ON SOME INDICATORS OF THE CAPABILITY TO EXERT MUSCLE FORCE OF HUMAN BODY On some influences of experimental conditions upon exertion of the maximal human muscle force
- VernacularTitle:筋力指標に関する研究筋力に及ぼす諸実験条件について
- Author:
NAOMICHI YAMAMOTO
- Publication Type:Journal Article
- From:Japanese Journal of Physical Fitness and Sports Medicine
1972;21(1):28-48
- CountryJapan
- Language:Japanese
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Abstract:
Some factors influencing the tension development of human muscles at the maximal exertion was analyzed in order to find out some desirable indicators of the characteristics of the voluntary exertion of muscle force.
1) The isometric tension development of the maximal exertion of hand-gripping and arm-bending was recorded simultaneously with the measurement of electromyogram, respiratory curve, electrocardiogram and reaction time. The subjects were all male and 22 to 61 years old.
2) The length of time needed to exert muscle force from 20 to 80% of each recorded maximal force exerted maximally was nearly constant so far as the interval and number of repetition was less than 5 sec and 30 respectively. The correlation coefficient between the standard deviation of the undulating descending curve of the decrease in maximal muscle force during repetition described above and that of this length of time from 20 to 80% definded here was +0.64.
3) The values of tan θ and tan ψ calculated from the (Pmax-P) -log t relation were in some cases found to decrease during repetitive exertion under the same conditions as mentioned above, but the decrease was in most cases not so remarkable. The values of tan θ and tan ψ ranged from 0.1 to 0.2 (kg/msec) and from 0.3 to 0.5 (kg) respectively.
4) The maximal force of hand gripping was measured immediately after a conditioning exertion of force of various intensity (i.e.25, 50 and 75% of the maximal force of hand gripping exerted maximally by each subject prior to the measurement) . The tan ψ and tan θ were maximal when no conditioning was loaded, and they decreased with increasing intensity of conditioning exertion.
5) The tan θ of the test exertion of hand gripping exerted maximally was larger when a very short time of pause was interposed between the conditioning and the test exertion than that without conditioning exertion at all.
6) Both tan ψ and tan θ were larger when the condition exertion was done by antagonistic muscle of hand gripping than without conditioning exertion at all.
7) The maximal force of flexion of the one arm was not influenced by the simultaneous maximal exertion of flexion of the other arm.
8) When a constant time interval (i.e. 0.5, 1.0 and 2.0 sec) was interposed between the time of beginning of the maintained maximal exertion of the one arm and that of the other arm, the decrease in the tension of the maximal flexion of the first arm due to the maximal flexion of the second arm was larger than that due to the maximal extension of the second arm. This decrease in tension was larger when the first arm was the left one than that when the first arm was the right one. This decrease in tension was also larger when the length of the time interval mentioned above was arbitrarily chosen by the subject than that when the time interval was prescribed.
On the basis of the results mentioned above, the characteristics of the voluntary exertion of muscle force was discussed.
