Training Effect and Electro-Myogram

Training effect was investigated electro-myographically. The subjects used and the muscles studied were the stevedores (heavy and static muscular laboures-M. rectus lemons), a long incumbent patient (M. soleus), and men trained to exercise the auricular muscle. For the controls, laboratory workers (men) were used. The interval diagrams were contructed and the τ-S relations were plotted. Following results were obtained.1. With regard to the interval diagram, very irregular variation and large u.ndulating fluctuation were seen in the long incumbent. The stevedores showed more steadiness than the control subjects.2. In all the instances, without exception, the τ-S relation dissolved into the K-and T-groups, indicating that the muscle studied under the above categories are composed of kinetic and tonic NMU.3. Training (the stevedores and men belong to the third group) caused rightward shifts of the K-and T-curves-the latters showing very distinct shifts.This rightward displacement increased with longer training.4. The trained showed longer plateaux (especially of the T-curves) than the less or untrained. But the S-values of the plateaux remained roughly unchanged by training.5. The long incumbent case showed a leftward shift of K-and T-curves, compared with normal control. Easy appearance of interference voltages in slight augmentation of contraction was remarkable.6. The recruitment-type discharges were distinctly noticiable with the stevedores, but were less so with the control subjects and hardly perceptible with the incumbent.In general, the training for heavy and static effort or a newly acquired movement in the unused muscle brings a change in the neural mechanism, so as to effect the smoothness of muscular contraction, in which the tonic element becomes highly employed. Conversely, total lack of exercise ensues in a definite inactivity of the tonic element, resulting in an enevenness of movement.