Metabolism & VO2max Tests for Crossfit Athletes

A scientific and proven approach to testing your fitness.

Aside from being the most accurate method of measuring cardiovascular fitness, completing a VO2max test means you will have a highly accurate idea of how your body burns fuel (fat / carbohydrate) at rest, and throughout exercise, for example – ANY WOD! The testing provides 5 key results that give you a precise profile of your fitness and uncover what is required for your body to perform at its optimum level.


1. VO2max:

Your body’s maximum capacity to perform aerobic exercise. The maximum amount of oxygen your body can use for energy production, expressed in millilitres per kilogram of bodyweight.

2. HR at RQ = 1.0:

The maximum workout intensity your body can handle before it switches entirely to carbohydrates as a fuel source. Once you are relying only on carbs to fuel your workout, it is only a matter of minutes, maybe seconds before you hit the wall. The heart rate that occurs at this exercise intensity is the measurement taken.

 3. Fuel burning profile:

Whether you’re asleep, awake, training, or reading a book, your body is constantly burning fuel (a mixture of fat and carbs). Throughout a given day your body will burn a total fuel amount that is expressed as kilojoules or calories, for example, an elite male athlete who trains 8 times per week may have a Total Daily Energy Expenditure (TEE) of around 3500 calories. As there are a multitude of factors that determine TEE, this number will vary greatly from person to person. There are a number of equations that will loosely predict TEE, however, the only accurate method of finding this information is measuring TEE using Indirect Calorimetry. The major advantage of measuring TEE is that you will know how much of your TEE is fat, and how much is carbs. The elite male athlete with a TEE of 3500 calories might burn 1750 calories of carbs per day and 1750 calories of fat, this would be a fuel burning ratio of 50:50, which is not ideal. An ideal daily fuel burning profile is up around 70:30 (fat:carbs), which is seen in most elite athletes.

4. LIPOXmax:

The maximum amount of fat your body can use to fuel a workout. The greater your ability to use fat, the more carbs you can spare for when you really need to push to the next level throughout a WOD, or any event. LIPOXmax is expressed as an amount of fat per minute, for example, 6 calories of fat per minute.

5. PWFR:

Pre-WOD Fuel Requirement. Knowing precisely how your body burns fuel while you workout means you can plan, very precisely, your fuel intake before training or competition, to optimise performance. This also means you can accurately plan your nutrition post-workout to ensure the best recovery.


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Thomas Foster /