Low(er) Carb Crossfitters May be Missing Out | 11.1% vs. 4% Rep Increase With 6-8g/kg CHO in 12-Min Rohoi Benchmark

If there's one thing all crossfit WODs have in common it's their profoundly anaerobic, meaning glucose burning, nature

I don't care if you love or hate Crossfit. Why's that? "Liking" has nothing to do with science and science tells us that CrossFit is a highly demanding continuously glycogenolytic workout. In other words: while you will be burning fat, as well, the Crossfit workouts are mainly powered by glucose / glycogen.

Accordingly, scientists from the University of New Mexico, the California State and the Kennesaw State University speculated that with glucose / glycogen being the main energy resource crossfitters are using, adequate (or high) carbohydrate intakes may be "even more crucial to performance" for crossfitters than it is for other athletes.

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Now, it is one thing to be able to show that an acute failure of glycogen repletion will acutely impair your performance. performance. It is a whole different thing, however, to assess the long(er)-term effect of the relatively low carbohydrate intake that's still prevalent in the world of crossfitters; a study addressing metabolic and performance variables following CHO manipulation during a CrossFit workout; a study as the one Escobar et al. have recently conducted.

In their 9-day experiment, the scientists investigated the effect of three consecutive days of high CHO intake (6-8 g/kg/day) during a period of training on CrossFit performance and corresponding metabolically-related variables in strength-trained individuals who have previously maintained a moderately-low CHO intake <6 g/kg/d.

The 12-minute Rahoi workout is used as a performance benchmark in the CrossFit community. It involves doing as many  rounds of the above box jump, thruster and bar facing burpee cycle (img from ifailedfran.com)

"CrossFit performance was measured in repetitions completed during a 12 minute CrossFit workout (Rahoi) performed on days 1, 5, and 9. From days 6- 8, the CHO group increased CHO intake from < 6 g/kg/day to 6-8 g/kg/day whereas the C group maintained their current intake of < 6 g/kg/day.

Subjects performed prescribed CrossFit workouts on days 6 and 7, followed by a day of rest prior to the final performance test on day 9. The present design was aimed to mimic a mid CrossFit-training period thereby investigating the effect of CHO intake and performance amidst a period of training.

During performance tests (days 1, 5, 9), in addition to repetitions completed, oxygen consumption (VO2), respiratory exchange ratio (RER), and blood lactate (BL) were measured" (Escobar. 2016).

As the authors point out, there was a main effect for time, meaning that both groups saw an increase in repetitions completed.

What about the "real long term"? Unfortunately, there is only one study that comes remotely close to an actual long-term study. It's Outlaw's et al.'s 2014 study in which crossfitters received 19 g of a pre-workout drink (extracts of pomegranate, tart cherry, green and black tea) 30 minutes before and a post-workout protein (females: 20 g; males: 40 g) and carbohydrate (females: 40 g; males: 80 g) with every workout. A study which found only likely beneficial (74.40%) for increasing power and maintaining VO2MAX (78.16%) during CrossFit-type training... and no, that's it: there ain't more research on CHO modifications and long(er)-term adapation to CrossFit workouts.

The data in Figure 1 tells you, however, "a more notable change was observed in the CHO group (+15.22; +10.9%) vs. that in the baseline sessions" (Escobar. 2016). That the difference didn't reach statistical significance is, as the scientists point out, possibly due to the large standard deviations and the small effect size (.354) in this 9-day study (you cannot expect a huge adaptational response within only what effectively were only 3 days, i.e. days 6-9 during which the subjects consumed their extra-carbs while training on day 6 and 7, rest on day 8 and the re-test on day 9).

Figure 1: Pre- vs. post changes in reps performed, Mean VO2 and respiratory exchange ratio (Escobar. 2016).

Needless to say that we cannot tell if the additional reps will translate to a more rapid adaptational response in form of strength or size gains. What is quite interesting, though, is that the high-CHO group improved their intra-workout fat burning rate (as evidenced by a lower RER) more than the subjects on the moderate carbohydrate diets. Diets of which common wisdom would tell you that their <6g/kg body weight CHO content should favor fatty acid oxidation compared to the 6-8g/kg high carbohydrate intake - that's also interesting, because, in a dietary isocaloric scenario, doing more reps and thus burning more calories at a slightly lower RER should promote not (as many of you  may fear) reduce fat loss. Eventually, future studies will have to show, though, whether this is "just" a transient performance increase due to better.-stocked glycogen stores or a training advantage that could give you the adaptational edge that makes the difference between "making gains" and "making outstanding gains" and thus, eventually, amateur- vs. pro-performance.

The number of studies on CrossFit has increased, but it doesn't match the 15-20x increase in interest Google Trends recorded from 2007 to today; below you will find a brief overview of recent and not so recent study results.

Speaking of gains, can you even make gains on CrossFit or will you just injure yourself? Well, even though the number of studies on CrossFit has been continuously increasing over the decade, what we can tell for sure is this:

• CrossFit-based high-intensity power training improves maximal aerobic fitness and body composition -- in Smith et al. 2013, for example, the male and female subjects lost 4% body fat (from 22%) and 3% (from 26%), respectively, while significantly improving their VO2max - irrespective of their baseline fitness level
• CrossFit workouts are injury-prone - not more injury prone than O-lifting, though -- that's at least what Hak et al. (2013) found; in their 2013 paper they report an injury rate of 3.1 per 1000 hours trained [shoulder (1.18 per 1000 hours training | Summitt. 2016) and spine injuries predominate] - a result that is "similar to that reported in the literature for sports such as Olympic weight-lifting, power-lifting and gymnastics [but] lower than competitive contact sports such as rugby union and rugby league" (Hak. 2013); more recently, Weisenthal, et al. (2014) reported injury rates of approximately 20%, with men being more prone to injuries than women (leave your ego at the door, boys!)
• CrossFit is so successful, because it's motivating -- Katie Heinrich et al. (2014) confirmed that two years ago in a study that compared a CrossFit™ workout to a classic aerobic + resistance training combination and found the former workout to keep people on track, i.e. they maintained their exercise enjoyment and were more likely to intend to continue after the 8-week intervention; and, more recently, Eather et al. (2016) showed that teens love it (rather the teen version), too - a satisfaction score ranging from 4.2 to 4.6 out of 5 points ain't bad, for sure
• CrossFit is not more taxing than running -- at least if we measure "taxing" by the oxidative stress that's generated during a workout, a measure of which Kliszczewicz, et al. (2015) have recently shown that they are similar for treadmill running and crossfitting

Now, this is not a CrossFit advertisment-article, so, I would like to remind you that, even if you're not CrossFitting, an increased or at least adequate carbohydrate intake will have scientifically proven benefits for athletes from various other sports - with the "optimal" intake depending on the pecularities of the sports / training and individual (Jeukendrup. 2014; Pöchmüller. 2016).

Want to put your carbs to good use? Try these "Two Crazy, but Scientifically Proven Workouts if You Want to Gain Muscle While Losing Fat" | more

Crossfitters, is it time to carb up? It's too early to answer this question with a clear "yes" or "no". The study at hand does, however, suggest that the "CrossFit-embraced practice of a moderately-low CHO diets such as the Paleolithic (Paleo) and Zone Diets (40% of daily energy intake)" (Escobar. 2016), may provide adequate CHO intakes during the short run (3 days); in periods of daily or almost daily training that last longer than 3 days, however, the observed trend of decreasing performance gains could be of concern. So, if 5-7 highly glycolytic workouts (CrossFit or not) a week sounds like you, it may at least be worth experimenting with an increased (not necessarily 8g/kg body weight ;-) CHO intake and/or strategic refeeds | Comment!

References:

• Eather, Narelle, Philip James Morgan, and David Revalds Lubans. "Improving health-related fitness in adolescents: the CrossFit Teens™ randomised controlled trial." Journal of sports sciences 34.3 (2016): 209-223.
• Escobar, Kurt A., Jacobo Morales, and Trisha A. VanDusseldorp. "The Effect of a Moderately-low and High Carbohydrate Intake on Crossfit Performance." International Journal of Exercise Science 9.4 (2016): 8.
• Hak, Paul Taro, Emil Hodzovic, and Ben Hickey. "The nature and prevalence of injury during CrossFit training." Journal of strength and conditioning research/National Strength & Conditioning Association (2013).
• Heinrich, Katie M., et al. "High-intensity compared to moderate-intensity training for exercise initiation, enjoyment, adherence, and intentions: an intervention study." BMC Public Health 14.1 (2014): 1.
• Jeukendrup, Asker. "A step towards personalized sports nutrition: carbohydrate intake during exercise." Sports Medicine 44.1 (2014): 25-33.
• Kliszczewicz, Brian, et al. "Acute Exercise and Oxidative Stress: CrossFit™ vs. Treadmill Bout." Journal of human kinetics 47.1 (2015): 81-90.
• Outlaw, Jordan J., et al. "Effects of a pre-and post-workout protein-carbohydrate supplement in trained crossfit individuals." Springerplus 3.1 (2014): 369.
• Pöchmüller, Martin, et al. "A systematic review and meta-analysis of carbohydrate benefits associated with randomized controlled competition-based performance trials." Journal of the International Society of Sports Nutrition 13.1 (2016): 27.
• Smith, Michael M., et al. "Crossfit-based high-intensity power training improves maximal aerobic fitness and body composition." The Journal of Strength & Conditioning Research 27.11 (2013): 3159-3172.
• Summitt, Ryan J., et al. "Shoulder injuries in individuals who participate in crossfit training." Sports Health: A Multidisciplinary Approach (2016): 1941738116666073.
• Weisenthal, Benjamin M., et al. "Injury rate and patterns among CrossFit athletes." Orthopaedic journal of sports medicine 2.4 (2014): 2325967114531177.

From 16% to 8% Body Fat in 10 Weeks: Crossfit Workout Gets The Leanest Shredded - But Only the Fittest Survive

Crossfit doesn't fit well with everyone. In  fact you have to be pretty fit already if you intend to benefit - specifically if you don't have someone who tailors the workouts to your specific needs. If you don't or are still miles apart from being fit, don't be bamboozled by the results of people who have been training for years.

This certainly sounds a little sadistic, but I hope you've been missing the Science Round-Up last Thursday. If that's the case, you will be happy to hear that Carl and I are back on track, and ready to talk about topics ranging from magnesium supplementation over the potentially fatal combination of NSAIDs and exercise and what's that got to do with gut health / integrity, how light therapy won't make you lighter, but help you cut body fat, how intense workouts compromise your sleep, and how intense sweeteners make you fat - at least if you add them on top of a Western diet. If we will have time, we will also take a look at how much protein it actually takes to preserve lean mass on a diet and how protein supplementation is not necessary and in a recently published study not even conducive to building muscle. And while these were only 50% of the news I've on my list of potential topics, I won't give away more... just tune in live at 1PM EST on the Super Human Radio Network.

Retracted! The study under scrutiny has been retracted in June 2017, because of lack of institutional review board approval and false reporting of injury data. According to the editors of the Journal of Strength and Conditioning Research (read more), the 11 dropouts obviously suffered the consequences of the (somewhat insane) training protocol - at least this is what a judge who ruled on the misreporting in 2016 apparently believes. This doesn't make the data useless, though... at least if we assume that the rest of the study wasn't tempered with.

For the time that remains and for those of you who are just arriving here after having listened to the live-stream, I still have a special goodie... have you ever pondered over the following question:

How much can you achieve within 10 weeks of training?

Even if you have already decided on a certain type of training, for example HIIT, you will have to adjust your routine to "Make HIIT a HIT" read Part I and Part II of the eponymous series and learn how to turn a HIIT workout into your HIIT workout to avoid overtraining and maximize its efficacy (learn more)

There is obviously no definite answer to this question. I mean, it goes without saying that we would first have to define, whether we are talking about muscle growth, overall conditioning, fat loss, etc. - what people often overlook, however it also depends on where you are coming from. Sometimes I feel like I am the only one who dares telling someone who's been "running" - in most cases this is rather sitting and driving - around at 2x his/her normal weight for years, is past his early 20s and has a life beyond working out and dieting is very unlikely to ever achieve a cover model physique. On the other hand, we've got the average trainee, who's been training for years has a high degree of leanness and is just about to see his sixpack shine through, who will necessarily make much smaller improvements within a given time-frame than his obese colleague who's just about to start working out for the first time of his/her life.

The previous paragraph should have made it quite clear, compared to the (overweight) beginner, an advanced trainee must invest much more thought into his/her diet and exercise regimen. That real intermittent fasting would probably be a better alternative for him/her than the "buffered every other day fat" has already been mentioned in yesterday's SuppVersity Article, but what about the exercise regimen?

Working out for fat loss and conditioning - Crossfit rules!

Fast paced high intensity workouts are gathering more and more momentum even outside of Crossfit gyms. Some of them may look somewhat "Jane Fonda", but as a previous review of the workout DVDs Insanity vs. TurboFire revealed, even hopping around in front of your TV set is more productive than the fat burning zone on the treadmill in next to your sofa (learn more)

Let's say he or she is working out primarily to increase his/her conditioning and drop a (if by any means possible) a significant amount of body fat? What would be the best way to train, then?

According to the results of a soon-to-be-published study from the  Ohio State University Health & Exercise Science in Columbus, Ohio (Smith. 2013), there is no question that this would be a Crossfit-esque workout - or, as the scientists refer to it, a crossfit-based high intensity power training (HIPT) program, they describe as follows:

"[...] a crossfit-based HIPT program using basic gymnastic skills (hand- stands, ring, and bar exercises) and traditional multiple-joint, functional, resistance exercises (squat, press, deadlift, Olympic lifts) performed as quickly as possible at a high intensity (low repetition, high percentage of 1-RM)." (Smith. 2013; my italics)

The 10-week program was varied so that some exercises were performed for a best time, and others were performed in the “as many rounds as possible” style (AMRAP; for a little more versatility check out Adelfo's EDT-CrossOver training) within anything from 10 to 20 minutes.

While there were no prescribe recovery times during the strength/skill portion of the exercise session, the WOD portion of the session did not allow for any real "rest" between the sets, as all the exercises were to be performed as quickly as possible.

Wow, who survived that? - Good question, indeed!

Only the fittest survive: Please do me a favor - If you are the aformentioned overweight person who's still carrying around another guy/gal's weight as body fat, don't even think of crossfitting, if you don't want to end up like 9 of the 11 dropouts (the study started with 54 participants), who retired willingly due to overuse or injuries, ok?

I guess you won't be surprised to hear that the 23 men and 20 women who survived and of whom the scientists state that they were "spanning all levels of aerobic fitness and body composition" were actually the typical already reaonably fit Crossfit clientele of whom Smith et al. somwhat awkwardly point out that they "had already been following a 'Paleolithic' type diet prior to and following completion of the training protocol." In other words the "levels of aerobic fitness" the participants spanned ranged from the untrained yet 100% healthy male with a VO2max of ~35 ml/kg/min to the hardcore crossfitter with a starting VOMax of >50ml/kg/min - the aforementioned heavily overweight and thus by now average (see "Obese is Going About to Become the New Normal") Westerner was yet not part of the study population.

Still, the presence of subject spanning the divide between "just healthy" and ripped and well-conditioned is in fact what attracts me as the author of a webpage that's dedicated to anyone ranging from those who just want to be / get / remain healthy and look not all-too shabby in front of the mirror to those who are looking to max out on their own physical performance and appearance. Long story short: The data you see in figure 1 is relevant for all of you. Even if you are still a couple of inches away from matching at least the initially criteria, you will sooner or later arrive at a point, where you'll find a representative counterpart of yours among the subjects of the study at hand.

Figure 1: Body fat percentage (left) and VO2Max (right) before and after the intervention (Smith. 2013)

I guess the data in figure 1 do actually speak for themselves: There is actually pretty much you can achieve within just 10-weeks of serious training: A significant (P<0.05) improvement of VO2max of 2.64% if you are a man and 11.78% if you are a women and (probably much sexier in the eyes of most of you) a 4% respectively 3% decreaes in body fat!

"To our knowledge no research on the aerobic benefits of HIPT has been conducted. HIPT focuses on high intensity resistance training usingmultiple joint exercises, with little to no focus on traditional aerobic activities. In spite of this, our results show that this type of training also provides aerobic and body composition benefits. Theincreased aerobic capacity of the subjects in our HIPT study were similar to those found in past research (Tremblay. 1994; Burgomaster. 2005). Based on the results presented here, individuals of all fitness levels and either gender can realize body composition and aerobic benefits from HIPT. Given that our subjects were following a Paleolithic diet, we cannot relate all of the observed weight loss to HIPT training. However, HIPT and Paleolithic diet in combination could be used to promote positive changes in body composition."

Now, all the scientists write is unquestionably true (also the part on the "paleo diet", as long as it is not very low carb paleo, cf. "Carbohydrate Shortage in Paleoland") and still, for me there are two things Smith et al. don't mention in the paragraph cited about and these are (A) the sex differences in terms of the VO2Max gains (maybe a result of the fact that women are not the ones who would otherwise do HIIT-esque workouts (=aerobic training at high intensities), so that the new stimulus will yield a greater results and (B) the fact that Crossfit is a workout regimen, from which even those benefit who are already fit and lean (keep in mind that the 16% in the lean group are for men and women, so that is lean!).

Bottom line: Crossfit appears to be the high intensity workout regimen which can help experienced trainees to make the transition from lean to ripped!

Want to do some more aerobics but also stick your classic weight lifting routine and just add cardio in? Now you are asking yourself, when this would make sense? Before, after or in between? Is that's you, go back in the SuppVersity archives and learn more.

As exciting as this may seem, a brief glance at the data in figure 1 will yet also tell you that those who are not up to the intensity and athletic demands of crossfitting don't just risk getting injured (please read the red box further up in the article, as well), they are also wasting their time with a workout that's not designed for their fitness level an will thus yield suboptimal results. This may not necessarily be the case in absolute terms - after all -4% body fat reduction certainly is not bad, but that's -4% from a pretty chubby baseline of 33% and actually could be achieved with basically any well-planned nutrition + exercise regimen. The latter obviously cannot be said of the -50% relative reduction in body fat percentage in the lean subjects on the other side of the "body fat divide". These men and women are most likely people who have been working out for all their lives in one way or another.

The "gifted ones" are in fact rather the ones who are often literally accused of being "genetically gifted" by accusers who simply don't take into consideration that it is above all the epigenetic priming of years of high school, college and other sports that renders them ostensibly resistant to the "obesity virus".

If you are still infected with the obsisty virus and have just found your way to physical culture you hardly qualify as one of those individuals by whom the original Crossfit workouts were created and are therefore certainly not among those people for whom these metabolically and technically demanding workouts were and still are designed. 

If you do "qualify", however (and that is nothing you have to be born wirth, I myself once believed that I just did not have the genes to see my abs), cross fitting could fit in particularly well in your "beach-ready" plan, of which I'd hope you are already thinking about... I mean, spring is less than 3 weeks away (click here to learn more about setting up a workout routine)!

Addendum: Since I got several people asking for the lean mass changes, I thought I'd mention that there was a +1kg increase in lean mass in men and women. Unfortunately the scientists don't provide differential information for lean and heavier subjects, but if your body fat percentage decreases you do at least have  to lose much more fat than lean mass and since there was no dieting involved, I bet the lean guys and girls did not lose any muscle..

References:

• Burgomaster KA, Hughes SC, Heigenhauser GJ, Bradwell SN, Gibala MJ. Six sessions of sprint interval training increases muscle oxidative potential and cycle endurance capacity in humans. J Appl Physiol. 2005 Jun;98(6):1985-90.
• Smith MM, Sommer AJ, Starkoff BE, Devor ST. Crossfit-based high intensity power training improves maximal aerobic fitness and body composition. J Strength Cond Res. 2013 Feb 22. 
• Tremblay A, Simoneau JA, Bouchard C. Impact of exercise intensity on body fatness and skeletal muscle metabolism. Metabolism. 1994 Jul;43(7):814-8.