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Is creatine hydrochloride better than creatine monohydrate for the improvement of physical performance and hormonal changes in young trained men?
Abstract
Objectives
The production and sale of performance-enhancing drugs (PEDs) with annual increase in number and diversity have now become a beneficial industry. At present, there is a kind of creatine supplement, called as creatine hydrochloride (CHCL), which is claimed to have a much higher absorption compared to creatine monohydrate (CRM) supplementation and does not require a loading period. However, this claim has not been fully examined yet. Therefore, the present study aimed to compare the effects of two types of creatine (CHCL and CRM) on physical activity, plasma levels of testosterone (T), and cortisol (Cor) in trained young men.
Equipment and methods
The statistical population of this study included 36 healthy subjects selected by purposive sampling method and with at least six months of resistance training. The subjects were randomly divided into four groups (Group 1: 20 g of CRM, Group 2: 3 g of CRM, Group 3: 3 g of CHCl per day for a week, and Group 4: placebo). The supplements were given to subjects by double-blind manner. Physical performance variables were evaluated on the morning of the first day and before the supplementation, and blood samples (5 cc) were taken in fasting conditions (8–10 hours) to measure the plasma levels of T and Cor. The blood samples were taken again after seven days for physical performance measurements.
Results
The results showed that there were no significant differences between the effects of 3 and 20 g of CRM and 3 g of CHCL on the vigor, power, plasma levels of T and Cor, and T/C ratio. In other words, 3 g of CHCL did not result in improved performance and hormonal changes compared to 20 g of CRM.
Conclusion
According to the results, the multi-day period of supplementation with CHCL in comparison to CRM cannot have much effect on performance and improve the hormonal status of individuals in the short term.
... There is limited information on the effect of Cr-HCl and there is a need for more research in this field. There have been few studies on the effects of Cr-HCl; the results of Tayebi and Arazi [18] showed that Cr-HCl supplementation did not have a significant effect on performance and hormonal response compared to CrM [18,19]. Additionally, de Franca et al. [19] stated that Cr-HCl and CrM improved muscle strength after four weeks of RT, but only Cr-HCl changed body composition in recreational weightlifters [19]. ...
... There is limited information on the effect of Cr-HCl and there is a need for more research in this field. There have been few studies on the effects of Cr-HCl; the results of Tayebi and Arazi [18] showed that Cr-HCl supplementation did not have a significant effect on performance and hormonal response compared to CrM [18,19]. Additionally, de Franca et al. [19] stated that Cr-HCl and CrM improved muscle strength after four weeks of RT, but only Cr-HCl changed body composition in recreational weightlifters [19]. ...
... More research needs to be done on the hormonal compatibility of Cr-HCl supplementation. Only a few studies [18,36] have examined the effects of this type of creatine supplementation on testosterone and cortisol levels. In this regard, Tayebi and Arazi showed that multiday supplementation (7 days) of Cr-HCl (3 gr) compared with CrM (3 gr) did not have a significant effect on the hormone levels of cortisol and testosterone [18]. ...
The purpose of this study was to determine the effects of resistance training (RT) alongside creatine-hydrochloride (Cr-HCl) or creatine monohydrate (CrM) supplementation on anabolic/catabolic hormones, strength, and body composition. Forty participants with an age range of 18-25 years were randomly divided into four groups (n=10): RT+Cr-HCl (0.03 g.kg-1 of body mass), RT+CrM-loading phase (CrM-LP) (0.3 g.kg-1 of body mass for five days (loading) and 0.03 g.kg-1 body mass for 51 days (maintenance)), RT+CrM-without loading phase (CrM-WLP) (0.03 g.kg-1 body mass), and RT+placebo (PL). The participants consumed supplements and performed RT with an intensity of 70-85 % 1RM for eight weeks. Before and after the training and supplementation period, strength (1RM), body composition (percent body fat (PBF), skeletal muscle mass (SMM), muscular cross-sectional area (MCSA)) and serum levels of testosterone, growth hormone (GH), insulin-like growth factor-1 (IGF-1), cortisol, adrenocorticotropic hormone (ACTH), follistatin and myostatin were measured. The results showed that in the supplementation groups, strength, arm and thigh MCSA, and SMM significantly increased, and PBF significantly decreased (P≤0.05); this change was significant compared to the PL group (P≤0.05). In addition, the results showed a significant increase in GH, IGF-1 levels, the ratio of follistatin/myostatin, testosterone/cortisol (P≤0.05), and a significant decrease in cortisol and ACTH levels (P≤0.05) in the supplementation groups. Hormonal changes in GH, IGF-1, testosterone/cortisol, cortisol, and ACTH levels in the supplementation groups were significant compared to the PL group (P≤0.05). The results showed that CrM and Cr-HCl significantly enhanced the beneficial effects of RT on strength, hypertrophy, and hormonal responses, with Cr-HCl showing no benefit over CrM.
... Cr-HCl supplementation (for two years) significantly reduced brain atrophy and provided better molecular absorption compared to CrM in patients with Huntington's disease [22]. Also, Tayebi and Arazi [23], de France et al. [24] and McDonogh [25] showed the positive effect of Cr-HCl on performance in their research. No research has been done on the effects of Cr-HCl on antioxidant indices and muscle damage, but some studies have been done on the effect of CrM and they have expressed conflicting results. ...
... Changes in body composition between the two supplementation groups were not significant, but the changes were significant compared to those of the control group. Regarding the comparison of the effect of Cr-HCl on performance, it is possible to refer to the studies of Tayebi and Arazi [23], de France et al. [24] and McDonogh [25]. Similar to the results of the present study, the results of Tayebi and Arazi showed that a few days (7 days) of Cr-HCl supplementation does not have a significant effect on performance compared to CrM [23]. ...
... Regarding the comparison of the effect of Cr-HCl on performance, it is possible to refer to the studies of Tayebi and Arazi [23], de France et al. [24] and McDonogh [25]. Similar to the results of the present study, the results of Tayebi and Arazi showed that a few days (7 days) of Cr-HCl supplementation does not have a significant effect on performance compared to CrM [23]. Moreover, the results of McDonogh showed that Cr-HCl supplementation (4 gr for 7 days) in healthy resistance trained men significantly increased the number of repetitions of chest press and VJCM and body mass [25]. ...
This study aimed to compare the effect of creatine hydrochloride (Cr-HCl) and creatine monohydrate (CrM) supplementation alongside resistance training (RT) on oxidative stress, muscle damage, performance, and body composition in soldiers. In this research, 36 male soldiers aged 18–28 years voluntarily participated in the study. Participants were randomly divided into three groups (n = 12): 1- RT + Cr-HCl, 2- RT + CrM, and 3- RT + placebo (PL). The participants performed RT with an intensity of 70–85% 1RM for eight weeks (three days a week). Also, during this period, they used Cr-HCl and CrM supplements. Before and after supplementation and training periods, body composition (percent body fat (PBF) and skeletal muscle mass (SMM)), performance (muscular strength, muscular endurance and power), blood sample (total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), lactate dehydrogenase (LDH), Creatine kinase (CK)) were taken. The results showed that muscle strength, muscle endurance, power and SMM increased while PBF decreased in the RT + Cr-HCl and RT + CrM groups compared to the PL group (P ≤ 0.05). In addition, regarding antioxidant indices changes, the results showed decreased MDA and increased SOD in RT + Cr-HCl and RT + CrM groups compared to the RT + PL group (P ≤ 0.05). However, no significant group × time interactions were noted for levels of LDH and CK (P > 0.05). In general, the results showed that Cr-HCl and CrM, along with RT can positively affect oxidative stress, performance and body composition of soldiers, but it does not affect muscle damage indicators. According to the results, Cr-HCl does not cause more effects than CrM.
... A pesar de que las reacciones adversas relacionadas con su uso son escasas, se pueden presentar síntomas gastrointestinales, sobre todo en las fases en las que se administra una mayor concentración del suplemento, conocidas como fase de carga, debido a que el MC es una molécula que no presenta una gran solubilidad acuosa y la ingesta hídrica requerida durante su consumo es alta. Si no se tiene en cuenta este parámetro, la absorción gastrointestinal puede ser limitada (22)(23)(24)(25)(26)(27); por esta razón, se ha comercializado la creatina CLCH como una forma análoga que, según su patente de desarrollo, "tiene una solubilidad hídrica por lo menos 15 veces mayor, y dada su mejorada biodisponibilidad, su consumo se traduce en menores dosis para alcanzar efectos ergogénicos con escasos efectos secundarios comparados con las formas anteriores de creatina" (28). ...
... Como ya se ha mencionado, el MC ha sido ampliamente estudiado por sus efectos ergogénicos, con ventajas demostradas sobre todo en deportes intermitentes y estímulos de fuerza máxima; además, es aceptado como un suplemento de categoría A por el Instituto Australiano del Deporte. Con todo ello, algunos investigadores se han preguntado si dichos resultados pueden ser igualados o mejorados con una molécula teóricamente más soluble como el CLCH, tal es el caso de Tayebi et al. (23), quienes compararon los efectos de la suplementación con ambas moléculas en un grupo de 36 sujetos moderadamente entrenados en fuerza, en lo que constituyó un estudio doble ciego controlado en el que se repartieron los sujetos en cuatro grupos con distintos protocolos de suplementación durante una semana (Grupo1: 20 g de MC, Grupo2: 3 g de MC, Grupo3: 3 g de CLCH y Grupo4: placebo). Al final de la intervención, se encontró que no hubo diferencias en los niveles plasmáticos de testosterona y cortisol por separado, ni en la relación entre ellas (testosterona/cortisol) cuando se hizo la comparación entre grupos; sin embargo, el grupo de 20 g de MC sí tuvo cambios en cuanto a los valores pre y postest. ...
Antecedentes:
la creatinina monohidratada ha sido ampliamente estudiada en el rendimiento deportivo. Desde hace poco, se han explorado otras moléculas que suponen resultados superiores, como el clorhidrato de creatina, que promete tener una mejor solubilidad y beneficios similares en el rendimiento deportivo y la composición corporal.
Objetivo:
presentar las diferencias entre creatinina monohidratada y clorhidrato de creatina en términos de solubilidad, rendimiento deportivo y composición corporal.
Materiales y métodos:
revisión de artículos científicos en humanos y animales, publicados entre el 2009 y el 2020.
Resultados:
en relación con la solubilidad y las propiedades químicas, el clorhidrato de creatina tiene mayor peso molecular, solubilidad, absorción y biodisponibilidad, y menor pH, efectos adversos y dosis para logar efectos ergogénicos que la creatina monohidrato. Respecto al rendimiento deportivo y composición corporal, ambas moléculas presentaron mejoras en el rendimiento y fuerza máxima. No todos los estudios mostraron disminución en la masa grasa para clorhidrato de creatina, la cual presentó menor retención intramuscular de agua.
Conclusión:
existe una tendencia a favor del clorhidrato de creatina respecto a la solubilidad y la composición corporal. No se encontró evidencia suficiente para concluir que sus efectos en el rendimiento deportivo, sobre todo en términos de fuerza, sean superiores a los del clorhidrato de creatina.
... Según la Sociedad Internacional de Nutrición Deportiva, el monohidrato es la forma química de creatina, no solo más estudiada, sino también más efectiva en términos de aumento de la masa muscular y efectos ergogénicos (1); a pesar de que las reacciones adversas relacionadas con su uso son escasas, se pueden presentar síntomas gastrointestinales, especialmente en las fases donde se administra una mayor concentración del suplemento, esto es conocido como fase de carga; debido a que el MC es una molécula que no presenta una gran solubilidad acuosa y la ingesta hídrica requerida durante su consumo es alta, si no se tiene en cuenta este parámetro la absorción gastrointestinal puede ser limitada (22)(23)(24)(25)(26)(27); por esta razón, se ha comercializado la creatina CLCH como una forma análoga que, según su patente de desarrollo, "tiene una solubilidad hídrica por lo menos 15 veces mayor, y dada su mejorada biodisponibilidad, su consumo se traduce en menores dosis para alcanzar efectos ergogénicos con escasos efectos secundarios comparados con las formas anteriores de creatina" (28). ...
Antecedentes: la creatinina monohidratada ha sido ampliamente estudiada en el rendimiento deportivo. Recientemente se han explorado otras moléculas que suponen resultados superiores, como el clorhidrato de creatina que promete tener una mejor solubilidad y similares beneficios en el rendimiento deportivo y composición corporal. Objetivo: presentar las diferencias entre creatinina monohidratada y clorhidrato de creatina en términos de solubilidad, rendimiento deportivo y composición corporal. Materiales y métodos: revisión de artículos científicos en humanos y animales, publicados entre el año 2009 y 2020. Resultados: en relación con la solubilidad y propiedades químicas, el clorhidrato de creatina tiene mayor peso molecular, solubilidad, absorción y biodisponibilidad y menor pH, efectos adversos y dosis para logar efectos ergogénicos que la creatina monohidrato. Respecto al rendimiento deportivo y composición corporal ambas moléculas presentaron mejoras en el rendimiento y fuerza máxima, no todos los estudios mostraron disminución en la masa grasa para clorhidrato de creatina, la cual presentó menor retención intramuscular de agua. Conclusión: existe una tendencia a favor del clorhidrato de creatina respecto a la solubilidad y la composición corporal. No se encontró evidencia suficiente para concluir que sus efectos en el rendimiento deportivo, específicamente en términos de fuerza, sean superiores a los del clorhidrato de creatina.
... Creatine Citrate Some Evidence Studies provide evidence it can increase blood creatine levels in a similar manner as CM and there is some data supporting an ergogenic benefit, but the impact of supplementation has not been assessed on muscle or brain creatine content. No studies currently indicate it is more effective or safe than CM [16,19,24,25,35,61] Creatine Hydrochloride Some Evidence This creatine salt should disassociate into creatine and HCL and is bioavailable, but there is no evidence that it is absorbed more effectively than CM in humans, promotes greater muscle creatine retention than CM at same dosages, or that lower doses are more effective than standard CM doses [15,35,63,71] Creatine Ethyl Ester (CEE) Some Evidence Likely that some of the ingredient is degraded into creatinine during normal digestion, but some creatine will be delivered to blood. Supplementation has shown increases in muscle creatine content vs. placebo after 27 days of supplementation, but less than those taking CM. ...
Creatine monohydrate (CM) is an established and effective dietary supplement, but it is not the only form of creatine. We analyzed forms of creatine for sale on Amazon.com" title="http://Amazon.com">Amazon.com and evaluated if the advertised claims are supported by the available scientific evidence. We also analyzed the cost per gram of the forms of creatine. A total of 175 creatine supplements were included and we reported the total creatine content per serving, form(s) of creatine in products, product claims, and prevalence of products third party certified. The identified products contained 16 forms of creatine other than CM. The prevalence of products containing functional ingredients with CM or forms of creatine was 29.7%, and the prevalence of products containing blends of different forms of creatine was 21.7%. Only 8% of products were third party certified. The products using only CM (n=91) had a mean price per gram of 0.26 ± 0.17. Approximately 88% of alternative creatine products in this study are classified as having limited to no evidence to support bioavailability, efficacy, and safety.
... This would be expected, given the creatine content based on molecular weight in these dosages was 35.1 g in the Cr-HCl group compared to 131.9 g in the CrM group over the 30-day period. Finally, a study conducted by Tayebi and Arazi [202] evaluated the effects of ingesting 3 g/day of Cr-HCL, 3 g/day of CrM, and 20 g/day of CrM, or a placebo for 7 days on anaerobic power and hormone levels. Results revealed that ingestion of 3 g/day of Cr-HCl did not promote greater gains in performance or hormonal responses than 3 or 20 g/day of CrM as claimed. ...
In 2011, we published a paper providing an overview about the bioavailability, efficacy, and regulatory status of creatine monohydrate (CrM), as well as other “novel forms” of creatine that were being marketed at the time. This paper concluded that no other purported form of creatine had been shown to be a more effective source of creatine than CrM, and that CrM was recognized by international regulatory authorities as safe for use in dietary supplements. Moreover, that most purported “forms” of creatine that were being marketed at the time were either less bioavailable, less effective, more expensive, and/or not sufficiently studied in terms of safety and/or efficacy. We also provided examples of several “forms” of creatine that were being marketed that were not bioavailable sources of creatine or less effective than CrM in comparative effectiveness trials. We had hoped that this paper would encourage supplement manufacturers to use CrM in dietary supplements given the overwhelming efficacy and safety profile. Alternatively, encourage them to conduct research to show their purported “form” of creatine was a bioavailable, effective, and safe source of creatine before making unsubstantiated claims of greater efficacy and/or safety than CrM. Unfortunately, unsupported misrepresentations about the effectiveness and safety of various “forms” of creatine have continued. The purpose of this critical review is to: (1) provide an overview of the physiochemical properties, bioavailability, and safety of CrM; (2) describe the data needed to substantiate claims that a “novel form” of creatine is a bioavailable, effective, and safe source of creatine; (3) examine whether other marketed sources of creatine are more effective sources of creatine than CrM; (4) provide an update about the regulatory status of CrM and other purported sources of creatine sold as dietary supplements; and (5) provide guidance regarding the type of research needed to validate that a purported “new form” of creatine is a bioavailable, effective and safe source of creatine for dietary supplements. Based on this analysis, we categorized forms of creatine that are being sold as dietary supplements as either having strong, some, or no evidence of bioavailability and safety. As will be seen, CrM continues to be the only source of creatine that has substantial evidence to support bioavailability, efficacy, and safety. Additionally, CrM is the source of creatine recommended explicitly by professional societies and organizations and approved for use in global markets as a dietary ingredient or food additive.
Study aim: The aim of this study to determine whether creatine ethyl ester (CEE) supplementation combined with resistance training (RT) is effective for improving hormonal changes, body composition and muscle strength in underweight non-athlete men.
Materials and methods: Sixteen underweight non-athlete men participated in this double-blind study and were randomly assigned to one of two groups: RT with placebo (RT + PL, n = 8) and RT with CEE supplementation (RT + CEE, n = 8). The participants performed 6 weeks of RT (60–80% 1RM) combined with CEE or PL. 48 hours before and after the training period, muscle strength (1RM for leg press and bench press), body composition (percentage of body fat, circumference measurements of the arm and thigh), serum levels of testosterone, cortisol, and growth hormone (GH) of the participant were measurements.
Results: Significant increases were observed for weight, muscle strength and muscle mass, serum levels of testosterone and GH between pre and post-test in the RT + CEE group (p < 0.05). In addition, cortisol level was significantly decreased in the post-test in the RT+CEE group. The decrease in fat percent was greater in the RT + PL group than in the RT + CEE group (%change = –6.78 vs. –0.76, respectively). Weight and leg strength changes in the RT + CEE group were significant compared to the RT + PL group (p < 0.001, p = 0.05, p = 0.001; respectively). However, in other variables, despite the increase of GH and testosterone levels and lower levels of cortisol in the RT + CEE group, no significant differences were observed between the two groups (p < 0.05).
Conclusion: It seems that the consumption of CEE combined with RT can have significant effects on body weight and leg strength in underweight non-athlete men. This supplement may provide a potential nutritional intervention to promote body weight in underweight men.
Background Creatine monohydrate (CrM) and caffeine are two of the main substances used to enhance athletic performance although some studies say that they impair each other and CrM could promote weight gain. Objective evaluate the association of CrM or creatine hydrochloride (CrHCl) with caffeine (Caf) supplementation on runners’ performance and body composition. Methods 16 individuals, both genders (20-30 years) were randomly divided in 3 groups 1) CrM+Caf (n=6), 2) CrHCl+Caf (n=5) and 3) Placebo+Caf (n=5), they did four running sessions per week, during four weeks. Supplementation was given on a double blind manner, CrM+Caf (20g.day-1 per 7 days + 5 g.day-1 per 21 days of CrM), CrHCl+Caf (6g.day-1 per 7 days + 1.5 g.day-1 per 21 days of CrHCl) and Placebo+Caf (20g.day-1 per 7 days + 5 g.day-1 per 21 days of resistance starch). Caffeine ingestion was acutely administered for all groups, 6mg/kg-1 body weight, only in the last day of the experimental protocol. We collected PRE and POST-treatment, body fat (BF), body weight (BW), 10 km time trial (TT), rating of perceived exertion (RPE), delayed onset muscle soreness (DOMS) and gastrointestinal discomfort perception (GDP). Results No differences were found between groups for RPE, DOMS, BF, BW and GDP. TT decreased significantly for CrM+Caf and CrHCl+Caf group, but no for Placebo+Caf. BF decreased significantly in CrHCl+Caf group and lean body mass increased in CrM+Caf and CrHCl+Caf group. Conclusion These data suggest that either CrM or CrHCLsupplementation works synergistically with acute CAF supplementation improving running performance.
Background:
Athletic performance can be substantially enhanced with supplements and functional food which are considered by scientists as efficient, safe and legal, such as protein, carbohydrate and protein-carbohydrate supplements, isotonic sports drinks, carbohydrate-protein bars, carbohydrate bars, creatine and caffeine.
Objective:
The study is aimed at an analysis and evaluation of the prevalence of using effective ergogenic aids (creatine, caffeine, isotonic drinks, carbohydrates, and proteins) in a group of Polish professional athletes.
Material and methods:
The research was conducted on 600 athletes (216 women, 384 men) practicing various sports disciplines; the younger group (18-23 years old) consisted of 307 people, while the older one (24-35 years old) was comprised of 293 subjects. A questionnaire was used with questions concerning the frequency and types of consumed supplements.
Results:
Nearly half of the athletes (48,2%) admitted to taking supplementation, of which 36.7% consumed the supplements occasionally and 11.5% continually. The majority of the group (75.4%) claimed to be consuming isotonic drinks, which were the most commonly chosen nutritional aid enhancing physical performance, most frequently supplementing the diet in a continuous manner (41.2%). The least frequently used supplement was creatine, chosen by only one in three interviewees (34,5%). The ergogenic aids were used more often by men than women (50.5% vs. 44.1%), and so were nutrients based on proteins (51.8% vs. 32.0%), carbohydrates (60.7% vs. 46.8%), protein-carbohydrates (45.6% vs. 32.9%), as well as creatine (39.8% vs. 25.0%). The studies showed the inessential difference in the frequency of taking supplementation based on the interviewees' age (0.4%).
Conclusions:
Competitors who use supplements over those who choose not to, seems to reflect the continuous lack of the athletes' sufficient awareness of the effectiveness, safety, and health benefits of dietary supplementation that enhances physical performance.
Key words:
supplements, dietary supplementation, sport, performance-enhancing substances, athletes.
It is the position of the Academy of Nutrition and Dietetics (Academy), Dietitians of Canada (DC), and the American College of Sports Medicine (ACSM) that the performance of, and recovery from, sporting activities are enhanced by well-chosen nutrition strategies. These organizations provide guidelines for the appropriate type, amount, and timing of intake of food, fluids, and supplements to promote optimal health and performance across different scenarios of training and competitive sport. This position paper was prepared for members of the Academy, DC, and ACSM, other professional associations, government agencies, industry, and the public. It outlines the Academy’s, DC’s, and ACSM’s stance on nutrition factors that have been determined to influence athletic performance and emerging trends in the field of sports nutrition. Athletes should be referred to a registered dietitian nutritionist for a personalized nutrition plan. In the United States and in Canada, the Certified Specialist in Sports Dietetics is a registered dietitian nutritionist and a credentialed sports nutrition expert.
Background: Creatine supplementation is a subject that is very well studied. New forms of creatine are suggesting improvements in this supplement performance. Creatine HCl is supposed to have better solubility and absorption than creatine. The aim of this study was to compare the effects of two different doses of creatine HCl with creatine monohydrate on the strength and body composition in recreational weightlifters and to verify the relationship between strength and body composition. Methods: 40 subjects were divided in four groups: Creatine Monohydrate (CMG) 5 g/daily; Creatine HCl-1 (HCl-1) 5 g/daily, Creatine HCl-2 (HCl-2) 1.5 g/daily and Control group (CG) = 5 g of resistant starch/daily. All groups performed a resistance training program during 4 weeks. Body composition and strength were evaluated pre and post intervention. Results: The 1 RM at the Leg press was increased significantly in all groups (CMG: pre = 264.4 ± 83.8 × post = 298.1 ± 90.9; HCl-1: pre = 295.0 ± 88.3 × post = 338.3 ± 86.8 and HCl-2: pre = 274.3 ± 57.1 × post = 305.7 ± 59.4; p < 0.05), Bench press 1 RM was increased significantly only in HCl-2 (pre = 72.4 ± 25.7 × post = 76.0 ± 25.0; p = 0.003), however, there was no statistically significant difference between groups. Fatmass was significantly decreased in HCl-1 (pre = 14.5 ± 8.0 × post = 13.3 ± 8.3; p = 0.034) and * Corresponding author.
Athletes experience minor fatigue and acute reductions in performance as a consequence of the normal training process. When the balance between training stress and recovery is disproportionate, it is thought that overreaching and possibly overtraining may develop. However, the majority of research that has been conducted in this area has investigated overreached and not overtrained athletes. Overreaching occurs as a result of intensified training and is often considered a normal outcome for elite athletes due to the relatively short time needed for recovery (approximately 2 weeks) and the possibility of a supercompensatory effect. As the time needed to recover from the overtraining syndrome is considered to be much longer (months to years), it may not be appropriate to compare the two states. It is presently not possible to discern acute fatigue and decreased performance experienced from isolated training sessions, from the states of overreaching and overtraining. This is partially the result of a lack of diagnostic tools, variability of results of research studies, a lack of well controlled studies and individual responses to training.
The general lack of research in the area in combination with very few well controlled investigations means that it is very difficult to gain insight into the incidence, markers and possible causes of overtraining. There is currently no evidence aside from anecdotal information to suggest that overreaching precedes overtraining and that symptoms of overtraining are more severe than overreaching. It is indeed possible that the two states show different defining characteristics and the overtraining continuum may be an oversimplification. Critical analysis of relevant research suggests that overreaching and overtraining investigations should be interpreted with caution before recommendations for markers of overreaching and overtraining can be proposed. Systematically controlled and monitored studies are needed to determine if overtraining is distinguishable from overreaching, what the best indicators of these states are and the underlying mechanisms that cause fatigue and performance decrements. The available scientific and anecdotal evidence supports the existence of the overtraining syndrome; however, more research is required to state with certainty that the syndrome exists.
The main objective of this study was to investigate the effects of alkaline creatine supplementation and resistance training termination on anaerobic power and chosen biochemical variables in men. Twenty-three untrained male subjects, which participated in this study, were divided into supplemented (S) (n=13, age 21.4±2.3 y) and placebo (PL) (n=10, age 22.1±2.6 y) groups. The participants from both groups performed resistance training 3 times a week, while subjects from group S were supplemented with alkaline creatine (ACr) for 4 weeks on their training day's with 66.8 mg/kg b.m., and on non training day's with 33.8 mg/kg b.m.
To evaluate anaerobic power, the 30s Wingate test was applied. The following variables were registered: relative mean power - RMP (W/kg), relative peak power - RPP (W/kg), time of reaching peak power - TRPP (s) and relative total work - RTW (J/kg). The test was administrated 5 times - before and after 4 weeks of training and supplementation, as well as the first, second and third week after terminating creatine intake and the resistance exercise protocol. Body mass and body composition was also evaluated during the same time span. Blood samples were drawn at rest before the Wingate test for the assessment of IGF-1, hGH, LA and CrN concentration, as well as creatine kinase (CK) and lactate dehydrogenase (LDH) activities. Supplementation with alkaline creatine, combined with a progressive resistance training program, did not significantly influence (ANOVA) the level of RMP (p=0.49), RPP (p=0.31), TRPP (p=0.51), and RTW (p=0.58) in untrained male subjects. In the supplemental group, there was a significant decrease (p<0.01) in TRPP following creatine supplementation and training, yet these values were not significantly different from the control group. The supplementation and training protocol did not influence significantly body mass (p=0.68), yet post hoc analysis indicate a significant increase in body mass (p<0.001) only in group S. The applied supplementation and training protocol did not influence (ANOVA) the concentration of serum CrN (p=0.81), hGH) (p=0.26), CK (p=0.49) and LDH (p=0.64) activities. No significant changes were observed in resting blood LA concentrations of the tested subjects. It can be concluded that the ergogenic effect of creatine intake and resistance training was maintained for a week after terminating supplementation and exercise. During the next 2 weeks de-adaptation occurred and most indices of anaerobic power returned to initial values.
Creatine has become one of the most popular dietary supplements in the sports nutrition market. The form of creatine that has been most extensively studied and commonly used in dietary supplements is creatine monohydrate (CM). Studies have consistently indicated that CM supplementation increases muscle creatine and phosphocreatine concentrations by approximately 15-40%, enhances anaerobic exercise capacity, and increases training volume leading to greater gains in strength, power, and muscle mass. A number of potential therapeutic benefits have also been suggested in various clinical populations. Studies have indicated that CM is not degraded during normal digestion and that nearly 99% of orally ingested CM is either taken up by muscle or excreted in urine. Further, no medically significant side effects have been reported in literature. Nevertheless, supplement manufacturers have continually introduced newer forms of creatine into the marketplace. These newer forms have been purported to have better physical and chemical properties, bioavailability, efficacy, and/or safety profiles than CM. However, there is little to no evidence that any of the newer forms of creatine are more effective and/or safer than CM whether ingested alone and/or in combination with other nutrients. In addition, whereas the safety, efficacy, and regulatory status of CM is clearly defined in almost all global markets; the safety, efficacy, and regulatory status of other forms of creatine present in today's marketplace as a dietary or food supplement is less clear.
Sports nutrition is a constantly evolving field with hundreds of research papers published annually. For this reason, keeping up to date with the literature is often difficult. This paper is a five year update of the sports nutrition review article published as the lead paper to launch the JISSN in 2004 and presents a well-referenced overview of the current state of the science related to how to optimize training and athletic performance through nutrition. More specifically, this paper provides an overview of: 1.) The definitional category of ergogenic aids and dietary supplements; 2.) How dietary supplements are legally regulated; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of the ergogenic value of nutrition and dietary supplementation in regards to weight gain, weight loss, and performance enhancement. Our hope is that ISSN members and individuals interested in sports nutrition find this review useful in their daily practice and consultation with their clients.
We used meta-analytic methods to examine the influence of acute exercise on sleep. Thirty-eight studies were reviewed yielding 211 effects on 401 subjects. Mean effect sizes were calculated for sleep onset latency (SOL), stage 2, slow-wave sleep (SWS), rapid eye movement (REM) sleep, REM latency (REM-L), total sleep time (TST), and wakefulness after sleep onset (WASO). Moderating influences of subject fitness, heat load, exercise duration, time of day, associated light environment (i.e. indoor or outdoor), sleep schedule, and the scientific quality of the studies were examined.
Effect sizes for SWS, REM, REM-L, and TST were moderate [0.18–0.52 standard deviation (SD)] and their associated 95% confidence intervals did not include zero. Exercise duration and time of day were the most consistent moderator variables. In contrast with previous hypotheses, heat load had little influence on sleep.
The results of our quantitative synthesis of the literature are inconsistent with previous narrative reviews (1,2) which suggested that exercise elicits larger changes in sleep than those quantified in this meta-analysis. A major delimitation of published studies on the effects of acute exercise has been an exclusive focus on good sleepers. Hence, the effects we report herein may be underestimates of the efficacy of exercise for enhancing sleep among people with sleep disturbances.
Creatine monohydrate (CrM) supplementation during resistance exercise training results in a greater increase in strength and fat-free mass than placebo. Whether this is solely due to an increase in intracellular water or whether there may be alterations in protein turnover is not clear at this point. We examined the effects of CrM supplementation on indexes of protein metabolism in young healthy men (n = 13) and women (n = 14). Subjects were randomly allocated to CrM (20 g/day for 5 days followed by 5 g/day for 3-4 days) or placebo (glucose polymers) and tested before and after the supplementation period under rigorous dietary and exercise controls. Muscle phosphocreatine, creatine, and total creatine were measured before and after supplementation. A primed-continuous intravenous infusion of L-[1-(13)C]leucine and mass spectrometry were used to measure mixed-muscle protein fractional synthetic rate and indexes of whole body leucine metabolism (nonoxidative leucine disposal), leucine oxidation, and plasma leucine rate of appearance. CrM supplementation increased muscle total creatine (+13.1%, P < 0.05) with a trend toward an increase in phosphocreatine (+8.8%, P = 0.09). CrM supplementation did not increase muscle fractional synthetic rate but reduced leucine oxidation (-19.6%) and plasma leucine rate of appearance (-7.5%, P < 0.05) in men, but not in women. CrM did not increase total body mass or fat-free mass. We conclude that short-term CrM supplementation may have anticatabolic actions in some proteins (in men), but CrM does not increase whole body or mixed-muscle protein synthesis.
This study determined the effects of 28 days of oral creatine ingestion (days 1 to 5 = 20g/d; [5 g 4 times daily]: days 6 to 28 = 10 g/d; [5 g twice daily]) alone and with resistance training (5 hours/week) on resting metabolic rate (RMR), body composition, muscular strength (1RM), and limb blood flow (LBF). Using a double-blind, placebo-controlled design, 30 healthy male volunteers (21 +/- 3 years; 18 to 30 years) were randomly assigned to 1 of 3 groups; pure creatine monohydrate alone (Cr; n = 10), creatine plus resistance training (Cr-RT; n = 10), or placebo plus resistance training (P-RT; n = 10). Body composition (DEXA, Lunar DPX-IQ), body mass, bench, and leg press 1RM (isotonic), RMR (indirect calorimetry; ventilated hood), and forearm and calf LBF (venous occlusive plethysmography) were obtained on all 30 subjects on 3 occasions beginning at approximately 6:00 AM following an overnight fast and 24 hours removed from the last training session; baseline (day 0), and 7 days and 29 days following the interventions. No differences existed among groups at baseline for any of the variables measured. Following the 28-day interventions, body mass (Cr, 73.9 +/- 11.5 v 75.6 +/- 12.5 kg; Cr-RT, 78.8 +/- 6.7 v 80.8 +/- 6.8 kg; P <.01) and total body water (Cr, 40.4 +/- 6.8 v 42.6 +/- 7.2 L, 5.5%; Cr-RT, 40.6 +/- 2.4 v 42.3 +/- 2.2 L, 4.3%; P <.01) increased significantly in Cr and Cr-RT, but remained unchanged in P-RT, whereas, fat-free mass (FFM) increased significantly in Cr-RT (63 +/- 2.8 v 64.7 +/- 3.6 kg; P <.01) and showed a tendency to increase in Cr (58.1 +/- 8.1 v 59 +/- 8.8 kg; P =.07). Following the 28-day period, all groups significantly increased (P <.01) bench (Cr, 77.3 +/- 4 v 83.2 +/- 3.6 kg; Cr-RT, 76.8 +/- 4.5 v 90.5 +/- 4.5 kg; P-RT, 76.0 +/- 3.4 v 85.5 +/- 3.2 kg), and leg press (Cr, 205.5 +/- 14.5 v 238.6 +/- 13.2 kg; Cr-RT, 167.7 +/- 13.2 v 238.6 +/- 17.3 kg; P-RT, 200.5 +/- 9.5 v 255 +/- 13.2 kg) 1RM muscular strength. However, Cr-RT improved significantly more (P <.05) on the leg press 1RM than Cr and P-RT and the bench press 1RM than Cr (P <.01). Calf (30%) and forearm (38%) LBF increased significantly (P <.05) in the Cr-RT, but remained unchanged in the Cr and P-RT groups following the supplementation period. RMR expressed on an absolute basis was increased in the Cr (1,860.1 +/- 164.9 v 1,907 +/- 173.4 kcal/d, 2.5%; P <.05) and Cr-RT (1,971.4 +/- 171.8 v 2,085.7 +/- 183.6 kcal/d, 5%; P <.05), but remained unchanged from baseline in P-RT. Total cholesterol decreased significantly in Cr-RT (-9.9%; 172 +/- 27 v 155 +/- 26 mg/dL; P <.01) compared with Cr (174 +/- 46 v 178 +/- 43 mg/dL) and P-RT (162 +/- 32 v 161 +/- 36 mg/dL) following the 28-day intervention. These findings suggest that the addition of creatine supplementation to resistance training significantly increases total and fat-free body mass, muscular strength, peripheral blood flow, and resting energy expenditure and improves blood cholesterol.
The purpose of this study was to quantify which dietary supplements augment lean mass and strength gains during resistance training. Peer-reviewed studies between the years 1967 and 2001 were included in the analysis if they met a predetermined set of experimental criteria, among which were at least 3-wk duration and resistance-training 2 or more times a week. Lean mass and strength were normalized for meta-analysis by conversion to percent change per week and by calculating the effect size for each variable. Of the 250 supplements examined, only 6 had more than 2 studies that met the criteria for inclusion in the meta-analysis. Creatine and beta-hydroxy-beta-methylbutyrate (HMB) were found to significantly increase net lean mass gains of 0.36 and 0.28%/wk and strength gains of 1.09 and 1.40%/wk (P < 0.05), respectively. Chromium, dehydroepiandrosterone, androstenedione, and protein did not significantly affect lean gain or strength. In conclusion, two supplements, creatine and HMB, have data supporting their use to augment lean mass and strength gains with resistance training.
The purpose of this study was to investigate the prevalence of dietary supplement use among adolescent athletes. The project was also directed at identifying the sources these student-athletes used for acquiring information about dietary supplements. One hundred thirty nine high school athletes (99 males; 34 females; mean age = 15.8 +/- 1.19 years) volunteered to participate in this study. A 16-question anonymous survey instrument examined use of dietary supplements, reasons for use, type of sport participation, and sources of information regarding dietary supplements. Of the participants in this study, 22.3% (N = 31) reported currently taking dietary supplements. There was no relationship found between dietary supplement use and age. There were a significantly higher number of males reporting current dietary supplement use. Of those who reported to be currently taking dietary supplements, sports performance (N = 25) was the most reported reason for use. There were no significant differences found in reported dietary supplement use between any of the sports. Of the participants, 38.1% (N = 53) listed their coach as their best source of information on dietary supplements. The results of this study offer the current literature some additional insight into trends in supplement use among high school student athletes. Practical implications suggest that it may be necessary to ensure coaches have sufficient knowledge about dietary supplements so that adolescent athletes are receiving accurate information.
Position Statement: The following nine points related to the use of creatine as a nutritional supplement constitute the Position Statement of the Society. They have been approved by the Research Committee of the Society .
Muscle loss with age has a negative effect on strength and functional independence. Age-related loss of muscle is the result of decreased muscle fiber number and size, which are functions of altered hormonal status, physical inactivity, and variations in nutritional intake. Resistance training has a positive effect on muscle mass and strength in the elderly. Studies of protein or creatine supplementation for increasing muscle mass and strength in older individuals are equivocal. The timing of nutritional supplementation may be more important than the absolute daily intake of supplements. Protein or creatine ingestion proximate to resistance-training sessions may be more beneficial for increasing muscle mass and strength than ingestion of protein or creatine at other times of the day, possibly because of increased blood flow and therefore increased transport of amino acids and creatine to skeletal muscle.
Objectives: This review aims to analyze the available data, mainly the most recent, regarding L-carnitine supplementation and exercise performance, in order to understand if L-carnitine can still be considered an ergogenic supplement. Moreover, it also aims to briefly analyze other potential uses, more specifically the effects on weight loss, recovery after exercise and aging.
News: A literature search, using the online scientific databases PubMed and Scopus, was conducted to identify studies related to L-carnitine supplementation and athletic performance. The discovery that skeletal muscle carnitine content can be increased through oral supplementation in humans represented a significant progress in this area. More recently, due to this discovery, new research has been done to investigate whether
L-carnitine supplementation could have an impact on fuel metabolism. However, the inconsistency of results led to a change in the focus of research, shifting towards the investigation of the impact L-carnitine could have on the process of recovery after exercise and on aging.
Prospects and projects: In future research, this new area needs to be more explored. Nevertheless, the study of the L-carnitine supplementation impact on fuel selection during exercise should continue and it is crucial to use athletes.
Conclusion: Despite some performance benefits have been demonstrated, more research needs to be done. Presently, the available data is still not enough to widely recommend the use of L-carnitine supplements with the aim of improving exercise performance.
Caffeine has become a popular ergogenic aid amongst athletes and usage to improve athletic performance has been well documented. The effect of caffeine on anabolic and catabolic hormones in a sleep-deprived s tate has had little investigation to date. The purpose of the current study was to investigate the potential of caffeine to offset the effects, if any, of short-term sleep deprivation and exercise on an athlete’s testosterone and cortisol concentrations via salivary technique. Eleven competitive male athletes volunteered to be part of this prospective double-blinded study. Three test days were scheduled for each athlete; one non-sleep deprived, one sleep-deprived with caffeine supplementation (6 mg.kg⁻¹) and one sleep-deprived with placebo ingestion. Sleep deprivation was defined as 24-h without sleep. Each test day was composed of 2 aerobic components: a modified Hoff test and a Yo-Yo test. Testosterone and cortisol concentrations were measured via salivary analysis at 4 different time-points; T1 to T4, representing baseline, and pre- and post-aerobic components, respectively. Overall no significant differences were detected comparing the different sleep states for testosterone or cortisol concentrations. A trend existed whereby the sleep-deprived with caffeine ingestion state mirrored the non-sleep deprived state for cortisol concentration. Therefore, caffeine supplementation may have potential benefits for athletes during short-term aerobic exercise when sleep-deprived. An increase in mean testosterone concentration post-aerobic exercise was only observed in the sleep-deprived with caffeine ingestion state.
This review article aimed to summarize the current state of understanding on creatine supplementation for soccer players. In other words, it investigated the beneficial (and potentially negative) effects of this supplementation on sport-specific skills and performance in soccer players. Furthermore, this article accordingly discussed the safest and most recommended protocols for the consumption of creatine by these athletes.
Research has indicated that combined aerobic and anaerobic training (concurrent training) may improve aerobic performance greater than aerobic training alone. The purpose of this investigation was to establish any associations between aerobic and anaerobic performance. Eleven participants (n = 11, age = 34.1 ± 13 years, VO2max = 58.4 ± 7.8) volunteered for this study. Participants were asked for endurance training experience (4.7 ± 3.7 years) and resistance training experience (4.1 ± 4.6 years). To meet training status, participants were to have a VO2max in the 80th percentile as per ACSM guidelines. The Bruce treadmill test was used to measure aerobic performance. In order to measure anaerobic performance, several tests were completed utilizing a force platform. A Pearson Product R Correlation Coefficient was calculated to determine correlations between variables. The results show significant correlation between VO2max and RFD (r = 0.68). Further analyses utilizing Cohen’s effect size indicated a strong association between VO2max and peak force, as well as running efficiency and peak power, relative peak power, and power endurance. These results indicate an existing possibility that anaerobic performance measures such as RFD may have a positive relationship with aerobic performance measures such as VO2max. Therefore, it may be beneficial to integrate specific training components which focus on improving RFD as a method of improving running performance.
Objectifs
Le but de cette étude était de déterminer l’influence à court terme d’une supplémentation en créatine sur la performance lors de sprints en natation (50 et 100 m) et sur les réponses hormonales (hormone de croissance, testostérone et le cortisol).
Méthodes
Vingt nageurs amateurs ont ingéré du monohydrate de créatine (CR) ou un placebo (PL) pendant six jours pendant lesquels ils ont poursuivi leur entraînement de natation. Les performances et les réponses hormonales ont été enregistrées le jour précédent et après cette période de charge orale en créatine.
Résultats
Le temps de nage moyen du groupe CR sur 50 m était significativement diminué (53,1 ± 3,73 secondes avant charge vs 50,7 ± 2,84 secondes après supplémentation). L’hormone de croissance et le cortisol n’ont pas été affectés par cette charge en créatine. En revanche, la concentration de testostérone était significativement plus élevée dans CR par rapport à PL après la période de supplémentation (p < 0,05).
Conclusion
Nos résultats suggèrent qu’une supplémentation de courte durée en créatine a amélioré de manière significative la performance lors de sprints sur 50 m chez des nageurs amateurs sans que l’on puisse imputer de manière objective une médiation hormonale.
To determine the prevalence and pattern of creatine use among varsity athletes at a National Collegiate Athletic Association (NCAA) Division I athletic program.
Anonymous descriptive survey.
Institutional.
Collegiate varsity and junior varsity athletes.
Self-reports of creatine use, including pattern of use and dose, source of information on creatine, and expected and perceived effects from creatine use.
Surveys were obtained from 93% of 806 eligible athletes. Overall, 68% of athletes had heard of creatine and 28% reported using it. Forty-eight percent of men reported having used creatine as compared with 4% of women. With two exceptions, all men's teams had at least 30% of athletes who reported a history of creatine use. Of athletes that had used creatine, about one-third had first used it in high school. Friends and teammates were the most common sources of creatine information. Increased strength and muscle size were the most common effects the athletes expected and perceived from creatine use.
In this population of collegiate athletes, creatine use was widespread among men but was minimal among women. Athletes learned about creatine supplementation primarily from their peers, and substantial numbers began to take creatine while still in high school. Most athletes could not report their dosing of creatine. This study reported findings at one location for one academic year. Studies are needed at multiple locations and over time to further delineate creatine use patterns.
In this study, the effect of short-term creatine supplementation on the growth hormone, testosterone, and cortisol response to heavy resistance training was investigated.
According to a double-blind crossover study design, 11 healthy young male volunteers underwent a 1-h standardized heavy resistance training session (3 series of 10RM; 12 exercises), both before (pretest) and after (posttest) 5 d of either placebo (P, maltodextrine) or creatine (CR; 20 g.d-1, 5 d) supplementation. A 5-wk washout period separated the treatments. Thirty minutes before each training session, CR subjects ingested 10 g of creatine monohydrate (CR) while P subjects received placebo. Venous blood was sampled before, immediately after, and 30 and 60 min after the training session.
The exercise-induced increase (P < 0.05) of serum growth hormone was not altered by acute creatine intake and was similar in P and CR. The weight training session, either or not in conjunction with acute or chronic creatine intake, did not significantly impact on serum testosterone. However, serum cortisol during recovery tended to be higher in CR than in P.
It is concluded that short-term creatine supplementation does not alter the responses of growth hormone, testosterone, and cortisol to a single bout of heavy resistance training.
This study examined 12 wk of creatine (Cr) supplementation and heavy resistance training on muscle strength and myosin heavy chain (MHC) isoform mRNA and protein expression.
Twenty-two untrained male subjects were randomly assigned to either a control (CON), placebo (PLC), or Cr (CRT) group in a double-blind fashion. Muscle biopsies were obtained before and after 12 wk of heavy resistance training. PLC and CRT trained thrice weekly using three sets of 6-8 repetitions at 85-90% 1-RM on the leg press, knee extension, and knee curl exercises. CRT ingested 6 g.d-1 of Cr for 12 wk, whereas PLC consumed the equal concentration of placebo.
There were no significant differences for percent body fat (P > 0.05). However, for total body mass, fat-free mass, thigh volume, muscle strength, and myofibrillar protein, CRT and PLC exhibited significant increases after training when compared to CON (P < 0.05), whereas CRT was also significantly greater than PLC (P < 0.05). For Type I, IIa, and IIx MHC mRNA expression, CRT was significantly greater than CON and PLC, whereas PLC was greater than CON (P < 0.05). For MHC protein expression, CRT was significantly greater than CON and PLC for Type I and IIx (P < 0.05) but was equal to PLC for IIa.
Long-term Cr supplementation increases muscle strength and size, possibly as a result of increased MHC synthesis.
To describe creatine supplementation patterns and behaviors associated with creatine supplementation in high school football players.
A cross-sectional, multisite, anonymous, descriptive survey was conducted between October 1999 and February 2000.
37 public high schools in Wisconsin.
A total of 1,349 high school football players, grades 9-12.
Self-reported prevalence of creatine use, as well as perceived benefits and risks. In addition, sources of information and influence regarding creatine supplementation were assessed.
30% of the respondents reported using creatine. Creatine use was lowest in the 9th grade (10.4%) and highest in the 12th grade (50.5%). 41% of the players at small schools stated they used creatine compared with 29% of the players in large schools. Enhanced recovery following a workout was the most likely perceived benefit of creatine supplementation, while dehydration was cited most often as a risk of creatine use. Users were encouraged to take creatine most often by their friends while their parents discouraged creatine use.
Creatine use is widespread in high school football players. High school football players who use creatine may not be aware of the risks and benefits associated with creatine supplementation. Sports medicine professionals who work with this population need to educate athletes, coaches, and parents about the use of creatine as a performance-enhancing supplement.
To learn more about the prevalence of dietary supplement and medication use by Canadian athletes in the Olympic Games in Atlanta 1996 and Sydney 2000.
Data were collected from personal interviews with Canadian athletes who participated at the 1996 Atlanta and 2000 Sydney Olympic Games. The athletes were interviewed by Canadian physicians regarding the use of vitamins, minerals, nutritional supplements, and prescribed and over-the-counter medications. Of the 271 Canadian athletes who participated at the Atlanta Olympics, 257 athletes were interviewed; at the Sydney Olympics, 300 of 304 Canadian athletes were interviewed.
A quantitative and qualitative description of the use of dietary supplements by Canadian athletes at the Atlanta and Sydney Olympics.
At the Atlanta Games, 69% of the athletes used some form of dietary supplements, whereas 74% of the athletes used dietary supplements at the Sydney Games. Vitamins were taken by 59% of men and 66% of women in Atlanta, and 65% of men and 58% women in Sydney. Mineral supplements were used by 16% of men and 45% of women in Atlanta, and 30% of men and 21% of women in Sydney. Nutritional supplements were used by 35% of men and 43% of women in Atlanta, and 43% of men and 51% of women in Sydney. The most popular vitamins were multivitamins in both Olympics. The most popular mineral supplements were iron supplements. The most commonly used nutritional supplement in Atlanta was creatine (14%), but amino acids (15%) were the most commonly used nutritional supplement in Sydney. In Atlanta, 61% of the athletes were using some form of medication, 54% of the athletes were using medications in Sydney. Nonsteroidal antiinflammatory drugs (NSAIDS) were the most commonly used medications at both Olympic Games. Among all sports, the highest prevalence of vitamin use occurred in boxing (91%) in Atlanta and swimming (76%) in Sydney. Rowers (56%) and cyclists (73%) demonstrated the highest use of mineral supplements. Nutritional supplement use occurred most often in swimming (56%) and cycling (100%). The use of NSAIDs was highest in softball (60%) in Atlanta and gymnastics (100%) in Sydney.
This review demonstrates that dietary supplement use was common among Canadian athletes at both the Atlanta and Sydney Olympic Games. There was a slight increase in total dietary supplement use at the Sydney Games. Widespread use of supplements, combined with an absence of evidence of their efficacy and a concern for the possibility of "inadvertent" doping, underscore the need for appropriately focused educational initiatives in this area.
Creatine monohydrate has become the supplement of choice for many athletes striving to improve sports performance. Recent data indicate that athletes may not be using creatine as a sports performance booster per se but instead use creatine chronically as a training aid to augment intense resistance training workouts. Although several studies have evaluated the combined effects of creatine supplementation and resistance training on muscle strength and weightlifting performance, these data have not been analyzed collectively. The purpose of this review is to evaluate the effects of creatine supplementation on muscle strength and weightlifting performance when ingested concomitant with resistance training. The effects of gender, interindividual variability, training status, and possible mechanisms of action are discussed. Of the 22 studies reviewed, the average increase in muscle strength (1, 3, or 10 repetition maximum [RM]) following creatine supplementation plus resistance training was 8% greater than the average increase in muscle strength following placebo ingestion during resistance training (20 vs. 12%). Similarly, the average increase in weightlifting performance (maximal repetitions at a given percent of maximal strength) following creatine supplementation plus resistance training was 14% greater than the average increase in weightlifting performance following placebo ingestion during resistance training (26 vs. 12%). The increase in bench press 1RM ranged from 3 to 45%, and the improvement in weightlifting performance in the bench press ranged from 16 to 43%. Thus there is substantial evidence to indicate that creatine supplementation during resistance training is more effective at increasing muscle strength and weightlifting performance than resistance training alone, although the response is highly variable.
The purpose of this study was to determine the effect of 30 days of single-dose creatine supplementation with phosphate salts (CPS) on body weight (BW) and anaerobic working capacity (AWC) in men. Using a double-blind design, 32 men randomly received 1 serving of either CPS (5 g Cr + 4 g phosphate) (n = 17) or 20 g of dextrose as placebo (PL) (n = 15) for 30 days. AWC determined from the Critical Power Test and BW were measured at baseline, 10 days, 20 days, 30 days, and 10 days post-supplementation. Results (2 x 5 ANOVA) showed no significant differences between groups for AWC at any time point; however, BW was significantly increased at 10 days in the CPS group (1.0 kg) vs. PL (0.0 kg), and remained elevated for the duration of the study. These findings suggest that a single 5 g x d(-1) dose of CPS for 30 days increases BW but is not effective for increasing AWC in men.
The Effect of Short-term Supplementation of Creatine Monohydrate on Performance, Power and Muscle Work
- Garazhian