Muscle glycogen content

Figure 8. A. Glycogen content in the vastus lateralis muscle after a mixed diet (a) and during 5 days of total starvation ( ) in one subject and eight days of carbohydrate-poor diet (o) followed by a carbohydrate-rich diet ( ) in a second subject. B. Muscle glycogen content before and after exercise. Before exercise the diet was mixed (a) and in the following days was either total starvation ( ) or carbohydrate-poor (o) and finally followed by 1-2 days of a carbohydrate-rich diet ( ). Note the slow rate of glycogen resynthesis when the diet is carbohydrate-poor compared to the rate when the diet is carbohydrate-rich. Redrawn from Hultman and Bergstrom (1967).

Bergstrom et al. (1967) examined the relationship between initial muscle glycogen content and the capacity for prolonged submaximal exercise. Subjects cycled to exhaustion at 75% VO2 max on three occasions, each separated by three days. 

Figure 9. One-legged exercise studies showing the muscle glycogen content of the exercised (—) and rested legs (—) in two subjects. A. Muscle biopsy samples were obtained immediately after exercise (a) and during three days when fed a carbohydrate-rich diet (a). B and C. The diet was total starvation (z) for two days following exercise (B) or carbohydrate-poor (o) for three days following exercise (C). This was followed by a second one-leg exercise bout (T) and a carbohydrate-rich diet ). Redrawn from Bergstrom and Hultman (1966) in panel A, and from Hultman and Bergstrom (1967) in panels B and C.

Figure 13.23 Depletion of muscle glycogen content during prolonged physical activity. The units of glycogen are xmoLs glucose-equivalent per gram fresh muscle. Glycogen content was measured in biopsy samples taken from the vastus lateralis muscle. Exhaustive physical activity was performed on a bicycle ergometer. Exhaustion coincided with the glycogen content when it was close to zero. (Data from Hermansen et ai, 1967).

Table VI. Effect of Diet on Muscle Glycogen Content and Duration of Exercise...

Subjects Diet Muscle glycogen content before exercise (umol/g) Duration of exercise (minutes)... 

High muscle glycogen content (2.5-4.1% versus 0.2-0.9% normal) fall in blood lactate and pyruvate after exercise (normal is sharp rise) with no postexercise drop in pH normal hyperglycemic response to epinephrine (thus normal hepatic enzyme) myoglobinuria after strenuous exercise autosomal recessive. 

Keller, C., Steensberg, A., Pilegaard, H. et al.. Transcriptional activation of the IL-6 gene in human contracting skeletal muscle influence of muscle glycogen content, FASEB J, 15, 2748, 2001. 

Vamier, M., Sarto, R, Martines, D., Lora, L., Carmignoto, E, Leese, G.R., and Naccarato, R., Effect of infusing branched-chain amino acid during incremental exercise with reduced muscle glycogen content, Eur. J. Appl Physiol, 69, 26-31, 1994. 

Roberts, K.M., Noble, E.G., Hayden, D.B., and Taylor, A.W., Simple and complex-rich diets and muscle glycogen content of marathon ruimers, Eur. J. Appl. Physiol, 57, 70-74, 1988. 

Berri, C., M. Debut, V. Sante-Lhoutellier, C. Amould, B. Boutten, N. Sellier, E. Baeza, N. JeU, Y. Jego, M. J. Duclos and E. Le Bihan-Duval, 2005. Variations in chicken breast meat quality implications of struggle and muscle glycogen content at death. Br Poult Sci. 46, 572-579. 

Using the values in Table 24.1 for body glycogen content and the data in part b of the illustration for A Deeper Look (page 759), calculate the rate of energy consumption by muscles in heaty exercise (in J/sec). Use the data for fast-twitch muscle. 

Figure 6. Glycogen content in the vastus lateralis muscle as a function of cycling time at 75-80% of maximal oxygen uptake (VO2 max). Data points are mean values from 10 subjects. For each subject, exercise was performed repeatedly in periods of 15 min separated by 15 min rest periods. At the point of exhaustion and muscle fatigue, muscle glycogen stores were depleted. From Bergstrom and Hultman (1967) with permission from the publisher.

A normal mixed diet was given prior to the first ride, a CHO-poor diet prior to the second, and a CHO-rich diet before the third. The mixed, CHO-poor, and CHO-rich diets produced mean preexercise concentrations of 118,42, and 227 mmol/kg wet muscle, respectively. The corresponding exercise times were 126,59, and 189 min. An excellent correlation existed between preexercise glycogen content and cycling... 

Figure 10. The relationship between the initial glycogen content in vastus lateralis muscle and work time in six subjects who cycled to exhaustion at 75% VO2 max. Each subject cycled to exhaustion on three occasions. The first experiment was preceded by a mixed diet (a), the second by a carbohydrate-poor diet (o), and the third by a carbohydrate-rich diet ( ). The energy contents of the diets were identical. In all experiments depletion of the muscle glycogen store coincided with exhaustion and muscle fatigue. From Bergstrom et al. (1967) with permission from the publisher.

The glycogen content in the liver of a well-fed individual is 3-5 times the level found in muscle (Table 1). However, since the mass of the liver is small, the total amount of energy that can be provided from liver CHO is much less than muscle. The liver s primary responsibility with respect to CHO metabolism is to maintain... 

TypeV Myophosphorylase deficiency, McArdle s syndrome Absence of muscle phosphorylase Diminished exercise tolerance muscles have abnormally high glycogen content (2.5-4.1%). Little or no lactate in blood after exercise. 

Marathon, ultramarathon almost total glucose -1- O2 — CO2 -1- H2O fatty acid -I- O2 — CO2 -I- H2O glycogen -I- O2 — CO2 -I- H2O limiting (together with content of muscle glycogen) ... 

Glycogen content (% of initial content) Concentration in muscle (pmol/g wet weight of muscle) ... 

In (a) the sprint, and middle-distance running there is little change in the glycogen content but a marked decrease in that of phosphocreatine and a marked increase in that of phosphate and a decrease in pH. The precise and relevant concentration of ADP in muscle is not easy to measure, since most of it is bound. Hence the data are not presented but the concentration can be calculated from the change in phosphocreatine concentration. This indicates that the decrease in the ATP/ADP ratio is tenfold. 

Table 13.13 Changes in glycogen content, distance covered and intensity of activity during two soccer games in which the average content of glycogen in the guadriceps muscles of players before the game is different...

Note that the players who had a higher content of muscle glycogen before the game performed almost twice the amount of high activity bursts (i.e. sprints) and had a lower percentage of resting activities (i.e. low activity) compared with the players who started with a low content of muscle glycogen. 

The human organism can store up to 450 g of glycogen—one-third in the liver and almost all of the remainder in muscle. The glycogen content of the other organs is low. 

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