The Effect of a Low Carbohydrate Beverage with Added Protein on Cycling Endurance Performance in Trained Athletes

Abstract

Ingesting carbohydrate plus protein during prolonged variable intensity exercise has demonstrated improved aerobic endurance performance beyond that of a carbohydrate supplement alone. The purpose of the present study was to determine if a supplement containing a mixture of different carbohydrates (glucose, maltodextrin, and fructose) and a moderate amount of protein given during endurance exercise would increase time to exhaustion (TTE), despite containing 50% less total carbohydrate than a carbohydrate-only supplement. We also sought post priori to determine if there was a difference in effect based on percentage of ventilatory threshold (VT) at which the subjects cycled to exhaustion. Fifteen trained male and female cyclists exercised on 2 separate occasions at intensities alternating between 45 and 70% VO2max for 3 hours, after which the workload increased to ∼74-85% VO2max until exhaustion. Supplements (275 mL) were provided every 20 minutes during exercise, and these consisted of a 3% carbohydrate/1.2% protein supplement (MCP) and a 6% carbohydrate supplement (CHO). For the combined group (n = 15), TTE in MCP did not differ from CHO (31.06 ± 5.76 vs. 26.03 ± 4.27 minutes, respectively, p = 0.064). However, for subjects cycling at or below VT (n = 8), TTE in MCP was significantly greater than for CHO (45.64 ± 7.38 vs. 35.47 ± 5.94 minutes, respectively, p = 0.006). There were no significant differences in TTE for the above VT group (n = 7). Our results suggest that, compared to a traditional 6% CHO supplement, a mixture of carbohydrates plus a moderate amount of protein can improve aerobic endurance at exercise intensities near the VT, despite containing lower total carbohydrate and caloric content.

Addition of Protein in Carbohydrate Supplementation Does not Improve Performance of Amateur Runners in Exercise above the Anaerobic Threshold

“…Some authors proposed an initial exercise protocol with a much longer time (≥ 120 minutes) and an intensity for the athletes to reach exhaustion at the end of exercise much lower (80 to 85% VO2Max) [9,11,12] when compared to the present study (60 minutes and 90% VO2Max, respectively). Another study [10] that also showed a positive effect on protein addition used this intervention in a chronic way (for 8 days) with ad libitum intake of the supplement making it difficult to compare with our research.…”

“…Study with trained cyclists verified that those who received CHO+PTN supplementation in an interval activity characterized by 45 to 75% of the Maximum Oxygen Consumption (VO2Max) with 3 hours of duration obtained a longer time to exhaustion (TTE) in a subsequent activity to 85% VO2Max when compared to groups that received only CHO or placebo (PLA) [9]. In line of this, other studies also found an improvement in performance after the addition of PTN in the CHO supplement [10,11,12]. On the other hand, other authors [13,14,15] did not observe improvement in the performance of individuals who received CHO+PTN supplementation.…”

Effects of Respiratory Muscle Warm-up on High-Intensity Exercise Performance

“…Volume of oxygen exhaled (VO2), volume of carbon dioxide exhaled (VCO2), RER, minute ventilation (VE), and HR were recorded using 15 s averages during the TTE. The TTE was terminated when the exerciser failed to maintain ≥60 revolutions per minute for five consecutive seconds [23,24]. Blood lactate was taken immediately after TTE was terminated.…”

Necesidades proteicas de los deportistas y pautas diétetico-nutricionales para la ganancia de masa muscular

“…En un estudio basado en una dieta hipocalórica, con un porcentaje de HC bajo (45-50%) y con un leve aumento de la ingesta proteica (13-20%), se observó un aumento del rendimiento deportivo en atletas femeninas 31 . Asimismo, en otros trabajos se señala que la adición de una ligera cantidad de proteína a las bebidas de reposición con concentraciones de un 6% de HC aumenta el rendimiento deportivo aun disminuyendo ligeramente la cantidad de HC de la ingesta diaria 32 . Las necesidades mínimas recomendadas de proteínas para los deportistas varían según el carácter del esfuerzo 33 .…”

“…En cuanto a la calidad de la fuente proteica, cabe destacar que, aunque las de origen animal suelen ser las más completas y de mejor valor biológico, las de origen vegetal pueden ofrecer la misma calidad o incluso superior siempre y cuando se acompañen de manera adecuada con diferentes grupos alimentarios, como es el caso de las legumbres con los cereales 40,50,75 , como podemos observar en la tabla 3. Según las evidencias publicadas, tras el entrenamiento sería conveniente añadir alimentos ricos en HC, junto con una pequeña cantidad de proteínas, para restablecer cuan-05 REVISION (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) to antes el balance anabólico. Para unas rápidas digestión y asimilación de estos alimentos se debería consumirlos en forma de bebida, con una proporción de HC:proteínas de 4-3 g:1 g 25,30 .…”