This means that when you first lift the dumbbell there is a large portion of bicep muscle fibers that are not being activated. If you lift that weight over and over and over, you will tire out those first few fibers, at which point the brain will fire a new batch of fibers within the bicep to contract and allow you to continue lifting the weight. As you continue lifting, the working fibers will tire out, and new bunches of fibers will be activated. Eventually, after enough repetitions, you will have trained the entire muscle by using all of the available fibers.
We know that progressive weight training (where you increase the amount of weight being lifted and the level of intensity, over time) will produce bigger and stronger muscles due to this process of total muscle fiber exhaustion. The more fibers of the muscle you train, the stronger you will get. So in weight lifting, repetition plays a very important role. You must tire out the first groups of fibers to be able to train and strengthen the fibers that do not normally get used at the onset of training. Out of its desire for efficiency, your body will always use the same group of fibers first. So only after prolonged repetition will you begin to use the remainder of the fibers within the muscle being trained. Training every muscle fiber within each muscle is the ultimate goal. Ok, let's move on to the really exciting stuff.
The same goal can be accomplished without weights or training equipment of any kind, and in a mere fraction of the time, through isometrics.
"Iso" means "same," and "metric" means "length." Isometric means muscle contraction where the length (shortening or lengthening) of the muscle does not change. Looking once again at a bicep curl, on the way up, the bicep muscle is contracting, and is shortening its overall length. This is known as a concentric contraction. As you lower the dumbbell slowly, the bicep is lengthening while still in contraction. This is known as an eccentric contraction. If you were to hold the dumbbell half of the way up, and continue to hold it there, the length of the muscle is not changing during the contraction, and this is known as an isometric contraction.
Now remember what we know about muscle contraction. As you lift weights (continually apply force against resistance), the fibers that are working will tire out, and new ones will be fired by the brain to take over. During an isometric contraction, you are applying force to maintain the position of the dumbbell. As you do, the first fibers will tire out, and new ones will be fired, which will tire out and be replaced, and so on. So by simply holding the weight in place until near or total failure, you will have trained all of the individual fibers, and you will have accomplished the same result as performing multiple sets of weight-lifting repetitions.
Another example of an isometric contraction is pushing your hands together at chest level, and continuing to push for 10 to 20 seconds. This is where the magic begins!
As you push your hands together with equal force, your brain fires the first batch of fibers to push this object. Of course, your hands don't budge, but because you are still trying to push, your brain will continue to fire more and more fibers in an attempt to move it. In 10 to 20 seconds, with continuous maximum effort, all of the fibers in the muscle you are training will be activated. This is what was happening to our bound and tethered frogs. Keeping the frog's leg tethered to the post forced the frog to use all the fibers in the leg muscles as it tried to move. The pushing and pulling bound leg was performing an isometric contraction, which drastically improved the size and strength of the leg. In contrast, it only took a small percentage of the frog's free leg muscle fibers to move, and neither the size nor strength of the free leg was noted to have changed. The bound leg was restrained, and for two straight weeks, was continually pushing and pulling against an immovable object, forcing all of the fibers in its leg muscles to be activated. The benefits of isometric training had been scientifically validated!
Isometric exercises can build strength in a shorter time, with less overall effort, and with far less chance of injury than heavy weightlifting. FYI, I totally support the practice of lifting weights. This article is intended to illustrate the effectiveness of isometric exercises, compared to the effectiveness of weight training. Weight training has been proven by countless people around the globe to be effective in building muscular strength and size. Isometric training does, however, present some rather unique advantages. As discussed, training time and overall effort can be reduced without sacrificing results. Isometrics can be done anywhere with no need for a single piece of equipment. There is one more advantage that is, for me, by far the most important, and that is that isometric training will not only make you stronger and increase your endurance, but it will also make you faster.
"How?" I thought you'd never ask!
THE ANATOMY OF MUSCLE SPEED
Ok so we know that muscle fibers, or muscle cells, run the entire length of the muscle, and there are, depending on the size of the muscle, hundreds to thousands of muscle fibers within each muscle. The individual muscle fibers within a muscle are divided into three groups, defined by their speed of contraction:
Type I - Slow Twitch Fibers: These are used during endurance type exercise, such as running long distances, and are also found in higher concentrations in the body's postural muscles, allowing you stand upright all day long. These muscle fibers have the highest number of mitochondria (energy-producing organelles inside our cells), and are highly resistant to fatigue.
Type IIa - Fast Twitch Fibers: These fibers contract two to three times faster than Type I Slow Twitch Fibers. They have a slightly decreased amount of mitochondria compared to Type I, and will fatigue quicker.
Type IIb - Fast Twitch Fibers: These are the fastest of our muscle fibers, with the least amount of mitochondria. These fibers will tire quickly but have explosive energy. These fibers are used for intense, short bursts of exertion, such as sprinting and jumping.
During proper isometric contractions, you will activate ALL of your muscle fibers, including the slow twitch AND the fast twitch muscle fibers. The maximum speed of these fibers are set from birth, and will not get slower or faster. They can only get stronger or weaker. The stronger your fast twitch fibers are, the faster you will be.
We know that lifting weights with enough intensity and repetitions will increase muscle mass. Unfortunately, there is a sacrifice - studies have shown that a muscle's overall speed of contraction may be reduced due to the added weight of the increased muscle mass.
The bigger the mass of the muscle fibers, the more weight the fibers have to move, which will slow the speed of the contraction. Think of a train with 10 cars and 1 steam engine locomotive at the front. Add ten more cars and the locomotive engine will have a tougher time getting it up to speed. The maximum speed of the engine does not change; it only has to pull more weight, which will slow it down. This is what happens to muscles when they increase in size. Now instead of adding more cars, increase the horsepower by adding a second engine to the original 10 cars and the now doubled horsepower will get those cars up to top speed twice as fast. By training all the fibers to be stronger (slow twitch and fast twitch), without them becoming much heavier, you will increase the strength and speed of your movements.
During isometric training, both strength and speed are increased, but the benefits do not end here. It will also increase your endurance. Keep in mind, traditionally, training to increase speed required practicing moving body parts quickly, isolating the fast twitch fibers. Increasing endurance required a similar isolation strategy, training just your slow twitch muscles by performing repetitive motions for extended periods of time. Endurance, however, is actually increased by what could be the single most amazing component of our bodies - the mysterious, enigmatic, and highly controversial, energy-producing Mitochondria.
THE MAGIC & MYSTERY OF MITOCHONDRIA
Inside every one of your cells are microscopic organelles called Mitochondria. Mitochondria are the "power plants" of your cells, and are responsible for cellular respiration - they breathe oxygen. In fact, the main reason we breathe oxygen is for their use. Mitochondria breathe in oxygen and use it to create a chemical fuel called Adenosine Tri-Phosphate or ATP. Much like your car's combustion engine, which burns a mixture of oxygen and gasoline to create energy, the mitochondria burn a mixture of oxygen and, instead of gasoline, they use sugar and fat. The ATP created during this process is the chemical fuel that our muscle cells use to contract. So mitochondria burn sugar and fat (aka - calories), and provide our muscles with the chemical fuel they need to move.
"OK, so they produce the energy our muscles need to move, but why are they mysterious?" Well look at you with all the great questions. I will tell you!
We have all heard about DNA. This is our unique genetic blueprint -the instructions detailing how to build our own bodies. Inside every one of our estimated 10 trillion cells is a nucleus. Inside that nucleus is our DNA, also called Nuclear DNA ("inside the nucleus"). Leaving a single hair at the scene of a crime may be enough to get a criminal convicted because scientists can extract the DNA from that hair, and compare it with DNA from any other cell in his/her body. If it matches, they will know for sure who the hair belonged to, and have "hard evidence." Our DNA is our genetic blueprint and copies of it exist in every one of our cells - but not inside Mitochondria!
Mitochondria have their own DNA, which is quite different from ours. That's right, they have their own genetic blueprint, which is not a human blueprint. They are not us.
Our DNA is arranged in a double-helix pattern, and contains all the information needed for life. Mitochondrial DNA is not arranged in a double helix, but instead, a double stranded, closed loop. The only other life form with this configuration of DNA is bacteria.
"So mitochondria are bacteria?" Ehhh, sort of, but not really. This is where the controversy lies. Just what they are is not generally agreed upon by cellular biologists. Some scientists believe that at some point along the evolution/adaptation of life, cells which have a nucleus like ours (eukaryotic cells), joined forces with mitochondria which, like bacteria, have no nucleus (prokaryotic cells). These two different forms of life were able to construct a symbiotic relationship, where they would rely on each other for survival.
"So are Mitochondria bacteria or not?" There is one glaring difference between Mitochondria and bacteria. Bacteria are found EVERYWHERE - inside and outside of our bodies. They are truly everywhere. Mitochondria, on the other hand, are only found inside cells - in both plants and animals. They cannot survive on their own like regular bacteria. And, our nuclear DNA, the DNA that makes us who we are, actually plays a role in producing the protein needed to help build the mitochondria in our cells. We give them the structure they need for existence, and they give our cells the energy we need for existence. They can't live without our help, and we can't live without theirs! Yes, magically mysterious!!!
"So what does all this have to do with Isometrics?" Your questions are amazing!
EFFECTS OF EXERCISE ON MITOCHONDRIA
The single greatest fact concerning energy production within our cells is that mitochondria increase in both size and number with exercise. When you push your muscles past their everyday workload, mitochondria will grow and divide to keep up with the fuel you have demanded. This process of self-replication is called Mitochondrial Biogenesis. So when you exercise regularly, mitochondria will grow and divide, boosting the size and number of these calorie-burning power plants. The more mitochondria you have, the more oxygen you will be able to process, and the more fat and sugar you will be able to burn. Studies have found that the people with the highest numbers of mitochondria have the highest metabolisms. Simply, the more mitochondria you have, the more calories you can burn, and the more energy you can generate. Mitochondrial Biogenesis happens with ALL types of progressive exercise. It is very important to note the key word here, "progressive." Mitochondria will increase when you do more today than you did yesterday. If you do the same amount of exercise as you have been, there will be no need for mitochondria to reproduce. They have already reproduced to handle whatever demands you place on your muscles regularly. If you want more mitochondria (and trust me, you do), you need to push the body past the limits of what it is used to. This means you must continually train harder.
Isometrics allows you to always push yourself to your max, safely and efficiently. The longer you hold an isometric contraction, the more mitochondria you will create. This means more fuel for your muscles, and the ability to burn more calories.
CONCLUSION (Yes, we made it!)
Isometrics are the bomb-diggity.
There are an estimated 250 million muscle fibers in the human body. I have designed a series of isometric exercises that train as many of those 250 million fibers as possible, from multiple angles, to give you the widest range of strength and speed possible. No weights. No machines. No equipment of any kind. The power of your will is all that is needed.
Now if you absolutely must build muscle mass, you can perform isometrics for more than 20 minutes in a single session. 30 to 40 minutes will give the muscle sufficient exertion to build mass. Just be aware that your overall speed will be less than optimal with the increased weight of the muscle. Start with 20 minutes a day, and check your progress in a few weeks - you will be amazed!
For a comprehensive system of Isometric training techniques, click the link below!