| Autor: |
de Haan A; Department of Exercise Physiology and Health, Faculty of Medicine, University of Amsterdam, The Netherlands., Rexwinkel R, van Doorn JE, Westra HG, Hollander AP, Huijing PA, Woittiez RD, Sargeant AJ |
| Jazyk: |
angličtina |
| Zdroj: |
European journal of applied physiology and occupational physiology [Eur J Appl Physiol Occup Physiol] 1988; Vol. 57 (1), pp. 64-9. |
| DOI: |
10.1007/BF00691240 |
| Abstrakt: |
The effect of muscle dimensions on economy (force-time integral divided by the amount of energy utilized) was investigated in male rats (body mass range 95-490 g), anaesthetized with pentobarbital. The medial gastrocnemius muscle in situ performed 6 maximal isometric contractions of 350 ms duration (1.s-1) at twitch optimum length at 35 degrees C. The areas under the 6 time-force curves were added to obtain force-time integral of the experiment. Differences of concentrations of ATP, phosphocreatine and lactate between experimental and contralateral (resting) muscles were used to calculate high-energy phosphate consumption due to stimulation. Muscle mass and cross-sectional area increased (approximately +400% and +300%, respectively) over the rat body mass range studied. Muscle length and length of the most distal fibre bundle increased by approximately 17 mm and 4 mm, respectively. Force-time integral (N.s) increased proportional to cross-sectional area whereas high-energy phosphate consumption (mumoles) increased proportional to muscle mass. The relative fraction of the total energy consumption utilized for force-independent processes was independent of rat body mass. The economy of the actomyosin system was unaffected during growth, whereas economy of the whole muscle decreased during growth by approximately 30% (p less than 0.001). The effect of muscle dimensions on economy is discussed with respect to human endurance capacity measured by voluntary isometric contractions. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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