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The search for the best combination of sets and repetitions to achieve ultimate size and strength appears to be a never-ending process. At this time it is just
not possible to claim with complete certainty that any one program will work for everyone all the time. One of the major reasons for this is the fact that size
and strength are not completely synonymous. That is, as a muscle gets stronger, it does not necessarily get bigger. How many of you have added a significant
amount of weight to your maximum lift on any particular exercise only to find that your body weight has remained the same and the tape or visual inspection
have also failed to reveal any noticeable change in the muscle's size? Need I say more? As it turns out, most bodybuilders attempt to increase the size of the
muscle by training for gains in strength. Some of this type of training is all right, but for the most part such training will lead to considerable disappointment
when done to achieve gains in lean body mass. There are scientific reasons for this that, when fully understood and ap-plied properly in the gym, can lead to
the development of a program which will produce explosive muscle growth.
Muscle strength is the result of the interaction between numerous biological and biomechanical factors. Two of the biological factors have special relevance to the topic of this article. It has been assumed in the past that for a muscle to get bigger you need to lift very heavy weights in order to activate all the muscle's available fibers. However, lifting heavy weights is really no more effective than lifting moderate weights in this regard and the reason for this is based on the following:
There are three basic types of muscle fibers: (1) slow-twitch fibers, (2) fast-twitch fibers, and (3) intermediate-twitch fibers. Slow-twitch fibers are endurance fibers that are capable of contracting for very prolonged periods. These fibers require oxygen to sup-port their energy requirements and they can even store small amounts of oxygen for use when working oxygen demand exceeds the available supply. Slow-twitch fibers have an increased number of mitochondria in them since mitochondria are life-sustaining organelles (tiny structures inside body cells) which produce energy in the presence of oxygen and nutrients. Because of the relatively small size and aerobic capacity of slow-twitch fibers, they can exert only relatively low levels of pulling force. These fibers take about 100 one-thousandths of a second to contract.
Fast-twitch fibers, on the other hand, are at the opposite end of the spectrum. These fibers have a large cross-sectional diameter, and because of this they are capable of exerting a high degree of pulling force, and their contraction speed is about 10 times faster than that of the slow-twitch fibers (10 one-thousandths of a second). These fibers are also thought to have the greatest potential for growth in response to resistance training, although slow-twitch fibers have been found to increase in size as well. Fast-twitch fibers utilize carbohydrates (glycogen) stored in the muscle and liver for quick energy, but they fatigue very quickly.
Intermediate-twitch fibers have characteristics common to both the slow- and fast-twitch fibers. Thus, these fibers can perform like either fast-twitch or slow-twitch fibers, depending upon the performance demands of the individual's exercise program. Intermediate fibers can be altered somewhat through regular training to emphasize either their fast- or slow-twitch characteristics. Consequently, it is possible to shift the emphasis of these fibers to either endurance or strength attributes.
There is a definite order in which the three fiber types are activated. Since slow-twitch fibers are endurance fibers they are activated at low muscle tension, whereas fast-twitch fibers are much stronger and, therefore, they are activated during greater muscle tensions to lift heavier loads. The intermediate fibers can be thought of as "transition fibers" since their mixed bio-logical contraction characteristics result in their activation during the midtension levels. Thus, the smaller-diameter fibers are recruit-ed first during light levels of activity and the fast-twitch fibers come into play as greater ! muscle-contracting forces are required.
In the gym there is considerable confusion when identifying the amount of weight required to activate all the available muscle fibers to achieve the best possible growth stimulation - that is, how much weight is really required to activate slow-, intermediate-, and fast-twitch fibers. It has naturally been assumed by almost everyone that lifting very heavy loads is required to trigger the fast-twitch fibers since their purpose is to exert greater pulling forces and they presumably have the greatest growth potential. However, laboratory experimentation has revealed some interesting findings that turn out to be very useful when applied properly in the gym.
As it turns out, there is indeed an orderly recruitment of muscle fibers that depends directly upon the load applied on the muscle. At light load the slow-twitch muscle fibers are called into play as expected and, as the load increases, intermediate and fast-twitch fibers start to contribute to the muscle-pulling forces. The orderly pattern of activation is more dependent upon the load imposed on the muscle than the speed at which the muscle contracts (as some would have you believe). It just turns out that a stronger muscle fiber will contract faster than a weaker one.
The real key to all of this is that over 90 percent of all available muscle fibers will be activated (including the slow-, intermediate-, and fast-twitch fibers) at a load of only about 50 percent of maximum. Surprising, isn't it? So all this time you have been thinking, and have been told by various authorities, that you need to pile on the weights and force your muscles, tendons and ligaments to the point of almost utter disaster to fully stimulate all your muscle fibers into growth. How wrong you have been!
I know the next question that is going to come immediately to mind is, if most of the muscle fibers are activated at only 50 percent of maximum, how is it that I can still lift much more weight? The answer to this is quite easy. The nervous system actually increases its impulse traffic to the muscles which force the activated fibers to contract harder. This is the basis for a widely recognized principle in neuromuscular physiology termed "frequency discharge." That is, as the load increases beyond the moderate range (i.e. 50 to 60 percent of maximum), the nervous system discharges more frequently and the muscle fibers respond by greater increases in pulling force. Thus, the entire time you were lifting heavy weights (weights exceeding about 60 percent of your maximum), thinking you were activating more muscle fibers, you were actually taxing and "depleting" your nervous system's energy reserves. While the nervous system does adapt to such training by "learning" to synchronize its impulses to induce a more forceful muscle contraction, such an adaptation is really more beneficial for increasing the strength of the muscle rather than its size. This is why weight-lifters and powerlifters in general do not possess the muscle mass of bodybuilders but have far more strength and explosive power. These athletes essentially "learn" to send powerful surges of nerve impulse traffic to the lifting muscles all at once, creating a more powerful muscle contraction.
Knowing all this, what then is the best approach for the bodybuilder to take to increase muscle mass and, believe it or not, strength as well? Since the load does not have to be all that heavy, volume is the key to stimulating the muscle to develop and grow. A greater volume of work of any given muscle is achieved by increasing both sets and repetitions of each specific exercise. Low repetitions are definitely out. Repetitions of 6 to 8 are not the way to go. Repetitions should probably never go lower than 12 and could go as high as about 25 per set. Sound ridiculous? You'd better really try it first before you knock it. The load at his repetition range should probably be anywhere between 50 and 60 percent of maximum and certainly no more than 70 percent of maximum. Of course, the load used will I depend upon your actual repetitions per set, total number of sets per exercise, rest period between sets, and the bodypart being exercised.
What can you expect to gain from following such a program? In the scientific arena it has been demonstrated that per-forming a high number of sets with a weight that induces fatigue at 25 repetitions will produce about a 200 percent increase in muscle performance capability in as little as a 15-workout session. In addition to this, similar studies have found that lifting loads for as many as 40 repetitions per set will increase strength and endurance of a muscle as well as a program using heavier weight for 10 repetitions per set. So ! do not worry about becoming weaker or not getting any stronger on this type of program. Although such a program is designed to accelerate muscle-size gains, increases in muscle strength and endurance can also be anticipated. (Just do not expect strength gains to j reach the level that could be achieved with heavy lifting.)
Accelerated gains in muscle size from lifting moderate weights for high repetitions have also been verified in the gym. One competitive bodybuilder in the off- season, at a body weight of 200 pounds, decreased his bodyfat 2 percent and increased his lean body mass (muscle) from 167 to 175 pounds in only two weeks following a moderate-weight, high-volume training program under my direction. His changes in body composition were not derived by conjecture but were verified by two independent measurements of body composition taken by me before and after the two-week period. The measurement techniques I used to document his training response were skinfold anthropometry and bioelectric impedance analysis. These two tests provided an objective determination of his actual change in bodyfat and lean body mass.
There are many examples of top body-builders who employ similar training techniques. Serge Nubret immediately comes to mind. He reportedly could bench press around 500 pounds but preferred training with a weight of about 225 pounds for around 20 sets of 20 repetitions when seeking gains in muscle development. His chest development certainly speaks for itself. Or how about Tom Platz and his 50-repetition squat workouts! In his competitive days Tom probably had about the best leg development in modern bodybuilding history.
In addition to promoting muscle-size gains, moderate-weight, high-volume training has other advantages. There is a decrease in the risk for muscle, tendon and ligament injury. The nervous system and one's psyche are not taxed as much and, therefore, overall recovery is improved. Better exercise form and muscle stimulation are more easily achieved, and a tremendous pump also occurs with fewer exercises. Given the scientific evidence and gains experienced in the gym using such training principles, don't you think it is time to reconsider your training philosophy for size? I must warn you, however, that such training is not easy, but the gains are likely to be very rapid if the exercises are performed properly.