The purpose of this study was to observe the effect of concentric and eccentric training on the strength of cervical muscle. The subjects were 18 adult males of whom 6 were exposed to concentric training, 6 were exposed to eccentric training, and 6 were exposed to control. Training intensity was the exertion of maximum isotonic strength on the extension, flexion, left bending and right bending of the neck. All training exercises for concentric and eccentric groups were given 10 times a set, 3 sets in a day, 3 times a week for 8 weeks. The changes in the strength of cervical muscle and in the girth of neck due to muscular training were measured regularly once a week. The results were as follows : 1) Maximum 'isometric strength increased significantly (p0.001) by 37.8% in concentric training group, and 39.6% in eccentric training group. No significant difference of strength increase was observed between concentric and eccentric training group. There was a significant decrease in the strength of cervical muscle in the early stage of muscular training, accompanied by severe muscule fatigue, but a remarkable increase in strength due to concentric and eccentric training was observed during the 8 weeks. 2) The girth of neck increased significantly (p 0.001) by 4.9% in concentric training group, and 5.5% in eccentric training group. Significant difference of girth increase was observed after 3 and 4 weeks of muscular training of cervlcal muscle, meanwhile the girth of neck increased slightly by 1.3% in control group. 3) The effect of training on the strength of cervical muscle was found in the increase of the girth of neck at first, and then in the increase of the concentric and eccentric strength.

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The purpose of the present study was to compare the impedance derivative waveforms using spot and band electrode array and to assess applicability of automated signal processing system for cardiac output kinetics. Five healthy male subjects were tested. Cardiac output (Q) were measured using spot electrode array. Each subject performed rest-exercise transitions in leg and arm exercise on an electrically braked ergometer. The intensities of leg exercise were 25, 50, and 100 W for 5 min and those of arm exercise were 25 and 50 W. Comparisons between spot and band electrodes were made for the absolute magnitude of Q and stroke volume (SV), as well as for impedance derivative waveforms. The waveforms for spot electrodes showed less fluctuation by breathing and movement artifacts than for band electrodes. Q for spot electrodes were larger than those for band electrodes. There was a significant correlationship between oxygen uptake (Vo₂) and Q. There was a significant correlationship between Q using spot electrode and Q measured by CO₂ rebreathing method. Nonlinear correlation coefficient to exponential curve of Q kinetics for leg exercise was more than 0.7 and for arm exercise more than 0.4 in spite of large movement of upper body. It is suggested that the present system using spot electrodes is superior in signal processing to those for band electrodes and able to evaluate Q kinetics without multiple repetition of exercise tests.

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