Hostname: page-component-5d59c44645-klj7v Total loading time: 0 Render date: 2024-02-29T09:12:58.510Z Has data issue: false hasContentIssue false

Nutritional ergogenic aids and exercise performance

Published online by Cambridge University Press:  14 December 2007

R. J. Maughan*
University Medical School, Foresterhill, Aberdeen AB25 2ZD, UK
Corresponding author: Dr R. J. Maughan, fax +44 (0) 1224 662990, email
Rights & Permissions [Opens in a new window]


Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The use of nutritional supplements in sport is widespread and few serious athletes do not, at some stage in their career, succumb to the temptation to experiment with one or more nutritional supplements. Nutritional ergogenic aids are aimed primarily at enhancing performance (either by affecting energy metabolism or by an effect on the central nervous system), at increasing lean body mass or muscle mass by stimulation of protein synthesis and at reducing body fat content. Although not strictly ergogenic (i.e. capable of enhancing work performance), supplements aimed at increasing resistance to infection and improving general health are seen by athletes as important in reducing the interruptions to training that minor illness and infection can cause. Creatine is perhaps the most widely used supplement in sport at the moment. Supplementation can increase muscle creatine phosphate levels and, although not all published studies show positive results, there is much evidence that performance of short-term high-intensity exercise can be improved by supplementation. Ingestion of large doses of bicarbonate can enhance performance of exercise where metabolic acidosis may be a limiting factor, but there is a significant risk of adverse gastrointestinal side effects. Caffeine can also improve performance, in part by a stimulation of fatty acid mobilization and sparing of the body's limited carbohydrate stores, but also via direct effects on muscle and possibly by central nervous system effects on the perception of effort and fatigue. Carnitine plays an essential role in fatty acid oxidation in muscle but, although supplements are used by athletes, there is no good evidence of a beneficial effect of supplementation. None of these products contravenes the International Olympic Committee regulations on doping in sports, although caffeine is not permitted above a urine concentration of 12 mg/l. Supplementation is particularly prevalent among strength and power athletes, where an increase in muscle mass can benefit performance. Protein supplements have not been shown to be effective except in those rare cases where the dietary protein intake is otherwise inadequate. Individual amino acids, especially ornithine, arginine and glutamine, are also commonly used, but their benefit is not supported by documented evidence. Cr and hydroxymethylbutyrate are also used by strength athletes, but again there are no well-controlled studies to provide evidence of a beneficial effect. Athletes use a wide variety of supplements aimed at improving or maintaining general health and vitamin and mineral supplementation is widespread. There is a theoretical basis, and limited evidence, to support the use of antioxidant vitamins and glutamine during periods of intensive training, but further evidence is required before the use of these supplements can be recommended.

Research Article
Copyright © CABI Publishing 1999


Abrahamsson, K, Eriksson, BO, Holme, E, Jodal, U, Jonsson, A & Lindstedt, S (1996) Pivalic acid-induced carnitine deficiency and physical exercise in humans. Metabolism: Clinical and Experimental 45, 15011507.CrossRefGoogle ScholarPubMed
Balsom, PD, Ekblom, B, Soderlund, K, Sjodin, B & Hultman, E (1993 a) Creatine supplementation and dynamic high-intensity intermittent exercise. Scandinavian Journal of Medicine and Science in Sport 3, 143149.CrossRefGoogle Scholar
Balsom, PD, Harridge, SDR, Soderlund, K, Sjodin, B & Ekblom, B (1993 b) Creatine supplementation per se does not enhance endurance exercise performance. Acta Physiologica Scandinavica 149, 521523.CrossRefGoogle Scholar
Balsom, PD, Soderlund, K & Ekblom, B (1994) Creatine in humans with special reference to creatine supplementation. Sports Medicine 18, 268280.CrossRefGoogle ScholarPubMed
Barnett, C, Costill, DL, Vukovich, MD, Cole, KJ, Goodpaster, BH, Trappe, SW & Fink, WJ (1994) Effect of L-carnitine supplementation on muscle and blood carnitine content and lactate accumulation during high intensity sprint cycling. International Journal of Sport Nutrition 4, 280288.CrossRefGoogle ScholarPubMed
Bessman, SP & Geiger, PJ (1981) Transport of energy in muscle: the phosphorylcreatine shuttle. Science 211, 448452.CrossRefGoogle ScholarPubMed
Bird, SR, Wiles, J & Robbins, J (1995) The effect of sodium bicarbonate ingestion on 1500-m racing time. Journal of Sports Sciences 13, 399403.CrossRefGoogle ScholarPubMed
Boobis, LH (1997) Metabolic aspects of fatigue during sprinting. In Exercise: Benefits, Limits and Adaptations, pp. 116140 [Macleod, D, Maughan, R, Nimmo, M, Reilly, T and Williams, C, editors]. London: Spon.Google Scholar
Bouissou, P, Defer, G, Guezennec, CY, Estrade, PY & Serrurier, B (1988) Metabolic and blood catecholamine responses to exercise during alkalosis. Medicine and Science in Sports and Exercise 20, 228232.CrossRefGoogle ScholarPubMed
Brien, DM & McKenzie, DC (1989) The effect of induced alkalosis and acidosis on plasma lactate and work output in elite oarsmen. European Journal of Applied Physiology 58, 797802.CrossRefGoogle ScholarPubMed
Burke, LM & Inge, K (1994) Protein requirements for training and “bulking up”. In Clinical Sports Nutrition, pp. 124150 [Burke, LM and Deakin, V, editors]. Sydney: McGraw Hill.Google Scholar
Burke, LM & Read, RSD (1993) Dietary supplements in sport. Sports Medicine 15, 4365.CrossRefGoogle ScholarPubMed
Castell, LM & Newsholme, EA (1997) The effects of oral glutamine supplementation on athletes after prolonged exhaustive exercise. Nutrition 13, 738742.CrossRefGoogle ScholarPubMed
Castell, LM, Poortmans, JR, Leclerq, R, Brasseur, M, Duchateau, J & Newsholme, EA (1997) Some aspects of the acute phase response after a marathon race, and the effects of glutamine supplementation. European Journal of Applied Physiology 75, 4753.CrossRefGoogle ScholarPubMed
Castell, LM, Poortmans, JR & Newsholme, EA (1996) Does glutamine have a role in reducing infestions in athletes? European Journal of Applied Physiology 73, 488490.CrossRefGoogle ScholarPubMed
Clarkson, PM (1997) Eccentric exercise and muscle damage. International Journal of Sports Medicine 18, S314S317.CrossRefGoogle ScholarPubMed
Clarkson, PM (1998) Nutritional supplements for weight gain. Sports Science Exchange 11, 110.Google Scholar
Collomp, K, Ahmaidi, S, Audran, M, Chanal, J-L & Prefaut, C (1991) Effects of caffeine ingestion on performance and anaerobic metabolism during the Wingate test. International Journal of Sports Medicine 12, 439443.CrossRefGoogle ScholarPubMed
Costill, DL, Dalsky, G & Fink, WJ (1978) Effects of caffeine ingestion on metabolism and exercise performance. Medicine and Science in Sports 10, 155158.Google ScholarPubMed
Costill, DL, Verstappen, F, Kuipers, H, Jansson, E & Fink, W (1984) Acid–base balance during repeated bouts of exercise. Influence of HCO3. International Journal of Sports Medicine 5, 228231.CrossRefGoogle ScholarPubMed
Coyle, EF (1997) Fuels for sports performance. In Optimizing Sports Performance, pp. 95137 [Lamb, DR and Murray, R, editors]. Carmel, CA: Cooper Publishing.Google Scholar
Dekkers, JC, van Doornen, LJ & Kemper, HC (1996) The role of antioxidant vitamins and enzymes in the prevention of exercise-induced muscle damage. Sports Medicine 21, 213238.CrossRefGoogle ScholarPubMed
Dill, DB, Edwards, HT & Talbot, JH (1932) Alkalosis and capacity for work. Journal of Biological Chemistry 97, 1.Google Scholar
Dodd, SL, Herb, RA & Powers, SK (1993) Caffeine and endurance performance: an update. Sports Medicine 15, 1423.CrossRefGoogle ScholarPubMed
Dohm, GL (1986) Protein as a fuel for endurance exercise. Exercise and Sports Science Reviews 14, 143173.CrossRefGoogle ScholarPubMed
Earnest, CP, Snell, PG, Mitchell, TL, Rodriguez, R & Almada, AL (1994) Effect of creatine monohydrate on peak anaerobic power, capacity and fatigue index. Medicine and Science in Sports and Exercise 26, S39.CrossRefGoogle Scholar
Evans, GW (1989) The effect of chromium picolinate on insulin controlled parameters in humans. International Journal of Biosociology and Medical Research 11, 163180.Google Scholar
Goldfinch, J, McNaughton, L & Davies, P (1988) Induced metabolic alkalosis and its effect on 400m racing time. European Journal of Applied Physiology 57, 4548.CrossRefGoogle ScholarPubMed
Graham, TE, Rush, JWE & van Soeren, MH (1994) Caffeine and exercise: metabolism and performance. Canadian Journal of Applied Physiology 2, 111138.CrossRefGoogle Scholar
Green, AL, Greenhaff, PL, Macdonald, IA, Bell, D, Holloman, D & Stroud, MA (1993) The influence of oral creatine supplementation on metabolism during sub-maximal incremental treadmill exercises. Proceedings of the Nutrition Society 53, 84A.Google Scholar
Green, AL, Hultman, E, Macdonald, IA, Sewell, DA & Greenhaff, PL (1996 a) Carbohydrate ingestion augments skeletal muscle creatine accumulation during creatine supplementation in humans. American Journal of Physiology 271, E821E826.Google ScholarPubMed
Green, AL, Simpson, EJ, Littlewood, JJ, Macdonald, IA & Greenhaff, PL (1996 b) Carbohydrate ingestion augments creatine retention during creatine feeding in humans. Acta Physiologica Scandinavica 158, 195202.CrossRefGoogle ScholarPubMed
Green, HJ, Jones, S, Ball-Burnett, ME, Smith, D, Livesey, J & Farrance, BW (1991) Early muscular and metabolic adaptations to prolonged exercise training in man. Journal of Applied Physiology 70, 20322038.CrossRefGoogle Scholar
Greenhaff, PL (1995) Creatine and its application as an ergogenic aid. International Journal of Sport Nutrition 5, S100S110.CrossRefGoogle ScholarPubMed
Greenhaff, PL, Bodin, K, Soderlund, K & Hultman, E (1994) Effect of oral creatine supplementation on skeletal muscle phosphocreatine resynthesis. American Journal of Physiology 266, E725E730.Google ScholarPubMed
Greenhaff, PL, Casey, A, Short, AH, Harris, RC, Soderlund, K & Hultman, E (1993) Influence of oral creatine supplementation on muscle torque during repeated bouts of maximal voluntary exercise in man. Clinical Science 84, 565571.CrossRefGoogle ScholarPubMed
Greenhaff, PL, Harris, RC & Snow, DH (1990 a) The effect of sodium bicarbonate (NaHCO3) administration upon exercise metabolism in the thoroughbred horse. Journal of Physiology 420, 69P.Google Scholar
Greenhaff, PL, Snow, DH, Harris, RC & Roberts, CA (1990 b) Bicarbonate loading in the thoroughbred horse: dose, method of adminstration and acid–base changes. Equine Veterinary Journal 19, 8385.CrossRefGoogle Scholar
Harridge, SDR, Balsom, PD & Soderlund, K (1994) Creatine supplementation and electrically evoked human muscle fatigue. Clinical Science 87, Suppl., 124125.CrossRefGoogle Scholar
Harris, RC, Hultman, E & Nordesjo, LO (1974) Glycogen, glycolytic intermediates and high-energy phosphates determined in biopsy samples of musculus quadriceps femoris of man at rest. Scandinavian Journal of Clinical and Laboratory Investigation 33, 109120.CrossRefGoogle ScholarPubMed
Harris, RC, Marlin, DJ & Snow, DH (1987) Metabolic response to maximal exercise of 800 and 2,000 m in the thoroughbred horse. Journal of Applied Physiology 63, 1219.CrossRefGoogle Scholar
Harris, RC, Soderlund, K & Hultman, E (1992) Elevation of creatine in resting and exercised muscle of normal subjects by creatine supplementation. Clinical Science 83, 367374.CrossRefGoogle ScholarPubMed
Harris, RC, Viru, M, Greenhaff, PL & Hultman, E (1993) The effect of oral creatine supplementation on running performance during maximal short term exercise in man. Journal of Physiology 467, 74P.Google Scholar
Heigenhauser, JF & Jones, N (1991) Bicarbonate loading. In Ergogenics: The Enhancement of Sports Performance, pp. 183212 [Williams, MH and Lamb, DR, editors]. Carmel, CA: Benchmark Press.Google Scholar
Heymsfield, SB, Arteaga, C, McManus, C, Smith, J & Moffitt, S (1983) Measurement of muscle mass in humans. American Journal of Clinical Nutrition 37, 478494.CrossRefGoogle ScholarPubMed
Horswill, CA, Costill, DL, Fink, WJ, Flynn, MG, Kirwan, JP, Mitchell, JB & Houmard, JA (1988) Influence of sodium bicarbonate on sprint performance: relationship to dosage. Medicine and Science in Sports and Exercise 20, 566569.CrossRefGoogle ScholarPubMed
Hultman, E, Bergstrom, J & Anderson, NM (1967) Breakdown and resynthesis of phosphorylcreatine and adenosine triphosphate in connection with muscular work in man. Scandinavian Journal of Clinical and Laboratory Investigation 19, 5666.CrossRefGoogle ScholarPubMed
Hultman, E & Sahlin, K, (1980) Acid–base balance during exercise. Exercise and Sports Science Reviews vol. 8, pp. 41128 [Hutton, RS and Miller, D, editors]. Philadelphia, PA: Franklin Institute Press.Google Scholar
Hultman, E & Sjoholm, H (1983) Substrate availability. In Biochemistry of Exercise, vol. 13, pp. 6375 [Knuttgen, HG, Vogel, JA and Poortmans, J, editors]. Champaign, IL: Human Kinetics Publishers.Google Scholar
Hultman, E, Soderlund, K, Timmons, JA, Cederblad, G & Greenhaff, PL (1996) Muscle creatine loading in men. Journal of Applied Physiology 81, 232237.CrossRefGoogle ScholarPubMed
Inbar, O, Rotstein, A, Jacobs, I, Kaiser, P, Dlin, R & Dotan, R (1983) The effects of alkaline treatment on short term maximal exercise. Journal of Sports Sciences 1, 95104.CrossRefGoogle Scholar
Jackman, M, Wendling, P, Friars, D & Graham, TE (1996) Metabolic, catecholamine and endurance responses to caffeine during intense exercise. Journal of Applied Physiology 81, 16581663.CrossRefGoogle ScholarPubMed
Jansson, E, Dudley, GA, Norman, B & Tesch, PA (1987) ATP and IMP in single human muscle fibres after high intensity exercise. Clinical Physiology 7, 337345.CrossRefGoogle ScholarPubMed
Jones, NL, Sutton, JR, Taylor, R & Toews, CJ (1977) Effects of pH on cardiorespiratory and metabolic responses to exercise. Journal of Applied Physiology 43, 959964.CrossRefGoogle ScholarPubMed
Kanter, M (1995) Free radicals and exercise: effects of nutritional antioxidant supplementation. Exercise and Sports Science Reviews 23, 375397.CrossRefGoogle ScholarPubMed
Karlsson, J & Saltin, B (1970) ATP and CP in working muscles during exhaustive exercise in man. Journal of Applied Physiology 29, 598602.CrossRefGoogle ScholarPubMed
Kelso, TB, Hodgson, DR, Witt, EH, Bayly, M, Grant, BD & Gollnick, PD (1987) Bicarbonate administration and muscle metabolism during high intensity exercise. In Equine Exercise Physiology, vol. 2, pp. 438477 [Gillespie, J and Robinson, NE, editors]. Davis, CA: ICEEP Publications.Google Scholar
Kindermann, W, Keul, J & Huber, G (1977) Physical exercise after induced alkalosis (bicarbonate or tris-buffer). European Journal of Applied Physiology 37, 197204.CrossRefGoogle ScholarPubMed
Kowalchuk, JM, Heigenhauser, GJF & Jones, NL (1984) Effects of pH on metabolic & cardiorespiratory responses during exercise. Journal of Applied Physiology 57, 15581563.CrossRefGoogle Scholar
Kowalchuk, JM, Maltais, SA, Yamaji, K & Hughson, RL (1989) The effect of citrate loading on exercise performance, acid–base balance and metabolism. European Journal of Applied Physiology 58, 858864.CrossRefGoogle ScholarPubMed
Lang, F, Busch, GL & Volkl, K (1998) The diversity of volume regulatory mechanisms. Cell Physiology and Biochemistry 8, 145.CrossRefGoogle ScholarPubMed
Lemon, PWR (1991) Effect of exercise on protein requirements. Journal of Sports Science 9, 5370.CrossRefGoogle ScholarPubMed
Lemon, PWR (1995) Do athletes need more dietary protein and amino acids? International Journal of Sports Nutrition 5, S39S61.CrossRefGoogle ScholarPubMed
Low, SY, Rennie, MJ & Taylor, PM (1996) Modulation of glycogen synthesis rate in skeletal muscle by changes in cell volume. Journal of Physiology 495, 299303.CrossRefGoogle Scholar
Low, SY, Rennie, MJ & Taylor, PM (1997) Signalling elements involved in amino acid transport responses to altered muscle cell volume. FASEB Journal 11, 11111117.CrossRefGoogle ScholarPubMed
McCord, JM (1979) Superoxide, superoxide dismutase and oxygen toxicity. Reviews of Biochemistry and Toxicology 1, 109124.Google Scholar
McKenzie, DC, Coutts, KD, Stirling, DR, Hoeben, HH & Kuzara, G (1986) Maximal work production following two levels of artificially induced metabolic alkalosis. Journal of Sports Sciences 4, 3538.CrossRefGoogle ScholarPubMed
McNaughton, L (1990) Sodium citrate and anaerobic performance: implications of dosage. European Journal of Applied Physiology 61, 392397.CrossRefGoogle ScholarPubMed
Maganaris, CN & Maughan, RJ (1998) Creatine supplementation enhances maximum voluntary isometric force and endurance capacity in resistance trained men. Acta Physiologica Scandinavica 163, 279287.CrossRefGoogle ScholarPubMed
Malm, C, Svensson, M, Sjoberg, B, Ekblom, B & Sjodin, B (1996) Supplementation with ubiquinone-10 causes cellular damage during intense exercise. Acta Physiologica Scandinavica 157, 511512.CrossRefGoogle ScholarPubMed
Margaritis, I, Tessier, F, Richard, MJ & Marconnet, P (1997) No evidence of oxidative stress after a triathlon in highly trained competitors. International Journal of Sports Medicine 18, 186190.CrossRefGoogle ScholarPubMed
Maughan, RJ (1995) Creatine supplementation and exercise performance. International Journal of Sports Nutrition 5, 94101.CrossRefGoogle ScholarPubMed
Maughan, RJ, Leiper, JB & Litchfield, PE (1986) The effects of induced acidosis and alkalosis on isometric endurance capacity in man. In Exercise Physiology. Current Selected Research, vol. 2, pp. 94101 [Dotson, CO and Humphrey, JH, editors]. New York: AMS Press Inc.Google Scholar
Maughan, RJ & Shirreffs, SM (1998) Fluid and electrolyte loss and replacement in exercise. In Oxford Textbook of Sports Medicine, 2nd Edition, pp. 97113 [Harries, M, Williams, C, Stanish, WD and Micheli, LL, editors]. New York: Oxford University Press.Google Scholar
Mertz, W (1992) Chromium: history and nutritional importance. Biological Trace Element Research 32, 38.CrossRefGoogle ScholarPubMed
Meyer, RA, Brown, TA, Kirlowicz, BL & Kushmerick, MJ (1986) Phosphagen and intracellular pH changes during contraction of creatine-depleted rat muscle. American Journal of Physiology 250, C264C274.CrossRefGoogle ScholarPubMed
Meyer, RA, Sweeney, HL & Kushmerick, MJ (1984) A simple analysis of the “phosphocreatine shuttle”. American Journal of Physiology 246, C365C377.CrossRefGoogle ScholarPubMed
Moriguchi, S, Miwa, H & Kishino, Y (1995) Glutamine supplementation prevents the decrease of mitogen response after a treadmill exercise in rats. Journal of Nutritional Science and Vitaminology 41, 115125.CrossRefGoogle ScholarPubMed
Mujika, I & Padilla, S (1997) Creatine supplementation as an ergogenic aid for sports performance in highly trained athletes: a critical review. International Journal of Sports Medicine 18, 491496.CrossRefGoogle ScholarPubMed
Newsholme, EA (1994) Biochemical mechanisms to explain immunosuppression in well-trained and overtrained athletes: a critical review. International Journal of Sports Medicine 15, Suppl. 3S142S147.CrossRefGoogle Scholar
Nieman, DC (1997) Exercise immunology: practical applications. International Journal of Sports Medicine 18, Suppl. 1S91S100.CrossRefGoogle ScholarPubMed
Nieman, DC, Henson, DS, Gusewitch, G, Warren, BJ, Dotson, RC, Butterworth, DE & Nelson-Cannarella, SL (1993) Physical activity and immune function in elderly women. Medicine and Science in Sports and Exercise 25, 823831.CrossRefGoogle ScholarPubMed
Nieman, DC, Nelson-Cannarella, SL, Henson, DA, Koch, AJ, Butterworth, DE, Fagaoga, OR & Utter, A (1998) Immune response to exercise training and/or energy restriction in obese women. Medicine and Science in Sports and Exercise 30, 679686.CrossRefGoogle ScholarPubMed
Nissen, S, Sharp, R, Ray, M, Rathmacher, JA, Rice, D, Fuller, JC, Connolly, AS & Abumrad, N (1996) Effect of leucine metabolite β-hydroxy β-methylbutyrate on muscle metabolism during resistance-exercise training. Journal of Applied Physiology 81, 20952104.CrossRefGoogle ScholarPubMed
Odland, LM, MacDougall, JD, Tarnopolsky, M, Eloraggia, A, Borgman, A & Atkinson, S (1994) The effect of oral Cr supplementation on muscle [PCr] and power output during a short-term maximal cycling task. Medicine and Science in Sports and Exercise 26, S23.CrossRefGoogle Scholar
Oopik, V, Timpmann, S, Medijainen, L & Aleksejeva, T (1996) Effect of creatine administration on blood urea and post-exercise glycogen repletion in liver and skeletal muscle in rats. Annals of Nutrition and Metabolism 40, 359363.Google Scholar
Oopik, V, Timpmann, S, Medijainen, L & Viru, A (1994) Effect of in vivo creatine administration on creatine content in skeletal muscle of rat. Clinical Science 87, Suppl., 116.CrossRefGoogle Scholar
Packer, L (1997) Oxidants, antioxidant nutrients and the athlete. Journal of Sports Sciences 15, 353363.CrossRefGoogle ScholarPubMed
Parry-Billings, M & Maclaren, DPM (1986) The effect of sodium bicarbonate and sodium citrate ingestion on anaerobic power during intermittent exercise. European Journal of Applied Physiology 55, 524529.CrossRefGoogle ScholarPubMed
Peters-Futre, EM (1997) Vitamin C, neutrophil function, and URTI risk in distance runners: the missing link. Exercise and Immunology Reviews 3, 3252.Google ScholarPubMed
Phillips, B (1996) 1996 Supplement Review. Golden, CO: Mile High Publishing.Google Scholar
Poortmans, JR, Auquier, H, Renault, V, Durussel, A, Saugy, M & Brisson, GR (1997) Effect of short-term creatine supplementation on renal responses in men. European Journal of Applied Physiology 76, 566567.CrossRefGoogle ScholarPubMed
Poulus, AJ, Doctor, HJ & Westra, HG (1974) Acid–base balance and subjective feelings of fatigue during physical exercise. European Journal of Applied Physiology 33, 207213.CrossRefGoogle ScholarPubMed
Rehunen, S & Harkonen, M (1980) High-energy phosphate compounds in human slow-twitch and fast-twitch muscle fibres. Scandinavian Journal of Clinical Laboratory Investigation 40, 4554.CrossRefGoogle ScholarPubMed
Rennie, MJ, Low, SY, Taylor, PM, Khogali, SE, Yao, PC & Ahmed, A (1998) Amino acid transport during muscle contraction and its relevance to exercise. Advances in Experimental Medicine and Biology 441, 299305.CrossRefGoogle ScholarPubMed
Robertson, RJ, Falker, JE, Drash, AL, Swank, AM, Metz, KF, Spungen, SA & LeBoeuf, JR (1996) Effect of blood pH on peripheral and central signals of perceived exertion. Medicine and Science in Sports and Exercise 18, 114122.Google Scholar
Rohde, T, MacLean, DA & Pedersen, BK (1998) Effect of glutamine supplementation on changes in the immune system induced by repeated exercise. Medicine and Science in Sports and Exercise 30, 856862.Google ScholarPubMed
Ronsen, O, Sundgot-Borgen, J & Maehlum, S (1999) Supplement use and nutritional habits in Norwegian elite athletes. Scandinavian Journal of Medicine and Science in Sports 9, 2835.CrossRefGoogle ScholarPubMed
Rowbottom, DG, Keast, D, Goodman, C & Morton, AR (1995) The haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome. European Journal of Applied Physiology 70, 502509.CrossRefGoogle ScholarPubMed
Rowbottom, DG, Keast, D & Morton, AR (1996) The emerging role of glutamine as an indicator of exercise stress and overtraining. Sports Medicine 21, 8097.CrossRefGoogle ScholarPubMed
Sahlin, K (1986) Metabolic changes limiting muscle performance. In Biochemistry of Exercise VI, pp. 323344 [Saltin, B, editor]. Champaign, IL: Human Kinetics Publishers.Google Scholar
Sahlin, K & Katz, A (1988) Purine nucleotide metabolism. In Principles of Exercise Biochemistry, pp. 120139 [Poortmans, JR, editor]. Basel, Switzerland: Karger.CrossRefGoogle Scholar
Shephard, RJ & Shek, PN (1997) Heavy exercise, nutrition and immune function: is there a connection? International Journal of Sports Medicine 16, 491497.CrossRefGoogle Scholar
Smith, JK, Grisham, MB, Granger, DN & Korthus, RJ (1989) Free radical defense mechanisms and neutrophil infiltration in postischemic skeletal muscle. American Journal of Physiology 56, H789H793.Google Scholar
Snow, DH, Harris, RC & Gash, SP (1985) Metabolic response of equine muscle to intermittent maximal exercise. Journal of Applied Physiology 58, 16891697.CrossRefGoogle ScholarPubMed
Sobal, J & Marquart, LF (1994) Vitamin/mineral supplement use among athletes: a review of the literature. International Journal of Sports Nutrition 4, 320324.CrossRefGoogle ScholarPubMed
Soderlund, K, Balsom, PD & Ekblom, B (1994) Creatine supplementation and high intensity exercise: influence on performance and muscle metabolism. Clinical Science 87, Suppl., 120121.CrossRefGoogle Scholar
Spriet, LL (1995) Caffeine & performance. International Journal of Sports Nutrition 5, S84S99.CrossRefGoogle ScholarPubMed
Spriet, LL (1997) Ergogenic aids: recent advances and retreats. In Optimizing Sports Performance, pp. 185238 [Lamb, DR and Murray, D, editors]. Carmel, CA: Cooper Publishing.Google Scholar
Stroud, MA, Holliman, D, Dell, B, Green, AL, Macdonald, IA & Greenhaff, PL (1994) Effect of oral creatine supplementation on respiratory gas exchange and blood lactate accumulation during steady-state incremental treadmill exercise and recovery in man. Clinical Science 87, 707710.CrossRefGoogle ScholarPubMed
Sutton, JR, Jones, NL & Toews, CJ (1981) Effect of pH on muscle glycolysis during exercise. Clinical Science 61, 331338.CrossRefGoogle ScholarPubMed
Swank, A & Robertson, RJ (1989) Effect of induced alkalosis on perception of exertion during intermittent exercise. Journal of Applied Physiology 67, 18621867.CrossRefGoogle ScholarPubMed
Tiidus, P, Pushkarenko, J & Houston, ME (1996) Lack of antioxidant adaptation to short-term aerobic training in human muscle. American Journal of Physiology 271, R832R836.Google ScholarPubMed
Toler, SM (1997) Creatine is an ergogen for anaerobic exercise. Nutrition Reviews 55, 2123.CrossRefGoogle ScholarPubMed
Vandenburge, K, Goris, M, Van Hecke, P, Van Leemoutte, M, Vangerven, L & Hespel, P (1997) Long-term creatine intake is beneficial to muscle performance during resistance training. Journal of Applied Physiology 83, 20552063.CrossRefGoogle Scholar
Volek, JS, Kraemer, WJ, Bush, JA, Boetes, M, Incledon, TClark, KL & Lynch, JM (1997) Creatine supplementation enhances muscular performance during high-intensity resistance exercise. Journal of the American Dietetic Association 97, 765770.CrossRefGoogle ScholarPubMed
Vukovich, MD, Costill, DL & Fink, WJ (1994) Carnitine supplementation: effect on muscle carnitine and glycogen content during exercise. Medicine and Science in Sports and Exercise 26, 11221129.CrossRefGoogle ScholarPubMed
Waldegger, S & Lang, F (1997) Cell volume and gene expression. Journal of Membrane Biology 162, 95100.CrossRefGoogle Scholar
Walker, JB (1979) Creatine biosynthesis, regulation and function. Advances in Enzymology 50, 117142.Google Scholar
Walker, LS, Bemben, MG, Bemben, DA & Knehans, AW (1998) Chromium picolinate effects on body composition and muscular performance in wrestlers. Medicine and Science in Sports and Exercise 30, 17301737.CrossRefGoogle ScholarPubMed
Wemple, RD, Lamb, DR & McKeever, KH (1997) Caffeine vs caffeine-free sports drinks: effects on urine production at rest and during prolonged exercise. International Journal of Sports Medicine 18, 4046.CrossRefGoogle ScholarPubMed
Wiles, JO, Bird, SR, Hopkins, J & Riley, M (1992) Effect of caffeinated coffee on running speed, respiratory factors, blood lactate and perceived exertion during 1500-m treadmill running. British Journal of Sports Medicine 26, 116120.CrossRefGoogle ScholarPubMed
Wilkes, D, Gledhill, N & Smyth, R (1983) Effect of acute induced metabolic alkalosis on 800-m racing time. Medicine and Science in Sports and Exercise 15, 277280.CrossRefGoogle ScholarPubMed
Williams, C (1998) Diet and sports performance. In Oxford Textbook of Sports Medicine, 2nd ed., pp. 7797 [Harries, M, Williams, C, Stanish, WD and Micheli, LL, editors]. New York: Oxford University Press Williams.Google Scholar
Williams, MH (1983) Ergogenic Aids in Sport. Champaign, IL: Human Kinetics Publishers.Google Scholar
Williams, MH & Branch, JD (1998) Creatine supplementation and exercise performance: an update. Journal of the American College of Nutrition 17, 216234.CrossRefGoogle ScholarPubMed
Ziegenfuss, TN, Lemon, PWR, Rogers, MR, Ross, R & Yarasheski, KE (1997) Acute creatine ingestion: effects on muscle volume, anaerobic power, fluid volumes, and protein turnover. Medicine and Science in Sports and Exercise 29, S127.CrossRefGoogle Scholar