Outlaw, J. J., Wilborn, C. D., Smith-Ryan, A. E., Hayward, S. E., Urbina, S. L., Taylor, L. W., & Foster, C. A. (2014). Effects of a pre-and post-workout protein-carbohydrate supplement in trained crossfit individuals. SpringerPlus, 3(1), 369. doi:10.1186/2193-1801-3-369
Introduction: Combined intake of certain nutraceuticals around training sessions has been purported as a method to reduce muscle damage and improve performance. Specifically, pomegranate, tart cherry, and green tea extracts are believed to offer overall health benefits and potential performance enhancement. Pomegranate contains both nitrates and polyphenolic molecules which minimize inflammation, interleukin-6, reduce cortisol, and provide anti-oxidants. Additionally, it has been shown ingestion of pomegranate has increased strength and reduced muscle soreness following eccentric upper extremity based exercise in trained individuals. The same benefit was not found in lower extremity eccentric based exercise. Tart cherry extract has also been shown to reduce markers of inflammation and promote recovery following exercise. Supplementation has demonstrated improved exercise recovery, decreased pain while running, and reduced strength loss following exercise. Similarly, green tea extract has been shown to enhance antioxidant status and inhibit creatine kinase and xanthine oxidase associated with exercise. Additionally, green tea has exhibited the ability to decrease respiratory exchange ration during aerobic exercise following supplementation. Ingesting combined carbohydrate and protein is a common practice among trained individuals to promote muscle protein synthesis and restore glycogen levels. High intensity exercise combined with protein consumption results in a positive net protein balance. The increase in protein synthesis and reduction in protein breakdown leads to increases in lean body mass. Combining this strategy with the ingestion of pomegranate, tart cherry, and green tea extracts may be an ideal strategy to augment gains in lean body mass and maximize performance. Therefore, the purpose of this study was to investigate the changes in body composition, sport-specific performance, and aerobic and anaerobic capacity after six weeks of pre and post-workout supplementation combined with high-intensity exercise in trained CrossFit individuals.
The introduction section was done well. The authors were able to highlight the background information on the potential benefits of supplementing carbohydrates, protein, and the three extracts. It will be interesting to read the results as it is possible that combining three anti-oxidants pre-workout may be overkill. In regards to anti-oxidants, more is not always better. This reminds me of the majority of vitamin C data. Mega-dosing vitamin C around workouts tends to have a negative impact on training adaptation.
Subject Description: The study examined 29 subjects (n = 29, males = 13, females = 16; mean ± standard deviation; age: 31.87 ± 7.61 years; weight: 78.68 ± 16.45 kg;% body fat: 21.97 ± 9.02%). The study duration was 6 weeks. The subjects had been regularly participating in CrossFit at least 3 times per week and for a duration of 6 months. All subjects were considered healthy and did not consume dietary supplements which could influence performance over the past 3 months.
The subject description was done very well. The standard deviations were provided and the reader can see this was an experienced training group with an average age of 31. The details were provided for what the authors considered trained individuals (3 x week for 6 months).
Methods: A familiarization session was completed to reduce the learning effect. This session included a practice VO2max and Wingate power test. Testing included participants completing two workouts of the day (WOD1 and WOD2). WOD1 consisted of a 500m row, 40 wall balls, 30 push-ups, 20 box jumps, and 10 thrusters as quickly as possible. Time to completion was recorded in seconds. The subjects then rested for 20 minutes and completed WOD2. WOD2 consisted of an 800m run followed by as many rounds as possible (AMRAP) of 5 burpees, 10 kettlebell swings, 15 air squats within a 15 minute time frame. The number of completed repetitions was recorded for this workout. Baseline testing (T1) was performed within 48 hours of this workout which consisted of anthropometric, aerobic, and anaerobic testing. Testing included VO2MAX, Wingate, and body composition. These measures were repeated at the same time frame following the same WODs upon completion of the six-week study (T2). Dual-Energy X-ray Absorptiometry was used to record body fat percentage (%BF), fat mass (FM), and lean body mass (LBM). Maximal oxygen consumption (VO2MAX) was competed using a running treadmill test. The Bruce protocol was used for VO2 which consists of three minute stages with increasing speed and incline. VO2MAX was recorded in mL/kg/min. Fifteen minutes of rest was provided and then subjects completed the Wingate power test for anaerobic capacity. Wingate consisted of pedaling as fast as possible for 30 seconds with a constant load on the fly wheel [(0.7 N∙kg−1 body mass) × (participant’s body mass (kg)]. Peak Power (WPP) and mean power (WMP) were recorded in Watts. A four day diet log was completed prior to T1 and T2. A single day diet log (1-d) was completed on the last workout day of each week. Subjects were asked to record all food and beverage intake. A four day average was created for calories, protein, carbohydrates, and fat.
Subjects were matched according to sex and number of days they participated in CrossFit per week. Following matching subjects were randomly allocated to one of two groups supplement (SUP) or control (CTL). SUP group received a pre-workout supplement which was ingested 30 minutes prior to each training session (Dymatize, 19g, Pursuit Rx Pre-Workout). This supplement contained pomegranate fruit extract (NITRO2GRANIT), tart cherry extract, beet root extract, green tea extract (AssuriTEA™), and black tea extract (InnovaTEA®). Post-workout nutrition consisted of 20 g protein with 40 g carbohydrates for females and 40 g protein and 80 g carbohydrates for males (dymatize, recovery blend). Control group was instructed to refrain from supplementation during the study period and were to consume only water for one hour pre and post workout. After each workout subjects completed a perception of mood, rating of perceived exertion (RPE), and delayed-onset muscle soreness (DOMS) survey. The SUP group completed a supplement follow-up questionnaire at the end of each week to ensure adherence and to monitor side effects. Subjects were asked to continue participating in the average number of workouts participated in prior to the study (3-5). WODs were performed at the CrossFit gym and were different than WOD1 and WOD2.
The methods section was reported in detail with the exception of the training. The authors explained the pre and post-workout nutrition protocol. One issue is the confounding variables with the pre-workout supplementation. The introduction included background on green tea, tart cherry, and pomegranate extracts. Clearly, this pre-workout supplement contains black tea extract along with beet root, which provides nitrates. Nitrate supplementation may improve endurance by inducing vasodilation, improving blood flow, and reducing the oxygen cost of exercise. Supplementation of nitrates typically takes 2-3 hours to peak in the blood stream because it has to be digested, and then make its way to the mouth where it is converted into nitrite by bacteria. This is called the nitrite-nitrate pathway. Digesting nitrates 30 minutes pre-workout does not seem to fit this window and will likely provide little benefit. The training program was not monitored, and the workouts likely consisted of WODs created by the gym where the subjects were training. I would have much preferred a more structured, periodized program using either a linear, undulating, or block model. At the minimum I would have liked to see the training monitored and reported. Without monitoring the training, how can we expect there to be gains in specific tests such as VO2max and anaerobic power capacity if individuals are not training to improve them? Additionally, a power analysis would have given more insight into the authors’ choice of study size.
Results: All subjects completed the trial and adhered to the guidelines in regards to diet logs and supplementation. Protein and carbohydrate intake significantly increased in the SUP group compared to the control (Protein: +21.64 g vs −9.50 g, p = 0.023; Carbohydrate: +23.34 g vs −46.19 g, p = 0.016). Total fat and calories were not statistically significant. There were no group x time interactions for any of the measured variables. Supplementation had not effect on body composition (% BF: p = 0.70, FM: p = 0.80, LM: p = 0.41). SUP group had a non-significant increase in FFM of 1.67%. SUP group experienced a likely beneficial effect on VO2MAX (78.16%) and Wingate peak power (73.40%)(magnitude inferences). VO2MAX was maintained in the SUP group, while decreased for CTL. Wingate peak power changes were also significant based on 95% confidence intervals. Performance improvements in WOD1 and WOD2 were potentially meaningful with mean improvements in time of -38.79s for SUP compared to -8.62s for CTL and +16.79 reps (SUP: 10.01%) vs +6.31 reps (CTL; 2.41%) in AMRAP in WOD2. Time to completion was not statistically significant. WOD2 performance improvement was likely beneficial (84.95%) for SUP.
The results were adequately reported. The authors used a combination of statistical significance and magnitude analysis using confidence intervals to interpret the data. Tests of statistical significance revealed little benefit of the supplementation group with only Wingate peak power reaching significance. Magnitude testing revealed the supplementation group had likely benefits for performance in the WOD’s, VO2, and Wingate. The reduction in the CTL VO2MAX suggests the training most likely was not geared towards aerobic capacity. Without monitoring the training program there it is impossible to comment on the adequacy of the training.
Discussion: Six weeks of combined pre and post workout supplementation had likely beneficial changes in cardiorespiratory fitness, anaerobic power, and sport-specific endurance. The pre-workout supplement being high in polyphenols and nitrates demonstrated improved efficiency during exercise. This is consistent with previous work identifying dietary nitrate’s ability to reduce the demand for oxygen during aerobic exercise and improving time to exhaustion. The improvements in oxygen consumption explains the maintenance of VO2MAX in the SUP group and reduction in the CTL group. Future work should focus on chronic nitrate supplementation in CrossFit athletes. The influence of tart cherry may also help explain the recovery of VO2 and improvement in Wingate peak power. It appears logical to infer if the individual’s recovery improved following their workouts, they would be able to handle the subsequent testing better. From the results it is clear the subjects did not train specifically for the lab tests. It does appear pre and post supplementation had likely benefits on the anaerobic system, as demonstrated by the improvement in peak power and magnitude inference (73.4% likely). The authors also acknowledge the impact caffeine may have had on the performance increases. Caffeine supplements are often used to delay fatigue. Green tea extract probably had similar effects as pomegranate by increasing the anti-oxidant status of the subjects, although this would have to be analyzed with further testing. Although FFM increase did not reach statistical significance, the gain in FFM in the SUP group was 1.67%, which may be of importance to highly trained individuals. Limitations to this study include the lack of a placebo group. The CTL group was aware they were not being supplemented.
Conclusion: In conclusion pre and post workout supplementation combining pomegranate, tart cherry, green tea, carbohydrate, and protein leads to a likely benefit in CrossFit performance and fitness testing (VO2MAX, Peak Power). Further research should emphasis combined nutraceutical supplements ergogenic effects.
My Thoughts: There were some things I liked and some things I did not like about this study. First off, I thought the authors were bold in doing research on combined pre-workout and post-workout supplementation. I feel like this is the most likely real world scenario where individuals often ingest both pre and post workout nutrition. There should have been more testing to determine the effects of the pre-workout supplementation, such as tests for muscle damage, anti-oxidant status, and maximal strength or MVC. It would also be interesting to see if consumption of the anti-oxidants decreased muscle protein synthesis. This would in-part explain the minimal changes in lean body mass despite the SUP group consuming significantly more protein and carbohydrates (other than misinformation on total calorie intake). I did appreciate authors examining both statistical significance and tests of magnitude. Many times only the former is done. I was not a fan of the monitoring, or lack thereof the training, this could have led to individuals training differently and it is hard to interpret the true effects of the supplementation. Individuals training 5 days per week would get 5 dosages while 3 days a week would only get 3 dosages. This could play a huge part in the results. Additionally, I don’t think the nitrate explanation is adequate and the authors failed to address the fact it takes roughly 2-3 hours for dietary nitrates to peak. Not to mention digestion was most likely slowed due to the individuals working out 30 minutes post-ingestion. Lastly, the authors failed to account the increase in carbohydrate post-workout may have fueled better glycogen stores in the SUP group, resulting in the improved Wingate testing. It may not have been the extracts but the improved glycogen stores accounting for the difference.
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