ON SOME INDICATORS OF THE CAPABILITY TO EXERT MUSCLE FORCE OF HUMAN BODY FROM THE STAND POINT OF THE TIME COURSE OF TENSION DEVELOPMENT OF ISOMETRIC TETANUS
- VernacularTitle:等尺性強縮時の張力時間関係からみた筋力指標について
- Author:
Reiji Natori
;
Chotaro Isojima
;
Syuzo Tsubota
;
Yoshiki Umazume
;
Hiroshi Kurata
;
Akihito Yanagimoto
;
Yoshiro Morishita
;
Naomichi Yamamoto
;
Reizo Ishii
- Publication Type:Journal Article
- From:Japanese Journal of Physical Fitness and Sports Medicine
1970;19(3):75-85
- CountryJapan
- Language:Japanese
-
Abstract:
1) The time course of nearly isometrical tension development of human voluntary muscular contraction was analyzed for the purpose of finding some desirable indicators of the capability of human body to exert maximal muscle force as fast as possible.
2) The isometric tension curves of maximal exertion of hand gripping, arm and indexfinger bending recorded, the linear relation between Pmax-P, which is a difference between its maximal tension and each value of tension in the time course, and log t, which is the logarithm of time corresponding to each value of tension, was found in each of three portions of a whole curve of time course of tension, the three portions being a range from P0 (log t0) to P1 (log t1), from P1 (log t1) to P2 (log t2) and from P2 (log t2) to Pmax (log tmax.) respectively.
3) The range from P1 (log t1) to P2 (log t2) is a phase in which the tension increases most rapidly from an initial small tension to a large tension and is, therefore, regarded as a most characteristic one with respect to the time course of muscle force development exerted voluntarily as fast as possible.
4) The angles of intersection of the line connecting P1 (t1) with P2 (t2) or P1 (log t1) with P2 (log t2), with the abscissa in the tension-time or tension-log t curve, which are denoted as or respectively, were found to be able to be adopted as indicators of the capability of human body to exert maximal muscular force for a short period of time.
5) The tension curves were found to be nearly the same each other when they were recorded three or four times in the interval of 30 seconds with one and the same subject. If the difference is small between the first and the second record of the time course of a given subject, either of them may be adopted, but if not so, one have to only record the third curve and adopt either of the two resembling each other among the three records.
6) Concerning the subjects of the same age, the difference between Pmax and P2 was small and the tan was large with a subject whose P was large. The tan ψ or tanθ was as a rule smaller with subjects of middle and high ages than with younger ones.
7) The Pmax decreased with lapse of time when the maximal effort of contraction whose duration was one second was repeated in the interval of three seconds for two minutes. Under this condition the tan ψ increased in some cases, but did not in other cases. Also there were some cases in which t1 remained constant in spite of a decrease in the Pmax with subjects of middle and high ages, P1 of them decreased with decreasing t1. In short the change of the characteristics of the tension curves due to fatigue showed some individual variation.
8) The decrease in the Pmax during a continuation of maximal effort of contraction was more remarkable than in the case of repeated contraction mentioned above, but the changes of the values of indicators were nearly the same in both cases.
9) The Pmax of hand gripping and index-finger bending decreased to some extent when examined immediately after the effort of contraction had been continued under the condition that the blood stream in the fore-arm was stopped by applying the maximal blood pressure by a manchette of sphygnomanometer. The change of the values of the indicators under this condition was nearly the same as under the condition without the application of pressure, but under the former condition there were some cases in which a portion of the tension curve corresponding to P1 (log t1) deviated from the intersection of the lines, or some cases in which the records of one
