High‐intensity exercise and muscle glycogen availability in humans
- 1 April 1999
- journal article
- research article
- Published by Wiley in Acta Physiologica Scandinavica
- Vol. 165 (4), 337-345
- https://doi.org/10.1046/j.1365-201x.1999.00517.x
Abstract
This study investigated the effects of muscle glycogen availability on performance and selected physiological and metabolic responses during high-intensity intermittent exercise. Seven male subjects completed a regimen of exercise and dietary intake (48 h) to either lower and keep low (LOW-CHO) or lower and then increase (HIGH-CHO) muscle glycogen stores, on two separate occasions at least a week apart. On each occasion the subjects completed a short-term (30 min) intermittent exercise (IEX) protocol, 24 h apart, which consisted of 6-s bouts of high-intensity exercise performed at 30-s intervals on a cycle ergometer. Glycogen concentration (mean +/- SEM) in m. vastus lateralis before both IEx(short) and IEx(long) was significantly lower following LOW-CHO [180 (14), 181 (17) mmol kg (dw)(-1)] compared with HIGH-CHO [397 (35), 540 (25) mmol kg (dw)(-1)]. In both IEx(short) and IEx(long), significantly less work was performed following LOW-CHO compared with HIGH-CHO. In IEx(long), the number of exercise bouts that could be completed at a pre-determined target exercise intensity increased by 265% from 111 (14) following LOW-CHO to 294 (29) following HIGH-CHO (P < 0.05). At the point of fatigue in IEx(long), glycogen concentration was significantly lower with the LOW-CHO compared with HIGH-CHO [58 (25) vs. 181 (46) mmol kg (dw)(-1), respectively]. The plasma concentrations of adrenaline and nor-adrenaline (in IEx(short) and IEx(long)), and FFAand glycerol (in IEx(long)), increased several-fold above resting values with both experimental conditions. Oxygen uptake during the exercise periods in IEx(long), approached 70% of Vo2max. These results suggest that muscle glycogen availability can affect performance during both short-term and more prolonged high-intensity intermittent exercise and that with repeated exercise periods as short as 6 s, there can be a relatively high aerobic contribution.Keywords
This publication has 34 references indexed in Scilit:
- Diet composition and the performance of high-intensity exerciseJournal of Sports Sciences, 1997
- Creatine supplementation and dynamic high‐intensity intermittent exerciseScandinavian Journal of Medicine & Science in Sports, 1993
- Effect of diet on performance during recovery from intermittent sprint exerciseJournal of Sports Sciences, 1993
- The Effect of Carbohydrate Diet on Intermittent Exercise PerformanceInternational Journal of Sports Medicine, 1992
- Topographical localization of muscle glycogen: an ultrahistochemical study in the human vastus lateralisActa Physiologica Scandinavica, 1989
- Influence of Carbohydrate-status on Performance During Maximal ExerciseInternational Journal of Sports Medicine, 1984
- Determination of plasma catecholamines by high performance liquid chromatography with electrochemical detection: Comparison with a radioenzymatic methodLife Sciences, 1979
- Glycogen, Glycolytic Intermediates and High-Energy Phosphates Determined in Biopsy Samples of Musculus Quadriceps Femoris of Man at Rest. Methods and Variance of ValuesScandinavian Journal of Clinical and Laboratory Investigation, 1974
- Diet, Muscle Glycogen and Physical PerformanceActa Physiologica Scandinavica, 1967
- II. Hypoglykämie, Arbeitsfähigkeit und Ermüdung1Skandinavisches Archiv Für Physiologie, 1939