Carritt's blog: My GSSI visit

The Gatordae Institute of Sports Science is a brand new (as of Feburary 2012) lab kitted up to administer a full spectrum of testing and run by Dr Ian Rollo and Dr Jimmy Carter in their wide ranging research around sports nutrition, hydration and performance. In conjunction with the other GSSI laboratories around the world, they are building a data base of physiological data of elite athletes across all sports. So, as well as the Aerobic Metabolism testing that I was primarily interested in for my training, I contributed results across a wide range of tests from a detailed body composition examination, nutrition and sleep habits surveys, cognitive function, reaction times to the strength of my hand-shake!

The first step for me was a morning of fasting and a break from training. I was not complaining about the latter following a weekend of back-to-back triathlon and half marathon racing, though the fasting (which included coffee!) was another matter - I usually feel faint if it’s more than 2hours between snacks.

I was shown around the gleaming lab, which resembled something between a very modern gym and a space-ship, then asked to pop into the bathroom and pee into a vial. This would be used to test my Acute Hydration status. With a specific gravity of <1 .01=".01" first="first" hydrated.="hydrated." i="i" nbsp="nbsp" passed="passed" test="test" was="was" well="well">

The lab have 3 methods of analysing Body Composition and are collecting data to for the calibration between two sophisticated methods: BioImpedence Analysis and Air Displacement Plethysmograhy (the BodPod) and comparing both to the classic “skin-fold” measure. I was pleased to discover that I am 86% fat free and have some muscles. So, I’ll call that a “pass” too.

Dressed in my cycling kit and ready to get on the spin bike, Jimmy first took some pre-workout blood samples which will be sent away for a detailed analysis for indicators of general health and mineral composition, and also compared to a final sample collected immediately post-exertion.

The Aerobic Metabolism and Aerobic performance tests can be carried out on either a watt-bike or treadmill. It is more common to do this type of testing on a stationary bike because it’s a lot easier to control the work-load, easier to collect the athlete samples, and less of a nuisance for the athlete working at high intensity (we’ll get onto that later!) The “samples” that were to be collected in this case was my exhaled breathe for measuring the oxygen conversion that was occurring in my system which meant riding with a mask with placed tightly over my nose and mouth. The test starts by cycling at a low power for 3minutes whilst heart-rate is measured, and my exhaled gases are fed through an analysis machine. The power is then increased in 35watt increments every 3minutes. As I ride, I am asked to indicate the level of perceived effort on a chart which is held up in front of me. The progression typically goes like this –“very easy”, “easy”, “easy”, “moderate”, “moderate”, “quite hard”, ”let me off!!”, ”arrghhhnnpphhhckckkk!!!”. In other words, it’s very noticeable when a “threshold” has been reached, and for me there’s not a lot of go after that point. It’s important that the testing team provide plenty of encouragement for during the test – some good music and plenty of verbal, as wearing that sweaty mask and uninspiring nature of pedalling a stationary bike adds another dimension of discomfort and may accelerate the desire to terminate. My team did a good job, and I was able to push out a full minute longer in my final step than I had on my prior visit 3 moths ago. Jimmy guided me off the bike and into a seat in order to collect a second round of blood samples.

Whilst they got busy in the office working through my data, I sat down and filled in a number of surveys around my sleep, training, nutrition and drinking habits and perceptions. The lab is funded by Pepsico, fundamentally for the research into Gatorade sports nutrition product. My answers will help provide some insight into the differing habits and attitudes around nutrition of elite athletes from various sports, as well as highlighting areas in my own performance which might be enhanced. I scored only 64% on the Nutritional Habits questionnaire - it’s encouraging to know that I have so much scope for improvement by making some simple changes.

The data obtained from my Aerobic Metabolism test is what will really inform me about my nutrition requirements, and we next sat down to discuss my results and the significance that they have for my training and nutrition.

Most athletes understand that we have two sources of fuel for exercise: fat and carbohydrate. At lower intensities we burn mostly fat, from our abundant body stores. For very high intensity exercise, like sprinting or power sports, is fuelled by carbohydrate (CHO) which initially comes from the finite glycogen stores in our muscle and then must be ingested as various forms of sugar. The Fat: CHO ratio varies as exercise intensity (which is measured by heart-rate) increases, and the rate of change of this relationship is different for everyone. Doing a Aerobic Metabolism test, as I have described above, will produce your unique “Fat-buring” curve, identify significant training thresholds and determine training zones to improve relevant aspects of your metabolic response. My test results show my FATmax HR to be around 110bpm, or ~40% Vo2max. At 140bpm, 60% Vo2max, it’s about 50:50 – a point commonly termed Aerobic Threshold since beyond this Fat oxidisation drops off rapidly and CHO becomes the critical fuel source. At the Intensity that I target for my Ironman racing (one stage above this), I’m closer to 60% CHO:40% fat - which has an effect on the amount of hydrogen accumulation in my muscles as well as fuel consumption requirements.

As an endurance athlete competing in day-long events, my objective would be to “shift the curve” through training methods such that I’m utilising higher proportions of fat for fuel at higher intensity. Ian and Jimmy had some interesting and useful suggestions for me around the type of training that I could incorporate into my off-season to help with this.

The Aerobic Performance element of the same test is focused around a well-known factor called Vo2 Max. It’s essentially a measure of the amount of oxygen that can be consumed whilst exercising at maximum effort. It’s pretty difficult to determine absolutely, since not only is it pretty difficult to attain “maximal effort” in test conditions (see the following description of my run-based test) but it’s also weight dependant (i.e. you can improve your Vo2max by dropping a kg), but is nonetheless thought to be a good indicator of athletic potential especially in sports where high intensity work is required.

We repeated the same test the following day running on a treadmill. Using the same apparatus and basic procedure, I was tied to a harness and run at increasing speeds on a slightly inclined (1 degree) treadmill with the face-mask on. We started off at walking pace and increased by 1kph every 3 minutes, measuring my heart-rate and indication of level of perceived effort. It did not take very long for that perceived effort to reach “hard”, though this was more due to the very confined feeling of running with my head held in place by the mask and no visual feedback as I ran as the mask and tubes almost entirely blocked my vision. I think that this test takes a bit of getting used to and I had to really focus on how my legs and breathing felt rather than how uncomfortable and annoyed I felt by the contraption that I was wearing at each stage. Once we’d reached a critical speed (governed by how fast my legs were actually capable of turning over!) the intensity was increased by means of adding gradient. I made it through 9 ½ stages, and reached a max HR of 172bpm - about 90% of what we’d got to the previous day.The FAT% graphs here made interesting reading –unfortunately not as smooth as the cycling test due to a very different set of circumstances. Whilst the cycling test was conducted according to the usual fasted and rested protocol, this running test followed an hour swim set, a typical breakfast, then a 3hour ride and …probably the most significant….a recovery bag of Jelly Snakes. However, this was planned, as we felt that it would provide me with some real race- relevant data. And, anyway – sweets are not entirely off the agenda in my training or racing.

I was to be tested on my Cognitive Function and Motor Skills. The former was actually rather enjoyable and tested my awareness of changing environment and ability to react to it quickly and calmly. The "D2" machine really does resemble part of a spaceship’s controls, with an array of LED buttons in a radial pattern surrounding a small central digital screen at eye level. The test subject de-activates each button as quickly as possible, whilst simultaneously reading out the numbers which appear on the little screen in the centre in order to measure mental processing and reaction time skills. Certainly something which one would very quickly improve on with practice. My score was a comfortably above average 85% hit-to-miss ratio with a slightly above average reaction time of .68 seconds. This does not tell us too much other than that I’m more accurate than I am fast!

Testing my Motor Skills was an exercise in real humiliation for me – putting me in mind of playground games! The "Ispan" consists of nine illuminated discs mounted around a goal-like frame, with 3 on each post and 4 across the top bar. They are movement sensitive and the lights are de-activated by waving a hand in front of it. Once de-activated, the next light will come on, and the test is a time-trial through a random sequence of 12 lights - the faster you can switch each light off, the faster your test result. It’s exactly the sort of skill set that the lack of drove me away from sports in school, and a comparison of my test results against average (5% below) were not too surprising given that I spend most of the 23 seconds tripping over my own feet.

The next test uses a very clever machine to take a very simple measurement. The strength of the muscles in the forearm and hand are here used as an indictor of overall Muscular Strength, and are measured by simply squeezing a solid metal sensor. To my surprise, my readings spat out a score of close to 70kg, which is right at the top of the “above average” range for females.

Finally we move onto the final test of the day, and in a sick sort of way, my favourite. Probably because I like the name: the Wingate Test. The test itself is quite horrendous, but is over very quickly. Back on the watt bike, in order to measure peak Power and Anaerobic Capacity – the ability to use the muscle-bound energy sources of Adenosine TriPhospahte (ATP), Creatine Phosphate (PC) and glycosis in a short max effort burst.

For this test, only power is recorded – the effort is too short and sharp for heart-rate to be of much relevance. On the Watt Bike I pedal with low resistance, and over a 30 second period gradually increase my cadence from a start-point of my comfortable 80rpm up to my maximum of around 120rpm. At this point I have 5 further seconds, with the very loud encouragement form the testing team, to spin my legs even faster before the resistance goes on. All of a sudden, I’m churning out close to 700Watts before my legs realise what has happened to them. This will be the Peak Power that I produce. The test lasts for 30 more seconds at this level of resistance and I pedal furiously to maintain as high a power as I can for that time. The power graph on the screen shows a clear peak at 0 seconds and then a shallow drop off until about 20 seconds, where I manage to pick it up again for a final 10 second all-out effort. My peak and average numbers, and the 20% loss in power over the duration compared very well against the collected data averages for females. For an endurance athlete, who’s training really is quite specific to this sort of test, this should not come as too much of a surprise.

At the end of my visit I’m given a full report of all my testing results, which Ian and Jimmy are happy to discuss, as well as other questions and ideas about nutrition that I have for them. I’m keen to return in another 3 months time to see if these recommended tweaks have a measurable effect in that short period. I may also do a little work on my motor skills!