A Prediction Method of Local Muscle Metabolic Rate

Abstract

Though the total energy metabolic rate during exercise was three times of that duringrest, the sum of energy metabolic rates of internal organs during exercise was as same as that during rest (see Table 1; LEHMANN, 1953).JANSKÝ (1964) pointed out that when the maximal metabolic rate occured in human body assame as many other mammals the total energy metabolic rate ncreased to about ten times of basal metaboric rate (BMR). It was achieved mainly by muscle and the sum of metabolic rates except that of muscle increased to only two times of that during BMR at most. Therefore selecting different items of exercise in which the total energy metabolic rates are similar, we can assume that the sum of energy metabolic rate other than that of muscle is constant. And under the condition that metabolic changes are restricted to n muscle groups, we can express the total energy metabolic rate during i-th exercise Hi as follows.Hij=nΣnj=1Mij+B1 (1)Where mij: energy metabolic rate in j-th muscle at i-th exercise [Kcal/h] ; B1: energy metabolic rate in organs other than n muscle groups [Kcal/h].It is difficult to measure mij directly but mij can be decided by using a indicator fij, which is in linear proportion to mij.mij=cjfij (2)where cj is the coefficient, of which value is dependent on a kind of muscle in individuals.Hi=nΣj-1cjfij+B1 (1)'Selecting κ different exercises in which the total energy metabolic rates are similar and equation (2) can be consisted among active muscles, we can obtain the following equation (3).Solving equation (3) for c1-cn, we can get each local muscle energy metabolic rate by use of equation (2).The possibility that the integrated surface EMG mij was applied to a linear indicator of mij was described. In isometric sustained muscle contractions, the relationship between mij and mij can be expressed as the following equation, which is exactly the same as equation (2).Mij=cjmij (6)And it was pointed out that equation (6) was adopted under some kinds of dynamic muscle contraction. In the other muscle contracting type, it was necessary to confirm equation (6) at first in order to use the present prediction method. The validity of equation (1) and (3)was discussed concentrating on an accuracy of prediction. A few formation methods of equation (3) for solving c1-cn were explained concerning with a real experimental situation.The effect of muscle fatigue and thermal environmental factor on equation (6) was discussed, too. It was emphasized that the data during muscle fatigue and in an extreme thermal condition especially a cold stress should be avoided.An applied example was given to clarify the present prediction method of local muscle metabolic rate.