Wednesday, December 11, 2019

A testing time at the Triathlon Show - part two - Surrey Human Performance Institute

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After my stress-free visit to Precision Hydration, where they kindly made me sweat without me having to barely lift a finger, he next stop was not going to be quite so easy.

I headed off to meet the sports science boffins from Surrey Human Performance Institute (SHPI) to have my blood lactate levels assessed. Or more accurately, to have the increases in blood lactate measured at different intensity levels.

 

SHPI had originally offered to test me for both the bike and run in a single day, but with the Bath half marathon looming just two days away, I decided to err on the side of caution and just do the running test.  The principles of training to heart rate zones are well established and so I won't go into them here. But, a little like with the last blog on hydration, we are all a little different and so training to a mathematically-calculated formula might not always be optimum.

 

That's where blood lactate testing comes in. I'm sure we've all read about "lactic threshold" before (it's a common mistake, but 'lactic' is actually the wrong word here), the idea that it's the level at which the body can no longer flush the lactate from the muscles as quickly as it builds up - and consequently the lactate/lactic levels start to build more quickly.

Many HR-based training programmes use lactic threshold workouts - the theory being that training in the zone helps the body to learn to flush the lactate more effectively and thus, over time, the threshold level increases.

The problem with this is that when training to HR alone, the "threshold" zone can only be an estimation and is this prone to error.

That's a long way to explain why there is a place for lactate testing. It gives a more accurate calculation of how the body is coping with lactate at different levels of exercise, including pinpointing that magical threshold level I referred to earlier.

I've described the process in a previous blog, where I visited Bath University in xxx. The protocol used by SHPI at The Triathlon Show was very similar and involved running three-minute reps on a treadmill at increasing speeds, with a small blood sample analysed after each rep. In this case, the blood sample was taken from my ear lobe (Bath had used a finger stab).

Working up a sweatNow in the interests of full transparency, I should point out that the test didn't quite go as smoothly as the staff SHPI staff might have liked. As a consequence of doing the test in an exhibition hall rather than their own lab, they were using rented equipment and let's just say the treadmill wasn't the best.  It cut out a couple of times and the fastest speed was 16kph - too slow for even most age groupers.

Anyway, niggles aside, we started with a blood sample at rest then proceeded with the first three-minute rep at 11kph.  After this, more blood was collected from my ear, my heart rate was recorded and I was asked to give a perceived rate of exertion on a rate of 6-20.  And so the test continued until we had finished the 16kph rep and could go no further. Perhaps that was a good thing for my ego, as I reckon I could handle maybe 17 and 18kph for three minutes, but beyond that...

Unlike my visit to Precision Hydration, I was at least now drenched in sweat. Maybe I should have done my visits the other way round!

A few days later and the results of the test were emailed to me. Although not conducted under "perfect" lab conditions, the results did make for interesting reading.

The results showed that from 11kph up to 16kph my increase in heart rate was pretty linear, while my lactate response was more ‘stepped’.  For example, while my heart rate increased by around 6bpm between 11kph and 12kph, my lactate levels didn’t change at all. Only when the speed increased to 13kph was there an increase in lactate, which then again remained unchanged up to 14kph. Only past 14kph did the lactate increase start to climb more sharply, culminating at 4 mmol/l at 16kph (the maximum speed of the treadmill, remember).

The report finished with a table of target heart rates and running paces for different sessions including Endurance, Tempo and Threshold.

I’m now using this new information to determine my different run sessions, safe in the knowledge that they are based on actual lactate readings, not just mathematical calculations of theoretical zones.  For anyone that’s serious about getting their training zones right, testing your lactate build up makes a lot of sense.  A good coach will be able to use the information to help shape the training plan and re-testing six or 12 months later is a great way to see if progress is being made.

Speaking of checking progress, one thing I can probably take some comfort from is that at 16kph back in November 2012 (when tested at Bath Uni), my lactate level was 5.09 mmol/l compared to 4 mmol/l this time round.  However, my lactate at lower speeds hasn’t changed much at all, so perhaps that suggests that I still have work to do on my running efficiency (maybe all those people who keep criticizing me for running too fast on my slow runs have a point…).

I’m hoping to get the opportunity to re-take the run test – and maybe the bike test too – under proper controlled conditions in the Surrey HPI lab in the future.  If I get the chance, I’ll report back on the finding and any advice I receive from the sports scientists.

For more information on the Surrey Human Performance Institute, visit http://www.surreysportspark.co.uk/performanceservices/shpi/

Here's a video from the show: https://www.youtube.com/watch?v=nD82Z5YeZRw

 

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Matt Fisher runs TriathletesDiary.com - so it's all his fault! He pretends to be a triathlete, but really he is a husband, father and company VP. But he has raced for the GB Age Group squad a few times and is a two-times qualifier for the IM70.3 world champs

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