Guest guest Posted March 19, 2007 Report Share Posted March 19, 2007 Below are a number of excellent posts from Loren Chiu, the late Dr Siff et al., regarding " Superslow " training: ===================== Loren Chiu wrote: [Your above comment (regarding the negative acceleration) is true for most typical resistance exercise movements, however, an exercise such as the squat can be performed in such a way that high force is produced throughout the movement (ie. by rising onto the toes). Some evidence suggests that the intent to accelerate is more important than the actual movement velocity (Behm and Sale). The issue regarding the force expression ignores the important issue of rate of force development (both production by the muscle and expression as measured via the force platform). The transfer of training effect in performing lifts in this fashion can be explained biomechanically and physiologically within the framework of the Principle of Dynamic Correspondence (see the " Supertraining " book). Based on research by Newton, the deceleration issue is most critical for low-to-moderate loads (and his group investigated the bench press, which cannot be performed using " maximal acceleration " as the squat can). With sufficient load (and driving onto the toes), high force is generated throughout the range of motion (ROM). The other issue regarding the " super slow " squats Steve Plisk referred to was the load used. To perform the squat (10s down, 10s up), the subject could only use 65% 1RM (I was involved to some degree with the pilot work presented by Dr Fry in San ). The intentionally slow velocity to perform the squat may result in high metabolic demand (ie. energy required), however, this does not train explosive strength qualities typically required for sport. For more regarding these force expression parameters, Keough (sp.) et al., (JSCR, 1998- maybe?) published force platform data regarding various modes of executing the same exercise. As a strength exercise, the squat is best performed with near-maximal loads (which requires the use of " maximal acceleration " ). As a strength-speed exercise, partial ROM speed or jump squats can be performed, or better still, the weightlifting movements (snatch, clean, jerk, and derivatives). No one has provided a good rationale for the use of submaximal velocity, submaximal load squats. [several scientists such as Verkhoshansky have researched the value of using submaximal loads to enable one to train with maximal peak power, while Louie appears to have produced empirical evidence that this sort of training has produced large improvements among his Westside lifters. Since large RFDs (Rates of Force Development) are also more readily produced under submaximal loading conditions, this offers yet another rationale for the use of rapid submaximal squat training. Anyway, I am sure that your above comments really are meant to apply only to submaximal velocity, submaximal conditions and not to maximal velocity, submaximal conditions. Right? Mel Siff] ================= Loren Chiu wrote: The use of submaximal loads at maximum velocity is well established. This has been called the dynamic method, weightlifting method, speed-strength method, etc. by various authors. The whole notion of using weightlifting movements in strength and conditioning is based on the submaximal load idea (ie. the load used for a clean is submaximal to that of a biomechanically similar but lower velocity lift such as the clean deadlift). As you mention, this method trains rate of force development (or in general explosive strength) provided that maximal acceleration (ie. maximal FORCE application) occurs. In fact, if a load is moved at the maximal velocity possible, it is technically no longer submaximal (as a heavier load could not be at that velocity). The term relative load may be more appropriate (ie. 60% 1RM is lower relative load than 80% 1RM). The problem arises when a load is lifted using submaximal velocity, meaning that no matter what the load, it is never maximal (because it can be moved faster). The capability of the neuromuscular complex is thus never challenged and the training effect diminishes. =================== From our research (some presented at last year's NSCA, some to be presented this year), the contribution of muscle and neural factors to explosive strength is approximately equal. Thus, the distinction that higher power output training results in neural fatigue (only) is questionable. Additionally, in Lieber's text, it is pointed out that muscle fiber adaptations may be directly related to their neural innervation. For example, with more frequent, lower intensity (electrical) stimulation of muscle results in fast glycolytic fibers becoming more like slow oxidative (a negative adaptation for sports requiring explosive strength regardless of the amount of muscle hypertrophy). This commonly held distinction that neural and muscular adaptations are seperate underestimates the complex interaction between these physiological systems. For example, most people still believe that initial adaptations to training are primarily neural, whereas prolonged adapatations are muscular. Staron et al. however, has shown that myosin heavy chain protein expression changes in as little as 2 weeks (and subsequently at 4, 6, and 8 weeks) in untrained individuals. Thus both neural and muscle factors contribute to early strength adaptations (andmaybe more importantly, are inter-related). =================== [ Burkhardt wrote: < The bottom line is that a 90%1RM squat (concentric phase only) performed in 0.8 seconds is of much higher quality than lifting 90% in 1.0 seconds. Force-time (force plate) measurements would clearly illustrate this. Maybe Loren Chiu would like to comment on the importance of including high loading (i.e. >90%1RM) for athletes who perform at high velocities against only the resistance of their body weight (volleyball – vertical jumping), and, or low load implements (i.e. throwing a baseball).> ** For the most part I agree with . However, as important as the force platform measures may be for assessing the outward movement characteristics, they tell little about the neuromuscular mechanics. This does not change the point that has made though, but rather helps to illustrate the importance of " intentionally " high movement velocity as opposed to actual. As I pointed out in the box squats vs. weightlifting thread, one must consider the neuromuscular activation and muscle force generation patterns, as opposed to external movement. The maximal rate of contraction and the maximal muscle tension are the stresses placed on the neuromuscular apparatus, and thus the stimulus for adaptation. The external load is of much lesser importance, and the external movement velocity a consequence of the neuromuscular activation and the externalload. For example: Max rate of contraction + max muscle tension + low load = high velocity Max rate of contraction + max muscle tension + high load = low velocity The problem that arises with (relatively) low loads is that they do not impose much of a stress on the body. Lower loads may not allow the maximal muscle tension to be achieved, therefore lessening the stimulus on the neuromuscular system. Thus the benefit of (relatively) higher loads is the ability to achieve maximal muscle tension. Schmidtbleicher (1994) recommends loads in excess of 90% 1RM in training maximal rate of (mechanical) force development. I should also add that, at least empirically, there appears to be an inverse relationship between load and amplitude of motion in training rate of (mechanical) force development. It may be prudent to use a briefer range of motion when utilizing higher loads. While the greater loads over a large range of motion may improve strength, rate of (mechanical) force development is a more specific adaptation and occurs in a relatively short period (typically less than 250-300ms). The higher loads are necessary to " challenge " the neuromuscular apparatus, therefore, the amplitude of motion should be decreased to allow for specificity. This also allows the athlete to focus on the " intentionally " high velocity and less so on trying to successfully make a lift over a large range of motion. An example of this is the use of mid-thigh pulls in weightlifting to improve the second pull. Supramaximal loads are used over a short range of motion where the athlete focuses on finishing the pull and not on pulling under the bar.] ======================== [< The problem that arises with (relatively) low loads is that they do not impose much of a stress on the body. Lower loads may not allow the maximal muscle tension to be achieved, therefore lessening the stimulus on the neuromuscular system. Thus the benefit of (relatively) higher loads is the ability to achieve maximal muscle tension. Schmidtbleicher (1994) recommends loads in excess of 90% 1RM in training maximal rate of (mechanical) force development.> man: < Interesting. And really, it does make sense when training for a movement that will have a high external loading. I have to ask how effective this would be in a powerlifting routine, in contrast to a Westside-style dynamic workout.> LZFC reply: The use of 90%+ loads for training rate of (mechanical) force development can be applied to activities that have external loading ranging from high to low. I don't know enough about powerlifting, but I believe that many powerlifters use heavy partial movements which may be effective at increasing mechanical RFD during portions of the lift. Loren Chiu: I should also add that, at least empirically, there appears to be an inverse relationship between load and amplitude of motion in training rate of (mechanical) force development. It may be prudent to use a briefer range of motion when utilizing higher loads. While the greater loads over a large range of motion may improve strength, rate of (mechanical) force development is a more specific adaptation and occurs in a relatively short period (typically less than 250-300ms). The higher loads are necessary to " challenge " the neuromuscular apparatus, therefore, the amplitude of motion should be decreased to allow for specificity. This also allows the athlete to focus on the " intentionally " high velocity and less so on trying to successfully make a lift over a large range of motion. man: <* That almost seems counter to reason-- I would think that in order to develop the RFD across the full ROM, you'd need to use a full ROM.> LZFC reply: The mechanical RFD-time curve shows peaks at certain portions. When force is (relatively) constant, RFD=0 (or is minimal). In training mechanical RFD for sports activities, it would be prudent to apply maximal RFD at these points in the range of motion. Maximal mechanical RFD only occurs for brief periods of time, therefore, the amplitude of motion should be minimal. man: < Say in a movement like the squat-- if you were to use partial 1/4 reps with a high load, >90% 1RM, could this translate to an improved RFD across the entire ROM? Or would you need to use partial repetitions across each segment of the ROM to develop RFD fully?> LZFC reply: In training for improvement in athletic performance, the use of exercises should be selected such that the most specific adaptations occur. In training the full squat, the best exercise is the full squat. In training for most sporting movements (ie. running, jumping, etc.), the " partial " range of motion lifts offer more specific neuromuscular adaptations.] ==================== Mel Siff: [MESSAGE: 4245 How it is possible to lift a weight WITHOUT the use of momentum? Momentum is defined as the product of mass x velocity (p = M.V) for a mass M moving at a constant velocity V, so that movement at ANY velocity creates momentum. Some change of momentum is necessary to change the existing state of a body at rest or constant velocity - at least that is what Newton's First Law implies. 2. One does not use momentum to lift a weight. One uses FORCE to overcome the weight exerted by a load being kept on the surface of the Earth by the pull of gravity. Momentum is the result of force being exerted on the body. Since Brzycki quoted Newton's 2nd Law, then he should surely remember the 1st Law by the same 'dude', which ran something like this: " A body will remain in its original state of rest or movement at constant velocity unless acted upon by an outside force. " Note that Newton wrote about force and not momentum - he only wrote about momentum in his 2nd Law, which was not really stated as F = Mass x Acceleration. What Newton actually wrote was close to this: " The force (implied by the 1st Law) acting on a body is proportional to the rate of change of momentum " . This, of course, emphasizes that it is not momentum, but rate of momentum change which gives rise to a force, but if one has received a rather limited exposure to biomechanics and physics during formal training, some of the precise subtleties of these subjects may be missed.] -------- [MESSAGE: 4309 ...EMGs recorded from many muscle groups reveal that there is continued muscular activity throughout all of the Olympic lifts. I have scanned in a few images of the EMGs and biomechanical curves recorded during the Olympic lifts - go to the home page of the Supertraining group at: </group/supertraining> Type in your password and open the " Files " section on the left hand side of the page. Open the files called " Biomechanics Graphs of Clean " and " Biomechanics Graphs of Jerk " . Examine the curves and you will notice that there are varying spurts of electrical activity in all of the muscles involved in the actions. In other words, as I noted in my original article, the Olympic lifts involve a combination of ballistic and non-ballistic action. If the load is light enough to be projected upwards so that the arms simply follow the action, then the action tends to be far more ballistic, but that is not the case in Olympic weightlifting or powerlifting, where the loads are very heavy and the initial momentum imparted by the first stage of the pull does not propel the bar very far. That is why the lifter has to interact with the bar to push the body beneath the load, according to Newton's Third Law ( " For every action there is an equal and opposite reaction " ).] -------- [MESSAGE: 4316 As we also know, the simple equation for momentum, namely: Momentum p = Mass x Velocity is correct only if the velocity of the load M remains constant or unchanged. Since velocity is a function of time, this equation really needs to be written thus: Momentum p = M. V(t) To compute the momentum from point to point, we have to know the equation which describes how velocity changes with time in this situation. In lifting a heavy load, there is no such thing as a lifter simply offering an initial explosive pull followed by total relaxation of any more pulling muscles. The load is not projected upwards by an explosive " charge " so that the lifter has enough time to propel the body under the still rising bar. That is something like the scene envisaged by fitness gurus such as Brzycki, but in 'real life', the lifter continues to apply force throughout the upward movement in as efficient a way as possible, so that the bar will overcome the attraction of gravity - as anyone may observe in the EMG studies that I appended to the " Files " section of our Supertraining website.] -------- [MESSAGE: 4336 All athletes involve or use momentum in all movements, as I explained before. It is impossible NOT to implicate momentum in any dynamic activity. What you and Dan are referring to is the use of large magnitudes of momentum or kinetic energy to " carry " a movement from point A to point B without any further use of muscle contraction during the motion. This sort of action clearly is the case in throwing or kicking objects, but in the case of Olympic style weightlifting, there is ongoing concurrent facilitation of movement by muscle action and 'momentum'/ kinetic energy. This is the point that some folk are still struggling to accept - Olympic lifting is NOT mainly 'momentum driven' or ballistic for most of its range. In fact, elastic energy (a type of potential energy) from flexion of the lifting bar also is released as kinetic energy during the explosive parts of the pull and the jerk, so that the Olympic lifts are a little more complex than is being implied by Brzycki and others on this list who seem to feel that Brzycki's physics and biomechanics is correct.] -------- [MESSAGE: 9152 Cheating can permit one to produce a very different and more appropriate 'strength' (torque, power or force) curve to enable one to overcome a load more competently and safely. Very often, adherents of the slow training philosophies militate against the power clean or derivates of it, and even refer to such movements as 'cheating' movements which make 'unsafe' use of momentum and ballistic activity. In fact, this type of 'cleaning' movement is a far more efficient way of lifting a bar from the ground to the chest compared with the crude sort of deadlift, reverse curl, upright row combination that so many folk use. There are several other so-called 'cheating' movements which offer safer, stronger and more efficient ways of overcoming a load. (A brief aside: If HIT or Slow is Best (SIB) methods are indeed 'better' than Olympic and other ballistic methods, can one explain how SIB adherents raise a bar from the ground to the shoulders? Do they always unload the bar, slowly raise it with a reverse curl to the shoulders, place it on a rack, add more weights and only then perform the exercise?)] -------- [MESSAGE: 10227 The bar reaches those heights, not because of its own momentum acquired during a powerful single impulse at the beginning of the movement, but because the lifter continues to exert force on the bar. Other research shows that the momentum does not result in much more than about a maximum 10cm in rise of the bar after the pull has ceased. This scientists involved stressed that the lifter must start dropping into the squat before the bar reaches its peak height, because the effect of momentum is not large enough to the lifter to wait until the bar reaches its zenith.] -------- [MESSAGE: 13451 The term " ballistic " refers to objects or body parts that are thrown like projectiles, where the momentum produced during one stage of the action carries the object or person to a point without any further muscle action. Thus, throwing baseballs, basketballs, jumping, kicking, running and similar activities involve considerable ballistic action, but near maximal lifting does not. ..... For example, Brzycki reiterates the common error that lifters use momentum to lift weights, something that becomes increasingly difficult as the load increases. While that may well be the case with the lighter, safer sort of HIT training that Mannie advocates, it is not true of maximal or near maximal attempts. Research shows that the lifter relies more on Newton III to push himself under the bar, rather than momentum to complete important stages of the Olympic lifts] -------- [MESSAGE: 14124 Don't believe what some people maintain about explosive movements and momentum, namely that one relies on stored momentum to keep the bar moving upwards against gravity while you simply drop passively under the load. With circa-maximal and maximal loads, that simply does not happen, because the momentum of the bar as it reaches the zenith of its trajectory is far too small to offer you much help.] -------- [MESSAGE: 20996 According to Newton's 2nd Law, an increase in upward acceleration will INCREASE and not " offload " the force exerted on the lifter. The only way to offload is to accelerate downwards with a load, not to slow it down while going upwards. The only way to totally eliminate production of momentum is to do isometric training. Incidentally, load or force do not change with speed of repetition, but with ACCELERATION, no matter what speed you are moving at. This is very easy to prove - take a bathroom scale into an elevator, stand on it and see when it registers the greatest weight - when the elevator is stationary, is moving upwards or moving downwards. You will note that " offloading " takes place when the elevator accelerates downwards and that enhanced " loading " takes place as you begin to accelerate upwards. ..... It is laughable to even suggest that one uses momentum to complete any maximal lift. If momentum were playing a significant role, then we could stop pushing well before the end of a very heavy bench press or squat and the momentum would simply carry the load to the end. As I have stated before, this certainly is possible with light loads, but not with the sort of heavy loads which really increase strength or test you at the limits of your performance. It would seem that SuperSlow fans must always be training with lighter loads if they can use momentum to complete a lift. Weightlifters and Powerlifters are among the many who do not wish to train in such an unchallenging fashion of force production.] -------- [MESSAGE: 21056 ...many biomechanists have analysed on thousands of occasions the Olympic lifts, bench press, squats and various other exercises by having them perform the lifts on force plates and indeed have shown that the alleged " offloading " is not of any major consequence. One wonders who so many SuperSlow proponents continue to argue with this abundance of very clear evidence that their beliefs about the effect of momentum are grossly inaccurate and misleading. Even if they do not have access to force plates, they can use bathroom scales, leave a video running while the lift is being performed and play back the video in slow motion or freeze frame to read off the approximate force registered by the scale at all stages of the lift. This is a simple technique that any of you can use if you are ever curious to obtain some estimate of how force varies throughout any lift.] -------- [MESSAGE: 23179 Momentum doesn't simply appear from nowhere - it is the result of very powerful muscle action, especially via the use of reflex activation and stretch-shortening which allows the muscles to produce tension beyond their voluntary capabilities] ============== Carruthers Wakefield, UK Quote Link to comment Share on other sites More sharing options...
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