Hideji Matsui

Oxygen uptake and blood flow of the lower limb in maximal treadmill and bicycle exercise.

SummaryThe present study was undertaken to compare the effects of maximal treadmill and bicycle exercise on maximum oxygen uptake and blood flow in the lower extremity. Mean maximum oxygen uptake in maximal treadmill exercise was higher than that in bicycle exercise (p<0.001). Mean values and standard errors of blood flow measured immediately after maximal treadmill and bicycle exercise in the thigh were 39.1±4.0 and 44.2±2.8 ml/100 ml·min, the difference not being significant. However, a significant difference in blood flow in the calf measured immediately after both types of exercise was observed (p< 0.001). Blood flow in the thigh immediately after bicycle exercise was significantly higher than that in the calf (p<0.001), whereas the difference between thigh and calf in treadmill exercise was small and statistically not significant. Leg blood flow, the average value of blood flow of the thigh and calf added together, was used as an index of blood flow in the lower extremity. It was found that the leg blood flow was significantly higher on the treadmill than with bicycle exercise (p<0.05). From these results, it is suggested that the lower maximum oxygen uptake observed during bicycle exercise as compared with treadmill exercise seems to be due to a lower blood flow in the lower limb.

Longitudinal study of aerobic power in superior junior athletes

The effects of endurance training on aerobic power, and the relationship between aerobic power and running performance were investigated in 11 junior runners over a period of 5-to-7 years, starting from the age of 14. Aerobic power was measured using treadmill running and a protocol that involved increasing speed. The six subjects who comprised group I were those who continued competitive training, while the five in group II had stopped training by the age of 18. The subjects in group I demonstrated greater aerobic power (l x min-1) and better running performance than those in group II. Aerobic power for group I increased from 3.54 l x min-1 (65.4 ml x kg-1 x min-1) to 4.49 l x min-1 (75.5 ml x kg-1 x min-1) between the ages of 14.8 and 18.8 yr. The increase in l x min-1 and ml x kg-1 x min-1 was statistically significant (p less than 0.01, p less than 0.05). The greatest aerobic power found in subject A corresponds to the data from world-class runners: 3.63 l x min-1 (61.5 ml x kg-1 x min-1) at age 14.7 yr; 4.67 l x min-1 (74.6 ml x kg-1 x min-1) at 17.8 yr; and 5.04 l x min-1 (76.3 ml x kg-1 x min-1) at 20.7 yr. After their training was discontinued, aerobic power for those in group II decreased to the level of ordinary schoolboys. Improvement in running performance was closely related to the increase of aerobic power in l x min-1. Superior running performance seems to be associated with high aerobic power in l x min-1, rather than in ml x kg-1 x min-1 for junior runners.

Measurement of the Reaction Time of Muscular Relaxation

The reaction time of muscular relaxation was investigated in the elbow flexors. The time interval from the onset of a light stimulus to the response of the elbow flexors was measured using EMG. The subjects were 20 healthy male adults. There was no difference in the reaction time between muscular relaxation and muscular contraction. In terms of mean values for twenty subjects, there was no significant difference in the electrical response of M.biceps brachii between muscular contraction and relaxation. Significant individual differences were noted.

Photographic method of analyzing the pressure distribution of the foot against the ground

Most human activities are based on the movement of both legs. Therefore, in order to analyze the mechanics of human activities, it is essential to record the forces exerted against the ground through the feet.

Biomechanics of bowling

Although many books and papers describing bowling techniques have been published, there is little information dealing with the mechanics of bowling. The present study was undertaken to investigate bowling performances by analyzing with cinematography the motion of the bowling ball during the approach and delivery.