Isometric Exercise for Muscle Growth PDF

It is clear that isometric training can result in significant hypertrophy. -Fleck, et al.1- 3. Isometric exercise is at least as effective as dynamic exercise for muscle growth. You can get bigger...

It is clear that isometric training can result in significant hypertrophy. -Fleck, et al.1- 3. Isometric exercise is at least as effective as dynamic exercise for muscle growth. You can get bigger using isometrics. In athletics training, many myths seem to hang around through the years—despite being repeatedly disproven. A good example of such a myth is the idea of spot reduction; the notion that, simply by working the abdominals, belly fat will melt away, leaving the abs more visible. In fact, this theory was demonstrated to be a fallacy decades ago; the body loses fat proportionately, no matter how you train.^ Yet we still see this concept touted in training courses and exploited in infomercials. Another myth which is still in wide circulation despite being completely rejected by science is the idea that isometric training does not trigger hypertrophy—that it doesn't produce significant muscle growth. Nothing could be further from the truth, as we shall see. Early studies of isometrics vs other methods of training tended to be based around function. They mainly examined strength increases and endurance. However, the bodybuilding boom could not be ignored forever, and in the mid-eighties researchers at the Department of Medicine of the University College London sought to finally discover the truth regarding the effects of isometric work versus dynamic work in relation to hypertrophy. In other words: can isometrics make you bigger as well as stronger? Amazing as it seems, nobody had really answered this question before. Yes, the Springfield Frog Experiment proved that isometrics increased muscle size in frogs, who—thanks to unilateral isometrics—wound up looking like lopsided aquatic Schwarzeneggers. But that was frogs. What about humans?  Over the course of twelve weeks, a sample population was split into two. One group performed dynamic thigh exercises on a leg-extension machine. The researchers had this group exclusively lift weights upwards (concentric movement) with one leg, and try to resist much heavier loads pushing downwards (eccentric movement) with the other leg. The second group performed the same thigh exercise, but isometrically—they statically fought against the leg extensions with one leg. (The unworked leg of the isometric party functioned as a control group.) Throughout the trial, measurements were taken with the most accurate instruments available to science (electromyographs, anthropometers and computerized topography). The results were highly interesting, to say the least. The strength of the isometrically-trained quadriceps was almost off the chart—more than doubling the eccentric strength increase, and tripling the concentric gain. There was no surprise there. But there were surprises in the hypertrophy—muscle gain—results. All three methods of resistance training caused some muscle growth; though nothing equal to strength gain/ The highest muscle gain came from the concentric training, where the muscles increased by an average of 3.8 cm2. Isometrics was hot on the heels of eccentrics, with a 3.7 cm2 increase; and eccentric lifting came in dead last, with a 2.4 cm2 size increase. The isometrically-trained muscles also gained more density (think "muscle tone") than the muscles trained by eccentric or concentric movements/  Muscle contractile strength Muscle size Muscle density Concentric □ Eccentric Isometric To summarize: isometric training actually causes more muscle gain than training with weights you can lift up repetitively. Not by a huge amount, mind you—but by a significant amount. Metastudies^ have confirmed the fact: if you want to gain muscle, you can do so with isometric training. So: if the science is already out there, why isn't everyone doing isometrics, in gyms all over the world? Sacred cows and Semmelweis The major difficulty in establishing a radical or novel practice lies not in its efficiency or validity. The major difficulty is psychological. Where sacred cows are established in any field of endeavor, they are incredibly hard to overcome—no matter how useful or powerful alternative theories may be.  In psychology this almost universal effect—the natural instinct to reject new ideas in favor of the status quo—is called the Semmelweis reflex. The Semmelweis reflex is named after a famous medical pioneer, Ignaz Semmelweis. Through rigorous experimentation, Semmelweis proved that childbed fever—a major cause of mortality in the 19th century— could be virtually eliminated if doctors simply washed their hands in an antiseptic solution. Despite this, the entire medical community (of scientists, remember!) automatically rejected Semmelweis's advice out of hand—simply because, throughout recorded history, doctors had never deigned to wash their hands. It didn't help that Semmelweis was ahead of his time: Pasteur wouldn't develop germ theory for several years, so nobody understood fully why his method worked. Eventually Semmelweis's ideas were gradually accepted, saving literally millions of lives, worldwide. But in his own time, Semmelweis was shunned by his colleagues and ultimately sent to an insane asylum, where he died from a beating by the guards—all because humans find it difficult to accept new ways of doing things, even if they work. Modern bodybuilders are not exempt from the Semmelweis reflex; in fact, they exemplify it. The idea of picking up objects and putting them down for multiple sets and reps is so deeply engrained in the psyche of the entire strength and conditioning world that its hold is virtually impossible to break for many people. This is a mistake. All athletes must be encouraged to base their training on logic and science, rather than primitive groupthink. There is nothing magical about lifting objects like barbells up and down, and up and down. As discussed in the previous chapter, the most basic biological science teaches us that muscle cells are binary. Like basic lightbulbs, they either switch on, or off. They either contract, or they don't. They do not know what the rest of your body is doing while they are doing this; they don't care whether your arms are moving up and down, or remaining in one position. All they know is on/off. So why should it matter whether you are lifting objects up or down, or keeping objects stationary, as in an isometric hold? Muscular growth: hypertrophy, load, fatigue Over a century ago, biologists believed that muscles grew larger via hyperplasia—cell splitting. It was believed that novel forms of resistance caused new muscles cells to split away and develop, much in the way embryos grow from initial gametes (sex cells). We now understand that this does not occur. Although hyperplasia is a real phenomenon in muscles, it accounts for less than 5% of any new growth, and can largely be discounted as a mechanism. We now know—and we have known for some time—that muscle growth is due to hypertrophy: cellular enlargement. Rather than splitting to make new cells, muscles respond to resistance by increasing the size of the individual cells. The biology of muscular hypertrophy is imperfectly understood. It is currently believed that microtrauma, metabolic stress, and mechanical tension all play major roles.^  One of the reasons why static exercise is effective for improving dynamic performance is that both static and dynamic training produce similar hypertrophic effects. -Morrissey, et al: Medicine and Science in Sports and Exercise^ Whatever the biology, what we can do with relative certainty is develop models which explain how muscular growth is triggered, according to empirical evidence. Recent studies seem to agree on one fundamental point: in terms of training, the 228 Highlighters---------- key factor is not the amount of force exerted by the muscles, per se: it's the depth of fatigue caused by that force: Heavier loading (usually expressed as percentage of a person's maximal strength or single repetition maximum - 1RM) is often recommended as the optimal way to maximize muscle hypertrophy with resistance training. However, there is very little empirical evidence to support this supposition and it is unclear as to the physiological mechanisms by which heavier training loads would provide a signal for greater muscle hypertrophy as compared to, for example, a lighter load lifted to the point of fatigue; both conditions would result in a large amount of muscle fibers being recruited. As proof-of-principle, we recently tested this idea and demonstrated that a single bout of resistance exercise performed at 30% of1RM to the point of momentary muscle fatigue (failure), was equally as effective in stimulating myofibrillar protein synthesis rates (MPS) as loads lifted at 90% of 1RM (also lifted to fatigue). -Mitchell, etal. 20122 The scientific verdict: high loads build strength. High volume builds endurance. Muscular fatigue generates growth. Of 279 Highlighters-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- course, there is some overlap, but the principle stands nevertheless. The seminal study quoted above was published in the Journal of Applied Physiology, where subjects were instructed to train to deep fatigue—"muscle failure"—using either 90% or 30% of their maximum training load. Using MRI scans and advanced histochemical testing, it was discovered that both training sessions produced similar levels of growth—as long as the training was taken to failure. The conclusion? Muscle 73 Highlighters fatigue triggers hypertrophy; not load or volume.8 Often science and in-gym experience (a.k.a. "broscience") find themselves at loggerheads, but in this case they seem to mesh perfectly. This principle explains why, traditionally, strength athletes use very low repetitions with heavy weights, and long breaks between sets—it allows them to exploit high levels of force without becoming exhausted. (If pure strength is what you want, exhaustion would simply hamper training volume and frequency, with no added benefit.) On the other hand, bodybuilders tend to focus on somewhat higher repetitions with (relatively) lighter weights, plus intensity techniques such as drop sets, forced reps, pre-exhaustion sets and rest-pause reps—these methods allowing them to deeply fatigue their muscles to a level heavier loads do not permit. They are rarely found in strength-training regimens, however. Anecdotally of course, this makes sense to anybody who has spent some time in the training world. It has long been realized that some athletes can train by lifting huge loads and remain relatively small—Olympic lifters are the prime example—while others can get away with lifting lighter loads and grow much larger muscles—here, bodybuilders are the prime example. The 324 Highlighters key to developing strength is repeated high muscular force; the key to hypertrophy is muscular fatigue. This is not to say that bodybuilders can't be strong. Many bodybuilders, plainly, are hugely strong—if not in the elite league of powerlifters or weightlifters. It is also not meant to imply that strength has nothing to do with bodybuilding: it does, precisely because in order to progressively fatigue their muscles over time, bodybuilders are forced to use incrementally heavier loads to prevent habituation. It just means that bodybuilders don't develop strength for its own sake—they learn to use strength, and the heavy loads it permits, as a tool to fatigue their muscles more and more deeply. Isometrics and muscular fatigue = growth This leads us neatly to the key question: if muscular fatigue is what causes growth, can isometric holds generate fatigue as well as dynamic repetitions? Simple math and physics can answer this question for us. Muscular fatigue is directly proportionate to the sum of muscular contraction. How do we measure muscular contraction? Muscular force multiplied by time. Muscular fatigue is directly proportionate to muscular force x time. In other words, fatigue can be defined by the amount of force your muscles can generate in a given period of time. More force in the same length of time results in more fatigue. This is sometimes known in hypertrophy science as TUT, or Time-Under- Tension. Research indicates that greater TUT leads to greater muscle fiber recruitment and muscle growth.^ We have already established that isometrics can result in more muscular force than dynamic reps—this is a consequence of the force-velocity relationship (page 21). But what about the time factor? Can you generate more force over time by lifting a load up and down or by holding it statically? Think of a standard bodybuilding exercise: a barbell press. When you perform a press, the level of force output in your muscles fluctuates. At the bottom of the movement, with the bar on your chest, there is virtually no force involved. As you lift the weight, force increases due to leverage until your upper arms are parallel to the floor, then maxes out; once you pass that point, force decreases, and at the top of the movement, the force radically reduces again. When you lower the bar back down, there is less force required than at any stage of the upwards movement, because gravity assists. The same phenomenon occurs with virtually all conventional lifting; the tension over time fluctuates, often like a sine wave; where tension should be kept as high as possible, it actually repetitively drops down into a low-tension state, which simply represents wasted time and energy. With isometric tension, there is no "wasted" fluctuation—the highest potential contraction/force output can be maintained throughout the exercise. In other words: it is mathematically impossible for dynamic movements to match isometrics in fatiguing the muscles. 172 Highlighters- You probably have subjective experience of this yourself. If you have ever had to pick up a heavy piece of furniture or a fridge and hold it steady briefly, you will have experienced how much "heavier" the load gets after just a few moments, until it becomes almost impossible to hold up. If you struggle on, your biceps will be screaming, cramping, and flushed with waste buildup. Eventually, the muscles will simply give out—seemingly quite quickly, if the weight is heavy. Isometric holds compare very favorably with dynamic movements in terms of short-term fatigue. Individuals who say otherwise are simply not performing them properly. TIME (length of set) c □ —* u T5 CL 0 TIME (length of set)  Traditional lifting tension over time (top) vs isometric tension over time (bottom) Isometrics is by no means new and untested Naturally, it might be argued: but lifting barbells up and down, works. It has made people bigger and stronger for generations. Why change to something new? Well, of course isometrics is not new. In terms of bodyweight holds—of the kind found in martial arts and calisthenics —it dates back thousands of years. The old-time strongmen who fathered strength training and bodybuilding as we know it today all used static isometric holds in training and as feats of power. The validity of isometrics, performed correctly, has been substantiated by experience and scientific studies. It has been used and praised by real-world experts from Eugen Sandow to Bruce Lee to Paul Anderson. By comparison, the adjustable barbell is only a little over a century old. If anything, barbells and dumbbells are "new". This section of the manual is not intended as an attack on conventional methods. We are not suggesting that lifting barbells dumbbells and machine levers up and down doesn't work. The science proves that it does—and, moreover, if your goal is to become good at lifting bars, kettlebells, or bags of sand, then you must use those tools. We're not saying that it's evil, or tha you should stop using conventional methods—if you wish to, there are plenty of ways you can combine regular lifting with isometrics (see bonus chapter). But just because something works, it doesn't mean we should close our minds to alternatives For thousands of years, people got around on horses and carts; does that negate the usefulness of jet planes and motor vehicles? *This is to be expected; if you double your strength, you don't double your muscle size. Much of the improvement comes from neurological recruitment: see page 19f.