A typical myth in bodybuilding circles is that you must exercise fast and slow twitch muscles separately for getting the best muscle building workout. This could not be further from the truth. In fact, you can easily exercise both muscle types at the same time and still get excellent results. Here is why and what you should do in your own workouts for optimum results.
Slow twitch muscles are the easiest to describe. They are very powerful aerobically, meaning that they are good at using oxygen. They are called slow twitch because of how slow they are to fatigue, not because of their speed of contraction. Muscles that are slow to fatigue are important for endurance. These types of fibers also recover fast after getting fatigued. That is why slow twitch muscle fibers are so important for long distance runners and similar endurance athletes.
Fast twitch muscles are more complicated, because they are classified into three subgroups. One is the Fast Oxidative fibers, which are good aerobically and are resistant to fatigue. Another type is Fast Glycolytic, which includes fibers that are more effective anaerobically (without oxygen transfer). They are the easiest to fatigue and the slowest to recover. The third type is intermediate, referred to as Fast Oxidative Glycolytic. The fast twitch muscles are so called because they fatigue fast. However, they recover slowly after being fatigued.
These are rather simple descriptions of muscle fiber types based on how well they use oxygen and on how fast they fatigue and recover. Indeed, so called slow twitch muscles actually contract faster and recover faster from workouts than do any subgroup of fast twitch fibers.
Muscle fibers are recruited by your brain to optimize force and not speed of contraction. Because of this, slow twitch muscles are the first and easiest fiber type to engage. This type also requires the least amount of energy. This means that if you lift weights too quickly, you will engage mostly your slow twitch muscles.
Slightly more energy is required to engage the Fast Oxidative muscle fibers, and still more for the Fast Oxidative Glycolytic fibers. The highest amount of energy is required to engage the Fast Glycolytic fibers.
The key for an optimum workout, therefore, is to take advantage of what physiologists call orderly recruitment. This means engaging each type of muscle fiber in sequence, from low energy and fast recovery to high energy and slow recovery. The important factors for accomplishing this in the same workout are: 1) sufficient weight for bringing on muscle failure (i.e., the point at which you can no longer lift the weight); 2) the right lifting speed for engaging all types of muscle fibers in sequence; and, 3) the total time under load (TUL) for a particular set or muscle group.
The optimum strategy for accomplishing all of the above entails a very slow lift rate and an equally slow return rate. One extra advantage of such super slow movements is that it is easier to use good form. Fast lifting leads to jerking weights rather than lifting them. Jerking weights merely recruits mostly slow twitch muscles and leaves other fiber types unchallenged.
All the recommendations in this article are backed by numerous scientific studies over the past few decades. The best summary of this research is now available in a book, 'Body by Science', by Dr. Doug McGuff, M.D., and John Little. It is the best and most recent book on this topic. By the way, the subtitle of this book is, 'A Research-Based Program for Strength Training, Body Building, and Complete Fitness in 12 Minutes a Week'. Based on my experience, 12 minutes a week may even be more than you need. My own muscle building improvements have accrued very effectively on about 10 minutes a week.
Slow twitch muscles are the easiest to describe. They are very powerful aerobically, meaning that they are good at using oxygen. They are called slow twitch because of how slow they are to fatigue, not because of their speed of contraction. Muscles that are slow to fatigue are important for endurance. These types of fibers also recover fast after getting fatigued. That is why slow twitch muscle fibers are so important for long distance runners and similar endurance athletes.
Fast twitch muscles are more complicated, because they are classified into three subgroups. One is the Fast Oxidative fibers, which are good aerobically and are resistant to fatigue. Another type is Fast Glycolytic, which includes fibers that are more effective anaerobically (without oxygen transfer). They are the easiest to fatigue and the slowest to recover. The third type is intermediate, referred to as Fast Oxidative Glycolytic. The fast twitch muscles are so called because they fatigue fast. However, they recover slowly after being fatigued.
These are rather simple descriptions of muscle fiber types based on how well they use oxygen and on how fast they fatigue and recover. Indeed, so called slow twitch muscles actually contract faster and recover faster from workouts than do any subgroup of fast twitch fibers.
Muscle fibers are recruited by your brain to optimize force and not speed of contraction. Because of this, slow twitch muscles are the first and easiest fiber type to engage. This type also requires the least amount of energy. This means that if you lift weights too quickly, you will engage mostly your slow twitch muscles.
Slightly more energy is required to engage the Fast Oxidative muscle fibers, and still more for the Fast Oxidative Glycolytic fibers. The highest amount of energy is required to engage the Fast Glycolytic fibers.
The key for an optimum workout, therefore, is to take advantage of what physiologists call orderly recruitment. This means engaging each type of muscle fiber in sequence, from low energy and fast recovery to high energy and slow recovery. The important factors for accomplishing this in the same workout are: 1) sufficient weight for bringing on muscle failure (i.e., the point at which you can no longer lift the weight); 2) the right lifting speed for engaging all types of muscle fibers in sequence; and, 3) the total time under load (TUL) for a particular set or muscle group.
The optimum strategy for accomplishing all of the above entails a very slow lift rate and an equally slow return rate. One extra advantage of such super slow movements is that it is easier to use good form. Fast lifting leads to jerking weights rather than lifting them. Jerking weights merely recruits mostly slow twitch muscles and leaves other fiber types unchallenged.
All the recommendations in this article are backed by numerous scientific studies over the past few decades. The best summary of this research is now available in a book, 'Body by Science', by Dr. Doug McGuff, M.D., and John Little. It is the best and most recent book on this topic. By the way, the subtitle of this book is, 'A Research-Based Program for Strength Training, Body Building, and Complete Fitness in 12 Minutes a Week'. Based on my experience, 12 minutes a week may even be more than you need. My own muscle building improvements have accrued very effectively on about 10 minutes a week.
About the Author:
Dr. Dennis Clark researches, reviews, and provides science-based advice on bodybuilding foods in his popular free report on the muscle building diet. Dr. Clark also offers tips on where to find the best bodybuilding supplements anywhere.
No comments:
Post a Comment