ON THE SIGNIFICANCE OF THE REACTION TIME OF AVOIDANCE MOVEMENT FROM THE STANDPOINT OF AN INDICATOR OF THE PHYSICAL FITNESS OF HUMAN BODY / 体力科学

ABSTRACT

1) The reaction time of the avoidance movement of jumping off toward a given place, which was regarded as an indicator of the quickness of movement of the group of muscles of the lower limbs, was measured and compared with the quickness of these of the upper limbs.<BR>2) The reaction time of movement of placing one's hand from one to the other of the two pushing-plates, by pushing which the electric circuits were closed, was measured. The reaction time of the commencement of the movement was similar to the simple reaction time, and its correlation with age was not high. The time taken to place one's hand on the other plate tended to be a little longer with subject of middle and high ages.<BR>3) The dispersion of the values of reaction time of both the commencement and the termination of movement when measured repeatedly was similar to that of the simple reaction time, but the dispersion of the difference between these two kinds of reaction times, that is, that of the time taken to move one's hand was smaller than that of the simple reaction time.<BR>4) Concerning one-step jumping aside to the right hand side, the reaction time of the commencement of movement under the condition that the legs were moved one by one was longer than the simple reaction time, and was also longer than that of the simultaneous movement of the both legs. The reaction time of both the commencement and the termination of movement was longer with higher ages, and was longer with women than with men. This relation was more evident in the successive movement of each legs than in the simultaneous one. The frequency distribution curve obtaind by repeating the measurement of the reaction time of jumping off showed a nearly normal distribution curve. The correlation between the reaction time of hand movement and that of jumping off was not so high.<BR>5) The scattering of the landing position of one-step jumping aside to the right hand side did not show any correlation with the values of the time taken to move one's legs.There was, however, a high correlation (r=+0.96) between the scattering of the landing position and that of the reaction time.<BR>6) There was no large difference between the reaction time of one-step jumping aside to the right hand side and that to the left hand side. With respect to forward jumping, the period of time during which the pressure at the first pushing-plate remained equal to the body weight was longer when the both legs were not simultaneously moved. There was no large difference between forward and backward jumping.<BR>7) The variation of the reaction time of two-steps jumping with respect to age was similar to that of one-step jumping.<BR>8) The results mentioned above indicate that one-step jumping aside is to be adopted as an indicator of the quickness of movement of the group of muscles of the lower limbs, and that it is practically useful to measure the time taken for one's one leg to tread on the second pushing-plate.