EFFECT OF WEIGHTLIFTING ON THE NUMBER OF MUSCLE FIBRES IN MAN / 中国运动医学杂志

ABSTRACT

Whether or not muscle hypertrophy induced by physical exercise will result in the increase in thenumber of muscle fibres is a question much debated in recent years. But little has been done so farin studying the effect of short and long term weight training on the changes in the number of muscle fibres in the human body. As an attempt to find out this effect, a research has been madeon 29 male subjects. Nine young trainees at spare-time sports schools were put through a weightliftingprogramme consisting of three hours of work a day, six days a week for 10 weeks. Before and afterthe 10-week period, the cross section of the musculus vastus lateralis was measured with computedtomography scanning (CT); maximal voluntary isometric torques of knee extension were alsomeasured; muscle biopsies were taken from the vastus lateralis to distinguish between muscle fibresof type I and type II and to find out their distribution and their average areas; and the number ofmuscle fibres was calculated by a formula. The results were compared with those obtained from thecontrol group of 13 persons and a group of seven weightlifters of national ranking. It was found thatthe 10 weeks of weight training did not result in the increase in the number of muscle fibres althoughit caused some change in the maximal torque; and that although long-term training resulted insignificant changes in the maximal torque and the area of muscle fibres, there was no significantdifference in the number of muscle fibres between the elite group on the one hand and the controlgroup and the group of trainees who had gone through 10 weeks of training on the other. Thesefindings supported Soviet scholars' idea that to respond to load stress, animals depend on bothhypertrophy and hyperplasia in the muscle while man relies on hypertrophy alone. They alsosuggested the need for further studies on this subject.