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Glycogen depletion sprints

Kate A Wickham, Lawrence L Spriet
There has been recent interest in the ergogenic effects of caffeine delivered in low doses (~ 200 mg or ~ 3 mg/kg body mass) and administered in forms other than capsules, coffee and sports drinks, including chewing gum, bars, gels, mouth rinses, energy drinks and aerosols. Caffeinated chewing gum is absorbed quicker through the buccal mucosa compared with capsule delivery and absorption in the gut, although total caffeine absorption over time is not different. Rapid absorption may be important in many sporting situations...
March 2018: Sports Medicine
Kristyen A Tomcik, Donny M Camera, Julia L Bone, Megan L Ross, Nikki A Jeacocke, Bill Tachtsis, Joan Senden, Luc J C van Loon, John A Hawley, Louise M Burke
INTRODUCTION: Creatine- and carbohydrate-loading are dietary strategies used to enhance exercise capacity. This study examined the metabolic and performance effects of a combined creatine and CHO-loading regiment on time-trial (TT) cycling bouts. METHODS: Eighteen well-trained (~65mL[BULLET OPERATOR]kg[BULLET OPERATOR]min VO2peak) males completed three performance trials (PT) comprised of a 120-km cycling TT interspersed with alternating 1- and 4-km sprints (6 sprints each) performed every 10-km followed by an inclined ride to fatigue (~90% VO2peak)...
August 11, 2017: Medicine and Science in Sports and Exercise
Kasper D Gejl, Niels Ørtenblad, Erik Andersson, Peter Plomgaard, Hans-Christer Holmberg, Joachim Nielsen
KEY POINTS: Glycogen is stored in local spatially distinct compartments within skeletal muscle fibres and is the main energy source during supramaximal exercise. Using quantitative electron microscopy, we show that supramaximal exercise induces a differential depletion of glycogen from these compartments and also demonstrate how this varies with fibre types. Repeated exercise alters this compartmentalized glycogen depletion. The results obtained in the present study help us understand the muscle metabolic dynamics of whole body repeated supramaximal exercise, and suggest that the muscle has a compartmentalized local adaptation to repeated exercise, which affects glycogen depletion...
May 1, 2017: Journal of Physiology
Joseph Kizzi, Alvin Sum, Fraser E Houston, Lawrence D Hayes
Attenuated performance during intense exercise with limited endogenous carbohydrate (CHO) is well documented. Therefore, this study examined whether caffeine (CAF) mouth rinsing would augment performance during repeated sprint cycling in participants with reduced endogenous CHO. Eight recreationally active males (aged 23 ± 2 yr, body mass 84 ± 4 kg, stature 178 ± 7 cm) participated in this randomized, single-blind, repeated-measures crossover investigation. Following familiarization, participants attended two separate evening glycogen depletion sessions...
November 2016: European Journal of Sport Science
William P McCormack, Jay R Hoffman, Gabriel J Pruna, Tyler C Scanlon, Jonathan D Bohner, Jeremy R Townsend, Adam R Jajtner, Jeffrey R Stout, Maren S Fragala, David H Fukuda
PURPOSE: During the competitive soccer season, women's intercollegiate matches are typically played on Friday evenings and Sunday afternoons. The efficacy of a 42-h recovery period is not well understood. This investigation was conducted to determine performance differences between Friday and Sunday matches during a competitive season. METHODS: Ten NCAA Division I female soccer players (20.5±1.0 y, 166.6±5.1 cm, 61.1±5.8 kg) were monitored with 10-Hz GPS devices across 8 weekends with matches played on Friday evenings and Sunday afternoons...
May 2015: International Journal of Sports Physiology and Performance
M Ron
The ability to perform exercise is impaired if the diet is inadequate. Conversely, performance may be improved by appropriate dietary manipulation. The primary need for the diet of athletes in training is to meet additional nutrient requirements imposed by the training load. Many athletes consider that a high protein diet is essential to stimulate muscle growth and promote repair. Evidence shows that hard exercise increases the protein requirement, but athletes eating a varied diet in sufficient quantity to meet their energy demands will obtain adequate protein...
November 1995: Asia Pacific Journal of Clinical Nutrition
Mathieu Nédélec, Alan McCall, Chris Carling, Franck Legall, Serge Berthoin, Gregory Dupont
In elite soccer, players are frequently required to play consecutive matches interspersed by 3 days and complete physical performance recovery may not be achieved. Incomplete recovery might result in underperformance and injury. During congested schedules, recovery strategies are therefore required to alleviate post-match fatigue, regain performance faster and reduce the risk of injury. This article is Part I of a subsequent companion review and deals with post-match fatigue mechanisms and recovery kinetics of physical performance (sprints, jumps, maximal strength and technical skills), cognitive, subjective and biochemical markers...
December 1, 2012: Sports Medicine
Akiko Sano, Keiichi Koshinaka, Natsuki Abe, Masashi Morifuji, Jinichiro Koga, Emi Kawasaki, Kentaro Kawanaka
A single bout of prolonged endurance exercise stimulates glucose transport in skeletal muscles, leading to post-exercise muscle glycogen supercompensation if sufficient carbohydrate is provided after the cessation of exercise. Although we recently found that short-term sprint interval exercise also stimulates muscle glucose transport, the effect of this type of exercise on glycogen supercompensation is uncertain. Therefore, we compared the extent of muscle glycogen accumulation in response to carbohydrate feeding following sprint interval exercise with that following endurance exercise...
January 2012: Journal of Physiological Sciences: JPS
Masashi Morifuji, Atsushi Kanda, Jinichiro Koga, Kentaro Kawanaka, Mitsuru Higuchi
OBJECTIVE: Depletion of glycogen stores is associated with fatigue during both sprint and endurance exercises and therefore it is considered important to maintain adequate tissue stores of glycogen during exercise. The aims of the present study in rats were therefore to investigate the effects of preexercise supplementation with carbohydrate and whey protein hydrolysates (WPH) on glycogen content, and phosphorylated signaling molecules of key enzymes that regulate glucose uptake and glycogen synthesis during exercise...
July 2011: Nutrition
J Bröjer, S Holm, R Jonasson, U Hedenström, B Essén-Gustavsson
REASONS FOR PERFORMING STUDY: The degradation of glycogen and its two forms, proglycogen (PG) and macroglycogen (MG) has been studied in horses performing different types of exercise, but no information is available about the resynthesis of PG and MG after exercise. OBJECTIVES: To determine the resynthesis of PG and MG in skeletal muscle after intermittent uphill exercise. METHODS: At a training camp 9 well-trained Standardbred trotters performed a training session comprising a warm-up period, 7 repeated 500 m bouts of exercise on an uphill slope and a recovery period...
August 2006: Equine Veterinary Journal. Supplement
Jane Shearer, Rhonda J Wilson, Danielle S Battram, Erik A Richter, Deborah L Robinson, Marica Bakovic, Terry E Graham
Glycogenin is the self-glycosylating protein primer that initiates glycogen granule formation. To examine the role of this protein during glycogen resynthesis, eight male subjects exercised to exhaustion on a cycle ergometer at 75% Vo2 max followed by five 30-s sprints at maximal capacity to further deplete glycogen stores. During recovery, carbohydrate (75 g/h) was supplied to promote rapid glycogen repletion, and muscle biopsies were obtained from the vastus lateralis at 0, 30, 120, and 300 min postexercise...
September 2005: American Journal of Physiology. Endocrinology and Metabolism
Harold W Goforth, Didier Laurent, William K Prusaczyk, Kevin E Schneider, Kitt Falk Petersen, Gerald I Shulman
Supercompensated muscle glycogen can be achieved by using several carbohydrate (CHO)-loading protocols. This study compared the effectiveness of two "modified" CHO-loading protocols. Additionally, we determined the effect of light cycle training on muscle glycogen. Subjects completed a depletion (D, n = 15) or nondepletion (ND, n = 10) CHO-loading protocol. After a 2-day adaptation period in a metabolic ward, the D group performed a 120-min cycle exercise at 65% peak oxygen uptake (VO2 peak) followed by 1-min sprints at 120% VO2 peak to exhaustion...
December 2003: American Journal of Physiology. Endocrinology and Metabolism
W J McFarlane, D G McDonald
This study examined fuel depletion in white muscle of juvenile rainbow trout sprinted to fatigue to determine whether the onset of fatigue is associated with a measurable metabolic change within the muscle and whether muscle glycogen levels influence endurance. In this study, "fuels" refer to any energy-supplying compounds and include glycogen, phosphocreatine (PCr), and ATP. Fuel depletion in white muscle was estimated by the calculation of the anaerobic energy expenditure (AEE; in micromol ATP equivalents g(-1)) from the reduction of PCr and ATP and the accumulation of lactate...
May 2002: Physiological and Biochemical Zoology: PBZ
M T Linossier, D Dormois, L Arsac, C Denis, J P Gay, A Geyssant, J R Lacour
The hyperoxia-improved tolerance to maximal aerobic performance was studied in relation to exercising muscle metabolic state. Five students were submitted to four different tests on a cycle ergometer, each being conducted under normoxia and hyperoxia (60% FiO2) on separate days: Test 1, a progressive exercise until exhaustion to determine the maximal work load (Wmax) which was unchanged by hyperoxia; Test 2, an exercise at Wmax (287 +/- 12 W) until exhaustion to determine the performance time (texh) which was elevated by 38% under hyperoxia but exhaustion occurred at the same arterial proton and lactate concentrations; Test 3 (S-Exercise test) consisted of cycling at Wmax for 90% normoxic-texh (4...
March 2000: Acta Physiologica Scandinavica
V Lacombe, K W Hinchcliff, R J Geor, M A Lauderdale
The purpose of this study was to develop a model of muscle glycogen depletion and to study the effect of this model on aerobic and anaerobic capacity of horses. The maximal rate of oxygen consumption (VO2max), maximal accumulated oxygen deficit (MAOD), muscle glycogen concentration and blood lactate concentration of 6 fit Standardbred horses were measured on 3 occasions 7 days apart (Trials 1, 2 and 3). Between Trials 2 and 3, strenuous exercise intended to deplete muscle glycogen was performed by exercising horses on the treadmill on 3 consecutive days...
July 1999: Equine Veterinary Journal. Supplement
H W Goforth, D A Arnall, B L Bennett, P G Law
Several carbohydrate (CHO)-loading protocols have been used to achieve muscle glycogen supercompensation and prolong endurance performance. This study assessed the persistence of muscle glycogen supercompensation over the 3 days after the supercompensation protocol. Trained male athletes completed a 6-day CHO-loading protocol that included cycle ergometer exercise and dietary manipulations. The 3-day depletion phase began with 115 min of cycling at 75% peak oxygen uptake followed by 3 x 60-s sprints and included the subjects consuming a low-CHO/high-protein/high-fat (10:41:49%) diet...
January 1997: Journal of Applied Physiology
L M Burke, G R Collier, P G Davis, P A Fricker, A J Sanigorski, M Hargreaves
We reported previously that intake of carbohydrate foods with a high glycemic index (GI) produced greater glycogen storage and greater postprandial glucose and insulin responses during 24 h of postexercise recovery than did intake of low-GI carbohydrate foods. In the present study we examined the importance of the greater incremental glucose and insulin concentrations on glycogen repletion by comparing intake of large carbohydrate meals ("gorging") with a pattern of frequent, small, carbohydrate snacks ("nibbling"), which simulates the flattened glucose and insulin responses after low-GI carbohydrate meals...
July 1996: American Journal of Clinical Nutrition
L M Burke, G R Collier, M Hargreaves
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)...
August 1993: Journal of Applied Physiology
J Dossett-Mercer, H J Green, E Chin, F Grange
To examine the effect of exercise on sarcoplasmic reticulum function in muscle tissue of different fibre composition, adult male Wistar rats weighing 388 +/- 23 g (x +/- SE) ran intermittently on a treadmill until fatigue. Fatigue was induced by 15-20 min of running performed at 52 m/min on an 8 degrees incline in periods of 2.5 min of exercise separated by 2 min of recovery. Analysis of sarcoplasmic reticulum Ca2+ ATPase activity determined in homogenates indicated no difference (p > 0.05) between age-matched control and exercised tissue for the soleus (SOL; 0...
October 1994: Canadian Journal of Physiology and Pharmacology
I Jacobs, P Kaiser, P Tesch
Two groups of male subjects were studied to examine the effects of different exercise protocols on performance of an isokinetic, short-time strength test, the performance of which is related to fast twitch (FT) muscle fiber recruitment. The laboratory group (LG) (n = 10) cycled (30 min, 70% VO2 max), ran (75 min), and performed repeated bouts of "sprint" cycling and rapid, maximal contractions of the quadriceps. The marathon group (MG) (n = 7) participated in and completed Stockholm's Marathon 1979. A strength test was performed before and within 1-2 h after completion of the group exercise protocol...
1981: European Journal of Applied Physiology and Occupational Physiology
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