Science in Crossfit: Research review: Part 1

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

Crossfit has been around for 10 years and has evolved massively within this time, what once seemed just random is now specifically programmed for a desired outcome. With this evolution has come a deeper interest in the science of performance specifically in the sport of Crossfit, previous research from other sports was taken and applied to Crossfit as best it could, but this approach could never fully answer the questions asked by coaches and athletes due to the complex interaction of all the part that make us the sport or Crossfit rather than simply looking at the parts insolation. For example, A study that showed an improvement in a rowing time trial could never be fully applied to improving a workout like ‘Jackie’ because of the other variables involved in that workout.

Fortunately, more and more research is being carried out directly on Crossfit performance, both from a nutritional and strength and conditioning standpoint, which makes the application of the results a little easier to apply, although not without it limitations.

This article will cover a study carried out by Outlaw et al, 2014, which looked at how pre and post workout supplementation would affect performance.

Common belief says that we have some fuel in the tank to use up before a training session, while also provide ergogenic substances that may improve performance by one mechanism or another above and beyond their caloric value, for example, improve buffering capacity of metabolic waste products, improving rate of muscular contractions, allowing the regeneration of high energy compounds within muscle tissue between sets and rounds. Once the session has finished its been widely suggested that we should get some more fuel in the tank to kick start the recovery process, restoring depleted muscle glycogen stores, helping to prevent further muscle breakdown and kick starting the re-building process while ensuring we are fully hydrated. The net effect is improved performance, faster recovery and a greater overall training stimulus over the course of a training cycle to allow the body to adapt to.

Kratos Fuel RXD Tropical Orange

One sure fire way to ensure your protein intake is used efficiently would be to bookend your training session with protein (and or carbs depending on diet set up). This allows the muscles to have a constant supply of available amino acids and has been shown to be a pretty effective at helping with increasing recovery and muscular gains by reducing muscle breakdown and helping muscle building.  Interestingly for us Crossfitters, a recent study looking at timed nutrition for Crossfit athletes was carried out late last year. The study found that consuming a supplement containing amino acids, anti- oxidants and polyphenols pre-training and a second supplement containing carbs, protein (20g protein 40g carbs for women, 40g protein 80g carbs for men) post training for 6 weeks led to improvements in aerobic endurance and anaerobic power as shown by a 38 second improvement in test WOD 1 (500 m row, 40 wall balls, 30 push-ups, 20 box jumps, 10 thrusters for time) and 16 reps more for test WOD 2 (15 minutes to complete an 800 m run “buy in”, followed by a AMRAP of 5 burpees, 10 Kettlebell swings, 15 air squats compared to the subjects that didn’t receive the supplements, while improving fat free mass by 1.67% (which was deemed non-significant by the stats). However it is important to take the results of this study with a pinch of salt and use it to explore timed nutrition for Crossfitters rather than taking the results as fact as the study had a few limitations such as a small sample size, no calorie matched double blind placebo, possible learning effect of the WOD’s for the rests (i.e. better strategy or pacing), all of which can affect the validity of a research study. So although improvements were made we can’t 100% be sure they were as a result of the timed nutrition.

Kratos Blackcurrant Recovery

So in short, it provides clues about how timed nutrition might help Crossfit athletes but doesn’t provide concrete information about the specific nature of how or why. Hopefully further studies will shed new light on this area in the future.

Supplements have their place when performance is the main focus, but these will have little impact on performance outcomes if the following factors aren’t focused on first

  • Total calorie intake
  • Total protein intake
  • Carb intake relative to training volume and goals
  • Overall quality of the diet (vitamins / minerals / fibre / hydration)
  • Training programme / Recovery Protocol (sleep / massage  / stress management)
  • Nutrition time


Outlaw JJ, Wilborn CD, Smith-Ryan AE, Hayward SE, Urbina SL, Taylor LW, Foster CA. Effects of a pre-and post-workout protein-carbohydrate supplement in trained crossfit individuals. Springerplus. 2014 Jul 21;3:369


Caffeine and Crossfit

Caffeine is a bit of a doubled edged sword, some people feel it gives them superpowers while others just get the jitters.

The use of caffeine is becoming more and more common among those looking to find a legal edge, there are 1000′s of studies that have been carried out on the safety and effectiveness of caffeine within sport, fitness and weight management, many crossfitters are now using caffeine to get more reps, faster times and lift more weight but it is important to note caffeine use has both pro’s and con’s that need to be considered before using it as a potential performance enhancing aid.




Positive Aspects of Caffeine

  • May encourage increased use of fat for fuel during exercise: caffeine causes adrenaline release and switches on the sympathetic nervous system (SNS) which helps to free up and burn fat, the benefit of this for crossfit is it may allow glycogen to be spared for the later end of training or event when we are pushing past the red line for the final couple of minutes.
  • May reduce perception of effort during exercise: making training feel easier at a relative intensity is a huge psychological boost, especially during longer EMOM’s / Met Con or mono-structural intervals.
  • May improve exercise endurance: The combination of the 2 above points leads to improved endurance which has been found repeatedly in research settings and carried over to real world event ranging in time frames and intensities.
  • May improve muscular strength: Due to its effect on the central nervous system (CNS) caffeine may help improve neural muscular recruit allowing bigger weights to be lifted.
  • May improve motivation to exercise. Caffeine causes the release of dopamine which acts on the reward and motivation regions on the brain.
  • Caffeine taken post training with carbs may promote increased levels of glycogen storage which could be useful on competition days when time between events is short and restoring depleted glycogen is important to allow high levels of performance across a full competition.

All these things can add up to lead to a noticeable improvement in athletic performance and this why caffeine is one of the key active ingredients in pre workout supplements

coffee 1

Negative Aspects of Caffeine

For some people however, caffeine can lead to some negative side effects, these are related to a person’s ability to metabolise caffeine (effecting how long it stays in the body for) or how sensitive they are to a specific dosage.

  • Caffeine acts on the CNS, this is what in part provides the positive effects by switching on the ‘Fight and flight: Sympathetic Nervous System’ branch of the CNS, but by doing this it will also shut down the ‘Rest and Digest: Parasympathetic Nervous System’ branch of the CNS. For some sensitive to caffeine this can cause the following issues
  • Spikes in heart rate: Potential issues with red lining at a slightly lower speed or intensity, more of an issue during short, fast met cons.
  • Cotton mouth: Salivary product is controlled by the PNS, hence caffeine can shut this down, Trying to Met Con / 2km Row with cotton mouth isn’t fun
  • Potential issues with grip: Caffeine causes vaso-constriction of the blood vessels, which can limit blood flow to the working muscles, this can be a nightmare for high rep pull up bar or barbell movements (17.2 anyone?)
  • The need to spend more time practicing your ‘toilet squat’, Caffeine acts on the SNS which also controls how the smooth muscles of the small and large intestine contract, helping move food through the digestive track to the ‘finish line’, this is why some of the super high caffeine pre-workout supplements used in the bodybuilding world have the nick name ‘super-dump 250’
  • Sleep is controlled by the PNS, hence to much caffeine or caffeine taken to close to bed can cause issues with (1) Getting to sleep and (2) Preventing us from getting in the deep more restorative stages of sleep, so even if your one of those people that does think caffeine keeps you awake, its can still have a detrimental effect on sleep quality.
  • Caffeine isn’t fuel: This may seem a little contradictive to some of the points made regarding the positive aspects of caffeine and fat burning, but caffeine doesn’t provide us with energy, its helps us obtain more energy (loosely speaking) from the energy we already have available. A potential issue with chronic caffeine use is that people use it as a crutch to gain energy at times when they feel they have none, this could be because of poor nutritional intakes and athletes simply aren’t meeting the calorific requirements for their training volume or they have poor sleep habits and are tired as a result of poor sleep quantity and quality. Caffeine in these situations is a case of treating the symptom (tiredness, lack of energy) rather than the cause (lack of quality food and sleep). ‘Kratos RXd: Fuel’ aims to help provide energy via carbohydrates along with a sensible amount of caffeine, ensuring training is powered by its preferred energy source and not simply replying of excessive caffeine intake.
  • Caffeine can become addictive, caffeine is the world’s most widely consumed drugs, it is socially acceptable and readily available, but like all drugs is can lead to tolerance, meaning larger and larger doses are required to get the desired effect or ’buzz’, but caffeine is one of those drugs that has a ceiling of tolerance, meaning there is a threshold dosage after which no further intake will lead to additional  benefits, this is commonly seen when people get a buzz from 1 cup of coffee, after a while they no longer get that buzz from one cup, instead they need two. Before they know it they can have 4-5 cups of caffeine and still not feel ‘wired’. At this point the only way of re-establishing the effects is to abstain from caffeine for 3-4 weeks, which can cause withdrawal symptoms such as headaches, fatigues and cravings for caffeine. High caffeine pre-workout supplements are notorious for this, leading to people double or triple scooping an already high caffeine product, this may lead to maintaining the positive aspects of caffeine but it also increases the adverse side effects of caffeine to.
  • Caffeine dependence. How many times have you heard people not ne-able to train or feel they have had a poor session if they haven’t had their pre training caffeine hit? This is  partly because of the points mentioned above, but it is also caused by a habit loop being formed

Have pre wod caffeine > Have a great session / hit a couple of PB’s > Association

The more this happens, the stronger then association becomes to the point where people feel they can’t have a good training session without the using caffeine before they train, if they do manage to train without it they feel the session was flat and not as sharp compared to a caffeine powered session.



Take Home Points

  • Before using caffeine pre training, decide whether it actually helps your performance as an individual or whether you simply take it out of habit. For some it may help performance, yet for others it has the potential in hinder it. Know which camp you’re in
  • Caffeine has the ability to improve strength, endurance, reduce perception of effort and training related pain while also improving the bodies ability to utilise fat for fuel. This can add up to improvements in performance for everything from a 1 rep max lift through to a marathon row.
  • For those sensitive to caffeine, the adverse effects of caffeine may occur at a relatively small dose, and although they are unlikely to cause long term harm, they may be uncomfortable at the time and lead to impaired performance.
  • If you do not regularly use caffeine pre training, don’t use it on a competition day if you are provided with free samples
  • Negative aspects of caffeine are mostly likely to occur when more caffeine is consumed than normal. The positive aspects of caffeine can be obtained with relatively small caffeine intakes (1 strong black coffee) approximately 30-60 minutes prior to the start of training.
  • If you are looking to reduce caffeine intake it is advisable to do so slowly to avoid withdrawal symptoms (headaches, lack of energy, mood swings, irritability). Switching from normal to half caf coffee, then from half caf to decaf coffee, or by swapping one of your regular cups of coffee during the day to decaf, then progressively having more decaf and less normal coffee could do this.
meal prep 1

Nutrition Basics: Setting the Foundations

These days you can’t open a magazine or newspaper without seeing a nutrition related article, and while this is helping inform us about some of the basics regarding healthy eating, it can also lead to confusion, misunderstandings and constant conflicts in advice or recommendation. This often causes us not knowing which advice to follow and which to dismiss.


What’s fact and what’s fad?

There are many different diets that are becoming more and more popular, the majority are based on some ‘loose science’ that has been tweaked and changed to support the authors concept. Many of these ‘fad diets’ rely restrict of certain foods or food groups in hope that it is these specific foods or groups that causes health issues or prevent weight loss, where in fact removal of these things helps reduce calorie intake which ultimately leads to weight loss or improvement in health. The exception to this is if a genuine food intolerance or allergy has been diagnosed and the removal of a specific foods or group will have additional benefits to health over and above simply the removal of calories.

Fad diets are often overly restrictive and have a set of rules that need to be followed in order to be successful; this can often make them difficult to adhere to and can lead to guilt or feelings of failure if these rules can’t be followed. Another thing fad diets often fail to mention is a balanced approach to nutrition, sadly a balanced diet doesn’t sell books or make the front page of a magazine but the realist is that a balanced approach to the foods we eat not only in food choices or portions but also the balance its plays in our lives and how easy they are to follow or enjoy special occasions with friends and family.


What is a balanced diet?

A Balanced food intake and lifestyle (rather than diet, which implies and start and an end point) provides:

  • A combination of fats, proteins and carbohydrates to adequate amounts based on your goals and activity levels
  • A wide variety of colours, textures and flavours which helps ensure a full range of vitamins and minerals are included in a eating plan
  • The correct amount of foods and controlled portions to be eaten, ensuring you are not excessively hunger, feeling deprived or restricted
  • Flexibility for you to enjoy any food within reason with a specific situation, allowing you to make an informed choice about whether you want to eat something or not.

Two set or guidelines that provide a balanced approach to healthy eating are the Eat well Guide, which are the government recommendations and B.A.N.T guidelines (British association of Applied Nutrition and nutritional therapy). Although they different slightly on their details the main message of both organisations is balanced approach to what we eat is vital for health, weight loss or performance and that no food is truly off limits in eaten to appropriate amounts. Common themes across both sets of guidelines

  • Eat a wide range of fruit and vegetables – The more colourful the better
  • Include starchy carbohydrates and base intake to activity level.
  • Include Lean protein such as chicken, turkey, lean red meat and fish often.
  • Include source or milk and dairy
  • Limit and be mindful about refined foods that high in fat or sugar.

sea bass

Food prep 101

Knowing what foods to eat is one thing, but putting it into practice can be a lot more difficult. We leave in a 24/7 world based around time constraints, work commitments and deadlines. This can make eating healthy a challenge even for the most dedicated person. Sometimes convenience comes before nutrition; this is where meal prep skills are so useful.  Having the ability to shop for the right foods and prepare them in ways that appeal to you more than takeaways and ready meals. The internet is full of healthy recipes and alternatives to takeaways for a fraction of the calorie intake and significantly more nutrition

Mexican Standoff

Meal prep tips

  • Go shopping with a weekly menu in mind, aim to only buy the ingredients required for your menu. This will save you money, prevent food wastage and prevent you from being tempted by specials offers on snack foods.
  • Cook in bulk. Whenever possible cook more than would be needed and freeze the leftovers, this is provides you with a healthy go to option if your short of time and looking for something to eat.
  • Set up a meal prep club. If you and your friends are all following a healthy eating plan why not each cook a meal in bulk and swap them between yourselves. For example, You could cooks a chili and friend could cook a cottage pie and a third friend could make a curry. Now for cooking one meal in bulk and swapping between each other, you each now have three different pre prepped meals for no extra time.
  • Have pre portioned fruit, nuts, high protein snacks available in your ‘danger zones’ such as the office, in the glovebox of your car, handbag or anywhere that is a potential situation your you are tempted to make less positive choices

Protein Pancakes

It’s ok not to be perfect

When people start a healthy eating plan they often feel they have to but only eat clean and 100% commitment otherwise they deem themselves as failing. Realistically, lapsing from an eating plan is normal and having a flexible approach to eating leads to better long term adherence and relationship with food. It’s better to eat well 80% of the time by making mindful decisions about what to eat then trying to eat well 100% of the time but not being able to maintain such a strict eating plan and ultimately failing to create new habits and reverting back to old ways.