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Understanding Nutrition For Functional Fitness

An Intro

The meteoric rise of functional fitness and sports like CrossFit (TM) has seen its training develop from sporadic, random HIT training, to what now produces some of the fitness athletes on earth. However, still, the dogma of eating ‘Paleo’ or ‘Zone’ giving flawed advice to the high intensity athlete refuses to go away.

Why isn't well accepted sports nutrition practice from elite sports and applying it to competitive fitness? Why aren’t more Box’s taking leaves out of sports like cycling, rowing, boxing, MMA and weightlifting and using these strategies to help their athletes.

OK but how?

Firstly, we need to consider what it actually is functional fitness (I'm not allowed to use the proper word)?!

"Constantly varied, high-intensity, functional movement, operated at a high intensity”. Sounds good doesn’t it, but what does this actually mean? What is involved…. Everything, literally! This is the beauty of the beast and what makes no other sport quite like it. ‘A core strength and conditioning programme with the aim to develop and broad, general and inclusive fitness' (, 2017). A combination of all its elements:

  1. Cardiovascular / respiratory endurance – The ability of body systems to gather, process, and deliver oxygen.

  2. Stamina – The ability of body systems to process, deliver, store, and utilize energy.

  3. Strength – The ability of a muscular unit, or combination of muscular units, to apply force.

  4. Flexibility – The ability to maximize the range of motion at a given joint.

  5. Power – The ability of a muscular unit, or combination of muscular units, to apply maximum force in minimum time.

  6. Speed – The ability to minimize the time cycle of a repeated movement.

  7. Coordination – The ability to combine several distinct movement patterns into a singular distinct movement.

  8. Agility – The ability to minimize transition time from one movement pattern to another.

  9. Balance – The ability to control the placement of the body’s center of gravity in relation to its support base.

  10. Accuracy – The ability to control movement in a given direction or at a given intensity.

As (Glassman, 2010) put it, the programme is designed to be as broad as possible, not specialised and aimed to elicit a response to all of the above components. But here lies the problem; its generic nature makes not just programming difficult but getting the nutrition right too. Eating to be faster, stronger and fitter…..

Where do you start?

When designing a nutrition plan for any sport, you need to asses its energy demands, energy systems used, type, volume of training and obviously the individual. From this you can apply what nutrition interventions will most suit that particular sport and person. This is usually relatively straight forward as there is plenty of research to guide you in the right direction. Not so much for functional fitness. There is currently very limited data specific to the sport and its uniqueness make it a little tricky to draw data from other intermittent sports and research methods.

However, by understanding the different aspects of the different types of WOD's, we can make some sound assumptions and build a solid nutrition strategy accordingly. This is when you have to take a flexible attitude to your nutrition whereby you must be willing to adjust it according to your activity levels and intensity. I’ve eluded to my context sensitive diet approach before which is especially true of sports like this. A typical ‘find your 1 rep max deadlift’ workout will obviously require a different fuelling strategy to running a 5k. This is why it makes sense to view your training as only an umbrella term, where more focus needs to be placed on its individual aspects.

Defining Functional Fitness

The physical features of functional fitness can be broadly broken down into weightlifting (WL) that include the major lifts (clean, squats, deadlift, presses and Olympic lifts), metcon/metabolic conditioning (cardio), which is typically swimming, running, rowing and cycling and the gymnastic element that includes typical bodyweight exercises like pull ups, rope climbs, push ups and handstands. All of the above with the emphasis on intensity and working hard. Utilising this range of exercises, the idea is to improve exercise capacity across the whole spectrum of fitness (the 10 components mentioned above) and develop all three energy systems (ATP- PCr, anaerobic glycolysis and the aerobic system).

These energy systems or metabolic pathways are a good way to determine where your workouts fall, which can ultimately help dictate the type of training and nutrition interventions needed. But what are they?

The Metabolic Pathways
  • ATP - PCr - This energy system provides energy for your highest powered activities, which typically last less than 10s. Imagine a 100m sprint or olympic weightlifting. This type of explosive activity can only be sustained for a short period of time due to the limited ATP and PCr stores (McArdle, et al., 2010, p. 227).

  • Anaerobic Glycolysis - The second energy system is used for more prolonged activity (10-60s) but still produces a relatively large amount of power (Morton, Maclaren, 2013, p. 6). Imagine a 400m run or some of your short benchmark workouts (Grace - elite level) that last around a minute with no rest. As this energy system works without oxygen, lactate is produced, which although is used later down the line as an energy source, it also results in an increase of hydrogen ions that reduce the PH of the cell reducing force production and glycogen breakdown (Wilmore and Costill, 2004, p. 125). So basically you're limited to sustain this amount of power.

  • Aerobic - The third energy system will not provide the same power as the previous two however, it can produce considerably more energy over a longer period of time. Oxygen being present enables more ATP (energy) to be produced so exercise can continue (McArdle, et al., 2010. p. 165). This would include your longer benchmark workouts like 'Angie' that can last up to 15 minutes.

An Overview of the Energy Systems

Although it suggests you move along the three energy pathways like a continuum, you will actually be relying on all of the energy systems at once, where one may dominate at different points of the activity. So even for WOD’s that are more aerobic in nature, the addition of a sprint, olympic lift, kick or quick change in pace will utilise the glycolytic and or ATP – PC system. Also in the more power based WOD’s where the majority of exercise is performed anaerobically, aerobic capacity will dominate recovery. Hence if you’re looking to become a proficient competitive fitness athlete, you will need a high degree of aerobic and anaerobic power, plus the ability to switch well between the two. This is important to know as by determining the type of workout you can manipulate your nutrition accordingly.

Competitive fitness typically aims to intersect all of these energy systems. In fact Glassman (2010) states that an athlete should be able to perform well in all three. However, depending on the workout, their contribution to overall energy supply will differ depending on intensity, recovery periods, duration of exercise and the fitness of the individual. (Maclaren & Morten, 2013). Some athletes maybe able to continue through many of the workouts without rest and use a higher percentage of aerobic pathways, whereas those utilising rest periods will work anaerobically or just using whatever they can!!

So how can you define the workouts in functional fitness?

You can't really. Like I mentioned above, you should not view functional fitness as one entity when developing your nutrition plan, rather, look at the individual elements and workouts. It will loosely be broken down into strength, aerobic or your typical WOD’s; a combination of high intensity (1s-4mins) and endurance workouts (5mins-4hs). And it's these types of workouts that feature mainly amongst competition.

OK so what's a WOD?!

‘Brief periods of high intensity exercise with periods of rest/low intensity' A WOD is a form of high intensity intermittent exercise (HIE) - (Morton et al.,2013). Unfortunately, not like typical HIT workouts where rest time is set, competitive fitness style HIE workout do not have prescribed rest periods and use high power multi joint exercises. This type of training has also been termed High Intensity Power Training (HIPT)(Smith et. al, 2013) where workouts will either be for time (as quick as possible) or ‘As many rounds as possible’ (AMRAP). Although there‘s little research on this type of training, we can still make good assumptions based on other types of HIT/HIE workouts similar to those in competitive fitness.

For the typical WOD’s, ATP production is fuelled by a combination both anaerobic and the aerobic energy system. In repeated sprints or high power exercises, glycogenolysis rate will decrease suggesting that aerobic metabolism becomes more important as the workouts progress (Paroling et al., 1999). Repeated efforts or sprints will also become more reliant upon aerobic capacity as they progress (Bogdanis et al., 1996) further highlighting the need for a well-developed aerobic system. Think it as the more aerobically fit you are, the more quickly you can generate this ATP between rest intervals. So it's safe to assume that as well as having a strong anaerobic capacity, you also need to be aerobically fit.

In a nutshell
  • The variety of WOD's will mean they utilise all of the energy systems

  • Workouts need to be viewed on their own merit rather than as a whole

  • Typical workouts or WODS predominantly rely upon aerobic and anaerobic glycolysis meaning they rely upon carbohydrates as their main energy source

  • As workout length increases there is higher reliance on the aerobic system

Final thought

Functional fitness is a training programme that looks to incorporate all three energy systems by utilising a wide range of exercises. Despite it being an all-encompassing fitness programme, depending on the workout, the contribution to overall energy supply will differ depending on intensity, recovery periods, duration of exercise and the fitness of the individual. Taking his on board you can manipulate your nutrition plan accordingly. In a sport like this where the energy demands will differ greatly from day to day, the importance of nutrition periodisation or where each training session must be considered in relation to energy demands and intensity. If you want to make the most out of performance, recovery, injury prevention and body composition then a flexible attitude to your nutrition is a must.

Book your FREE call

Want to keep achieving personal bests, want to increase strength, your engine, gymnastics or just want to look the part? Then Book a FREE Functional Fitness Strategy call with me. You’ll discover

  1. What’s your needs as a functional athlete

  2. A simple framework to help you boost performance, recovery and the way you look

  3. A supplement strategy to get most from your training

  • Bogdanis, G., Nevill, M., Boobis, L. and Lakomy, H. (1996). Contribution of phosphocreatine and aerobic metabolism to energy supply during repeated sprint exercise. Journal of applied physiology, 80, p.883.

  • Currell, K. (2016). Performance Nutrition. 1st ed. Crowood.

  • MacLaren, D. and Morton, J. (2012). Biochemistry for sport and exercise metabolism. 1st ed. Chichester, West Sussex: Wiley-Blackwell.

  • McArdle, W., Katch, F. and Katch, V. (2010). Exercise physiology. 1st ed. Baltimore, MD: Lippincott Williams & Wilkins.

  • Parolin, M., Chesley, A., Matsos, M., Jones, L. and Heigenhauser, G. (1999). Regulation of skeletal muscle glycogen phosphorylase and PDH during maximal intermittent exercise. American Journal of Physiology, 277(5), pp.890-900.

  • Smith, M., Sommer, A., Starkoff, B. and Devor, S. (2013). Crossfit-Based High-Intensity Power Training Improves Maximal Aerobic Fitness and Body Composition. Journal of Strength and Conditioning Research, 27(11), pp.3159-3172.

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