Effects of a pre-and post-workout protein-carbohydrate supplement in trained crossfit individuals

Pomegranate extract, tart cherry extract, and green tea extract (caffeine plus catechins) have health benefits related to improved antioxidant function, improved body composition, and antiatherosclerotic properties (Guo et al.2008; Howatson et al.2010; Wang et al.2010). Pomegranate, containing nitrates and polyphenolics molecules (Sumner et al.2005), has been used by researchers to alter inflammation, interleukin-6, and the activity of antioxidants (Guo et al.2003). In one such study, researchers discovered that trained individuals had greater strength and less muscle soreness in the upper body (elbow flexor) after performing eccentric exercise when taking a pomegranate juice supplement compared to consumingthea placebo (Trombold et al.2011). Further analysis showed that there were no differences between consuming pomegranate juice and consuming a placebo on either lower body strength or muscle soreness (knee flexors). In an earlier study conducted by Trombold and associations, strength was greater at 48 and 72 hours post eccentric exercise-induced muscle damage (elbow flexor) after nine days of pomegranate extract supplementation versus placebo (Trombold et al.2010). Blood analysis did not reveal any difference between groups that could further explain the mechanism of action.

Other research suggests that pomegranate pure juice significantly reduced urinary free cortisol after one week of supplementation. Participants completed two 30-minute treadmill exercise sessions before and after seven days of consuming 500 ml/day of either pomegranate juice or water. Systolic and diastolic blood pressure were both reduced significantly after the supplementation period (Tsang et al.2011).

Antioxidant-rich cherry extract has been linked by researchers to decreased inflammation and recovery from intense exercise. In various studies, cherry supplementation led to improved recovery from exercise (Bowtell et al.2011), decreased pain while running (Kuehl et al.2010), and decreased strength loss after damaging exercise (Connolly et al.2006).

Polyphenols in green tea, similar to pomegranate or tart cherry extract, have been linked to antioxidant enhancement and may be responsible for the inhibited increase in creatine kinase and xanthine oxidase associated with exercise (Ichinnose et al.2011). Green tea extract also decreases respiratory exchange ratio during aerobic exercise after seven days of supplementation (Panza et al.2008). Jowko and associates gave untrained males a green tea extract supplement for four weeks and measured markers of exercise-induced oxidative damage. After four weeks of strength training and supplementation, an upper and lower body muscular endurance test was performed. The supplement group had increased plasma total polyphenols, antioxidant status, and decreased creatine kinase activity 24-hours post-exercise (Jowko et al.2011). In addition, green tea has known anti-obesity effects (Wolfram et al.2006).

Furthermore, protein and carbohydrate after a workout is known to increase lean body mass and replenish glycogen stores in trained individuals (Borsheim et al.2004a; Kerksick et al.2008; Campbell et al.2007; Tremblay et al.1994; Tarnopolsky et al.1997). Carbohydrate post-exercise (100 g) has been shown to decrease muscle protein breakdown compared to consuming a placebo (Borsheim et al.2004b) and a small dose of protein (10 g whey protein) plus carbohydrate (21 g) increases synthesis significantly (Tang et al.2007). According to the research, high-intensity exercise, similar to that performed during a CrossFit workout, combined with protein consumption leads to positive net protein balance (Hulmi et al.2010). The increased muscle protein synthesis and inhibited protein breakdown leads to increase fat-free body mass. Ivy’s research has demonstrated the increase in glycogen resynthesis when protein and carbohydrates are combined and consumed immediately post-workout (Ivy et al.2002) as well as the increase in muscle protein synthesis and muscle tissue repair (Ivy2001). Combining these benefits may have a positive impact on an athlete’s performance and body composition although research is lacking in regards to athletes participating in high-intensity training such as CrossFit. The purpose of the current study was to investigate changes in body composition, sport-specific performance, and aerobic and anaerobic capacity after six weeks of pre-workout and post-workout supplementation combined with varied, high-intensity exercise in trained CrossFit individuals.

All participants completed the study and compliance for nutritional intervention and weekly workouts was assured through post-workout surveys and diet logs. Analysis of the dietary journals suggested that daily intake of protein as well as carbohydrate intake significantly increased from T1 to T2 for the SUP group compared to CTL (Protein: +21.64 g vs -9.50 g, p = 0.023; Carbohydrate: +23.34 g vs -46.19 g, p = 0.016) while fat (g) and total calories did not change. The statistical analysis revealed that there were no group × time interactions for any of the measured variables. 95% Confidence Intervals and magnitude inferences revealed that the supplement had no effect on measures of body composition (% BF: p = 0.70, FM: p = 0.80, LM: p = 0.41). The supplement group recorded an increase of FFM of 1.67%, which is statistically insignificant, but may be of interest to highly trained individuals as the ability to make improvements decreases as performance and training status increase.

The pre-workout supplement plus the post-workout protein had likely beneficial effects on VO_2MAX (78.16%) during recovery period and Wingate peak power (73.40%) over the duration of the intervention timeframe based on statistical analysis (magnitude inferences and 95% confidence intervals). VO_2MAX was maintained from T1 to T2 for SUP whereas VO_2MAX decreased from T1 to T2 (Figure 1). Wingate peak power changes were also significant based on 95% Confidence Intervals. The performance in WOD1 and WOD2 were potentially meaningful with mean performance improvements in time in WOD1 of -38.79 sec (SUP; 5.85%) vs -8.62 sec (CTL; 2.39%) and +16.79 reps (SUP: 10.01%) vs +6.31 reps (CTL; 2.41%) in AMRAP in WOD2. Although the time to completion was not determined to be significantly different for WOD1 T1 to T2, changes in WOD2 performance were likely beneficial (84.95%) for the supplement group according to magnitude inferences (SUP: +9.59 ± 10.91 W; CTL: -0.88 ± 18.25 W). Wingate mean power values can be seen in Figure 2, WOD1 and WOD 2 data is presented in Figure 3.

After six weeks of on-going CrossFit training and pre- and post -workout supplementation, the supplement group had likely beneficial changes in measures of cardiorespiratory fitness, anaerobic power, and sport-specific performance. The pre-workout contains pomegranate fruit extract that is standardized for polyphenols and nitrates. Based on other research involving nitrates and performance, dietary nitrate can decrease the demand for oxygen during aerobic exercise, allowing the exerciser to become more efficient (Larsen et al.2007). Furthermore, dietary nitrate given for two days before testing lead to a small decrease in VO_2MAX but allowed the participants to exercise for a longer duration (Larsen et al.2010). When a nitrate supplement (beetroot juice) was given to eight adult men (19–39 years), time to exhaustion during severe exercise was improved, oxygen uptake at the onset of moderate exercise was reduced, and systolic blood pressure was reduced (Bailey et al.2009). These adaptations in oxygen consumption and efficiency would explain the maintenance on VO_2MAX in the SUP group and the decrease in the CTL group. It may be of interest for future researchers to investigate the effects of chronic dietary nitrates taken by trained CrossFit participants.

Improved recovery after muscle damaging exercise was seen by Bowtell and colleagues when participants were given either cherry juice concentrate or a placebo for seven days before inducing muscle damage of the knee extensors (Bowtell et al.2011). Maximum voluntary contraction force recovered more quickly in the supplement group than the placebo. The participants drinking cherry juice also had a lower absolute and percentage increase in protein carbonyls, a marker of oxidative stress resulting in the breakdown of amino acids (Dalle-Donne et al.2003). These results suggest that cherry juice can counteract the damaging effects of intense exercise. If applied to the current study, it seems possible that the pre-workout supplement assisted the participants in recovering from the previous exercise bout and this might be reflected in the better recovery of VO₂max and improvement of WPP from T1 to T2. It seems logical that if one can recover more-quickly from exercise, then he or she will be more prepared to handle the physical stress of the subsequent workout.

Cherry juice supplementation (7-d) has also been shown to decrease the pain associated with running long distances although it is unclear whether this benefit could transfer over to resistance training but is an area for future research (Kuehl et al.2010). Considering the nature of the daily workouts in this sport, it is clear that the study participants did not train specifically for the lab tests. Wingate peak power, which was analyzed as 73.4% likely beneficial (magnitude inferences), suggests that the supplement had positive effects on the anaerobic system when combined with workouts that are varied in nature compared to the control.

Green tea extract may have played a similar role as that of pomegranate and tart cherry extract in terms of enhanced antioxidant activity although plasma analysis would be needed to further assess this variable. Additionally, caffeine can have positive effects on alertness, focus, and concentration and the pre-workout used in this study provided 160 mg derived from the tea ingredients. Caffeine and caffeine-containing supplements are often used by athletes to enhance performance by delaying fatigue (Mohr et al.2010) and decreasing reliance on muscle glycogen stores (Goldstein et al.2010). Green tea may have had an effect on plasma free fatty acid levels, which have been reported to increase with green tea consumption (Murase et al.2006), but fatty acid levels were not measured during the present study. In the future, researchers should investigate plasma free fatty acid levels and measure glycogen storage while consuming the products used in the current study.

In a study investigating the effects of caffeine on high-intensity interval exercise (repeated Wingates), caffeine had no effect on the first two Wingates and had a negative effect on the last two compared to a placebo (Greer et al.1998). Further research should be done to determine if the caffeine in the current pre-workout supplement (160 mg) played a role in the improved WOD2 performance.

While the pre-workout supplement was not consumed before T2 testing, the enhanced glycogen stores from the post-workout supplement perhaps allowed the SUP group to generate more power during the Wingate test. This, of course, is speculative as muscle glycogen content was not measured during this study. The combination of carbohydrate and protein ingested after a workout session has shown to improve protein synthesis rates as well as increase glycogen re-synthesis (Campbell et al.2007) and future research should focus on the benefits of glycogen loading for CrossFit athletes and how to maximize the benefits through nutrition. Further research should also be done on the post-workout protein-carbohydrate supplement to determine the effects it has on glycogen stores during CrossFit training.

Additionally, consuming protein immediately post-exercise has been shown to increase lean body mass and create an overall anabolic environment when combined with resistance training (Willoughby et al.2007). The lack of significant body composition changes could be attributed to the calorie count of the post-workout protein and carbohydrate supplement as well as the overall eating habits of the participants. Male participants consumed four scoops (480 calories) and female participants consumed two scoops (240 calories) immediately after exercise. Factoring in the dietary changes of both groups, one potential issue could be differences in protein and carbohydrate intake. Protein and carbohydrate intake increased for SUP and decreased for CTL. This difference could be due to the fact that the CTL group was asked to not eat one hour before or after workouts, leading to a decrease in overall protein and carbohydrate consumption from T1 to T2. Future research should focus on energy needs of athletes participating in high-intensity functional resistance training similar to CrossFit to determine the most beneficial combination of protein and carbohydrate post-exercise.

One specific limitation to this study is the lack of a placebo-controlled group, although it is common for investigators to utilize an open-label design. With this is mind, there is the need for future research on the utilized supplements with both a supplement and placebo group.

The proprietary blend pre-workout supplement used in the present study may be beneficial for increasing power (74.40% likely beneficial) and maintaining VO_2MAX (78.16% likely beneficial) during CrossFit-type training. Further research should be conducted to determine what other sport-related benefits may be achieved with the proprietary blend supplements (recovery during extended competition, recovery from multiple WODs, etc.).