The influence of exercise and nutrition on the bone mineral density in sportswomen / 体力科学

Recently, interest has been forcused on the increasing incidence of bone fracture due to low bone mineral density (BMD) in some sportswomen. Therefore the present study attempted to elucidate important factors associated with an increase or decrease of BMD in sportswomen.<BR>The results obtained were as follows;<BR>(1) Ball games appeared to be the most desirable main sports. Also it appeared necessary to increase lean body mass (weight) by maintaining a higher activity of daily living (ADL) index.<BR>(2) There were no clear nutritional factors that had a beneficial influence for increasing the BMD.<BR>These results suggest that sufficient exercise, at least, is necessary in order to increase BMD.

ANALYSIS OF HOLD STRENGTH, TWISTING HOLD STRENGTH AND TORQUE BY GRIP-TORQUE DYNAMOMETER / 体力科学

We have developed the new dynamometer to measure twist strength of upper limbs that was not investigated sufficiently before. This dynamometer can measure both twisting hold strength and torque at a time. Therefore, it can be applied to motion analysis at demonstrating muscle strength. Both development curve of the age group's average of the average hold strength of left and right hand { (LH⋅HS+RH⋅HS) /2} and the average twisting hold strength of left and right hand { (LF⋅HS+RF⋅HS) /2} showed the peak of development in man's thirties and in woman's twenties-thirties and then marked depreciation gradually with ageing. The average torque of forward twisting of left hand and that of right hand { (LF⋅T+RF⋅T) /2} showed the same tendency in respect of the peak of development too, but woman's curve showed the peak in twenties different from that in man and then didn't mark depreciation remarkably. From the analysis with respect to twisting motion by the subjects of right handedness, we have recognized that the twisting hold strength of right hand by the action of left or right forward twisting (LF·RH·HS, RF·RH·HS) is greater than that of left hand (LF·LH·HS, RF·LH·HS), the torque of forward twisting of left hand (LF·T) is greater than that of right hand (RF·T) and that the hand of back twisting supports the grip-torque dynamometer from the result of EMG. Therefore, we can understand that the stronger torque is generated by the motion of forward twisting of left hand which can support stronger than by that of right hand. But we have recognized too that the average hold strength and the average torque correlate to one another closely. Therefor, we can understand that it requires the stronger hold strength to generate the higher torque.