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| Introduction | You've heard that "a rose is a rose is a rose."
Well, resistance is resistance is resistance, as far as muscles are concerned.
Resistance usually connotes the so-called anaerobic exercises. But as one
noted author in exercise physiology emphasizes (Foxx), aerobic and anaerobic are
merely conceptual extremes in a continuum between the two, with resistance
intimately involved in both. You may notice ergonometric differences between different schemes of resistance (ie, in terms of like or dislike, comfort or discomfort), but essentially the effect on your muscles will be the same, for a given amount of mechanical work (average force through a distance). But even though the minutia of resistance does not really matter from a muscle point of view, it does from a consumer's point of view, and all that people are trying to hustle, I mean, sell. |
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| Calisthenics | Calisthenics are treated separately, but I just wanted to point out here that they are basically in the class of isotonics (weights). They simply use the body, or parts thereof, as the weight. Although they have lost ground to machines in terms of popularity, they are making a comeback, in part due to sites like this one. There was no need to have ever abandoned them. | |
| Isotonic Weights | Isotonic means "same weight". When you lift 50
lbs, that weight does not change anywhere in the range of motions--it is 50 lbs
forever! It is probably the best form of resistance in terms of feel,
simplicity, and absolute standardization (at least with free weights. With
machines, you are never quite sure what the true weight is...but then
this is not so important). There is only one glitch to weights. Although they themselves are isotonic, your muscle does not feelthem to be isotonic, because of the geometry of bone and muscle. In a curl, for example, the weight is more difficult to move in some parts of the motion than others. That is one reason why machines became popular, because the cams in these machines "equalizes" the load over the whole range of motion (more or less). This in fact is a great idea. The question is, Is it worth the effort in terms of machine size, cost, complexity, etc? Are there other alternatives. Indeed there are. It's called cheating! Previously, when trying to curl a weight, the lifter would use a little "body english" to "bump" the weight past the sticking point. And everyone would yell, Cheater!! Well, this is exactly what cams do for you! Through principles of torque, they lower the resistance at the sticking points so you can continue with what would in principle be too heavy a weight. There are certain exercises where this body english is not easily applied, such as in the bench press and heavy squats, but for many users these are not totally relevant. Calisthenics offers one of the best solutions to sticking points, but is better discussed under the HoloBarre technique. The bottom line to the isotonic category of resistance is that it is probably the best. |
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| Isometrics | Isometrics are very interesting. They are the exertion of
force but with no motion. The question is, Are they effective? Very. Are they
"satisfying"? Not very, which is why not many people do them. But here are some very interesting observations about isometrics. First, isometrics DO burn calories, as much as lifting. But, the physically astute among you might say, But, YOU said work (and calories) is force moving through a distance. There is no distance! Which is correct. Which means the mechanical work is in fact zero. But the CHEMICAL work is plenty! And we can in fact calculate what this is! Suffice it to say for now that if you are benchpressing 100 lbs for a number of repetitions that take 10 seconds, and you just push against a weight with a force of 100 lbs (with no motion, if the weight is, say, 120 lbs), you will have burned essentially the same number of calories!! So calorie burn in isometrics is the same as actually lifting! A series of isometrics at different positions is EQUIVALENT to the isotonic weight lifting motion. I will elaborate on this concept later, as it is a profoundly important concept, but not quick to explain. The posing that body builders do in competitions is partially responsible for their pump. It is highly muscle building in itself! Isometric or even isotonic exercises do not need weights, or limbs opposing limbs, or anything! You can, in principle, body build lying in bed! The principles behind this involve the action of antagonist muscles, and is sort of lengthy to describe, but if I get enough emails on it, I will do a whole writeup. The stretching and scratching of cats is a major (isometric) conditioning routine, which is eliminated by de-clawing a cat. They can even develop back problems by being declawed. Don't do it. |
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| Isokinetic | These require machines, generally, and have the feature where no matter how hard you exert yourself, the motion proceeds at the same dialed-in speed. A good example is pumping up a bicycle tire with a hand pump, or running through chest-high water. It is more of a laboratory technique, but found on some machines that use "weight boxes" or hydraulics. One of their advantages is that they can load the limb in the pull as well as the push. This gets two different muscles in one complete stroke. But isotonics gets the SAME muscle twice, so each has an advantage. Overall, in this regard, getting two separate muscles in one stroke is probably more economical, but not worth the overall poor "feel." And, because the the resistance is a function of the motion itself, there is no resistance at the end of your stroke! In other words, you can't "hold" a weight up! | |
| Friction disks | These are cheap means to the isokinetics described above. Instead of hydraulics, simple friction disks are used. They too have the advantage of getting two muscles in one stroke. They too don't feel right. | |
| Springs | Springs, rubberbands and the like are the most obvious substitute for weights. Their fundamental feature is that the farther you stretch them, the harder the exertion. Thus, there is quite a non-uniformity over the range of motion. They will certainly "do the job", but they too feel "unsatisfying". Also, they can be dangerous, as they can snap back faster than a dropped weight can fall. Many sprung designs compromise and offer below adequate resistance to begin with. | |
| Bottom Line: | Weights and calisthenics are the best and overall cheapest forms of calisthenics. Newton's Laws may be used to augment the characteristics of resistance to great advantage. These are discussed in the HoloBarre section. | |
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