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Effects of Varying Dosages of Oral Creatine Relative to Fat Free Body Mass on Strength and Body Composition
Abstract
This study compared the effects of different dosages of creatine relative to fat free mass on strength, % body fat, body mass (BM), fat free mass (FFM), 40-yd dash time, and vertical jump (VJ) height. In a true experimental double-blind design, 39 male college athletes were given either 5 g creatine mono-hydrate or a placebo 4 times a day for 5 days. For the rest of the 8 weeks they were given either a placebo or 100 or 300 mg * kg-1 FFM of creatine. During this period all subjects undertook a conditioning program 4 times a week emphasizing weight training and speed drills. Pre- and posttesting was conducted on all 6 variables. Both experimental groups had significant improvements in the bench press; the group ingesting 300 mg * kg-1 FFM of creatine improved significantly more than the control group (p < 0.05). Forty-yard dash improvement was significantly better as a result of ingesting 100 mg * kg-1 FFM of creatine compared to the control group. Only the 100-mg group significantly improved 40-yd time. No significant differences among groups were noted in BM, % body fat, FFM, or VJ. In conclusion, ingestion of 100 or 300 mg * kg-1 FFM of creatine for 8 weeks in conjunction with weight training and speed training significantly improved 40-yd dash time and bench press strength, respectively.
(C) 1998 National Strength and Conditioning Association
... Oral supplementation with creatine monohydrate (CM) has been shown to increase muscle strength and performance during both acute and chronic supplementation protocols (10,15,17,18,22,31). Most previous investigations have examined the effects of chronic creatine supplementation in conjunction with a structured resistance training regimen (3,19,23,25,26,28,30). For example, Willoughby and Rosene (32) reported an increase in leg extension 1 repetition maximum (1RM) strength after 12 weeks of resistance training combined with CM supplementation (26 gÁd 21 for 1 week and 6 gÁd 21 for the remaining 11 weeks). ...
... Several previous investigations (23,25,26,28,29,32) have demonstrated increases in muscular strength (i.e., 1RM) after CM supplementation. In the present study, 1RM BP and 1RM LP increased for all creatine groups (CM, PEG 1.25 , and PEG 2.50 ) after supplementation. ...
... In the present study, 1RM BP and 1RM LP increased for all creatine groups (CM, PEG 1.25 , and PEG 2.50 ) after supplementation. A unique aspect of this study was that subjects were allowed to maintain their current exercise schedule and did not perform a structured resistance training regimen like previous investigations (3,4,19,23,26). In addition, the daily dose of creatine consumed by the PEG groups (1.25 g and 2.50 g) was considerably less than that used in previous investigations that reported similar increases (26,28,29,32) in muscular strength. For example, several studies (25,26,29) have reported increases in muscular strength after a CM supplementation period that consisted of an initial loading period of 20 gÁd 21 , followed by a maintenance period of 5-10 gÁd 21 for the remainder of the supplementation period. ...
The purpose of this study was to examine the effects of a moderate dose of creatine monohydrate (CM) and two smaller doses of polyethylene glycosylated (PEG) creatine on muscular strength, endurance, and power output. Fifty-eight healthy men (mean +/- SD: age, 21 +/- 2 years; height, 176 +/- 6 cm; body mass [BM], 75 +/- 14 kg) volunteered and were randomly assigned to 1 of 4 groups: (a) placebo (PL; 3.6 g of microcrystalline cellulose; n = 15), (b) CM (5 g of creatine; n = 13), (c) small-dose PEG creatine (1.25 g of creatine: PEG1.25; n = 14), or (d) moderate-dose PEG creatine (2.50 g of creatine: PEG2.50; n = 16). Testing was conducted before (pre-) and after (post-) a 30-day supplementation period. Measurements included body mass, countermovement vertical jump (CVJ) height, power output during the Wingate test (peak power [PP] and mean power [MP]), 1 repetition maximum bench press (1RMBP), 1RM leg press (1RMLP) strength, and repetitions to failure at 80% of the 1RM for bench press (REPBP) and leg press (REPLP). BM and MP (W) increased (p <or= 0.05) from pre- to postsupplementation for the CM group only, whereas 1RMBP and 1RMLP increased (p <or= 0.05) for the CM, PEG1.25, and PEG2.50 groups. CVJ height (cm and cm.kg), MP (W.kg), PP (W and W.kg), REPBP, and REPLP increased (p <or= 0.05) for all groups. These findings indicated that the recommended safe dose of 5 g.d of CM increased BM and improved muscle strength (1RMBP and 1RMLP). Smaller doses of PEG creatine (1.25 and 2.50 g.d) improved muscle strength (1RMBP and 1RMLP) to the same extent as 5 g.d of CM, but did not alter BM, power output, or endurance. When compared to the PL group, neither CM nor PEG creatine supplementation improved peak power output (CVJ or PP), MP, or muscle endurance (REPBP or REPLP). Thus, PEG creatine may have ergogenic effects that are comparable to those of CM, but with a smaller dose of creatine.
... Experienced male weight lifters (19,21) supplemented for 28 d. Noonan et al. (25) had experienced male weight lifters supplement for 8 wk. These studies showed increases in 3RM muscular strength (19), 1RM bench press (25), the amount of weight lifted in one set (21), and the number of repetitions completed in five sets (19). ...
... Noonan et al. (25) had experienced male weight lifters supplement for 8 wk. These studies showed increases in 3RM muscular strength (19), 1RM bench press (25), the amount of weight lifted in one set (21), and the number of repetitions completed in five sets (19). Neither maximum isometric strength (21) nor vertical jump height (25) increased. ...
... These studies showed increases in 3RM muscular strength (19), 1RM bench press (25), the amount of weight lifted in one set (21), and the number of repetitions completed in five sets (19). Neither maximum isometric strength (21) nor vertical jump height (25) increased. Vanderberghe et al. (30) resistance trained inexperienced females for 10 wk with creatine supplementation. ...
The purpose of this investigation was to examine the effects of 6 wk of oral creatine supplementation during a periodized program of arm flexor strength training on arm flexor IRM, upper arm muscle area, and body composition.
Twenty-three male volunteers with at least 1 yr of weight training experience were assigned in a double blind fashion to two groups (Cr, N = 10; Placebo, N = 13) with no significant mean pretest one repetition maximum (IRM) differences in arm flexor strength. Cr ingested 5 g of creatine monohydrate in a flavored, sucrose drink four times per day for 5 d. After 5 d, supplementation was reduced to 2 g x d(-1). Placebo ingested a flavored, sucrose drink. Both drinks were 500 mL and made with 32 g of sucrose. IRM strength of the arm flexors, body composition, and anthropometric upper arm muscle area (UAMA) were measured before and after a 6-wk resistance training program. Subjects trained twice per week with training loads that began at 6RM and progressed to 2RM.
IRM for Cr increased (P < 0.01) from (mean +/- SD) 42.8 +/- 17.7 kg to 54.7 +/- 14.1 kg, while IRM for Placebo increased (P < 0.01) from 42.5 +/- 15.9 kg to 49.3 +/- 15.7 kg. At post-test IRM was significantly (P < 0.01) greater for Cr than for Placebo. Body mass for Cr increased (P < 0.01) from 86.7 +/- 14.7 kg to 88.7 +/- 13.8 kg. Fat-free mass for Cr increased (P < 0.01) from 71.2 +/- 10.0 kg to 72.8 +/- 10.1 kg. No changes in body mass or fat-free mass were found for Placebo. There were no changes in fat mass and percent body fat for either group. UAMA increased (P < 0.01) 7.9 cm2 for Cr and did not change for Placebo.
Creatine supplementation during arm flexor strength training lead to greater increases in arm flexor muscular strength, upper arm muscle area, and fat-free mass than strength training alone.
... In contrast, many have observed a mean 0.6-to 1.7-kg increase in body mass in Cr-supplemented subjects (11,16). However, an increase in body mass during short-term Cr supplementation is not a universal finding (5,23), even when an increase in muscle total Cr is confirmed following Cr supplementation (21). Furthermore, most studies that report greater mass gain following Cr supplementation than Pla treatment have incorporated resistance training into the experimental intervention or used subjects who continued their own resistance training program during the study (1,5,10,12,15,31). ...
... The failure of Cr supplementation to affect measures of muscle performance may also reflect the absence of a resistance training stimulus during the supplementation period. The most consistent performance-enhancing effects of Cr supplementation have been reported when Cr was combined with resistance-type exercise training (1,5,15,23,31,33). Almost all of the strength studies included in the metaanalysis of Dempsey and colleagues (4), who found a benefit of Cr supplementation using maximal weight lifted as an outcome variable and studied young, previously trained men undergoing resistance training during the supplementation period. ...
... These results confirm previous findings observed in our laboratory with highly trained soccer players (27) and others with handball players (1) and suggest that Cr supplementation provides a potential benefit in energy provision during very short-term, high-intensity exercise, especially when performed in repeated succession. However, these results differ from other studies in which no ergogenic effects (22,31,32) or mixed effects (29,34) were found on sprint running performance after Cr supplementation. The conflicting results between studies regarding the effects of Cr supplementation on sprint running performance could be attributed to differences in the amount of repetitions and frames or distances tested. ...
... The conflicting results between studies regarding the effects of Cr supplementation on sprint running performance could be attributed to differences in the amount of repetitions and frames or distances tested. Indeed, the studies that have found no effects or mixed effects of acute Cr loading tested sprint running performance with only a single bout (22,29,34) or with repeated bouts of distances greater than 15 m (31,32). As mentioned previously, a clearer improvement in sprint performance after Cr loading should be expected during repeated short supramaximal exercise of 1-to 2-s duration because: 1) during this time frame, PCr generates the highest peak rates of ATP production (13); 2) PCr availability is critical for power generation during the initial seconds of exercise (6); and 3) Cr loading may increase the rate of PCr resynthesis during recovery periods after muscle contractions (11,13). ...
To determine the effects of creatine (Cr) supplementation (20 g x d(-1) during 5 d) on maximal strength, muscle power production during repetitive high-power-output exercise bouts (MRPB), repeated running sprints, and endurance in handball players.
Nineteen trained male handball players were randomly assigned in a double-blind fashion to either creatine (N = 9) or placebo (N = 10) group. Before and after supplementation, subjects performed one-repetition maximum half-squat (1RM(HS) and bench press (1RM(BP)), 2 sets of MRPB consisting of one set of 10 continuous repetitions (R10) followed by 1 set until exhaustion (R(max)), with exactly 2-min rest periods between each set, during bench-press and half-squat protocols with a resistance equal to 60 and 70% of the subjects' 1RM, respectively. In addition, a countermovement jumping test (CMJ) interspersed before and after the MRPB half-squat exercise bouts and a repeated sprint running test and a maximal multistage discontinuous incremental running test (MDRT) were performed.
Cr supplementation significantly increased body mass (from 79.4 +/- 8 to 80 +/- 8 kg; P < 0.05), number of repetitions performed to fatigue, and total average power output values in the R(max) set of MRPB during bench press (21% and 17%, respectively) and half-squat (33% and 20%, respectively), the 1RM(HS) (11%), as well as the CMJ values after the MRPB half-squat (5%), and the average running times during the first 5 m of the six repeated 15-m sprints (3%). No changes were observed in the strength, running velocity, or body mass measures in the placebo group during the experimental period.
Short-term Cr supplementation leads to significant improvements in lower-body maximal strength, maximal repetitive upper- and lower-body high-power exercise bouts, and total repetitions performed to fatigue in the R(max) set of MRPB, as well as enhanced repeated sprint performance and attenuated decline in jumping ability after MRPB in highly trained handball players. Cr supplementation did not result in any improvement in upper-body maximal strength and in endurance running performance.
... (Takashi Abe et al., 2000) (Cribb, Williams, Carey, & Hayes, 2006) (Joy et al., 2016) (Naclerio, Seijo-Bujia, Larumbe-Zabala, & Earnest, 2017) (Taylor et al., 2011) (T. Abe, K. Kojima, C. F. Kearns, H. Yohena, & J. Fukuda, 2003) (Cribb, Williams, Stathis, Carey, & Hayes, 2007) (Kalman, Feldman, Martinez, Krieger, & Tallon, 2007) (Noonan, Berg, Latin, Wagner, & Reimers, 1998) (Juha P. Ahtiainen et al., 2011) ( ...
Variables de influencia en el proceso de hipertrofia en adultos sanos y su importancia en la elaboración de programas de entrenamiento
... More recently, Cr supplementation was also found to be able to stimulate protein synthesis [24] and to reduce exercise induced muscle damage [25]. Most studies with the Cr dose and treatment period comparable to that used presently reported gains in strength and power as measured by one-repetition maximum, (1-RM), vertical jump, and 40-year dash in subjects who resistance trained [26][27][28][29]. These studies also observed an increase in FFM presumably due to fluid retention because CrM can draw water into the intracellular compartment via osmosis [26,[28][29]. ...
The present study examined the effect of simultaneous ingestion of whey protein (WP) and creating monohydrate (CrM) on body composition, selected measures of muscular strength and power, and risks for potential renal dysfunction. Fifteen professional athletes including nine males and six females specialized in track and field, Olympic weight lifting, and modern pentathlon volunteered to participate in the study. Subjects underwent a four-week treatment period during which they ingested both (WP) and CrM while maintaining their regular diet and training intensity and volume. Body composition and performance of one-min pull-up, one-min push up, one-min squat-to-stand, standing long jump, triple jump, and 30-s single leg lateral jumps were measured before and after the treatment. Urine samples were collected throughout the treatment to determine albumin and creatinine concentrations. No changes in body weight, muscle mass, and % body fat were noted following the treatment. The treatment, however, improved (p < 0.05) scores in one-min pull-up, one-min push up, one-min squat-to-stand, triple jump, 30-s single leg lateral jump tests. No differences in urinary albumin and creatinine were found throughout the treatment period. In conclusion, co-supplementation of WP and CrM for four weeks is an effective yet safe ergogenic strategy in enhancing strength and power in professional athletes.
... Only 38 studies had a maintenance dose, which varied between 1.25 and 27.0 g/day [23,27]. The quantity of the maintenance dose varied more between studies compared with the loading dose. ...
Background
Creatine is the most widely used supplementation to increase performance in strength; however, the most recent meta-analysis focused specifically on supplementation responses in muscles of the lower limbs without regard to upper limbs.
Objective
We aimed to systematically review the effect of creatine supplementation on upper limb strength performance.
Methods
We conducted a systematic review and meta-analyses of all randomized controlled trials comparing creatine supplementation with a placebo, with strength performance measured in exercises shorter than 3 min in duration. The search strategy used the keywords ‘creatine’, ‘supplementation’, and ‘performance’. Independent variables were age, sex and level of physical activity at baseline, while dependent variables were creatine loading, total dose, duration, time interval between baseline (T0) and the end of the supplementation (T1), and any training during supplementation. We conducted three meta-analyses: at T0 and T1, and on changes between T0 and T1. Each meta-analysis was stratified within upper limb muscle groups.
Results
We included 53 studies (563 individuals in the creatine supplementation group and 575 controls). Results did not differ at T0, while, at T1, the effect size (ES) for bench press and chest press were 0.265 (95 % CI 0.132–0.398; p < 0.001) and 0.677 (95 % CI 0.149–1.206; p = 0.012), respectively. Overall, pectoral ES was 0.289 (95 % CI 0.160–0.419; p = 0.000), and global upper limb ES was 0.317 (95 % CI 0.185–0.449; p < 0.001). Meta-analysis of changes between T0 and T1 gave similar results. The meta-regression showed no link with characteristics of population or supplementation, demonstrating the efficacy of creatine independently of all listed conditions.
Conclusion
Creatine supplementation is effective in upper limb strength performance for exercise with a duration of less than 3 min, independent of population characteristics, training protocols, and supplementary doses or duration.
... ¿Cómo se debe administrar la creatina a lo largo del día?No existen, en lo que nosotros conocemos, trabajos que hayan estudiado los efectos de la administración de creatina en diferentes momentos del día, sobre la concentración muscular de creatina y la aptitud física. Noonan y col.91 , recomiendan que durante la fase aguda de suplementación (20-30 gramos diarios durante 5 a 6 días), los días de entrenamiento se administre el 25% de la dosis durante el desayuno, otro 25% de la dosis una hora antes de que comience el entrenamiento y el 50% restante inmediatamente después de haber finalizado dicho entrenamiento. Los mismos autores recomiendan que los días en los que no se entrene, se administre la dosis diaria, repartida en 4 tomas de igual cantidad a lo largo del día (una toma cada 6 a 7 horas).Cada toma de creatina debería ir acompañada de una ingesta de hidratos de carbono 24 .Durante la fase de administración de dosis de mantenimiento de creatina (2 a 5 gramos diarios), se suele aconsejar ingerirla en una sola toma diaria durante la comida el día en el que no se entrene, e inmediatamente después de haber finalizado el entrenamiento, el día en el que se entrene. ...
... L'alimentation reste un acteur majeur de la croissance musculaire: sans apports nutritionnels pas de reconstruction ni de surcompensation musculaire. Cette évidence semble admise par tous au vu du peu d'expérimentations retrouvées dans la littérature en dehors de celles traitant de l'utilisation de créatine [95][96][97] . Seuls certains auteurs prennent le soin d'évaluer l'alimentation des sujets et d'augmenter les apports dans le cadre de l'étude [14] mais ils ne prennent pas en compte le moment où les nutriments sont ingérés. ...
... Conversely, creatine supplementation may prove to be a safe and effective over-the-counter means to diminish age-related declines in muscle mass and strength as research has found creatine supplementation to increase strength[6] and type II muscle fiber diameter[7] independent of exercise. Moreover, creatine supplementation has repeatedly been found to increase performance in younger (≤ 35 yr)89101112131415 adults, particularly when consumed in conjunction with a resistance training regimen. However, studies examining the effects of creatine supplementation in older adults (> 55 yr) have yielded apparently equivocal results1617181920212223242526. ...
Creatine supplementation has been found to significantly increase muscle strength and hypertrophy in young adults (</= 35 yr) particularly when consumed in conjunction with a resistance training regime. Literature examining the efficacy of creatine supplementation in older adults (55-82 yr) suggests creatine to promote muscle strength and hypertrophy to a greater extent than resistance training alone. The following is a review of literature reporting on the effects of creatine supplementation on intramuscular high energy phosphates, skeletal muscle morphology and quality of life in older adults. Results suggest creatine supplementation to be a safe, inexpensive and effective nutritional intervention, particularly when consumed in conjunction with a resistance training regime, for slowing the rate of muscle wasting that is associated with aging. Physicians should strongly consider advising older adults to supplement with creatine and to begin a resistance training regime in an effort to enhance skeletal muscle strength and hypertrophy, resulting in enhanced quality of life.
... BARNETT et al., 1996 REDONDO et al., 1996; GRINDSTAFF et al., 1997; HAMILTON-WARD et al., 1997; PREVOST et al., 1997; TERRILLION et al., 1997; McKENNA et al., 1999; STOUT et al., 1999; ROSSOUW et al., 2000; FRANCAUX et al., 2000; PARISE et al., 2001; DAWSON et al., 2002; HUSO et al., 2002; WILDER et al., 2002. Longo prazo (crônica) VANDENBERGHE et al., 1997; KELLY & JENKINS, 1998; KNEHANS et al., 1998a;; NOOMAN et al., 1998;FRANCAUX E POORTMANS, 1999; PEETERS et al., 1999; STONE et al., 1999; VOLEK et al., 1999; VUKOVICH & MICHAELIS, 1999; BECQUE et al., 2000; VOLEK et al., 2000; BEMBEN et al., 2001; BURKE et al., 2001; FONTANA, 2003; ROGERS et al., 2006. EARNEST et al., 1995 THOMPSON et al., 1996; BERMON et al., 1998; LARSON et al., 1998; SYROTUIK et al., 2001 BARROS, 1999; MELBY et al, 1993; POLLOCK et al, 2000). ...
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências da Saúde, 2008. A creatina como suplementação nutricional tem se popularizado e sido indiscriminadamente utilizada por apresentar ganho de massa magra e melhora do desempenho de atividades que envolvam exercícios de curta duração e alta intensidade. Porém, as intercorrências advindas do seu uso não estão totalmente elucidadas. Os efeitos adversos, principalmente em relação à sobrecarga renal e/ou hepática, foram tratados neste estudo através de avaliações bioquímicas sobre uma amostra de 35 desportistas divididos em três grupos de consumo (PLA: placebo, CRE1: 0,03g de creatina por kg de massa corporal por dia e CRE2: 5g de creatina por dia) durante oito semanas de treinamento. Os voluntários foram avaliados, através de medidas antropométricas, quanto ao ganho de massa magra e composição corporal. Para avaliação da composição corporal utilizou-se o protocolo de sete dobras e os perímetros de braço e coxa. Os participantes foram submetidos a um programa de treinamentocom exercícios resistidos constituídos de três séries, variando entre 8 a 12 repetições em cada série, com intervalo de um minuto, quatro ou mais vezes por semana e não sofreram intervenção na composição de suas dietas, que foram registradas e analisadas. Houve ganho ponderal, de 2,1% (CRE1) e 3,5% (CRE2) e a massa corporal magra aumentou significativamente entre os grupos PLA–CRE1 e PLA–CRE2 (P<0,01). Entre o PRÉ e o PÓStreinamento foi registrado aumento das circunferências de braço tenso, coxa, circunferência muscular do braço e da perna e índice de massa magra do braço nos tratamentos CRE1 e CRE2 (P<0,01). Todos os resultados dos exames bioquímicos realizados permaneceram dentro das faixas de normalidade. Quanto à função renal a creatinina aumentou significativamente nos grupos suplementados com creatina, porém sem sair dos valores de normalidade. Os valores dos exames da função hepática diminuíram em quase todas as frações, em todos os tratamentos, entretanto sem significância estatística. Estes resultados contribuíram no esclarecimento dos efeitos advindos do uso de creatina, permitindo o uso mais seguro deste suplemento nutricional. Concluiu-se que ocorreu ganho de massa magra para os grupos suplementados com creatina, independentemente das dosagens oferecidas, e de forma segura, não encontrando efeitos adversos nas funções hepáticas e renais. _________________________________________________________________________________________ ABSTRACT The use of creatine as nutritional supplement has become popular and has been widely used because of its effect on mass gain and as a performance-enhancing supplement on short duration, high intensity exercises. The intercurrence of its usage has yet to be clarified. The adverse effects, especially in relation to kidney and liver overload, were treated on this study through biochemical analysis on 35 volunteers, divided in 3 study groups (PLA: Placebo, CRE1:daily ingestion 0,03g creatine/kg of bodyweight, CRE2: daily ingestion of 5g creatine/kg of bodyweight) during a 8 week period. The volunteers were submitted to anthropometric measurements in relation to muscle mass and body composition (skinfolds, arm and anterior thigh circumferences). The volunteers were in a resistance exercise program and did not have a dietary change (observed). The exercise program consisted in 3 sets, with 8 to 12 repetitions each, and a minute break between sets, 4 times a week. The overall gain was of 2.1% (CRE1) and 3.5% (CRE2) and the fat-free mass gain was significant among the supplemented groups compare to placebo (P<0.01). Between the pre and post treatments an increase in the arm and leg circumferences in both treatments CRE1 and CRE2 was found (P<0.01). All the biochemical tests made throughout the study were within the normality range. The kidney function had a significant increase with the creatine but without being abnormal. In relation to the liver function, it presented lower performance in all treatments without statistical significance. The results contributed to the enlightment on the usage of creatine supplementation allowing a safer use. In conclusion the fat-free mass increased in creatine supplemented groups, independent of the dosage used and in a safe manner without adverse affects on liver and kidney functions.
... Few data exist on the long-term benefits and risks of Cr supplementation in men and women. A number of studies indicate that Cr supplementation in conjunction with heavy-resistance exercise training (e.g., 4 -12 wk in duration) enhances the normal physiological adaptations to the weight-training program (51,55,66,73,108,112). Typical training adaptations, including increases in body mass, fat-free mass, maximal strength and power, lifting volume, and muscle fiber hypertrophy (73,108,112), are all significantly enhanced concurrent with Cr supplementation. ...
Creatine (Cr) supplementation has become a common practice among professional, elite, collegiate, amateur, and recreational athletes with the expectation of enhancing exercise performance. Research indicates that Cr supplementation can increase muscle phosphocreatine (PCr) content, but not in all individuals. A high dose of 20 g x d(-1) that is common to many research studies is not necessary, as 3 g x d(-1) will achieve the same increase in PCr given time. Coincident ingestion of carbohydrate with Cr may increase muscle uptake; however, the procedure requires a large amount of carbohydrate. Exercise performance involving short periods of extremely powerful activity can be enhanced, especially during repeated bouts of activity. This is in keeping with the theoretical importance of an elevated PCr content in skeletal muscle. Cr supplementation does not increase maximal isometric strength, the rate of maximal force production, nor aerobic exercise performance. Most of the evidence has been obtained from healthy young adult male subjects with mixed athletic ability and training status. Less research information is available related to the alterations due to age and gender. Cr supplementation leads to weight gain within the first few days, likely due to water retention related to Cr uptake in the muscle. Cr supplementation is associated with an enhanced accrual of strength in strength-training programs, a response not independent from the initial weight gain, but may be related to a greater volume and intensity of training that can be achieved. There is no definitive evidence that Cr supplementation causes gastrointestinal, renal, and/or muscle cramping complications. The potential acute effects of high-dose Cr supplementation on body fluid balance has not been fully investigated, and ingestion of Cr before or during exercise is not recommended. There is evidence that medical use of Cr supplementation is warranted in certain patients (e.g.. neuromuscular disease); future research may establish its potential usefulness in other medical applications. Although Cr supplementation exhibits small but significant physiological and performance changes, the increases in performance are realized during very specific exercise conditions. This suggests that the apparent high expectations for performance enhancement, evident by the extensive use of Cr supplementation, are inordinate.
... In several of our performance measures, creatine supplementation generally resulted in improved performance responses to the overreaching protocol [i.e., maintenance of muscular performance during the highvolume phase, a statistically greater improvement in the ballistic bench press peak power output, and a tendency (P=0.09) for a greater improvement in week squat]. Several other studies have reported that creatine supplementation augments gains in muscular after resistance training programs lasting 3 weeks (Burke et al. 2000), 4 weeks (Arciero et al. 2001; Earnest et al. 1995; Kelly and Jenkins 1998; Kreider et al. 1998), 5 weeks (Stone et al. 1999), 6 weeks (Burke et al. 2001), 8 weeks (Noonan et al. 1998), 9 weeks (Bemben et al. 2001), 10 weeks (Vandenberghe et al. 1997), 12 weeks (Volek et al. 1999), and 13 weeks (Larson-Meyer et al. 2000). Unique to this study, the same muscle groups were trained 5 days in a row, thus reducing the amount of recovery time between workouts to less than 24 h. ...
To determine the effects of creatine supplementation during short-term resistance training overreaching on performance, body composition, and resting hormone concentrations, 17 men were randomly assigned to supplement with 0.3 g/kg per day of creatine monohydrate (CrM: n=9) or placebo (P: n=8) while performing resistance exercise (5 days/week for 4 weeks) followed by a 2-week taper phase. Maximal squat and bench press and explosive power in the bench press were reduced during the initial weeks of training in P but not CrM. Explosive power in the bench press, body mass, and lean body mass (LBM) in the legs were augmented to a greater extent in CrM ( P<or=0.05) by the end of the 6-week period. A tendency for greater 1-RM squat improvement ( P=0.09) was also observed in CrM. Total testosterone (TT) and the free androgen index (TT/SHBG) decreased in CrM and P, reaching a nadir at week 3, whereas sex hormone binding globulin (SHBG) responded in an opposite direction. Cortisol significantly increased after week 1 in CrM (+29%), and returned to baseline at week 2. Insulin was significantly depressed at week 1 (-24%) and drifted back toward baseline during weeks 2-4. Growth hormone and IGF-I levels were not affected. Therefore, some measures of muscular performance and body composition are enhanced to a greater extent following the rebound phase of short-term resistance training overreaching with creatine supplementation and these changes are not related to changes in circulating hormone concentrations obtained in the resting, postabsorptive state. In addition, creatine supplementation appears to be effective for maintaining muscular performance during the initial phase of high-volume resistance training overreaching that otherwise results in small performance decrements.
Creatine supplementation has been shown to increase measures of lean body mass (LBM), however there is often high heterogeneity across individual studies. Therefore, we systematically reviewed and meta-analyzed randomized controlled trials (RCTs) investigating creatine supplementation on LBM. Sub-analyses were performed based on age, sex, and type of exercise. Based on PRISMA guidelines, we searched the following databases: Pubmed, SPORTDiscus, Web of Science, and Scopus (PROSPERO register: CRD42020207122) until May 2022. RCTs that investigated creatine supplementation on LBM were included. Animal studies and studies on individuals with specific diseases were excluded. Thirty-five studies were included, totaling 1192 participants. Overall (i.e., inclusion of all studies with and without exercise training interventions) revealed that creatine increased LBM by 0.68 kg (CI95%: 0.26, 1.11). Sub-analyses revealed greater gains in LBM when creatine was combined with resistance training [mean difference (MD): 1.10 kg; CI95%: 0.56, 1.65], regardless of age. There was no statistically significant effect of creatine on LBM when combined with mixed exercise (MD: 0.74 kg; CI95%: -3.89, 5.36) or without exercise (MD: 0.03 kg; CI95%: -0.65, 0.70). Further sub-analyses found that males on creatine increased LBM by 1.46 kg (CI95%: 0.47, 2.46), compared to a non-significant increase of 0.29 kg (CI95%: -0.43, 1.01) for females. In conclusion, the addition of creatine supplementation to a resistance training program increases LBM. During a resistance training program, males on creatine respond more favorably compared to females.
We performed a systematic review and meta-analysis to study all published clinical trial interventions, determined the magnitude of whole-body hypertrophy in humans (healthy males) and observed the individual responsibility of each variable in muscle growth after resistance training (RT). Searches were conducted in PubMed, Web of Science and the Cochrane Library from database inception until 10 May 2018 for original articles assessing the effects of RT on muscle size after interventions of more than 2 weeks of duration. Specifically, we obtain the variables fat-free mass (FMM), lean muscle mass (LMM) and skeletal muscle mass (SMM). The effects on outcomes were expressed as mean differences (MD) and a random-effects meta-analysis and meta-regressions determined covariates (age, weight, height, durations in weeks…) to explore the moderate effect related to the participants and characteristics of training. One hundred and eleven studies (158 groups, 1927 participants) reported on the effects of RT for muscle mass. RT significantly increased muscle mass (FFM+LMM+SMM; Δ1.53 kg; 95% CI [1.30, 1.76], p < 0.001; I2 = 0%, p = 1.00). Considering the overall effects of the meta-regression, and taking into account the participants' characteristics, none of the studied covariates explained any effect on changes in muscle mass. Regarding the training characteristics, the only significant variable that explained the variance of the hypertrophy was the sets per workout, showing a significant negative interaction (MD; estimate: 1.85, 95% CI [1.45, 2.25], p < 0.001; moderator: -0.03 95% CI [−0.05, −0.001] p = 0.04). In conclusion, RT has a significant effect on the improvement of hypertrophy (~1.5 kg). The excessive sets per workout affects negatively the muscle mass gain.
Aim of research was to examine the effects of consuming CR to muscle strength and bodycomposition. Duration of experimental treatment was 8 weeks. Sample consisted of 14 participantsaged 24±6months divided into two sub-samples: 6 participants who consumed CR and 8 participantswho were placebo group. Strength was assessed using 3 tests: Bench Press 1RM, Leg Press 1RM, andBarbell Biceps Scott – maximum number of repetitions with 15kg load. Following parameters wereobtained for the purpose of assessment of body composition: Body mass, Muscle mass, Body Fat,Body Water. Assessment of body composition was performed using bioelectric impedance TANITA BC-545n. Differences between the groups were assessed by ANOVA test of repeated measures. Upontaking insight into the results we may conclude that CR influences changes in body composition: Bodymass (.000), Muscle mass (.039), Body Water (.010); effects to Body Fat are not statisticallysignificant. In placebo group changes were noticed only in variable Body Water (.007). Effects to bodystrength were confirmed in all three variables: Bench Press (.050), Leg Press (.041), Barbell BicepsScott (.003)., whereas no significant changes were observed in placebo group. CR is efficient dietarysupplement for both professional and amateur athletes. Citation. Bojan Bjelica , Borislav Cicović,Dalibor Stević, Rosario D'Onofrio , Tijana Perović , Radomir Pržulj , Nebojša Mitrović ; Effects ofcreatine monohydrate (CR) to muscle strength and body composition ; Ita. J. Sports Reh. Po.; 2020;7; 3; 1624 -1637 ; ISSN 2385-1988 [online] IBSN 007-111-19 - 55; CGI J OAJI 0,101)]
(PDF) EFFECTS OF CREATINE MONOHYDRATE (CR) TO MUSCLE STRENGTH AND BODY COMPOSITION. Available from: https://www.researchgate.net/publication/329655673_EFFECTS_OF_CREATINE_MONOHYDRATE_CR_TO_MUSCLE_STRENGTH_AND_BODY_COMPOSITION [accessed Oct 12 2022].
Aim of research was to examine the effects of consuming CR to muscle strength and body composition. Duration of experimental treatment was 8 weeks. Sample consisted of 14 participants aged 24±6months divided into two sub-samples: 6 participants who consumed CR and 7 participants who were placebo group. Strength was assessed using 3 tests: Bench Press 1RM, Leg Press 1RM, and Barbell Biceps Scott-maximum number of repetitions with 15kg load. Following parameters were obtained for the purpose of assessment of body composition: Body mass, Muscle mass, Body Fat, Body Water. Assessment of body composition was performed using bioelectric impedance TANITA BC-545n. Differences between the groups were assessed by ANOVA test of repeated measures. Upon taking insight into the results we may conclude that CR influences changes in body composition: Body mass (.000), Muscle mass (.039), Body Water (.010); effects to Body Fat are not statistically significant. In placebo group changes were noticed only in variable Body Water (.007). Effects to body strength were confirmed in all three variables: Bench Press (.050), Leg Press (.041), Barbell Biceps Scott (.003)., whereas no significant changes were observed in placebo group. CR is efficient dietary supplement for both professional and amateur athletes. Citation. Bojan Bjelica , Borislav Cicović, Dalibor Stević, Rosario D'Onofrio , Tijana Perović , Radomir Pržulj , Nebojša Mitrović ; Effects of creatine monohydrate (CR) to muscle strength and body composition ; Ita.
INTRODUCTION
Very few nutritional supplements have scientifically demonstrated their effectiveness as an ergogenic aid. This review will examine creatine monohydrate (MC), the β-hydroxy-β-methylbutyrate (HMB), sodium bicarbonate (BS), the β-alanine and caffeine.
OBJECTIVES
To analyze the effi cacy, mechanisms of action, dose, side effects and some sports that can benefit from their consumption.
METHODS
Searching in PubMed bibliographic database reviews from the last 15 years and original articles from the last 5 years of the studied substances.
RESULTS
Doses of 20 mg/day for 4-7 days are effective in improving strength and muscular power and performance in short and repeated sprints. HMB at doses of 3 g/day for at least 2 weeks contributes to increased lean mass and fat-free mass. The intake of 0.3 g/kg of BS improves performance on tests of 400-1,500 meters in athletics and intermittent sprints. Meanwhile, doses of 80 mg/kg/day of β-alanine for 4-10 weeks may improve performance in high-intensity intermittent exercise. Finally, caffeine at doses of 2 mg/kg improves responsiveness and 3-6 mg/kg improves performance in endurance tests.
CONCLUSIONS
The revised supplements have shown their efficacy in physical performance, but it is needed to keep in mind that most studies have been conducted with recreational-level athletes. Generally, the better the individual´s fitness level is the less improvement in physical performance the supplement shows. However, an increase of only 1% may sometimes allow the athlete to advance several positions in a final. Finally, we should draw attention to the importance of optimizing nutrition before considering the introduction of sports supplements, especially in children and youth. All analyzed substances have scientific basis supporting its ergogenic effect. All of them can be found in the market with Certificate of Quality and Purit.
Introduction: Very few nutritional supplements have scientifically demonstrated their effectiveness as an ergogenic aid. This review will examine creatine monohydrate (MC), the β-hydroxy-β-methylbutyrate (HMB), sodium bicarbonate (BS), the β-alanine and caffeine. Objectives: To analyze the efficacy, mechanisms of action, dose, side effects and some sports that can benefit from their consumption. Methods: Searching in PubMed bibliographic database reviews from the last 15 years and original articles from the last 5 years of the studied substances. Results: Doses of 20 mg/day for 4-7 days are effective in improving strength and muscular power and performance in short and repeated sprints. HMB at doses of 3 g/day for at least 2 weeks contributes to increased lean mass and fat-free mass. The intake of 0.3 g/kg of BS improves performance on tests of 400-1,500 meters in athletics and intermittent sprints. Meanwhile, doses of 80 mg/kg/day of β-alanine for 4-10 weeks may improve performance in high-intensity intermittent exercise. Finally, caffeine at doses of 2 mg/kg improves responsiveness and 3-6 mg/kg improves performance in endurance tests. Conclusions: The revised supplements have shown their efficacy in physical performance, but it is needed to keep in mind that most studies have been conducted with recreational-level athletes. Generally, the better the individual's fitness level is the less improvement in physical performance the supplement shows. However, an increase of only 1% may sometimes allow the athlete to advance several positions in a final. Finally, we should draw attention to the importance of optimizing nutrition before considering the introduction of sports supplements, especially in children and youth. All analyzed substances have scientific basis supporting its ergogenic effect. All of them can be found in the market with Certificate of Quality and Purity.
Creatine remains one of the most extensively studied nutritional ergogenic aids available for athletes. Hundreds of studies have reported that increasing muscle creatine stores through creatine supplementation can augment muscle creatine content, improve exercise and training adaptations, and/or provide some therapeutic benefit to some clinical populations. Consequently, creatine represents one of the most effective and popular nutritional ergogenic aids available for athletes. The future of creatine research is very promising. Researchers are attempting to determine ways to maximize creatine storage in the muscle, which types of exercise may obtain the greatest benefit from creatine supplementation, the potential medical uses of creatine, and the long-term safety and efficacy of creatine supplementation. Among these, the most promising area of research is determining the potential medical uses of creatine, particularly in patients with creatine synthesis deficiencies and neuromuscular diseases. Nevertheless, in regard to athletes, creatine has continually proved itself to be one of the most effective and safe nutritional supplements to increase strength, muscle mass, and performance. This is despite oftentimes inaccurate and misleading information that has been written about creatine in the popular media over the last several years.
The purpose of this study is to investigate how effects creatine dosage has on the improvement of rowing athletes` performance ability. Rowing athletes were administered with creatine, through which to examine the change of athletic performance ability, blood fatigue substances, and muscular activity. The subjects (participants) of this Study consisted of 12 male rowing athletes at P University, with at least 5 years of rowing experiences, which divided into two groups - creatine dosing group of 6 persons and control group of 6 persons - for random sampling measurement. Enzymatic-colorimetric method using lacrate oxidase and 4-aminoantipyrine was performed for blood lactate level analysis, and wireless EMG system (QEMG-4: Lxtha Korea) for muscular activity analysis, with 4 channels set for data analysis. As body parts to be measured, two muscular parts - latissimus dorsi and lumbar spinel - were chosen. Then, on the 5th day from the date of administering them with creatine (that is, 4 days after dosing them with creatine), rowing movement with the highest level of activity was calculated as peak value, which was measured twice. The test data used for this Study were SPSS/PC 18.0, pre-movement and post-movement two-way ANOVA for repeated measurement for comparative analysis of each muscle, with significant level at .05. As a result, the change of blood lactate level was significantly higher in creatine dosing group than in non-dosing group (p
The efficiency, safety, and effectiveness of strength training programs are paramount for sport conditioning. Therefore, identifying optimal doses of the training variables allows for maximal gains in muscular strength to be elicited per unit of time and also for the reduction in risk of overtraining and/or overuse injuries. A quantified dose-response relationship for the continuum of training intensities, frequencies, and volumes has been identified for recreationally trained populations but has yet to be identified for competitive athletes. The purpose of this analysis was to identify this relationship in collegiate, professional, and elite athletes. A meta-analysis of 37 studies with a total of 370 effect sizes was performed to identify the dose-response relationship among competitive athletes. Criteria for study inclusion were (a) participants must have been competitive athletes at the collegiate or professional level, (b) the study must have employed a strength training intervention, and (c) the study must have included necessary data to calculate effect sizes. Effect size data demonstrate that maximal strength gains are elicited among athletes who train at a mean training intensity of 85% of 1 repetition maximum (1RM), 2 days per week, and with a mean training volume of 8 sets per muscle group. The current data exhibit different dose-response trends than previous meta-analytical investigations with trained and untrained nonathletes. These results demonstrate explicit dose-response trends for maximal strength gains in athletes and may be directly used in strength and conditioning venues to optimize training efficiency and effectiveness.
Creatine has become a popular nutritional supplement among athletes. Recent research has also suggested that there may be a number of potential therapeutic uses of creatine. This paper reviews the available research that has examined the potential ergogenic value of creatine supplementation on exercise performance and training adaptations. Review of the literature indicates that over 500 research studies have evaluated the effects of creatine supplementation on muscle physiology and/or exercise capacity in healthy, trained, and various diseased populations. Short-term creatine supplementation (e.g. 20 g/day for 5–7 days) has typically been reported to increase total creatine content by 10–30% and phosphocreatine stores by 10–40%. Of the approximately 300 studies that have evaluated the potential ergogenic value of creatine supplementation, about 70% of these studies report statistically significant results while remaining studies generally report non-significant gains in performance. No study reports a statistically significant ergolytic effect. For example, short-term creatine supplementation has been reported to improve maximal power/strength (5–15%), work performed during sets of maximal effort muscle contractions (5–15%), single-effort sprint performance (1–5%), and work performed during repetitive sprint performance (5–15%). Moreover, creatine supplementation during training has been reported to promote significantly greater gains in strength, fat free mass, and performance primarily of high intensity exercise tasks. Although not all studies report significant results, the preponderance of scientific evidence indicates that creatine supplementation appears to be a generally effective nutritional ergogenic aid for a variety of exercise tasks in a number of athletic and clinical populations.
The main objective of this research was the evaluation of anaerobic power indices after long term (30days) supplementation with Cr, HMB and a combination of Cr and HMB in basketball players. Fifty two well trained basketball players took part in the experiment, with two resigning do to injury. The players were randomly assigned to four groups. The control group included 13 basketball players which were given a placebo consisting of 750ml of CHO per day. The second group of 12 athletes received creatine monohydrate with CHO over the 30 day period. The third group was supplemented with HMB, while the fourth group was given both supplements simultaneously. The supplements were ingested with a CHO solution to increase creatine uptakeAll of the basketball players performed a triple Wingate test before and immediately after the 30 day supplementation and training protocol. At rest and during the 4th minute of recovery, blood samples were drawn from the fingertip, for the evaluation of lactate concentration and acid-base equilibrium. Additional blood samples were taken from the antecubital vein, at rest and 60 minutes after the cessation of exercise in order to evaluate CK and LDH activity. Long term supplementation with creatine monohydrate seems to have a buffering effect, since greater values of Pmax and Wt are not accompanied by significantly higher post exercise LA concentration or lower pH values. This suggests a decreased rate of glycolysis do to an increase in ATP resynthesis from PCr.
Strength-power athletes improve exercise performance primarily by improving their sport-specific skills. in addition, exercise performance can be enhanced by improving strength, lean muscle mass, and anaerobic exercise performance. several sports supplements have been documented to enhance these attributes, including creatine monohydrate, betaalanine, β-hydroxy β- methylbutyrate, and protein.
This article reviews current, as well as past, research on the topic of creatine supplementation. It is aimed toward industry professionals as a tool to update and increase their current knowledge on this topic.
The effects of oral creatine supplementation (CR) on body mass (BM), percent body fat (BF), fat mass (FM), and fat free mass (FFM) were examined. A double blind, crossover design compared 10 recreationally active college-aged men during a 10-week strength-training program. Five men were randomly assigned either 20 g creatine/day or 20 g/day of maltodextrine (PL) for five days, followed by a maintenance dose of 2 g/day for three weeks. Treatments were separated by a four-week washout period while training continued. Body composition was determined using whole body plethysmography (Bod Pod®). BM increased (1.52±1.76 kg) (P=0.028) following CR compared to PL. FFM increased (P<0.05) in both CR (1.93±2.61 kg) and PL (2.24±2.10 kg) whereas FM and BF decreased (P<0.018) following PL but not CR (FM -2.60±2.37 kg; BF -3.22±2.88 %). In conclusion, CR significantly increased BM, without lowering BF and did not increase FFM greater than strength training alone.
Resistance training increases muscle strength. Muscle strength gains are influenced by program design. This review attempted to identify design choices that would be best practices. A best practice is a design option that produces significantly better results than any other option. To ensure sensitive assessments of program design effects, statistical procedures adjusted for differences in program length, and allowed for the repeated measures structure of the study designs. Untrained individuals benefitted much more from training than trained individuals. Gender had little effect. Age effects differed for men and women. Given the impact of participant characteristics on the training response, the effects of different program design facets were examined separately for programs with untrained and trained participants. Periodization, number of sessions per week, number of sets per session, and intensity (number of repetitions per set) were significant moderators for untrained participants; sets per session and intensity were significant moderators for trained participants. However, comparisons generally showed that no single design option was significantly better than all others. The available evidence may rule out some design choices (e.g., a single set per session), but it is too limited to identify best practices.
Sixteen collegiate women lacrosse players consumed either creatine (C, n = 7) or a placebo (P, n = 9) for 5 weeks during their preseason conditioning program (20 g [middle dot] d-1 for 1 week and 2 g [middle dot] d-1 for 4 weeks). Pre-and posttesting consisted of body composition, muscle endurance test, blood lactate response to the endurance test, 1 repetition maximum (1RM) bench press and leg extension, and blood glutamyltransferase (GGL) and blood urea nitrogen (BUN). Testing revealed that 1RM bench press significantly increased in both groups, with the C group improving significantly more than the P group (6.2 +/- 2.0 and 2.8 +/- 1.8 kg). Percent body fat by skin-fold decreased significantly more in C than the P group (-1.2 +/- 0.9 and 0.3 +/- 0.8), but was not different by group by hydrodensitometry. No significant differences between groups were found for all other measures, but significant time effects were noted for body weight gain (0.5 +/- 3.2 kg), 1RM leg extension (1.4 +/- 4.1 kg), BUN (0.07 +/- 0.03 mmol [middle dot] L-1), total work during the muscle endurance test (283.5 +/- 387.3 watts), and fat-free mass by skinfold (0.7 +/- 1.2 kg). In summary, a regime of dietary creatine supplementation significantly improved upper-body strength gain and decreased the percent body fat as assessed by skinfold in women athletes engaged in a resistance-training program.
(C) 2000 National Strength and Conditioning Association
Creatine is a nutritional supplement widely used in sport, physical fitness training and bodybuilding. It is claimed to enhance performance. We describe a case in which serum creatinine is elevated due to the use of creatine ethyl esther. One week after withdrawal, the plasma creatinine had normalised. There are two types of creatine products available: creatine ethyl esther (CEE) and creatine monohydrate (CM). Plasma creatinine is not elevated in all creatine-using subjects. CEE , but not CM, is converted into creatinine in the gastrointestinal tract. As a result the use of CEE may be associated with elevated plasma creatinine levels. Since plasma creatinine is a widely used marker for renal function, the use of CEE may lead to a false assumption of renal failure.
Radiation recall dermatitis (RRD) is a rare cutaneous reaction occurring within a previously irradiated field, precipitated by certain drugs. A case of RRD most likely induced by doxorubicin is presented and illustrated together with a review of the literature.
Diabetes mellitus type 1 (DM1) is associated with other autoimmune disorders. To our knowledge, there are no longitudinal data considering the long-term clinical relevance of organ-specific antibodies (OS-Ab) in DM1 patients. We performed a long-term retrospective longitudinal study in order to investigate the presence and diagnostic accuracy (positive predictive value: PPV and negative predictive value: NPV) of OS-Ab in DM1 patients.
In a retrospective longitudinal study, the presence of OS-Ab and related organ function were analysed in 396 DM1 patients (184 F/212 M, age 44 ± 13 years, age at onset of DM1 21 ± 13 years), with a median follow-up time of 23 ± 10 years.
OS-Ab frequencies at baseline were: antibodies against thyroglobulin (Tg-Ab) 4.3%, antibodies against thyroid peroxidase (TPO-Ab) 8.1%, Tg- and/or TPO-Ab 10.4%, antibodies against parietal cells (PCA) 5.8% and antibodies against adrenal cortex (ACA) 0.5%. The occurrence of (sub)clinical hypothyroidism was higher in patients with Tg-Ab (47%) or TPO-Ab (42%) than in those without these antibodies (6.2 and 5.1%, respectively, p<0.001). PPV and NPV for Tg-Ab were 0.60 and 0.88, respectively, for TPO -Ab 0.54 and 0.91. Also in patients with PCA, organ dysfunction occurred more often (61%) than in patients without PCA (9.7%, p<0.001). PPV for PCA was 0.61 and NPV 0.90. NPV and PPV for ACA could not be calculated because of the low prevalence. Conclusion: Long-term follow-up of 396 DM1 patients shows that the presence of thyroid antibodies and/ or parietal cell antibodies is clearly associated with dysfunction of the corresponding organ.
A 28-year-old young woman was referred to our department of Internal Medicine for analysis of unintentional weight loss. At initial analysis, a persistent proteinuria was found with no evident relation to her weight loss. Anamnestic as well as additional studies showed no evidence of a primary kidney disease. After this exclusion, orthostatic proteinuria was confirmed by simple urine analysis. Since the weight loss had not yet been explained, an analysis followed at the Department of Gastointestinal and Liver Diseases where inflammatory bowel disease (IBD) was found. Literature study shows that proteinuria may be associated with IBD. This concerns mainly selective tubular protein loss, without a distinctive change in protein loss with a change in position. Orthostatic proteinuria, therefore, remained the most likely diagnosis. In this case, the patient was advised to check both urine and kidney function annually.
The enteric nervous system regulates diverse functions including gastrointestinal motility and nociception. The sensory neurons detect mechanical and chemical stimuli while motor neurons control peristalsis and secretion. In addition to this extensive neuronal network, the gut also houses a highly specialised immune system which plays an important role in the induction and maintenance of tolerance to food and other luminal antigens and in the protection of the epithelial barrier against pathogenic invasion. It is now increasingly recognised that the gastrointestinal immune system and the enteric nervous system closely interact. This review will focus on two common functional gastrointestinal disorders in which neuroimmune interaction is involved in the pathophysiology: i.e. postoperative ileus and irritable bowel syndrome. Postoperative ileus arises after almost every abdominal surgical procedure. Handling of the bowel results in local inflammation and activation of inhibitory neuronal pathways resulting in a generalised impairment of gastrointestinal motor function or ileus. On the other hand, postinfectious irritable bowel syndrome (PI-IBS) occurs in 10 to 30% of patients who suffer from infectious gastroenteritis. PI -IBS patients develop abnormal gastrointestinal sensitivity, motility and secretion which contribute to abdominal pain and discomfort, bloating and abnormal bowel function (diarrhoea and/or constipation). Biopsy studies revealed persistent low-grade inflammation and altered immunological function which may lead to abnormal pain perception and motor activity within the gastrointestinal tract.
System requirements: World Wide Web browser and PDF reader. Mode of access: Available through the Internet. Title from document title page. Document formatted into pages; contains xii, 156 p. : ill. (some col.). Thesis (Ph. D.)--West Virginia University, 2003. Includes abstract. Includes bibliographical references.
Do ponto de vista energético os esforços físicos podem classificar-se em aeróbios e anaeróbios. Esta terminologia de uso popular foi determinada por Luis Pastel, que classificou as bactérias entendendo a sua vitalidade na presença de oxigênio. A energia potencial que sustenta a vida dos seres vivos em nosso planeta é uma forma de energia química, adenosina trifosfato, que é formada por um grupo adenosina, um grupo ribose e três fosfatos ligados, e se conhece como ATP. A quebra dessa substancia quando atacada por uma enzima (ATPase) libera energia necessária para manutenção da vida. A quantidade de ATP em nosso organismo é suficiente para manter a vida durante um tempo inferior a 5 segundos, e para tanto a conservação da vida consiste em formação constante de ATP. Esta reação realiza-se nas mitocôndrias de todas as células. Quando há oxigênio suficiente nas células, o ATP é produzido na forma denominada aeróbia. A produção aeróbia de energia acontece no interior das mitocôndrias, por meio de duas vias metabólicas denominadas de (1) ciclo de krebs e (2) cadeia de transporte de elétrons. É lógico pensar que esta situação é da vida cotidiana e pequenos esforços.A maioria dos esforços esportivos (jogos, lutas, corridas, saltos, arremessos, lançamentos, etc) com exceção dos movimentos cíclicos de grande duração, o ATP se produz em forma anaeróbia. Por tanto o desenvolvimento da resistência anaeróbia é um problema fundamental e muito atual na fisiologia do exercício. A energia anaeróbia alatica ou fosfagênica resulta da formação de ATP a partir do ADP livre com uma molécula de fósforo doado por uma substancia macro energético denominada creatinofosfato, em todos os esforços explosivos e nas acelerações é esta energética que se utiliza. No organismo a reserva de creatinofosfato é de 02 a 03 gramas no total, o que permite uma pessoa não treinada um esforço Maximo de 3 segundos, e um atleta de elite esforços de até 08 segundos de duração. Os treinadores sonham em chegar a 20 segundos de duração, o que traz com sigo o aumento das reservas de creatinofosfato a níveis de até cinco vezes mais que de pessoas não treinadas. A produção anaeróbia lática ou glicolítica de ATP é aquela que se forma pela ação da enzima LDH (lactatodesidrogenase) na molécula de acido lático, este acido por simples perda do pH que produz, provoca alterações em todas as estruturas do sistema nervoso central e periférico, em especial nas sinapses neuromusculares. Sendo que limita a possibilidade de trabalho longo e intenso. O aumento das reservas de creatinofosfato muscular pela suplementação de creatina monohidratada produz alteração na síntese anaeróbia lática, tornando-se um amortizador do descenso do pH sanguíneo em esforços intensos, teoricamente em função da (1) maior concentração de creatinofosfato intracelular, o que retardaria a glicolise anaeróbia, produzindo um retardo na chegado do descenso do pH sanguíneo, como pode ser observado na pesquisa de curta duração de Rico Sanz (2000) citado por Roussel et al. (2000). Não podendo se esquecer que a capacidade de ressintese e armazenamento de creatinofosfato dependem do nível de utilização deste substrato, como já mencionado por Robergs (2001), com relação à bioenergética, ou seja, o sistema de produção de energia humano depende do estimulo (utilização) para poder adaptar-se ao amento na síntese e armazenamento.
This study examined the influence of dietary creatine (CR) supplementation upon mechanical and hypertrophic responses to a well-defined conditioning stimulus provided by electromyostimulation (EMS).
Eighteen resistance-trained subjects were assigned CR or a placebo (PL) in a randomized, double-blind fashion. After CR loading (20 g x d(-1) for 7 d), CR supplementation (5 g x d(-1)) or PL was continued for 8 wk. During supplementation, EMS (3--5 sets of 10 coupled eccentric and concentric actions) was applied to the left m. quadriceps femoris (QF) twice weekly while subjects continued voluntary resistance training of both lower limbs unsupervised. Cross-sectional area (CSA) of each QF was assessed with magnetic resonance imaging (MRI). Torque during EMS was analyzed to assess muscle loading and fatigue resistance.
Maximal torque and the torque time integral increased markedly over training (P < or = 0.0001). These responses reflected activation of more muscle as EMS current was increased (about 16%), greater recovery between sets (P < or = 0.0423), and less fatigue during sets over training (P = 0.0002). CR did not influence these responses (P = 0.8093). In accord with these results, the increase in CSA for the stimulated QF (11%) was comparable for CR and PL (P = 0.2190). CSA in the nonstimulated QF increased 5% in CR (P = 0.0091) but did not change in PL.
We conclude that CR supplementation did not augment the mechanical or hypertrophic response to a precisely measured conditioning stimulus that attenuated but did not ameliorate fatigue. We suggest that enhanced fatigue resistance may not explain the apparent ergogenic effect of CR during voluntary training.
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 identification of a quantifiable dose-response relationship for strength training is important to the prescription of proper training programs. Although much research has been performed examining strength increases with training, taken individually, they provide little insight into the magnitude of strength gains along the continuum of training intensities, frequencies, and volumes. A meta-analysis of 140 studies with a total of 1433 effect sizes (ES) was carried out to identify the dose-response relationship.
Studies employing a strength-training intervention and containing data necessary to calculate ES were included in the analysis.
ES demonstrated different responses based on the training status of the participants. Training with a mean intensity of 60% of one repetition maximum elicits maximal gains in untrained individuals, whereas 80% is most effective in those who are trained. Untrained participants experience maximal gains by training each muscle group 3 d.wk and trained individuals 2 d.wk. Four sets per muscle group elicited maximal gains in both trained and untrained individuals.
The dose-response trends identified in this analysis support the theory of progression in resistance program design and can be useful in the development of training programs designed to optimize the effort to benefit ratio.
Creatine monohydrate (CrH2O) supplementation has been demonstrated to increase skeletal muscle power output in men. However, its effect upon women is not as clearly defined. This study investigated the effect of oral creatine supplementation upon muscle function, thigh circumference, and body weight in women. Twenty-two consenting college-age women were assigned to 1 of 2 groups matched for dietary and exercise habits, phase of menstrual cycle, and fat-free mass (FFM). After familiarization with testing procedures, pretrial measures of muscle function (5 repetitions 60 deg x s(-1) and 50 repetitions 180 deg x s(-1) were conducted during maximal voluntary concentric contraction of the preferred quadriceps muscle using an isokinetic dynamometer. Subjects then ingested 0.5 g x kg(-1) FFM of either CrH2O or placebo (one fourth dosage 4 times daily) in a double-blind design for 5 days. Resistance exercise was prohibited. After the ingestion phase was completed, all measures were repeated at the same time of day as during pretrials. Statistical analysis revealed time to peak torque in quadriceps extension decreased from pre-test values of 255 +/- 11 ms (mean +/- SEM) to post-test values of 223 +/- 3 ms; average power in extension increased from 103 +/- 7 W pre-test to 112 +/- 7 W post-test; and, during flexion, average power increased from 59 +/- 5 W pre-test to 65 +/- 5 W post-test in the creatine group as compared to controls (p .05). FFM, percent body fat, mid-quadriceps circumference, skinfold thickness of the measured thigh, and total body weight did not change for both groups between trials. We conclude that CrH2O improves muscle performance in women without significant gains in muscle volume or body weight.
Creatine has become a popular nutritional supplement among athletes. Recent research has also suggested that there may be a number of potential therapeutic uses of creatine. This paper reviews the available research that has examined the potential ergogenic value of creatine supplementation on exercise performance and training adaptations. Review of the literature indicates that over 500 research studies have evaluated the effects of creatine supplementation on muscle physiology and/or exercise capacity in healthy, trained, and various diseased populations. Short-term creatine supplementation (e.g. 20 g/day for 5-7 days) has typically been reported to increase total creatine content by 10-30% and phosphocreatine stores by 10-40%. Of the approximately 300 studies that have evaluated the potential ergogenic value of creatine supplementation, about 70% of these studies report statistically significant results while remaining studies generally report non-significant gains in performance. No study reports a statistically significant ergolytic effect. For example, short-term creatine supplementation has been reported to improve maximal power/strength (5-15%), work performed during sets of maximal effort muscle contractions (5-15%), single-effort sprint performance (1-5%), and work performed during repetitive sprint performance (5-15%). Moreover, creatine supplementation during training has been reported to promote significantly greater gains in strength, fat free mass, and performance primarily of high intensity exercise tasks. Although not all studies report significant results, the preponderance of scientific evidence indicates that creatine supplementation appears to be a generally effective nutritional ergogenic aid for a variety of exercise tasks in a number of athletic and clinical populations.
OBJECTIVE: To compare the effects of low doses of creatine and creatine loading on strength, urinary creatinine concentration, and percentage of body fat. DESIGN AND SETTING: Division IA collegiate football players took creatine monohydrate for 10 weeks during a sport-specific, periodized, off-season strength and conditioning program. One-repetition maximum (1-RM) squat, urinary creatinine concentrations, and percentage of body fat were analyzed. SUBJECTS: Twenty-five highly trained, Division IA collegiate football players with at least 1 year of college playing experience. MEASUREMENTS: We tested strength with a 1-RM squat exercise before, during, and after creatine supplementation. Percentage of body fat was measured by hydrostatic weighing before and after supplementation. Urinary creatinine concentration was measured via light spectrophotometer at 0, 1, 3, 7, 14, 21, 28, 35, 42, 48, 56, and 63 days. An analysis of variance with repeated measures was computed to compare means for all variables. RESULTS: Creatine supplementation had no significant group, time, or interaction effects on strength, urinary creatinine concentration, or percentage of body fat. However, significant time effects were found for 1-RM squat and fat-free mass in all groups. CONCLUSIONS: Our data suggest that creatine monohydrate in any amount does not have any beneficial ergogenic effects in highly trained collegiate football players. However, a proper resistance training stimulus for 10 weeks can increase strength and fat-free mass in highly trained athletes.
Creatine supplementation (CS) has been reported to increase body mass and improve performance in high-intensity, short-duration exercise tasks. Research on CS, most of which has come into existence since 1994, has been the focus of several qualitative reviews, but only one meta-analysis, which was conducted with a limited number of studies.
This study compared the effects of CS on effect size (ES) for body composition (BC) variables (mass and lean body mass), duration and intensity (< or = 30 s, [ATP-PCr = A]; 30-150 s [glycolysis = G]; >150 s, [oxidative phosphorylation = O]) of the exercise task, type of exercise task (single, repetitive, laboratory, field, upper-body, lower-body), CS duration (loading, maintenance), and subject characteristics (gender, training status).
A search of MEDLINE and SPORTDiscus using the phrase "creatine supplementation" revealed 96 English-language, peer-reviewed papers (100 studies), which included randomized group formation, a placebo control, and human subjects who were blinded to treatments. ES was calculated for each body composition and performance variable.
Small, but significant (ES > 0, p < or = .05) ES were reported for BC (n=163, mean +/- SE=0.17 +/- 0.03), ATP-PCr (n=17, 0.24 +/- 0.02), G (n=135, 0.19 +/- 0.05), and O (n=69, 0.20 +/- 0.07). ES was greater for change in BC following a loading-only CS regimen (0.26 +/- 0.03, p=.0003) compared to a maintenance regimen (0.04 +/- 0.05), for repetitive-bout (0.25 +/- 0.03,p=.028) compared to single-bout (0.18 +/- 0.02) exercise, and for upper-body exercise (0.42 +/- 0.07, p<.0001) compared to lower (0.21 +/- 0.02) and total body (0.13 +/- 0.04) exercise. ES for laboratory-based tasks (e.g., isometric/isotonic/isokinetic exercise, 0.25 +/- 0.02) were greater (p=.014) than those observed for field-based tasks (e.g., running, swimming, 0.14 +/- 0.04). There were no differences in BC or performance ES between males and females or between trained and untrained subjects.
ES was greater for changes in lean body mass following short-term CS, repetitive-bout laboratory-based exercise tasks < or = 30 s (e.g., isometric, isokinetic, and isotonic resistance exercise), and upper-body exercise. CS does not appear to be effective in improving running and swimming performance. There is no evidence in the literature of an effect of gender or training status on ES following CS.
OBJECTIVE: To examine the effects of creatine supplementation on the incidence of cramping and injury observed during 1 season of National Collegiate Athletic Association Division IA football training and competition. DESIGN AND SETTING: In an open-label manner, subjects who volunteered to take creatine ingested 0.3 g.kg(-1).d(-1) of creatine for 5 days followed by an average of 0.03 g.kg.(-1)d(-1) after workouts, practices, and games. Creatine intake was monitored and recorded by researchers throughout the course of the study. SUBJECTS: Thirty-eight of 72 athletes (53.0%) participating in the 1999 Division IA collegiate football season from the same university volunteered to take creatine in this study. Subjects trained, practiced, or played in environmental conditions ranging from 15 degrees C to 37 degrees C (mean = 27.26 degrees +/- 10.93 degrees C) and 46.0% to 91.0% relative humidity (mean = 54.17% +/- 9.71%). MEASUREMENTS: Injuries treated by the athletic training staff were recorded and categorized as cramping, heat illness or dehydration, muscle tightness, muscle strains, noncontact joint injuries, contact injuries, and illness. The number of missed practices due to injury and illness was also recorded. Data were analyzed using a 2 x 2 chi(2) test to examine the first reported incidences of cramping and injury for creatine users and nonusers. RESULTS: Creatine users had significantly less cramping (chi(2)(1) = 5.35 P =.021); heat illness or dehydration (chi(2)(1) = 4.09, P =.043); muscle tightness (chi(2)(1) = 5.39, P =.020); muscle strains (chi(2)(1) = 5.36, P =.021); and total injuries (chi(2)(1) = 17.80, P<.001) than nonusers. There were no significant differences between groups regarding noncontact joint injuries (chi(2)(1)= 3.48, P =.062); contact injuries (chi(2)(1) = 0.00, P =.100); illness (chi(2)(1) = 6.82, P =.409); missed practices due to injury (chi(2)(1) = 1.43, P =.233); or players lost for the season (chi(2)(1) = 4.75, P =.491). CONCLUSIONS: The incidence of cramping or injury in Division IA football players was significantly lower or proportional for creatine users compared with nonusers.
The efficiency, safety, and effectiveness of strength training programs are paramount for sport conditioning. Therefore, identifying optimal doses of the training variables allows for maximal gains in muscular strength to be elicited per unit of time and also for the reduction in risk of overtraining and/or overuse injuries. A quantified dose-response relationship for the continuum of training intensities, frequencies, and volumes has been identified for recreationally trained populations but has yet to be identified for competitive athletes. The purpose of this analysis was to identify this relationship in collegiate, professional, and elite athletes. A meta-analysis of 37 studies with a total of 370 effect sizes was performed to identify the dose-response relationship among competitive athletes. Criteria for study inclusion were (a) participants must have been competitive athletes at the collegiate or professional level, (b) the study must have employed a strength training intervention, and (c) the study must have included necessary data to calculate effect sizes. Effect size data demonstrate that maximal strength gains are elicited among athletes who train at a mean training intensity of 85% of 1 repetition maximum (1RM), 2 days per week, and with a mean training volume of 8 sets per muscle group. The current data exhibit different dose-response trends than previous meta-analytical investigations with trained and untrained nonathletes. These results demonstrate explicit dose-response trends for maximal strength gains in athletes and may be directly used in strength and conditioning venues to optimize training efficiency and effectiveness.
The purpose of this study was to quantitatively combine and examine the results of studies examining the effectiveness of periodized (PER) compared to nonperiodized (Non-PER) training programs for strength and/or power development. Two analyses were conducted to (a) examine the magnitude of treatment effect elicited by PER strength training programs compared to Non-PER programs and (b) compare these effects after controlling for training volume, frequency, and intensity. Studies meeting the inclusion criteria were coded based on characteristics that might moderate the overall effects (i.e., participant characteristics and characteristics related to the training program). Effect sizes (ESs) were calculated for each study, and an overall ES of 0.84 (+/- 1.41) favoring PER training was found. Further analyses identified the treatment effect specific to training variation to be ES = 0.25. Significant moderating variables included age, training status, and length of training program. As a result of this statistical review of the literature, it is concluded that PER training is more effective than Non-PER training for men and women, individuals of varying training backgrounds, and for all age groups. In line with the overload principle, additions to volume, intensity, and frequency result in additional training adaptations.
Seven male subjects performed repeated bouts of high‐intensity exercise, on a cycle ergometer, before and after 6 d of creatine supplementation (20 g Cr H 2 O day ‐1 ). The exercise protocol consisted of five 6‐s exercise periods performed at a fixed exercise intensity, interspersed with 30‐s recovery periods (Part I), followed (40 s later) by one 10 s exercise period (Part II) where the ability to maintain power output was evaluated. Muscle biopsies were taken from m. vastus lateralis at rest, and immediately after (i) the fifth 6 s exercise period in Part I and (ii) the 10 s exercise period in Part II. In addition, a series of counter movement (CMJ) and squat (SJ) jumps were performed before and after the administration period.
As a result of the creatine supplementation, total muscle creatine [creatine (Cr) + phosphocreatine (PCr)] concentration at rest increased from (mean + SEM) 128.7 (4.3) to 151.5 (5.5)mmolkg _1 dry wt ( P < 0.05). This was accompanied by a 1.1 (0.5) kg increase in body mass ( P < 0.05). After the fifth exercise bout in Part I of the exercise protocol, PCr concentration was higher [69.7 (2.3) vs. 45.6 (7.5) mmol kg“‘ dry wt, P < 0.05], and muscle lactate was lower [26.2 (5.5) vs. 44.3 (9.9) mmol kg” ¹ dry wt, P < 0.05] after vs. before supplementation. In Part II, after creatine supplementation, subjects were better able to maintain power output during the 10‐s exercise period ( P < 0.05). There was no change in jump performance as a result of the creatine supplementation ( P > 0.05).
These findings show that enhanced fatigue resistance during short duration high‐intensity exercise following creatine supplementation is associated with a greater availability of PCr and a lower accumulation of lactate in the muscle. The finding that jump performance was not enhanced suggests that short‐term creatine feeding does not influence peak power output.