Is caffeine mouth rinsing an effective strategy to improve physical and cognitive performance? A systematic review.

The aim of this study was to perform a systematic review on the effects of caffeine mouth rinsing on physical and cognitive performance. Following a search through 4 databases, 18 studies were found meeting the inclusion criteria (15 for physical performance and 3 for cognitive performance). All selected studies found an improvement in cognitive performance with caffeine mouth rinse. Four studies found positive effects of caffeine mouthwash on physical performance when repeated during exercise, while one study detected a positive effect with a single mouthwash before exercise, but only in a fasted state. Among these studies that showed positive effects, however, three (2 for physical performance and 1 for cognitive performance) presented fair methodological quality. There was also a variety of methodological approaches in the studies that showed no improvement in physical performance with caffeine mouth rinse, which may have influenced the potential to detect the ergogenic effect of caffeine mouth rinse. Thus, the effects of caffeine mouth rinse on physical performance are mixed, but a potential ergogenic effect might be present in a fasted state and when mouthwash is repeated during exercise. Concerning cognitive performance, caffeine mouth rinse seems to be a beneficial strategy.

Ice Massage on the Calf Improves 4-km Running Time Trial Performance in a Normothermic Environment.

Purpose: Local cooling with ice massage is a practical and inexpensive technique to decrease perceptual stress and improve motor performance in hot environments. However, it is unknown whether local cooling with ice massage reduces perceptual responses to exercise and improves performance in a normothermic environment. Thus, we investigated whether ice massage on the calf muscles before a 4 km running time trial (TT4km) reduced the ratings of perceived exertion (RPE) and perceived muscle pain, thereby improving exercise performance in a normothermic environment. Methods: After familiarizations, fourteen recreationally endurance-trained men (age = 21.3 ± 1.2 years; body weight = 67.5 ± 9.2 kg; height = 173.0 ± 5.0 cm) underwent two TT4km on a 400 m track in normothermic conditions with or without ice massage before the trial. The time of running, RPE, and pain perception were recorded every 400 m throughout the TT4km. Results: The local cooling with ice massage increased the mean speed (~ 5.2%, p = 0.03) and decreased the time to complete the TT4km (~ 5.5%, p = 0.03). Accordingly, ice massage also reduced the exercise-derived pain perception (p = 0.028), although no effect has been found in the RPE during the TT4km (p = 0.32). Conclusion: Together, these results showed that local cooling with ice massage before the exercise reduced the exercise-derived pain perception, enabling runners to increase the speed for a comparable RPE during exercise, thereby improving the TT4km performance in a normothermic environment.

Relationship between recovery of neuromuscular function and subsequent capacity to work above critical power.

PURPOSE: To investigate the relationship between the recovery of neuromuscular fatigue and the recovery of amount of work done above critical power (W´). METHODS: Ten healthy men performed, on different days, constant work rate exercises until task failure to determine critical power (CP) and W´. In the three following visits, participants performed two exhausting constant work rate exercises estimated to induce task failure within 6 min (P61 and P62), interspaced by 3, 6 or 15 min of recovery. Neuromuscular function was assessed before and periodically after the P61 using percutaneous electrical femoral nerve stimulation. The W´ recovery was measured from the total work performed above CP during the P62. RESULTS: The P61 induced a full use of W´ and a reduction in maximal voluntary contraction (MVC, - 19 ± 4%), voluntary activation (VA, - 6 ± 2%) and twitch force stimulated at 1 Hz (- 37 ± 11%), 10 Hz (- 50 ± 16%) and 100 Hz (- 32 ± 11%), when compared to baseline (P < 0.05). The time constant of VA recovery was significantly faster than the time constant of W´ recovery (P < 0.05), but there was no significant difference between the time constant of W´ recovery and the time constant of recovery of MVC or twitch force stimulated at 1, 10 and 100 Hz (P > 0.05). However, the time constant of W´ recovery was only associated to the time constant of MVC recovery (r = 0.73, P < 0.05). CONCLUSION: The W´ recovery is not associated to the recovery of peripheral or central fatigue alone. Rather, W´ seems to be associated to the recovery of the overall capacity to generate force.

Allometric Scale Corrects Performance Outcomes in Special Judo Fitness Test.

We compared results of Special Judo Fitness Test (SJFT) performance of young athletes of two different age categories after correcting body mass (BM) variations by allometric scales. Thirty young judokas (14.2±3.6 years) belonging to two age categories underwent an SJFT: under 15 (U15) years old (12.1±2.4 years; 46.5±15.6 kg; 152.4±11.2 cm) and under 21 years old (U21) (18.2±0.8 years; 77.1±23.5 kg; 174.2±8.9 cm). Allometric exponents of -0.33 and 0.67 were used to correct the influence of BM variations on SJFT performance results. After correction using the -0.33 exponent, U21 showed a higher number of throws (TNT) than U15 (85.5±9.9 and 68.8±12.0, p<0.05, respectively), although the SJFT index had been similar between these groups (67.3±10.1 and 61.7±8.1, p>0.05, respectively). In contrast, TNT normalized by the 0.67 exponent was higher in U15 than U21 (1.55±0.29 and 1.17 ± 0.25, p<0.05, respectively). Likewise, the SJFT index was higher in U15 than in U21 when using the same exponent (1.55±0.29 and 1.17±0.25, p<0.05, respectively). In conclusion, the -0.33 exponent may be useful to remove the influence of BM variations, thus discriminating SJFT performance results in U15 and U21 judokas. Moreover, the 0.67 exponent may overestimate SJFT indices in low-age judokas.

Caffeine increases both total work performed above critical power and peripheral fatigue during a 4-km cycling time trial.

The link between total work performed above critical power (CP) and peripheral muscle fatigue during self-paced exercise is unknown. We investigated the influence of caffeine on the total work done above CP during a 4-km cycling time trial (TT) and the subsequent consequence on the development of central and peripheral fatigue. Nine cyclists performed three constant-load exercise trials to determine CP and two 4-km TTs ~75 min after oral caffeine (5 mg/kg) or cellulose (placebo) ingestion. Neuromuscular functions were assessed before and 50 min after supplementation and 1 min after TT. Oral supplementation alone had no effect on neuromuscular function ( P > 0.05). Compared with placebo, caffeine increased mean power output (~4%, P = 0.01) and muscle recruitment (as inferred by EMG, ~17%, P = 0.01) and reduced the time to complete the TT (~2%, P = 0.01). Work performed above CP during the caffeine trial (16.7 ± 2.1 kJ) was significantly higher than during the placebo (14.7 ± 2.1 kJ, P = 0.01). End-exercise decline in quadriceps twitch force (pre- to postexercise decrease in twitch force at 1 and 10 Hz) was more pronounced after caffeine compared with placebo (121 ± 13 and 137 ± 14 N vs. 146 ± 13 and 156 ± 11 N; P < 0.05). There was no effect of caffeine on central fatigue. In conclusion, caffeine increases muscle recruitment, which enables greater work performed above CP and higher end-exercise peripheral locomotor muscle fatigue. NEW & NOTEWORTHY The link between total work done above critical power and peripheral fatigue during a self-paced, high-intensity exercise is unclear. This study revealed that caffeine ingestion increases muscle recruitment, which enables greater work done above critical power and a greater degree of end-exercise decline in quadriceps twitch force during a 4-km cycling time trial. These findings suggest that caffeine increases performance at the expense of greater locomotor muscle fatigue.

Novel equations to predict body fat percentage of Brazilian professional soccer players: a case study / Equações para predição de novo percentual de gordura corporal de jogadores brasileiros profissionais de futebol: um estudo de caso / Ecuaciones nuevas para predecir el porcentaje de grasa corporal de los jugadores brasileños profesionales de fútbol: un estudio de caso

This study analyzed classical and developed novel mathematical models to predict body fat percentage (%BF) in professional soccer players from the South Brazilian region using skinfold thicknesses measurement. Skinfolds of thirty one male professional soccer players (age of 21.48 ± 3.38 years, body mass of 79.05 ± 9.48 kg and height of 181.97 ± 8.11 cm) were introduced into eight mathematical models from the literature for the prediction of %BF; these results were then compared to Dual-energy X-ray Absorptiometry (DXA). The classical equations were able to account from 65% to 79% of the variation of %BF in DXA. Statistical differences between most of the classical equations (seven of the eight classic equations) and DXA were found, rendering their widespread use in this population useless. We developed three new equations for prediction of %BF with skinfolds from: axils, abdomen, thighs and calves. Theses equations accounted for 86.5% of the variation in %BF obtained with DXA...

"Equações para predição de novo percentual de gordura corporal de jogadores brasileiros profissionais de futebol: Um estudo de caso." O objetivo do estudo foi analisar e desenvolver novas equações para predição do percentual de gordura corporal (%G) em atletas profissionais de futebol do sul do Brasil usando medidas de dobras cutâneas. Dobras cutâneas de trinta e um atletas profissionais de futebol do sexo masculino (idade de 21,48 ± 3,38 anos, massa corporal de 79,05 ± 9,48 kg e estatura de 181,97 ± 8,11 cm) foram aplicadas em oito modelos matemáticos existentes na literatura para predizer o %G e comparados com valores de %G obtidos pela absortometria de raios-X de dupla energia (DXA). As equações clássicas levaram em conta 65 a 79% da variação do %G no DXA. Foram encontradas diferenças significativas entre sete das oito equações clássicas e DXA. Foram desenvolvidas três novas equações para predição do %G usando as dobras: Axilar, abdominal, coxa, e panturrilha. Estas equações levaram em conta 86,5% da variação do %G do DXA...

"Ecuaciones nuevas para predecir el porcentaje de grasa corporal de los jugadores brasileños profesionales de fútbol: Un estudio de caso." El objetivo de este estudio fue analizar las ecuaciones clásicas y nuevos modelos matemáticos para predecir el porcentaje de grasa corporal (% bf) en el futbolista brasileño del sur, utilizando espesores mediciones de pliegues cutáneos. Los bordes/ pliegues cutáneos de 31 jugadores hombres de fútbol profesional (edad de 21,48 ± 3,38 años, la masa corporal de 79,05 ± 9,48 kg y altura de 181.97 ± 8.11 cm) se introdujeron en ocho modelos matemáticos de literatura para la predicción del% BF; estos resultados fueron comparados con los rayos X de energía dual absorciometría (DXA). Las ecuaciones clásicas fueron capaces de dar cuenta del 65% al ​​79% de la variación del% BF en DXA. No se encontraron diferencias estadísticas entre la mayor parte de las ecuaciones clásicas (es decir, siete de ocho ecuaciones clásicas) y DXA, haciendo su uso generalizado en esta población sea inútil. Nosotros sugerimos tres nuevas ecuaciones para la predicción del% BF con pliegues desde: axilas, abdomen, muslos y la pantorrilla. Estas ecuaciones representaron el 86,5% de la variación en% GC obtenidos con DXA...

Effect of a reduced-CHO diet on the rate of perceived exertion curve during an incremental test.

The objective of this study was to evaluate the effect of a reduced-carbohydrate (reduced-CHO) diet on the rate of perceived exertion (RPE) curve during an incremental test. Nine physically active men performed a progressive incremental test on a cycle ergometer (25 W · 2 min(-1)) after 72 hr on either a control diet (60% CHO) or a reduced-CHO diet (30% CHO). Lactate and RPE thresholds were identified using the Dmax method (DmaxLa and DmaxRPE, respectively). Power output, heart rate and RPE scores in DmaxLa and DmaxRPE were similar between the diets and were not different from each other, regardless of the diet. Lactate values were consistently higher (p < .05) in the control diet compared with the reduced-CHO diet during power output after the lactate breakpoint; however, they were not accompanied by a proportional increase in RPE scores. These results suggest that DmaxRPE and DmaxLa are not dissociated after a short-period reduced-CHO diet, whereas the lactate values after the lactate threshold are reduced with a reduced-CHO diet, although they are not accompanied by alterations in RPE.

Validade de limiares de transição identificados a partir da frequência cardíaca / Validity of the Transition Threshold identified from the heart rate

O objetivo do presente estudo foi verificar a validade do uso do ponto de inflexão da frequência cardíaca (PIFC) na identificação do primeiro limiar de lactato (LL1) e do limiar de variabilidade da frequência cardíaca (LiVFC) em teste progressivo em cicloergômetro. Nove indivíduos (26,0 ± 4,1 anos; 175,9 ± 8,5cm; 76,2 ±15,1Kg; 12,9 ± 4,1 %G) desempenharam um exercício progressivo em ciclo ergômetro com carga inicial de 25 W e incrementos de 25 W/2minutos. O ponto de inflexão da FC (PIFC) foi identificado no Dmáx negativo na diferença entre um ajuste polinomial de 3° ordem e um ajuste linear de todos os pontos da relação FC/W; o limiar de variabilidade da FC (LiVFC) foi identificado no primeiro estágio no decréscimo da curva em que as diferenças entre o SD1 de dois estágios consecutivos fosse menor que 1 ms; o primeiro limiar de lactato (LL1) foi identificado na carga referente ao estágio que precede um aumento de 0,5 mmol.l-1. Não foram encontradas diferenças significativas entre a potência e a FC de ocorrência do PIFC, LiVFC e LL1 (104,4 ± 21,5, 136,1 ± 37,7, 125,0 ± 48,4 W e 118 ± 17, 131 ± 17 e 123 ± 21 bpm, respectivamente, p > 0,05). Entrentato, foi observado um amplo viés de identificação do PIFC quando comparado ao LiVFC e um pequeno viés da intensidade de ocorrência do PIFC e LL1 e não foram encontradas associações significativas entre as variáveis identificadas no PIFC e as variáveis identificadas no LL1 e LiVFC, p > 0,05. De acordo com esses resultados, PIFC é encontrado em intensidades abaixo do LL1 e LiVFC.

The aim of this study was to verify the validity in the use of the Heart Rate Inflexion Point (HRIP) to identify the first Lactate Threshold (LT1) and the Heart Rate Variability Threshold (HRVT) in a progressive test with cycle ergometer. Nine individuals (26.0 ± 4.1 years; 175.9 ± 8.5cm; 76.2 ±15.1Kg; 12.9 ± 4.1 Fat %) performed progressive exercise in the cycle ergometer, with initial load of 25 W with increments of 25 W every 2 minutes. The Heart Rate Inflection Point (HRIP) was found in the negative Dmax of the difference between the 3rd degree polynomial fit and the linear fit of all the points in the HR versus Power plot. The Heart Rate Variability Threshold (HRVT) was identified in the first stage of the curve where the difference between the SD1 of two consecutive stages was less than 1 ms. The First Lactate Threshold (LT1) was identified in the load of the last stage before an increase of 0.5 mmol.L-1.There were no significant differences between the power and the HR of occurrence of the HRIP, HRVT and the LL1 (104.4 ± 21.5 W, 136.1 ± 37.7 W, 125.0 ± 48.4 W and 118 ± 17 bpm, 131 ± 17 bpm, 123 ± 21 bpm, respectively, p > 0.05). Nonetheless, a high bias in the identification of the HRIP when compared to the HRVT and a small bias of the intensity of occurrence of the HRIP and LT1 were observed. No significant associations between the HRIP and LT1 and HRVT identification variables was found, p > 0.05) These results show that HRIP is found in lower intensities than the LT1 and the HRVT.

Efeito da baixa disponibilidade de carboidrato na dieta sobre o primeiro limiar de variabilidade da frequência cardíaca em teste progressivo em cicloergômetro / Effect of low carbohydrates availability on the diet over the first threshold of heart rate variability in progressive test in cycloergometer

O Objetivo do presente estudo foi analisar o efeito de uma dieta pobre em CHO sobre o primeiro limiar de transição fisiológica (LT1) identificado a partir da análise do comportamento da Variabilidade da Frequência Cardíaca (VFC) em teste progressivo em ciclo ergômetro. Para tanto nove sujeitos de 18 a 32 anos foram submetidos a dois testes em cicloergômetro com carga inicial de 25 W e incrementos de 25 W a cada dois minutos. O teste foi encerrado quando o indivíduo não acompanhava a rotação determinada (60 a 70 rpm) ou por exaustão voluntária. Os sujeitos realizaram os testes separados por um período de uma semana em duas diferentes situações de dietas (isocalóricas) por um período de 72 horas prévias aos testes de Dieta Normal (DN) e de Dieta Hipoglicídica (DH). As seguintes variáveis foram mensuradas: VFC a cada estágio para identificação do limiar de VFC (LiVFC) e as concentrações de lactato [La] sanguíneo para identificação do primeiro limiar de lactato (LL1). As variáveis analisadas foram a carga e a Frequência Cardíaca no LiVFC e LL1. Foram encontrados maiores valores para o LL1 e LiVFC quando expressos em cargas relativas para DH. Esses resultados sugerem que o LiVFC e o LL1 podem ser alterados com a manipulação dos teores de carboidratos na dieta.

The aim of the present study was to analyze the effect of a low carbohydrate (CHO) diet on the first physiological transition threshold (TT1) indentified by using analysis of the behavior of Heart Rate Variability (HRV) in progressive test on cycle ergometer. Nine subjects of 18 to 32 years underwent two cycle ergometer tests with initial load of 25W and increments of 25W every two minutes. The test was over when the individual could not follow the determined rotation (60 to 70 rpm) or for voluntary exhaustion. The subjects underwent the tests with an interval of one week in two different dietetic situations (isocaloric diets) consumed in a period of 72 hours prior to testing Normal Diet (ND) and Hypoglicidic Diet (HD). The following variables were measured: HRV at each stage to identify HRV threshold (HRVT) and blood lactate [La] concentrations to identify the first lactate threshold (LT1). The analyzed variables were load and Heart Rate in HRVT and LT1. Higher values were found for LT1 and HRVT when expressed by relative loads in HD. These results suggest that LT1 and HRVT can be modified by manipulating CHO levels in a diet.