I was thinking the other day about why powerlifters, despite their greater strengh, as well as those who do one-set-to-failure protocols, do not grow muscles like bodybuilders who do a greater volume of work. These are my conclusions: hypertrophy of muscle fibers is but one mechanism through which muscles increase in strengh. Increasing strengh with few reps cause an increase in nervous as well as metabolic muscular efficiency without, necessarily, concomitant increases in the cross-sectional area of muscle. Strengh can be increased via increased ATP expedenture by increased mitochondrial density, creatine phosphate synthesis, increased motor neural number and/or activation via increased receptor sensitivity to Calcium ions, efficiency of lactic acid clearance ratio, etc. Only when muscular and neuromuscular metabolic function is maximized does the muscle increase it's cross-sectional area to increase strengh, because increasing strengh via improved metabolic function is less straining and a more efficient use of bodily resources than building more muscular tissue. The workload imposed by powerlifting style training doesen't strain the muscle fiber's ability to increase it's contractile force beyond what it can by becoming more efficient.
The problem is that there are limits to which muscle efficiency can be maximized. Following this point, only increases in the cross sectional area of muscle will result in strengh increases. Suppose you load a bar with 200 lbs and you have enough motor neuronal efficiency, ATP reserves and mucle fibers to bench it once for 300 lbs. If you bench it once, 100% of your motor neurons will fire and all ATP will be used. Now, imagine that instead of benching it once for 300 lbs, you load the bar with 200 lbs and do 10 reps. You will use the same amount of stored ATP for those 10 reps that you'd use for benching 300 lbs for one and you'll be demanding as much from your nervous system and all muscle fibers will need to contract for you to complete your tenth rep. Now you rest for a minute, and go again. Only 50% of your fibers will have recovered from the first set, and ATP will have been depleted significantly as well as the lactic acid won't have been completely removed from sites. The demand you put on the muscles will indicate that the further strengh increases with this work load exceeds what the current muscle fibers can accomplish with it's size. Since it is impossible to increase strengh by increasing the density of actin/myosin bridges that compose muscular fibers and are responsble for their contractive ability, the only way to increase the muscle's strengh is to increase the proteinaceous volume of actin and myoson itself. Result: hypertrophy. This explains why a powerlifter has similar muscular efficiency to a bodybuilder but less muscular volume.
Conclusion: muscular hypertrophy is only one of the mechanisms skeletal muscle have to become stronger and it is secondary in activation to several others. To achieve muscular hypertrophy, huge weights with low work load is ineffective because there is enormous room for your muscles to grow in strengh before growing in size. You'll need to use gigantic weights to achieve only a moderate degree of hypertrophy with a few contractions.
Conclusion II: To maximize hypertrophy, increase strengh enormously first via powerlifting or one-set-to-failure protocols, then stagnate the weight you're using and work on increasind the amount of work you can perform with that weight. Huge gains in the cross sectional area of muscle will follow. Once volume has increased to the point where you have observed that your gains have stagnated, work on increasing your strengh agains via powerlifting type training. Repeat ad infinitum.
SUCKMYMUSCLE