Muscle glycogen storage following prolonged exercise: effect of timing of ingestion of high glycemic index food

1997 ◽  
Vol 29 (2) ◽  
pp. 220-224 ◽  
Author(s):  
JO ANN M. PARKIN ◽  
MICHAEL F. CAREY ◽  
IVA K. MARTIN ◽  
LILLIAN STOJANOVSKA ◽  
MARK A. FEBBRAIO
Keyword(s):  
Glycemic Index ◽  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Glycogen Storage ◽  
Exercise Effect ◽  
High Glycemic Index

scholarly journals Muscle glycogen storage after prolonged exercise: effect of the frequency of carbohydrate feedings

1996 ◽  
Vol 64 (1) ◽  
pp. 115-119 ◽  
Author(s):  
L M Burke ◽  
G R Collier ◽  
P G Davis ◽  
P A Fricker ◽  
A J Sanigorski ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Glycogen Storage ◽  
Exercise Effect

Effect of coingestion of fat and protein with carbohydrate feedings on muscle glycogen storage

1995 ◽  
Vol 78 (6) ◽  
pp. 2187-2192 ◽  
Author(s):  
L. M. Burke ◽  
G. R. Collier ◽  
S. K. Beasley ◽  
P. G. Davis ◽  
P. A. Fricker ◽  
...  
Keyword(s):  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Glycogen Storage ◽  
Plasma Triglyceride ◽  
Dietary Guidelines ◽  
O2 Consumption ◽  
Serum Free Fatty Acid ◽  
Additional Energy ◽  
Serum Free ◽  
High Glycemic Index

Dietary guidelines for achieving optimal muscle glycogen storage after prolonged exercise have been given in terms of absolute carbohydrate (CHO) intake (8-10 g.kg-1.day-1). However, it is of further interest to determine whether the addition of fat and protein to carbohydrate feedings affects muscle glycogen storage. Eight well-trained triathletes [23.1 +/- 2.0 (SE) yr; 74.0 +/- 3.4 kg; peak O2 consumption = 4.7 +/- 0.4 l/min] undertook an exercise trial (2 h at 75% peak O2 consumption, followed by four 30-s sprints) on three occasions, each 1 wk apart. For 24 h after each trial, the subjects rested and were assigned to the following diets in randomized order: control (C) diet (high glycemic index CHO foods; CHO = 7 g.kg-1.day-1), added fat and protein (FP) diet (C diet + 1.6 g.kg-1.day-1 fat + 1.2 g.kg-1.day-1 protein), and matched-energy diet [C diet + 4.8 g.kg-1.day-1 additional CHO (Polycose) to match the additional energy in the FP diet]. Meals were eaten at t = 0, 4, 8, and 21 h of recovery. The total postprandial incremental plasma glucose area was significantly reduced after the FP diet (P < 0.05). Serum free fatty acid and plasma triglyceride responses were significantly elevated during the FP trial (P < 0.05). There were no differences between trials in muscle glycogen storage over 24 h (C, 85.8 +/- 2.7 mmol/kg wet wt; FP, 80.5 +/- 8.2 mmol/kg wet wt; matched-energy, 87.9 +/- 7.0 mmol/kg wet wt).(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle glycogen storage after prolonged exercise: effect of the glycemic index of carbohydrate feedings

1993 ◽  
Vol 75 (2) ◽  
pp. 1019-1023 ◽  
Author(s):  
L. M. Burke ◽  
G. R. Collier ◽  
M. Hargreaves
Keyword(s):  
Glycemic Index ◽  
Muscle Glycogen ◽  
Glycogen Content ◽  
Vastus Lateralis ◽  
Glycogen Storage ◽  
Carbohydrate Intake ◽  
Total Carbohydrate ◽  
Muscle Glycogen Content ◽  
Exercise Effect ◽  
Muscle Biopsies

The effect of the glycemic index (GI) of postexercise carbohydrate intake on muscle glycogen storage was investigated. Five well-trained cyclists undertook an exercise trial to deplete muscle glycogen (2 h at 75% of maximal O2 uptake followed by four 30-s sprints) on two occasions, 1 wk apart. For 24 h after each trial, subjects rested and consumed a diet composed exclusively of high-carbohydrate foods, with one trial providing foods with a high GI (HI GI) and the other providing foods with a low GI (LO GI). Total carbohydrate intake over the 24 h was 10 g/kg of body mass, evenly distributed between meals eaten 0, 4, 8, and 21 h postexercise. Blood samples were drawn before exercise, immediately after exercise, immediately before each meal, and 30, 60, and 90 min post-prandially. Muscle biopsies were taken from the vastus lateralis immediately after exercise and after 24 h. When the effects of the immediate postexercise meal were excluded, the totals of the incremental glucose and insulin areas after each meal were greater (P < or = 0.05) for the HI GI meals than for the LO GI meals. The increase in muscle glycogen content after 24 h of recovery was greater (P = 0.02) with the HI GI diet (106 +/- 11.7 mmol/kg wet wt) than with the LO GI diet (71.5 +/- 6.5 mmol/kg). The results suggest that the most rapid increase in muscle glycogen content during the first 24 h of recovery is achieved by consuming foods with a high GI.

Effect of Low- and High-Glycemic-Index Meals on Metabolism and Performance During High-Intensity, Intermittent Exercise

2010 ◽  
Vol 20 (6) ◽  
pp. 447-456 ◽  
Author(s):  
Jonathan P. Little ◽  
Philip D. Chilibeck ◽  
Dawn Ciona ◽  
Scott Forbes ◽  
Huw Rees ◽  
...  
Keyword(s):  
Glycemic Index ◽  
Muscle Glycogen ◽  
High Intensity ◽  
Perceived Exertion ◽  
Intermittent Exercise ◽  
Random Order ◽  
Rating Of Perceived Exertion ◽  
Repeated Sprint ◽  
High Glycemic Index ◽  
And Performance

Consuming carbohydrate-rich meals before continuous endurance exercise improves performance, yet few studies have evaluated the ideal preexercise meal for high-intensity intermittent exercise, which is characteristic of many team sports. The authors’ purpose was to investigate the effects of low- and high-glycemic-index (GI) meals on metabolism and performance during high-intensity, intermittent exercise. Sixteen male participants completed three 90-min high-intensity intermittent running trials in a single-blinded random order, separated by ~7 d, while fasted (control) and 2 hr after ingesting an isoenergetic low-GI (lentil), or high-GI (potato and egg white) preexercise meal. Serum free fatty acids were higher and insulin lower throughout exercise in the fasted condition (p < .05), but there were no differences in blood glucose during exercise between conditions. Distance covered on a repeated-sprint test at the end of exercise was significantly greater in the low-GI and high-GI conditions than in the control (p < .05). Rating of perceived exertion was lower in the low-GI condition than in the control (p = .01). In a subsample of 5 participants, muscle glycogen availability was greater in the low- and high-GI conditions versus fasted control before the repeated-sprint test (p < .05), with no differences between low and high GI. When exogenous carbohydrates are not provided during exercise both low- and high-GI preexercise meals improve high-intensity, intermittent exercise performance, probably by increasing the availability of muscle glycogen. However, the GI does not influence markers of substrate oxidation during high-intensity, intermittent exercise.

Glycemic Index—A New Tool in Sport Nutrition?

1998 ◽  
Vol 8 (4) ◽  
pp. 401-415 ◽  
Author(s):  
Louise M. Burke ◽  
Gregory R. Collier ◽  
Mark Hargreaves
Keyword(s):  
Glycemic Index ◽  
Nutritional Value ◽  
Prolonged Exercise ◽  
Glycogen Storage ◽  
Sport Nutrition ◽  
Insufficient Evidence ◽  
Metabolic Disturbances ◽  
Glucose Response ◽  
The Hours ◽  
And Performance

The glycemic index (GI) provides a way to rank foods rich in carbohydrate (CHO) according to the glucose response following their intake. Consumption of low-GI CHO-rich foods may attenuate the insulin-mediated metabolic disturbances associated with CHO intake in the hours prior to exercise, better maintaining CHO availability. However, there is insufficient evidence that athletes who consume a low-GI CHO-rich meal prior to a prolonged event will gain clear performance benefits. The ingestion of CHO during prolonged exercise promotes CHO availability and enhances endurance and performance, and athletes usually choose CHO-rich foods and drinks of moderate to high GI to achieve this goal. Moderate- and high-GI CHO choices appear to enhance glycogen storage after exercise compared with low-GI CHO-rich foods. However, the reason for this is not clear. A number of attributes of CHO-rich foods may be of value to the athlete including the nutritional value of the food or practical issues such as palatability, portability, cost, gastric comfort, or ease of preparation.

Muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion

1988 ◽  
Vol 64 (4) ◽  
pp. 1480-1485 ◽  
Author(s):  
J. L. Ivy ◽  
A. L. Katz ◽  
C. L. Cutler ◽  
W. M. Sherman ◽  
E. F. Coyle
Keyword(s):  
Muscle Glycogen ◽  
Vastus Lateralis ◽  
Glycogen Synthesis ◽  
Glycogen Storage ◽  
Cycle Ergometer ◽  
Carbohydrate Ingestion ◽  
Exercise Effect ◽  
Exercise Muscle ◽  
Reduced Rate ◽  
Carbohydrate Supplement

The time of ingestion of a carbohydrate supplement on muscle glycogen storage postexercise was examined. Twelve male cyclists exercised continuously for 70 min on a cycle ergometer at 68% VO2max, interrupted by six 2-min intervals at 88% VO2max, on two separate occasions. A 25% carbohydrate solution (2 g/kg body wt) was ingested immediately postexercise (P-EX) or 2 h postexercise (2P-EX). Muscle biopsies were taken from the vastus lateralis at 0, 2, and 4 h postexercise. Blood samples were obtained from an antecubital vein before and during exercise and at specific times after exercise. Muscle glycogen immediately postexercise was not significantly different for the P-EX and 2P-EX treatments. During the first 2 h postexercise, the rate of muscle glycogen storage was 7.7 mumol.g wet wt-1.h-1 for the P-EX treatment, but only 2.5 mumol.g wet wt-1.h-1 for the 2P-EX treatment. During the second 2 h of recovery, the rate of glycogen storage slowed to 4.3 mumol.g wet wt-1.h-1 during treatment P-EX but increased to 4.1 mumol.g wet wt-1.h-1 during treatment 2P-EX. This rate, however, was still 45% slower (P less than 0.05) than that for the P-EX treatment during the first 2 h of recovery. This slower rate of glycogen storage occurred despite significantly elevated plasma glucose and insulin levels. The results suggest that delaying the ingestion of a carbohydrate supplement post-exercise will result in a reduced rate of muscle glycogen storage.

scholarly journals Nutritional Peak Week and Competition Day Strategies of Competitive Natural Bodybuilders

Sports ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 126 ◽  
Author(s):  
Andrew Chappell ◽  
Trevor Simper
Keyword(s):  
Current Literature ◽  
Glycemic Index ◽  
Muscle Glycogen ◽  
Information Analysis ◽  
Qualitative Information ◽  
Water Loading ◽  
Item Questionnaire ◽  
High Glycemic Index ◽  
Fine Tune ◽  
Additional Space

Bodybuilders utilize peaking strategies in a bid to fine-tune their aesthetics for competition day. The most prevalent peaking strategies utilized by natural bodybuilders are unreported in the current literature. Eighty-one (M-59, F-22) natural bodybuilders were recruited from competitions during the 2016 and 2017 British Natural Bodybuilder Federation seasons. Competitors completed a 34-item questionnaire designed to investigate peaking and contest day strategies. The questionnaire listed commonly utilized peaking strategies and provided additional space for qualitative information. Analysis of the data indicated that carbohydrate (CHO), water, and sodium manipulation were the most commonly utilized peaking strategies. The consumption of high glycemic index CHO was the most common competition day strategy. Only 6.2% of competitors reported following their regular diet the week prior to competition. The CHO manipulation strategies followed were similar to classical CHO loading, whereby bodybuilders attempt to maximize muscle glycogen concentrations. Furthermore, bodybuilders attempted to remove superfluous water by exploiting the diuretic/polyuria effect associated with water loading/restriction. The potentially deleterious effects of peaking on bodybuilders’ health is considered and the efficacy of these strategies to enhance appearance is discussed. The findings of the present investigation are likely to be of interest to bodybuilders and their coaches.

The Effect of Timing of Ingestion of High Glycaemic Index Food on Muscle Glycogen Storage following Prolonged Exercise

1994 ◽  
Vol 87 (s1) ◽  
pp. 36-37 ◽  
Author(s):  
MA Febbraio ◽  
JM Parkin ◽  
IK Martin ◽  
L Stojanovska ◽  
MF Carey
Keyword(s):  
Muscle Glycogen ◽  
Prolonged Exercise ◽  
Glycaemic Index ◽  
Glycogen Storage

CHO feeding before prolonged exercise: effect of glycemic index on muscle glycogenolysis and exercise performance

1996 ◽  
Vol 81 (3) ◽  
pp. 1115-1120 ◽  
Author(s):  
M. A. Febbraio ◽  
K. L. Stewart
Keyword(s):  
Glycemic Index ◽  
Muscle Glycogen ◽  
Exercise Performance ◽  
Prolonged Exercise ◽  
Blood Glucose Concentration ◽  
Rest Period ◽  
Plasma Free Fatty Acid ◽  
Peak Oxygen Uptake ◽  
Plasma Insulin Concentration ◽  
Glycogen Utilization

This study examined the effect of preexercise carbohydrate (CHO) ingestion on muscle CHO metabolism and performance during prolonged exercise. Six endurance-trained men performed three exercise trials on a cycle ergometer after ingesting either a high glycemic index (HGI), low glycemic index (LGI), or placebo (Con) meal 45 min before exercise. During each trial, subjects cycled at a workload corresponding to 70% peak oxygen uptake for 120 min, followed by a 15-min performance cycle where total work (kJ) was measured. Ingestion of HGI resulted in an elevated (P < 0.01) blood glucose concentration 15 min after ingestion, compared with LGI and Con, but there were no differences in the glycemic responses to the meals thereafter, despite plasma insulin concentration being higher (P < 0.01) throughout the rest period after ingestion of HGI compared with LGI and Con. Plasma free fatty acid concentrations were lower (P < 0.05) throughout exercise in HGI compared with LGI and Con. In addition, concentrations of this metabolite were lower (P < 0.05) during the first hour of exercise in LGI compared with Con. Despite these results, no differences were observed in either the rate of muscle glycogen utilization during submaximal exercise or work output during the performance cycle when the three trials were compared. These results demonstrate that preexercise CHO ingestion has no effect on muscle glycogen utilization or exercise performance, irrespective of the glycemic or insulinemic responses to the ingested meals.

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