A Low Carbohydrate–Protein Supplement Improves Endurance Performance in Female Athletes

Exercise Physiology and Metabolism Laboratory, Department of Kinesiology and Health Education, The University of Texas at Austin, Austin, Texas, USA.
The Journal of Strength and Conditioning Research (Impact Factor: 2.08). 03/2011; 25(4):879-88. DOI: 10.1519/JSC.0b013e318207e98c
Source: PubMed


The purpose of this study was to investigate if a low mixed carbohydrate (CHO) plus moderate protein (PRO) supplement, provided during endurance exercise, would improve time to exhaustion (TTE) in comparison to a traditional 6% CHO supplement. Fourteen (n = 14) trained female cyclists and triathletes cycled on 2 separate occasions for 3 hours at intensities varying between 45 and 70% VO2max, followed by a ride to exhaustion at an intensity approximating the individual's ventilatory threshold average 75.06% VO2max. Supplements (275 mL) were provided every 20 minutes during exercise and were composed of a CHO mixture (1% each of dextrose, fructose, and maltodextrin) + 1.2% PRO (CHO + PRO) or 6% dextrose only (CHO). The TTE was significantly greater with CHO + PRO in comparison to with CHO (49.94 ± 7.01 vs. 42.36 ± 6.21 minutes, respectively, p < 0.05). Blood glucose was significantly lower during the CHO + PRO trial (4.07 ± 0.12 mmol · L(-1)) compared to during the CHO trial (4.47 ± 0.12 mmol · L(-1)), with treatment × time interactions occurring from 118 minutes of exercise until exhaustion (p < 0.05). Results from the present study suggest that the addition of a moderate amount of PRO to a low mixed CHO supplement improves endurance performance in women above that of a traditional 6% CHO supplement. Improvement in performance occurred despite CHO + PRO containing a lower CHO and caloric content. It is likely that the greater performance seen with CHO + PRO was a result of the CHO-PRO combination and the use of a mixture of CHO sources.

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    • "This may have then led to a more rapid and thorough recovery, contributing to the likely improvement in subsequent time-trial performance. Significantly lower heart rate during 3 h of varied-intensity cycling (McCleave et al. 2011) and a reduced RPE (Martínez-Lagunas et al. 2010) with CHO+PRO when compared with CHO have been reported previously. It has been suggested that adding PRO to beverages may produce synergistic effects with CHO that improve CHO, electrolyte, and fluid uptake and utilization (Saunders 2007). "
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    ABSTRACT: Researchers have focused primarily on investigating the effects of coingesting carbohydrate (CHO) and protein (PRO) during recovery and, as such, there is limited research investigating the benefits of CHO+PRO coingestion during exercise for enhancing subsequent exercise performance. The aim of this study was to investigate whether coingestion of CHO+PRO during endurance training would enhance recovery and subsequent exercise performance. Ten well-trained male cyclists (aged 29.7 ± 7.5 years; maximal oxygen uptake, 66.2 ± 6 mL·kg(-1)·min(-1)) took part in a randomized, double-blind, cross-over trial. Each trial consisted of a 2.5-h morning training bout during which the cyclists ingested a CHO+PRO or energy-matched CHO beverage followed by a 4-h recovery period and a subsequent performance time trial (total work, 7 kJ·kg(-1)). Blood was collected before and after exercise. Time-trial performance was 1.8% faster in the CHO+PRO trial compared with the CHO trial (p = 0.149; 95% CI, -13 to 87 s; 75.8% likelihood of benefit). The increase in myoglobin level from before the training bout to after the training bout was lower in the CHO+PRO trial (0.74 nmol·L(-1); 95% CI, 0.3-1.17 nmol·L(-1)) compared with the CHO trial (1.16 nmol·L(-1); 95% CI, 0.6-1.71 nmol·L(-1)) (p = 0.018). Additionally, the decrease in neutrophil count over the recovery period was greater in the CHO+PRO trial (p = 0.034), and heart rate (p < 0.022) and rating of perceived exertion (RPE) (p < 0.01) were lower during training in the CHO+PRO trial compared with the CHO trial. Ingesting PRO, in addition to CHO, during strenuous training lowered exercise stress, as indicated by reduced heart rate, RPE, and muscle damage, when compared with CHO alone. CHO+PRO ingestion during training is also likely to enhance recovery, providing a worthwhile improvement in subsequent cycling time-trial performance.
    Full-text · Article · Jun 2013 · Applied Physiology Nutrition and Metabolism
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    • "A limited number of runningbased investigations were instigated, notwithstanding the fact that they showed significant improvements when a CHO plus protein (CHO-P) beverage was compared with CHO matched in their CHO content (Betts et al. 2007) or caloric equivalency (Niles et al. 2001). More recently, protein coingestion was shown to maintain the efficacy of a CHO beverage, even when both CHO and caloric contents were reduced (Martínez-Lagunas et al. 2010; McCleave et al. 2011). Overall , there is clear evidence of an ergogenic benefit of CHO-P supplementation during exercise (Stearns et al. 2010) and following short-term recovery (Williams et al. 2003; Betts et al. 2007) when time to exhaustion is the performance measure. "
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    ABSTRACT: The majority of football players succumb to fatigue towards the end of the game. This study was designed to examine the influence of protein coingestion with carbohydrate (CHO) vs. an isocaloric CHO supplement on subsequent running capacity towards the end of a simulated football match. Six male amateur football players participated in 3 trials applied in a randomized cross-over experimental design. A laboratory-based, football-specific intermittent exercise was allocated for 75 min interspersed with a 15-min recovery, immediately followed by run time to fatigue (RTF) at 80% peak oxygen consumption. In each trial, prior to exercise and during half-time, participants randomly ingested a placebo (PLC), 6.9% CHO, or 4.8% CHO plus 2.1% protein (CHO-P) supplements matched for color and taste. CHO-P resulted in longer RTF (23.02 ± 5.27 min) than did CHO (16.49 ± 3.25 min) and PLC (11.00 ± 2.80 min) (p < 0.05). Blood glucose was higher in CHO-P at the point of fatigue (4.68 ± 0.64) compared with CHO and PLC (3.92 ± 0.29 and 3.66 ± 0.36, respectively; p < 0.05). Ratings of perceived exertion were lower in the CHO-P subjects at the onset of exercise and towards the end of intermittent exercise when compared with the PLC and CHO subjects (p < 0.05). When protein was added to a CHO supplement, subsequent running capacity following limited recovery from intermittent exercise was enhanced. This improvement suggests that protein coingestion may exert an ergogenic benefit upon endurance capacity during intermittent activity.
    Full-text · Article · Oct 2011 · Applied Physiology Nutrition and Metabolism
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    ABSTRACT: The objective of the study is to identify the changes in the nutritional parameters and the physical condition of teenage players after eating fishmeal as a nutritional complement. For this purpose, a quasi-experimental study, blinded for investigators, was conducted, involving 100 teenage football players, divided in two groups, homogeneous in terms of all study parameters, one of which received fishmeal for four months. After evaluating the nutritional status and physical condition, before and after the intervention, no change was found in the nutritional and anthropometric status or laboratory results, or in the physical condition. However, those who received fishmeal did report a change in their hemoglobin and hematocrit levelsin comparison to the control group. In conclusion, the consumption of fishmeal did not lead to changes in the nutritional status or the physical condition of teenage football players.
    Preview · Article · Mar 2013 · Revista peruana de medicina experimental y salud publica
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