Topic 02: Muscle Physiology Influence of Glycogen Levels on Endurance Type Performance

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Topic 02: Muscle Physiology Influence of Glycogen Levels on Endurance Type Performance Hermansen L, Hultman E, and Saltin B. Muscle glycogen during prolonged serve exercise.

Costill DL, Sherman WM, Fink WJ, Maresh C, Witten M, and Miller JM. The role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. American Journal of Clinical Nutrition.

1 Topic 02: Muscle Physiology Influence of Glycogen Levels on Endurance Type Performance Hermansen L, Hultman E, and Saltin B. Muscle glycogen during prolonged serve exercise. Acta Physiologica Scandinavica. 71: , Bergstrom J, Hermansen L, Hultman E, and Saltin B. Diet, muscle glycogen and physical performance. Acta Physiologica Scandinavica. 71: , Costill DL, Sherman WM, Fink WJ, Maresh C, Witten M, and Miller JM. The role of dietary carbohydrates in muscle glycogen resynthesis after strenuous running. American Journal of Clinical Nutrition. 34: , HPER 6760 Summer 2010 Dr. Cheatham The Players Lars Hermansen Lars Hermansen was born April 1, 1933 in the northern part of Norway. He received his BS degree from the University of Oslo in In 1964 he received his Master of Science degree from the Medical School and became a Doctor of Philosophy in During Dr. Hermansen's career he worked with renowned scientist from all over the world, like Eric Howh Christensen, P.O. Astrand, Bengt Saltin, Bjorn Ekblom, and Philip Gollnick. In addition, he received many honors and awards, including His Majesty King Olav V's Gold Medal for Medical Research from the University of Oslo. He was awarded the degree of Doctor Honoris Causa at the Medical Faculty, University of Gernoble. Dr. Hermansen also obtained a U.S. Public Health Service International Fellowship (The Fogarty Foundation) and a grant from the Perkins Fund of the American Physiological Society which allowed him to study at the University of Washington in Dr. Hermansen made many important contributions in the area of cardiac output, energy metabolism, and acid base balance. In later years his research focused on muscle pain and dysfunction, and problems that arose from various muscle diseases. He succeeded in establishing a research institute dedicated to the study of muscle physiology within the field of occupational health. 1

The Players Jonas Bergstrom Jonas Bergstrom is currently with the Department of Renal Medicine of Huddinge University Hospital which is affiliated with the Karolinska Institute.

Following publication of the biopsy technique paper he began a series of studies, in association with Eric Hultman, using biopsies to examine many aspects of muscle glycogen synthesis and utilization

2 The Players Jonas Bergstrom Jonas Bergstrom is currently with the Department of Renal Medicine of Huddinge University Hospital which is affiliated with the Karolinska Institute. Bergstrom was responsible for reintroducing the human muscle biopsy technique with his paper "Muscle electrolytes in man" published in Following publication of the biopsy technique paper he began a series of studies, in association with Eric Hultman, using biopsies to examine many aspects of muscle glycogen synthesis and utilization and carbohydrate metabolism. Bergstrom also published many papers on kidney disease and, again in association with Hultman, on the relationship between kidney disease and muscle glycogen. The Players Eric Hultman Eric Hultman was born October 10, 1925 in Kristinehamn, Sweden and is presently the head of the Department of Clinical Chemistry II of Huddinge University Hospital. His earliest work dealt with methods of glucose determination in the blood. These methods were later combined with the biopsy procedure in conjunction with Jonas Bergstrom and studies on glycogen depletion and synthesis and carbohydrate metabolism followed. Some of Hultman's other research interests include glycogen metabolism in the liver and measurement of mitochondrial respiration in muscle. 2

3 The Players David Costill Interesting profile article in the New York Times: 0/health/scientist work david costillcareer spent study training exerciselap grueling.html Energy Stores in Body 3

4 Role of CHO Muscle Glycogen Muscle glycogen is a readily available energy source for the working muscle. Values: ~ g/kg w.w. (~ g) Rate of utilization is highly dependant on exercise intensity: Low to moderate intensity Most of the energy can be obtained from the oxidation of acetyl CoA from CHO and Fat Moderate to high intensity Energy needs can not be met solely by the oxidation of CHO (blood) or fat Muscle glycogen utilization increases Anaerobic energy mostly derived from breakdown of muscle glycogen Role of CHO Muscle Glycogen 4

5 CHO and Performance Methods 5

6 RQ Values and Substrate Utilization Measuring Energy Expenditure Indirect Calorimetry and Substrate Utilization Gas exchange measurements allow an estimation of not only energy expenditure, but also the substrate mixture used. The substrate used for energy therefore determines the total amount of oxygen required and carbon dioxide produced Respiratory Quotient (RQ) RQ = VCO 2 / VO 2 Requires steady state measurements In theory, RQ can range from 0.7 to = 100% fat; 1.0 = 100% CHO 6

2 = 16CO 2 + 16H 2 O RQ = 16CO 2 / 23O 2 = 0.696 (0.

7 Measuring Energy Expenditure Indirect Calorimetry and Substrate Utilization (cont d) CHO C 6 H 12 O 6 + O 2 = CO 2 + H 2 O C 6 H 12 O 6 + 6O 2 = 6CO 2 + 6H 2 O RQ = 6CO 2 / 6O 2 = 1 Fat C 16 H 32 O 2 + O 2 = CO 2 + H 2 O C 16 H 32 O O 2 = 16CO H 2 O RQ = 16CO 2 / 23O 2 = (0.7) Limitations of using RQ Steady state conditions required Carbon dioxide produced must be entirely from the oxidation of substrates H + + HCO 3 H 2 CO 3 H 2 O + CO 2 Methods Needle Biopsy 7

8 Methods Needle Biopsy Hermansen et al.,

9 Hermansen et al., 1967 Hermansen et al.,

10 Hermansen et al., 1967 Hermansen et al.,

11 Bergstrom et al., 1967 Bergstrom et al.,

12 Bergstrom et al., 1967 Bergstrom et al.,

13 Bergstrom et al., 1967 Bergstrom et al.,

14 Costill et al., 1981 Costill et al.,

15 Costill et al., 1981 Glycogen Supercompensation 15

Topic 01: Muscle Physiology Influence of Exercise on Physiological Characteristics of Muscle Fibers

Topic 01: Muscle Physiology Influence of Exercise on Physiological Characteristics of Muscle Fibers Holloszy JO. Biochemical adaptations in muscle. Effects of exercise on mitochondrial oxygen uptake and