Isometric Exercise: Safer Than Dynamic Exercise PDF

The most important thing from the research? Tendons seem to love heavy isometric load and it reduced tendon pain immediately. -Dr Ebonie Kendra Rio1 5. Isometric exercise is less like...

The most important thing from the research? Tendons seem to love heavy isometric load and it reduced tendon pain immediately. -Dr Ebonie Kendra Rio1 5. Isometric exercise is less likely to incur injury, either chronic or acute, than dynamic exercise. Isometrics are safer, protect your joints and save your body from wear and tear. Even though isometric training has fallen out of favor in modern gymnasiums, there is one area where isometrics never lost its popularity: rehabilitation, or physical therapy. There are two excellent reasons why this is: A primary advantage of isometric exercise in musculoskeletal rehabilitation lies in the opportunity for Localized muscle exercise without moving joints. Strength increases more rapidly in isometric than in dynamic exercises. -Kuprian, Physical therapy for Sports^ The identical qualities which make isometrics so ideal for rehabilitation purposes also make it a remarkably safe form of resistance training. Not only does isometrics radically reduce chances of acute injuries—like torn muscles or ligaments—it is also exceptionally good at building strength while avoiding the kind of chronic aches and pains so common in resistance training. In fact, cutting-edge studies show that, far from generating joint pain as other training methods typically do, isometrics actually reduces itJ If you want to build optimal levels of strength and muscle while protecting and strengthening your joints for life, isometrics is the form of training for you. Super-safe isometrics: Hooke’s law and cortical inhibition The physics of acute musculoskeletal joint injuries—strains, sprains, tears and breaks—is well understood. These injuries are effects of Hooke's law: F = kx Hooke's law: where F is the force acting on an elastic body, x is the amount of deformation on the body caused by the force, and k is the tautness of the body. In physical therapy, Hooke's law has been defined thusly: The strain is proportional to the stress producing it (so long as the strain is not too great, for once the so called "elastic limit" is passed, injury occurs")A Muscles, tendons and bones all possess such a limit. When they are exposed to forces in excess of that limit, injury is the result. The degree of injury is proportionate to that excess force. An example might be a sprained ankle after jumping from too great a height, a torn muscle from lifting a heavy weight, or a broken bone after colliding with another football player. In all these cases, the stress—or force—which causes the injury is due to two related external factors: either load or momentum. When these forces surpass the elastic limit of the athlete's tissues, injuries occur. Once you understand this, you have the "secret" as to why isometric training is so safe. Although the forces generated in isometric training can be considerable, these forces are generated internally—by the athlete's own contractions. There is no external load, and no momentum to tackle. Human muscular contractions are actually capable of causing damage—there are innumerable instances of individuals struck by lightning, whose involuntary muscle contractions have been strong enough to literally break their own bones. However, in the case of voluntary muscular contractions—the kind employed in isometric training—the nervous system has evolved a highly protective feedback-based failsafe system. This system, known as cortical inhibition, automatically puts the brake on the muscle contraction before it reaches an unsafe levels As a result, pushing as hard as you possibly can on isometric exercises allows you to maximize your force production without exceeding your body's strain limit, effectively preventing injury.  When performing alternative forms of resistance training, such as explosive work, plyometrics or even regular weight­ training, you are much less well protected by cortical inhibition. Although your body will do its best to keep working inside its strain limit, your nervous system is no longer "in charge" as it is with isometrics. The effects of momentum, gravity, and altering leverage/strength through different ranges of motion all mean that that the body can be suddenly "caught out" by excessive levels of force which it is unable to handle. Compare a maximum isometric squat to a gymnast or parkour traceur landing a flip. In the first case, the forces on the knees are entirely dictated by the nervous system; in the second, they are dictated by the athlete's mass, speed, even landing surface. It the forces become excessive, there is no off-switch—the damage is done. Another example in the latter category might be the weightlifter who explodes up a bar using momentum, only to have it "catch" in the sticking point. With the momentum suddenly gone, the muscles alone might be momentarily incapable of the load, and an injury is the result.^  Uncontrolled external forces are typically the cause of acute injuries. This is not to say, of course, that explosive or uneven modes of training are bad. They certainly have their benefits. After all, safety is not the only consideration in training—just as it should not be for life in general. It is merely to explain why isometrics poses such a low risk of acute injury. Nagging injuries are not inevitable Chronic—i.e., persistent, recurrent injuries—typically have a different etiology than acute (sudden) injuries, although acute injury can precipitate or contribute to chronic pain. Whenever chronic injury is discussed in a context of athletic training —even in academic studies—one phrase is repeated over and over: that phrase is wear and tear. Just ask any intermediate or advanced weightlifter or bodybuilder: repeated resistance training drills can, undoubtedly, lead to differing levels of chronic pain over time. These chronic injuries can occur at different levels. At the more superficial level we have the kind of niggling aches which constitute tendon injury and tendonitis; sore elbows, painful rotator cuffs in the shoulders, etc. This kind of injury can clear up in weeks or months with the correct therapy. Going deeper we have damage like bursitis and ligament damage, which— where curable—may take months or even years to correct. Then, at a deeper level still, we have the kind of cartilage damage —painful knees, sore lower back, hips, etc.—which can ultimately result in osteoarthritis. The damage sustained as a result of these conditions are not thought to be reversible. Many trainees have come to accept some type of consistent joint pain as just "part of the game"—the price to be paid for the benefits of heavy training. But it doesn't have to be this way. To understand why, let's look more closely at what causes the damage. Why is it always the joints? You might have noticed that the tissue areas typically effected in chronic injuries—the tendons, bursae, cartilage, etc.— are all joint tissues. It's a truism in training that, while muscles can be subject to acute (sudden) injuries (e.g., tearing), it's the joints which are largely subject to chronic injury and pain. Why is this? The answer has nothing to do with force, per se. The muscles are subject to just as much force as the joints during exercise, and they also act as shock absorbers. It's also not that the joints are "weak links" in the human machine: tendons are, on average, twice as strong as muscle, and possess a tensile strength equivalent to bone. Lack of flexibility is not an answer, either—a flexible substance, like rubber, will wear out more quickly than a hard substance like iron, if both are subject to the same forces. Joints are subject to higher levels of chronic pain and "wear and tear" than other tissues for one major reason: mechanical abrasion. Joints have evolved to articulate, and give us superior ranges of movement. This is necessary for mobility, however the trade-off is that joints suffer proportionately higher levels of friction.  If you have ever had a bad knee, elbow, or shoulder, you may have felt this friction yourself during movement. When you lower into a deep squat, perform a bench press or a barbell curl, you can sometimes feel the tissues in the joint "grinding" away—with the typical result of pain and irritation during and after the exercise. Healthy knee (left) vs osteoarthritic knee (right). In this case, years of internal abrasion literally ground away the cartilage which cushions the femur and tibia (note the narrowing of the internal space of the joint). The result is bone-on-bone contact, and significant pain. Abrasion damage is cumulative Nagging joint injuries are often called cumulative strain injuries, although this is misleading: strain is not cumulative— although the effects of mechanical abrasion are. Due to the anatomy of the joints, once damage begins to take its toll it generally gets worse and worse.  The joints are protected from friction by various mechanisms. Even though surfaces rub against one another during joint movements, there is ideally very little friction inside the joints, because of their smooth cartilage, bursae cushioning, and synovial fluid which "oils" the movements. Normal movements actually stimulate healthy cartilage and synovial fluid circulation. Without movement, there could be no joint health. Unfortunately, if synovial fluid becomes compromised—as the result of overuse, impingement, inflammation, or other factors—friction in the joints significantly increases. With lubrication gone, tissues rub against each other. This in turn can "roughen" the gliding surfaces—damage to cartilage, adhesions in the tendons—which increases the surface area of those tissues, further increasing friction. This leads to more damage, more inflammation, and less synovial fluid, and so the vicious cycle continues. Increased tendon friction may result in mechanical wear and abrasion of the tendons. This mechanical wear could result in enough damage to the tendons to cause tendinitis. One explanation for the increased friction is a loss of the synovial fluid...synovial fluid is a non-Newtonian viscoelastic fluid that decreases viscosity with increases in shear rate. -Davis & Palfrey, Advances in Industrial Ergonomics and Safety, vol. IVZ Unfortunately for weightlifters, where significant friction already exists in the joints, moving heavy weights multiplies that friction. In physics, the coefficient of friction decreases as force is added, but as we add mass, frictional force increases proportionately. Imagine pressing a piece of sandpaper onto a wall. No matter how hard you press on the sandpaper, it's very hard to do damage to the wall if it remains still. Now begin to move the sandpaper up and down, still in contact with the wall. What happens? The sandpaper begins to noticeably damage the wall, even if you don't apply much pressure. If you do begin to push hard, the damage becomes worse, much quicker. The static solution When put into context, the solution for minimizing—or even curing—chronic joint pain in resistance training is fairly simple. Chronic joint pain is caused by mechanical abrasions—movement multiplied by load. We can't eliminate the load component—this is what makes the joints and muscles stronger—so we eliminate the movement. This is by no means a new discovery; it is, in fact, intuitive. If you ever speak to master bodybuilders about their training techniques, you will discover that most of them have discovered this instinctively. Typically, gym-trained athletes with pain will at some point begin to slow down their movements, and eventually begin using some kind of static hold.  I lately employ slow-tempo reps as joint problems are less aggravated and I’ve discovered an appeal for them as the body grows older. Too, static holds on later reps in different ranges of motion are gaining my interest for the same reason. I find them highly muscle-intense, satisfying and promising. -Dave Draper, Mr America, Mr World, Mr Universe^ Anyone with chronic joint pain as the result of training can explore this phenomenon themselves; with experimentation, you will be able to find some angle in which you can thoroughly contract a muscle without irritating your injury. The logical conclusion of this process is pure isometrics training. Retain the load, build the strength and the muscle, but without the abrasion and damage. Isometrics and injury prevention Anecdotally, footballers who have practiced isometrics have noted a definite "armor-building" benefit—isometrics tends to decrease injury potential. Russian researchers tested this and discovered the reason: isometrics have the capacity to strengthen ligaments—the fibrous connective tissue that holds the skeleton togetherLigaments are often ground zero for debilitating joint injuries, particularly to the knee and shoulder.^ Tendons are the other major location for joint injuries, and Japanese research has demonstrated than isometric training can also effectively increase the tensile strength of human tendons.il A later, more conclusive study in 2016 proved that isometric training does indeed have the power to significantly reduce athletic injuries, when employed as a means of general physical preparation: The analysis of the obtained data from the examination of players continuously doing isometric exercises indicates that the level of their physical fitness is higher. The following regularity has been found: the longer the period of continuous isometric exercises is, the higher the physical fitness level is, the lower the injury rate and fatigue are and, consequently, the greater the improvement of performance is. -Bolotin & Bakalev^ There’s more: instant isometric pain-relief As an added bonus—recent research— indicates that, not only does isometric exercise not contribute to joint pain, where pain already exists, isometrics may eliminate it: at least as well as some medications. It can also instantly relieve some of the dysfunction and weakness caused by the pain. Pain is ubiquitous in high-level athletics, so the potential of these findings is enormous; this research has already found practical applications in elite sports physiotherapy. In the words of the lead researcher: First of all, we found that people with patellar tendon pain had HUGE amounts of cortical inhibition (as if their motor cortex was trying to limit the use of the quads). However, a single bout of heavy (70% MVC) isometrics reduced tendon pain pretty much instantly (and lasted at least 45 minutes), it also reduced the associated muscle inhibition, resulting in an increase in muscle strength. It wasn't Just about heavy load though as this cross over study also examined isotonic (concentric / eccentric) contractions and found no effect on inhibition, and that isometrics were superior for pain relief...People can do isometrics prior to sport as it doesn't fatigue their muscles (in fact strength was improved in the study). Equally we have athletes that use isometrics after they play or train and they seem to pull up better the next day. -Dr Ebonie Rio^ If you don't have any chronic pain—fantastic. Why not employ isometrics as the mainstay of your training, and miss out on it completely? There's very little satisfaction in being old and in pain as a price for being young and strong. Why not seize the best of both worlds, and be young and strong, then grow old and strong? Isometric training can do that for you.