Structural Issues In Strength Training Part I

This is an extract from the book Supertraining, by Dr Mel Siff - we hope you enjoy it.

Tissues grow in response to resistance exercise by increasing the size of their components (hypertrophy) or increasing the number of components (hyperplasia). In the case of muscle fibres, occurrence of hypertrophy is a well-established fact, but there is considerable debate concerning muscle hyperplasia. However, hyperplasia of structures within the muscle fibre and cell does occur, namely sarcoplasmic hyperplasia, in which the number of sarcoplasmic organelles increases, and myofibrillar-mitochondrial hyperplasia, in which the number of myofibrils and mitochondria increases.

Two types of muscle hypertrophy have also been identified: sarcoplasmic hypertrophy, in which the volume of non-contractile protein and semifluid plasma between the fibres increases, and sarcomere hypertrophy, in which there is an increase in size and number of the sarcomeres comprising the myofibrils. This type of hypertrophy is far more important for most athletic activities.

The prescription of a specific type of resistance training to produce a given functional change depends on examining the concurrent effects of the training regime on muscle hypertrophy and subfibral hyperplasia. The popular view is that the greater the intensity of the load, the greater the activation of the motor apparatus, so that the amount of active muscle tissue grows. Despite abundant earlier research indicating that intense loading causes sarcomere hypertrophy, more recent findings, however, reveal the opposite result. The data shows that the longer and more intense the loading, the less there is sarcomere hypertrophy and the more there is sarcoplasmic hypertrophy. Although increase in load intensity and speeding up of its rate of increase promotes overall muscle hypertrophy, it is accompanied by a greater breakdown of muscle fibres and a decrease in the number of contractile structures. The hypertrophied muscle contains fewer sarcoplasmic organelles, myofibrils and mitochondria, so that the increased diameter of the muscle fibres is due largely to an increase in the volume of sarcoplasm (sarcoplasmic hypertrophy).

Other research has found that hypertrophied muscle fibres need a significantly larger tissue volume to perform a given quantity of work. This seems to corroborate the hypothesis that there may be an optimal size for muscle fibre hypertrophy. The importance of prescribing resistance training which produces the optimal balance between hypertrophy and specific strength then becomes obvious. Thus, it is not only prolonged cardiovascular training which can be detrimental to the acquisition of strength, but multiple fairly high repetition sets of heavy bodybuilding or circuit training routines may also inhibit the formation of contractile muscle fibres.

By: supertraininnu

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Mel C Siff www.supertrainingonline.com www.twitter.com/supertraining_1