The effect of creatine monohydrate loading on maximal intermittent exercise and sport-specific strength in well trained power-lifters

No additive effect of creatine, caffeine, and sodium bicarbonate on intense exercise performance in endurance-trained individuals

BACKGROUND

Athletes commonly use creatine, caffeine, and sodium bicarbonate for performance enhancement. While their isolated effects are well-described, less is known about their potential additive effects.

METHODS

Following a baseline trial, we randomized 12 endurance-trained males (age: 25 ± 5 years, VO2max: 56.7 ± 4.6 mL kg-1 min-1; mean ± SD) and 11 females (age: 25 ± 3 years, VO2max: 50.2 ± 3.4 mL kg-1 min-1) to 5 days of creatine monohydrate (0.3 g kg-1 per day) or placebo loading, followed by a daily maintenance dose (0.04 g kg-1) throughout the study. After the loading period, subjects completed four trials in randomized order where they ingested caffeine (3 mg kg-1), sodium bicarbonate (0.3 g kg-1), placebo, or both caffeine and sodium bicarbonate before a maximal voluntary contraction (MVC), 15-s sprint, and 6-min time trial.

RESULTS

Compared to placebo, mean power output during 15-s sprint was higher following loading with creatine than placebo (+34 W, 95% CI: 10 to 58, p = 0.008), but with no additional effect of caffeine (+10 W, 95% CI: -7 to 24, p = 0.156) or sodium bicarbonate (+5 W, 95% CI: -4 to 13, p = 0.397). Mean power output during 6-min time trial was higher with caffeine (+12 W, 95% CI: 5 to 18, p = 0.001) and caffeine + sodium bicarbonate (+8 W, 95% CI: 0 to 15, p = 0.038), whereas sodium bicarbonate (-1 W, 95% CI: -7 to 6, p = 0.851) and creatine (-6 W, 95% CI: -15 to 4, p = 0.250) had no effects.

CONCLUSION

While creatine and caffeine can enhance sprint- and time trial performance, respectively, these effects do not seem additive. Therefore, supplementing with either creatine or caffeine appears sufficient to enhance sprint or short intense exercise performance.

Nutrition Recommendations for Table Tennis Players-A Narrative Review

Table tennis (TT) is the second most popular racket sport globally and was the sixth most widely played Olympic sport in 2005. It is an indoor racket sport requiring a mixture of power, agility, alertness and fast reactions. Players need to move quickly around a table to receive the ball and produce powerful returns. New rules such as increased ball size and a change in ball material have changed the ball's trajectory, increasing the overall duration and intensity of game play. Scientific research on TT is growing but there has been no systematic review of nutrition for the sport. This review provides nutritional recommendations for TT athletes based on the physiological demands of TT, including energy expenditure during training and competitions, and the main metabolic pathways of TT. Guidelines on the daily intakes of carbohydrate, protein and fat are discussed in addition to hydration strategies. Micronutrients of concern for TT athletes include iron, magnesium and vitamin D and their recommended intakes are also provided. The timing and dose of ergogenic aids that may improve TT performance such as caffeine, creatine, lutein and zeaxanthin and beta-alanine are reviewed. Specific nutritional strategies for intakes leading up to competitions, post training and competition recovery and nutritional strategies for travel are also addressed.

Nutritional Compounds to Improve Post-Exercise Recovery

The metabolic and mechanical stresses associated with muscle-fatiguing exercise result in perturbations to bodily tissues that lead to exercise-induced muscle damage (EIMD), a state of fatigue involving oxidative stress and inflammation that is accompanied by muscle weakness, pain and a reduced ability to perform subsequent training sessions or competitions. This review collates evidence from previous research on a wide range of nutritional compounds that have the potential to speed up post-exercise recovery. We show that of the numerous compounds investigated thus far, only two-tart cherry and omega-3 fatty acids-are supported by substantial research evidence. Further studies are required to clarify the potential effects of other compounds presented here, many of which have been used since ancient times to treat conditions associated with inflammation and disease.

Creatine supplementation elicits greater muscle hypertrophy in upper than lower limbs and trunk in resistance-trained men

BACKGROUND

Creatine (Cr) supplementation associated with resistance training produces greater muscular strength improvements in the upper compared with the lower body; however, no study has investigated if such region-specific results are seen with gains in muscle mass.

AIM

We aimed to evaluate the effect of Cr supplementation in combination with resistance training on lean soft tissue changes in the upper and lower limbs and trunk in resistance-trained young adult men.

METHODS

In a randomized, double-blind and placebo-controlled design, 43 resistance-trained men (22.7 ± 3.0 years, 72.9 ± 8.7 kg, 177.9 ± 5.7 cm, 23.0 ± 2.5 kg/m²) received either creatine (Cr, n = 22) or placebo (PLA, n = 21) over an 8-week study period. The supplementation protocol included a loading phase (7 days, four doses of 0.3 g/kg per day) and a maintenance phase (7 weeks, single dose of 0.03 g/kg per day). During the same period, subjects performed resistance training four times per week using the following two-way split routine: Monday and Thursday = pectoral, shoulders, triceps, and abdomen, Tuesday and Friday = back, biceps, thighs, and calves. Lean soft tissue of the upper limbs (ULLST), lower limbs (LLLST), and trunk (TLST) was assessed by dual-energy X-ray absorptiometry before and after the intervention.

RESULTS

Both groups showed significant ( p < 0.001) improvements in ULLST, LLLST, TLST, and the Cr group achieved greater ( p < 0.001) increases in these outcomes compared with PLA. For the Cr group, improvements in ULLST (7.1 ± 2.9%) were higher than those observed in LLLST (3.2 ± 2.1%) and TLST (2.1 ± 2.2%). Otherwise, for PLA group there was no significant difference in the magnitude of segmental muscle hypertrophy (ULLST = 1.6 ± 3.0%; LLLST = 0.7 ± 2.8%; TLST = 0.7 ± 2.8%).

CONCLUSION

Our results suggest that Cr supplementation can positively augment muscle hypertrophy in resistance-trained young adult men, particularly in the upper limbs.

The effects of creatine supplementation on thermoregulation and physical (cognitive) performance: a review and future prospects

Creatine (Cr) is produced endogenously in the liver or obtained exogenously from foods, such as meat and fish. In the human body, 95 % of Cr is located in the cytoplasm of skeletal muscle either in a phosphorylated (PCr) or free form (Cr). PCr is essential for the immediate rephosphorylation of adenosine diphosphate to adenosine triphosphate. PCr is rapidly degraded at the onset of maximal exercise at a rate that results in muscle PCr reservoirs being substantially depleted. A well-established strategy followed to increase muscle total Cr content is to increase exogenous intake by supplementation with chemically pure synthetic Cr. Most Cr supplementation regimens typically follow a well-established loading protocol of 20 g day(-1) of Cr for approximately 5-7 days, followed by a maintenance dose at between 2 and 5 g day(-1) for the duration of interest, although more recent studies tend to utilize a 0.3-g kg(-1) day(-1) supplementation regimen. Some studies have also investigated long-term supplementation of up to 1 year. Uptake of Cr is enhanced when taken together with carbohydrate and protein and/or while undertaking exercise. Cr supplementation has been shown to augment muscle total Cr content and enhance anaerobic performance; however, there is also some evidence of indirect benefits to aerobic endurance exercise through enhanced thermoregulation. While there is an abundance of data supporting the ergogenic effects of Cr supplementation in a variety of different applications, some individuals do not respond, the efficacy of which is dependent on a number of factors, such as dose, age, muscle fiber type, and diet, although further work in this field is warranted. Cr is increasingly being used in the management of some clinical conditions to enhance muscle mass and strength. The application of Cr in studies of health and disease has widened recently with encouraging results in studies involving sleep deprivation and cognitive performance.

Short-term creatine supplementation has no impact on upper-body anaerobic power in trained wrestlers

Background

Creatine (CR) is considered an effective nutritional supplement having ergogenic effects, which appears more pronounced in upper-body compared to lower-body exercise. Nevertheless, results regarding the impact of CR loading on repeated high-intensity arm-cranking exercise are scarce and in some cases conflicting. Interestingly, few of the conducted studies have structured their research designs to mimic real world sporting events. Therefore, our purpose was to address the hypothesis that CR ingestion would increase anaerobic power output in consecutive upper-body intermittent sprint performance (UBISP) tests designed to simulate wrestling matches on a competition-day.

Methods

In a double-blind, placebo-controlled, parallel-group study, 20 trained wrestlers were assigned to either placebo or CR supplemented group (0.3 g ∙ kg⁻¹ of body mass per day). Four 6-min UBISP tests interspersed with 30-min recovery periods were performed before (trial 1) and after 5 days (trial 2) of supplementation. Each test consisted of six 15-s periods of arm-cranking at maximal executable cadence against resistance of 0.04 kg ∙ kg⁻¹ body mass interspersed with 40-s unloaded easy cranking periods and 5-s acceleration intervals (T1–T4). Mean power (MP), peak power (PP), fatigue index and heart rate parameters were measured during UBISP tests. Also, body weight and hydration status were assessed. Principle measures were statistical analysed with mixed-model ANOVAs.

Results

Mean individual CR consumption in the CR group was 24.8 ± 2.5 g ∙ d⁻¹. No significant (P > 0.05) differences occurred in body mass or hydration status indices between the groups or across trials. MP, PP and fatigue index responses were unaffected by supplementation; although, a significant reduction in MP and PP did occurred from T1 to T4 in both trial 1 and 2 (P < 0.001). Overall heart rate responses in the tests tended to be higher in the CR than PLC group (P < 0.05); but, trends in responses in trials and tests were comparable (P > 0.05).

Conclusion

These results suggest that 5-day CR supplementation has no impact on upper-body muscle anaerobic power output in consecutive UBISP anaerobic tests mimicking wrestling matches on a competition day.

Effect of creatine malate supplementation on physical performance, body composition and selected hormone levels in spinters and long-distance runners

PURPOSE

The aim of the study was to determine whether creatine malate (CML) supplementation results in similar ergogenic effect in sprinters and long-distance runners. The other goal was to compare changes in body composition, physical performance and hormone levels after six-week training in athletes, divided into subgroups supplemented with creatine malate or taking placebo.

RESULTS

Six-week supplementation combined with physical training induced different effects in athletes. Significantly higher increases in relative and absolute peak power and total work (p < 0.05) were found in sprinters compared to other groups. Except for growth hormone, post-exercise venous blood serum hormone levels exhibited no statistically significant differences in athletes. After CML loading period, a significant increase in growth hormone was found in the group of sprinters.

CONCLUSIONS

A significant ergogenic effect was found in sprinters, which was reflected by the increase in anaerobic exercise indices and morphological indices and elevated growth hormone level, after graded exercise testing. The significant increase in the distance covered during graded test was only observed in supplemented long-distance runners, whereas no significant changes in maximal oxygen uptake, relative peak power and relative total work were noticed. This could be caused by later anaerobic threshold appearance in exercise test to exhaustion.

Efeitos da suplementação de creatina na força máxima e na amplitude do eletromiograma de mulheres fisicamente ativas

A suplementação de creatina apresenta ação ergogênica na força muscular. Entretanto, não há consenso deste efeito na força isométrica máxima e na amplitude do eletromiograma (EMG). Assim, o objetivo deste estudo foi analisar os efeitos da suplementação de creatina na força isométrica máxima e na amplitude do EMG em mulheres fisicamente ativas. Vinte e sete mulheres (idade 23,04 ± 1,82 anos, massa corporal 58,37 ± 6,10kg, estatura 1,63 ± 0,05m e índice de massa corporal 21,93 ± 2,02kg/m²) foram designadas aleatoriamente para os grupos creatina (GCr) (n = 13) e placebo (GPL) (n = 14), os quais ingeriram diariamente, durante seis dias, 20g de creatina mono-hidratada e 20g de maltodextrina, respectivamente. Antes e depois da suplementação, a força foi medida em um dinamômetro isométrico durante contração isométrica voluntária máxima (CIVM) de extensão unilateral do joelho (três séries de 6s intervaladas por 180s), com captação simultânea dos valores root mean square (RMS) do EMG obtido no músculo vasto lateral. A ANOVA de dois critérios de classificação (dois momentos x dois grupos) e o teste de Wilcoxon foram utilizados na análise estatística dos dados paramétricos e não paramétricos (p < 0,05). Após a suplementação, o GCr aumentou significativamente a força, com incrementos de 7,85% (p = 0,002), 7,31% (p = 0,001) e 5,52% (p = 0,001) para a primeira, segunda e terceira séries, respectivamente. Para este mesmo grupo, os valores RMS aumentaram significativamente na terceira série (p = 0,026). O GPL não apresentou alterações significativas. Os resultados sugerem que a suplementação de creatina aumenta a força isométrica máxima e que a amplitude do EMG pode ser utilizada como indicador dessas alterações de desempenho.

Effects of two and five days of creatine loading on muscular strength and anaerobic power in trained athletes

The purpose of this study was to establish the effects of 2 and 5 days of creatine loading, coupled with resistance training, on muscular strength and anaerobic performance in trained athletes. Seventeen trained men were randomly assigned to a creatine or a placebo group. The creatine supplementation group consumed 20 g of creatine per day (4 doses of 5 g per day), whereas the placebo group was given a placebo similar in appearance and taste over the 5-day supplementation duration. Anaerobic power and strength performance measures, in addition to blood and urine analysis, were conducted in the morning before the supplementation began and on the third and sixth day to establish the effect of 2 and 5 days of creatine loading, respectively. The study found that a 5-day creatine loading regime coupled with resistance training resulted in significant improvements in both average anaerobic power, as measured by the 30-second Wingate test and back squat strength compared with just training alone. However, 2 days of supplementation was not sufficient to produce similar performance gains as that observed at the end of 5 days of loading in trained men, despite increases in creatine uptake in the body. The standard 5-day loading regime should hence be prescribed to individuals supplementing with creatine for enhanced strength and power.

Creatine supplementation and exercise performance: recent findings

Creatine monohydrate (Cr) is perhaps one of the most widely used supplements taken in an attempt to improve athletic performance. The aim of this review is to update, summarise and evaluate the findings associated with Cr ingestion and sport and exercise performance with the most recent research available. Because of the large volume of scientific literature dealing with Cr supplementation and the recent efforts to delineate sport-specific effects, this paper focuses on research articles that have been published since 1999.Cr is produced endogenously by the liver or ingested from exogenous sources such as meat and fish. Almost all the Cr in the body is located in skeletal muscle in either the free (Cr: approximately 40%) or phosphorylated (PCr: approximately 60%) form and represents an average Cr pool of about 120-140 g for an average 70 kg person. It is hypothesised that Cr can act though a number of possible mechanisms as a potential ergogenic aid but it appears to be most effective for activities that involve repeated short bouts of high-intensity physical activity. Additionally, investigators have studied a number of different Cr loading programmes; the most common programme involves an initial loading phase of 20 g/day for 5-7 days, followed by a maintenance phase of 3-5 g/day for differing periods of time (1 week to 6 months). When maximal force or strength (dynamic or isotonic contractions) is the outcome measure following Cr ingestion, it generally appears that Cr does significantly impact force production regardless of sport, sex or age. The evidence is much more equivocal when investigating isokinetic force production and little evidence exists to support the use of Cr for isometric muscular performance. There is little benefit from Cr ingestion for the prevention or suppression of muscle damage or soreness following muscular activity. When performance is assessed based on intensity and duration of the exercises, there is contradictory evidence relative to both continuous and intermittent endurance activities. However, activities that involve jumping, sprinting or cycling generally show improved sport performance following Cr ingestion. With these concepts in mind, the focus of this paper is to summarise the effectiveness of Cr on specific performance outcomes rather than on proposed mechanisms of action. The last brief section of this review deals with the potential adverse effects of Cr supplementation. There appears to be no strong scientific evidence to support any adverse effects but it should be noted that there have been no studies to date that address the issue of long-term Cr usage.

Oral creatine supplementation and skeletal muscle metabolism in physical exercise

Creatine is the object of growing interest in the scientific literature. This is because of the widespread use of creatine by athletes, on the one hand, and to some promising results regarding its therapeutic potential in neuromuscular disease on the other. In fact, since the late 1900s, many studies have examined the effects of creatine supplementation on exercise performance. This article reviews the literature on creatine supplementation as an ergogenic aid, including some basic aspects relating to its metabolism, pharmacokinetics and side effects. The use of creatine supplements to increase muscle creatine content above approximately 20 mmol/kg dry muscle mass leads to improvements in high-intensity, intermittent high-intensity and even endurance exercise (mainly in nonweightbearing endurance activities). An effective supplementation scheme is a dosage of 20 g/day for 4-6 days, and 5 g/day thereafter. Based on recent pharmacokinetic data, new regimens of creatine supplementation could be used. Although there are opinion statements suggesting that creatine supplementation may be implicated in carcinogenesis, data to prove this effect are lacking, and indeed, several studies showing anticarcinogenic effects of creatine and its analogues have been published. There is a shortage of scientific evidence concerning the adverse effects following creatine supplementation in healthy individuals even with long-term dosage. Therefore, creatine may be considered as a widespread, effective and safe ergogenic aid.

Selection for high voluntary wheel-running increases speed and intermittency in house mice (Mus domesticus)

In nature, many animals use intermittent rather than continuous locomotion. In laboratory studies, intermittent exercise regimens have been shown to increase endurance compared with continuous exercise. We hypothesized that increased intermittency has evolved in lines of house mice (Mus domesticus) that have been selectively bred for high voluntary wheel-running (wheel diameter 1.12 m) activity. After 23 generations, female mice from four replicate selection lines ran 2.7 times more revolutions per day than individuals from four random-bred control lines. To measure instantaneous running speeds and to quantify intermittency, we videotaped mice (N=41) during a 5-min period of peak activity on night 6 of a 6-day exposure to wheels. Compared with controls (20 revs min–1 while actually running), selection-line females (41 revs min–1) ran significantly faster. These instantaneous speeds closely matched the computer-recorded speeds over the same 5-min period. Selection-line females also ran more intermittently, with shorter (10.0 s bout–1) and more frequent (7.8 bouts min–1) bouts than controls (16.8 s bout–1, 3.4 bouts min–1). Inter-bout pauses were also significantly shorter in selection-line (2.7 s) than in control-line (7.4 s) females. We hypothesize that intermittency of locomotion is a key feature allowing the increased wheel-running performance at high running speeds in selection-line mice.