrates) has no place to go. Excess glucose causes the liver to convert it to fatty acids, which in turn increase artery-clogging LDL cholesterol.
However, here muscle comes to the rescue. Through a process called glycogenolysis, an exercised muscle will move the glycogen out of your blood and store it as a useful source of energy in the muscle itself. And depending on how intensely the muscle was exercised, this continues for hours, and even days, after exercising. Pretty cool.
We have over 600 of them, and they are mostly made of water. Tend them like a garden. Exercise them at least three times a week. Hydrate well and feed them with good food (mainly protein with some carbs). In exchange, they will take care of you, in more ways than you know.
Consider the obvious, and not so obvious, benefits:
Mobility - No muscle, no movement. That we can walk, dance, run, lift, pump, jump, kick is a miracle. The most advanced robot can only crudely mimic the incredible array of movements made possible by the interplay of our muscles and bones.
Protection - Muscles are our shock abosorber system. Whether your're an NFL football player or snow boarder or an old TOJ, the muscles buffer your bones and internal organs by dissipating the shock of a fall or blow. Muscles keep you from falling. The stronger and more resilient your muscles, the more protection you have.
Stability and Balance - We know where we are, and whether we're right side up, by a combination of the brain, nerves and muscles called proprioception. The muscles do the heavy lifting to keep us erect and in line with the forces of gravity, as well as the subtle adjustments to enable us to navigate uneven terrain, like rocky trails.
Bone and joint health - Muscle contractions move, and place force on the bones, which in turn strengthens them as they respond to the stress. The movement of the muscle also spreads the synovial fluid, a lubricant between bones in a joint, to help the bone surfaces work smoothly and painlessly.
Metabolism - The most over-looked function of muscle is its role in reducing inflammation, which has been associated with the killers like cancer, diabetes, and cardiovascular disease. A major cause of inflammation is insulin resistance, a condition in which the glucose in our blood (there from eating or drinking carbohydrates) has no place to go. Excess glucose causes the liver to convert it to fatty acids, which in turn increase artery-clogging LDL cholesterol.
However, here muscle comes to the rescue. Through a process called glycogenolysis, an exercised muscle will move the glycogen out of your blood and store it as a useful source of energy in the muscle itself. And depending on how intensely the muscle was exercised, this continues for hours, and even days, after exercising. Pretty cool.
We have over 600 of them, and they are mostly made of water. Tend them like a garden. Exercise them at least three times a week. Hydrate well and feed them with good food (mainly protein with some carbs). In exchange, they will take care of you, in more ways than you know.
Going, Going, Gone
With the start of the New Year, there's s surge in gym memberships and cable TV infomercials on how to lose weight. For many, getting in shape is synonymous with losing weight, though the two are not the same things.
You can lose weight by eating fewer calories and still be out of shape. Likewise, you can be in pretty good shape, i.e., normal blood pressure, OK lipids, and also overweight. Some 300 pound NFL lineman are in tremendous physical condition, while many skinny people are not.
However, most of us do equate fitness with leanness, which is usually measured in percentage of body fat. Exercise physiologist Covert Bailey was one of the first to get that concept in front of the general public in his Fit or Fat books over twenty years ago. Healthy range of body fat is different from males to females. In general, a healthy male may measure between 10-20% body fat, and women 15 to 25%. This number goes up slightly with age. The number also varies even in elite athletes, depending on their sport. Marathoners can be in the 5-7 range, while swimmers are twice that.
So what's the advantage of a low percentage and what does it have to do with fitness and health? Leanness means less wear and tear on your skeleton, especially your joints. Your heart does not have to work so hard for the same amount of physical work, thus improving your endurance. Most importantly, leanness, when combined with exercise, reduces the amount of body inflammation suspected to cause many chronic diseases.
I've recently been reading two excellent books on body fat and exercise: 1) Robb Wolf's The Paleo Diet, and 2) Tim Ferris' The 4-Hour Body. Both are based on a similar premise: you will lose weight if you restrict simple carbohydrates in your diet. Wolf says to eat mainly high quality protein, vegetables, and fruit, but no wheat or legumes. Ferris says okay to legumes (because if you don't eat them you won't feel full and be hungry all the time), but no to fruit (fructose is a sugar, the digested final product of all carbs). Both these books are based on good science; the references are there if you want to find out for yourself.
I think these authors are in their late 30's, about the time most humans have just passed their athletic prime and when percentage of body fat tends to start to drift up, especially around the gut. As a result, they are a little body image-obsessed. Ferris even goes so far as to have pictures of his shirtless torso as proof his diet works. (I'm much more impressed when he does 180+ kettlebell snatches on YouTube.) Ferris gets excited when his body fat percentage gets so low he can see the veins popping out underneath his skin. Pretty funny.
This TOJ thinks both of them offer sound advice on eating and exercise, and there's no doubt that for most people, lowering percentage of body fat by reducing simple carb intake (especially anything with white flour or sugar) is good for you. In the past few years, the evidence has mounted that consumption of simple carbs elevates insulin and causes insulin resistance, which is linked to Type-II diabetes, cardiovascular disease, and some cancers.
Percentage of body fat is a much more reliable indicator of health than the popular Body Mass Index (BMI). Many very fit athletes have high BMI's because muscle is much heavier that fat. Muscle is preferable to body fat because muscle raises your metabolic rate and lowers insulin levels, especially when the muscles have been exercised. Fat can't do that, it's just along for the ride.
If you follow the diet and exercise advice of either Wolf or Ferris, expect to lose fat, not necessarily weight. A pound of fat takes up four times as much space as a pound of muscle. When you combine a high protein diet with exercise, especially with lots of resistance exercise, you will lose body fat and increase muscle. The surest sign you are will be in looser clothing, especially around your waist, thighs, and butt.
Who knows if you'll see changes in the mirror, but you'll feel them. That's what really counts.
You can lose weight by eating fewer calories and still be out of shape. Likewise, you can be in pretty good shape, i.e., normal blood pressure, OK lipids, and also overweight. Some 300 pound NFL lineman are in tremendous physical condition, while many skinny people are not.
However, most of us do equate fitness with leanness, which is usually measured in percentage of body fat. Exercise physiologist Covert Bailey was one of the first to get that concept in front of the general public in his Fit or Fat books over twenty years ago. Healthy range of body fat is different from males to females. In general, a healthy male may measure between 10-20% body fat, and women 15 to 25%. This number goes up slightly with age. The number also varies even in elite athletes, depending on their sport. Marathoners can be in the 5-7 range, while swimmers are twice that.
So what's the advantage of a low percentage and what does it have to do with fitness and health? Leanness means less wear and tear on your skeleton, especially your joints. Your heart does not have to work so hard for the same amount of physical work, thus improving your endurance. Most importantly, leanness, when combined with exercise, reduces the amount of body inflammation suspected to cause many chronic diseases.
I've recently been reading two excellent books on body fat and exercise: 1) Robb Wolf's The Paleo Diet, and 2) Tim Ferris' The 4-Hour Body. Both are based on a similar premise: you will lose weight if you restrict simple carbohydrates in your diet. Wolf says to eat mainly high quality protein, vegetables, and fruit, but no wheat or legumes. Ferris says okay to legumes (because if you don't eat them you won't feel full and be hungry all the time), but no to fruit (fructose is a sugar, the digested final product of all carbs). Both these books are based on good science; the references are there if you want to find out for yourself.
I think these authors are in their late 30's, about the time most humans have just passed their athletic prime and when percentage of body fat tends to start to drift up, especially around the gut. As a result, they are a little body image-obsessed. Ferris even goes so far as to have pictures of his shirtless torso as proof his diet works. (I'm much more impressed when he does 180+ kettlebell snatches on YouTube.) Ferris gets excited when his body fat percentage gets so low he can see the veins popping out underneath his skin. Pretty funny.
This TOJ thinks both of them offer sound advice on eating and exercise, and there's no doubt that for most people, lowering percentage of body fat by reducing simple carb intake (especially anything with white flour or sugar) is good for you. In the past few years, the evidence has mounted that consumption of simple carbs elevates insulin and causes insulin resistance, which is linked to Type-II diabetes, cardiovascular disease, and some cancers.
Percentage of body fat is a much more reliable indicator of health than the popular Body Mass Index (BMI). Many very fit athletes have high BMI's because muscle is much heavier that fat. Muscle is preferable to body fat because muscle raises your metabolic rate and lowers insulin levels, especially when the muscles have been exercised. Fat can't do that, it's just along for the ride.
If you follow the diet and exercise advice of either Wolf or Ferris, expect to lose fat, not necessarily weight. A pound of fat takes up four times as much space as a pound of muscle. When you combine a high protein diet with exercise, especially with lots of resistance exercise, you will lose body fat and increase muscle. The surest sign you are will be in looser clothing, especially around your waist, thighs, and butt.
Who knows if you'll see changes in the mirror, but you'll feel them. That's what really counts.
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