Hudson Experiment and Physiological Testing

After 4 marathon cycles using Pete Pfitzinger's plans from his booked 'Advanced Marathoning', I decided to try something different and switched to use the plan from Brad Hudson's book - 'Run Faster' - for the London marathon.  Partly to try something different, and partly because the way I interpreted it - it was a little more intensity with the workouts, but less mileage each week.  I'd run over 3,000 miles in 2011, but didn't have the time to be able to do that with the demands of a new job that I'd started.

As you can read in my London race report - I performed okay.  Not as well as I might have hoped starting out in training, but based on my mental state going in - probably about as well as I could have expected.  My time was very similar to that of a year earlier running Boston.  Which told me that the lesser mileage and different training plan, wasn't hurting my performance.

Colorado is a hot bed of talent.  Many of the best runners and athletes in the world live or train here.  I found that Brad Hudson was actually located just up the road in Boulder.  Several of my (faster) running friends trained with the group, so one Sunday in May, I decided to tag along and run with the open Sunday run.

I recognized several of the elite runners there which was a little intimidating, but despite that - the run was fun.  There was enough variation in runners that I wasn't left on my own, and ended up running a reasonably fast - but controlled - 12 mile run. 

I talked briefly with Brad afterwards, and then started to read more about the training the group offered.  A few weeks later I went back and chatted with Benita Willis.  She's an elite Australian athlete trained by Brad, but also someone who trains other runners herself.  She was training another friend of mine - someone who's performed very well this year, winning multiple races.  The more we chatted, the more interested I became.  The group - Hudson Systems (link) is based on the European club system.  They have a club house, with a tv for live and replayed running events.  Despite having a number of elite athletes - no one was 'on a pedestal'.  Everyone was treated the same way.

The group is affiliated with the Boulder center for sports medicine.  Through them you could arrange a battery of tests to help improve training and get a better understanding of the way your body burns energy at different paces and thus fuel better in a race.

I went in to meet with Benita and James Carney, another athlete coached by Brad - and decided to sign up.  Coincidentally - Benita was the subject of the interview on the great Marathon Talk podcast that week (Marathon Talk Podcast )

Into the Boulder labs I went.

The test was in 2 sections.  

Both involved running on the treadmill with a metal frame on the top of my head supporting a face mask that measured oxygen intake and carbon dioxide exhaled.  A nose clip forcing all breathing to be done through the mouth.  It wasn't the most comfortable thing and made me concentrate on my breathing - something I rarely did.

The first test involved running for 4 minute intervals with a short break in between, each set at a faster pace.  The computer measured the inhaled and exhaled gases which could help evaluate the % of energy coming from fat burning, and the % from carbohydrate burning.  The faster you run - the more you end up using the carbohydrates as the primary energy source.  Your body only has a finite amount of carbohydrates stored in the muscles and liver, and when you run out - that's when you hit 'the wall'.  I'd visited Bonk City several times and hoped not to go back.

Knowing this ratio helps you plan a carb intake strategy to hopefully avoid that wall.

The other part of the first test was drawing blood after each 4 minutes to test the lactate levels - this to figure out how much the body was producing at different paces and also to figure out the lactate threshold.  That's the point over which your body is producing more lactate than it can break down - so a pace that isn't sustainable for long.  Combining the results of the tests - the doctor  is able to come up with the optimal paces and heart rates that you should be doing the different types of training runs at (recovery, base building, tempo, threshold etc).

My legs had been feeling heavy all week and my heart rate immediately seemed elevated to me, but I was able to suffer through and complete the test, although my finger looked like a pin cushion after blood had been drawn 8 times.

Then after a short break - the second test - running as long as I could at a set quick pace on the treadmill, as the incline was increased every minute.  You essentially run until you fall or jump off the treadmill.  Then blood is drawn again immediately after, and then a few minutes later.  This test finds the VO2 max - which measures the body's ability to transport oxygen during exercise.  That test was pretty miserable - I jumped off about 4.5 minutes in with the incline at 10% or so.  I was a bit disappointed feeling I'd quit too soon, but found out later I'd hit my VO2 max a minute before - so gutting it out longer wouldn't have gained me anything more than extra pain.  And it was pretty bloody painful enough already thank-you very much.

So what did the results tell us ?

Firstly my VO2 max reading is 61.6.  On the chart I was shown for 40-49 year old men, a 'good' reading is 44-47, a 'high' reading is 48-53, an 'athletic' reading is 54-60, and 60+ is 'olympic'.  LOL !

Although this was actually something I suspected.  Not that I have olympic level VO2 - but that oxygen deficit is not an issue for me.  When I go to sea level - I don't seem to get a lift.  I ran faster in a hilly 10K in Boulder, than I did on a flat sea level course.  When I go up higher in altitude - say to run in Breckenridge - I can maintain much the same pace as I can in Denver without a problem.  So this really wasn't good news for me - I don't get the lift that others do who live or train at altitude and then go to sea level.  I should probably try and run some of the higher altitude races - Pike's Peak, or Mount Evans Ascent...

I felt my HR was elevated for the tests.  Running at similar paces in the lab to those on a treadmill at home - my HR seemed to be at least 10-15 beats / minute higher than I saw there.

I hadn't slept well for several days previously, and it was a hot day which the doctor said could have been a factor.  Perhaps the 'lab' conditions and face mask had an impact too.

Based on the tests, it suggested my 'sub-threshold' level - a pace that I could maintain for about an hour - was 6.59 min/miles to 7.30 min/miles.  Given I've run multiple half marathons in the 6.24 - 6.35 range - that didn't sound right to me.  I can run for an hour and a half at that pace.  Hell - I've run for 3 hours and 4 minutes at 7:00 pace.  So I think the elevated heart rate perhaps played a part here.  The doctor suggested that I go and do a test on a track wearing a heart rate monitor - run for several minutes at the different ranges and get the average HR and see.  I'll be doing that later this summer.

However - the HR ranges themselves are still very relevant.  Knowing my minimum and maximum rates, as well as my lactate threshold - the sports doctor was able to identify that the HR ranges that would lead to optimal training for me.  Allowing me to recover, and get the most from each workout.

Even if my HR was elevated in the tests - these ranges will still hold true.  The theory is that I'll just be able to run faster paces within these HR ranges.

The other test of interest to me was the fuel test.  This is shown by the bar chart below.  The yellow bar shows the amount of carbs / hour I'm burning from fat stores running at that pace, the green showing the number of calories from carbohydrates.  The positive for me is that the yellow fat chart is fairly consistent across all paces, so my body continues to burn fat at a similar rate - even as I speed up.  I was told that in some people - it shelves off completely so that at high pace, all energy is coming from carbohydrate sources.  

What it shows me though is that I probably need to do a better job consuming carbs during a race.  It's hard to calculate exactly how many carbohydrate calories your body can store - the only accurate way would be to do a muscle and liver biopsy.  Not something I plan on doing....

The doctor believed it's normally between between 2,000 and 3,000 calories for someone of my weight.  If I want to run a marathon at 6:50 pace - then based on the results - I'd need to have at least 2600 calories of carbohydrates available (don't forget - you burn carbohydrates the morning of the race - getting to the start etc).  I struggle to eat gels - and often take none.  So if my body can only store 2500 calories as carbs - I'm going to come up short unless I can consume more during the race.

The next 2 days in training I ran by heart rate.  I was surprised to see at what I was considering a fairly 'easy' run pace (7.45 - 8:00 range) that my heart rate was in the 'tempo run' range.  I had been doing nearly all of my recent training at this level, except for the 'quality' runs when I'd run faster.  Based on what I now knew - I'd been training too fast.  It was no wonder that my legs were feeling heavy - I wasn't giving my body time to recover. 

The 2 key things I'm taking from this test are:

- until I can re-calibrate my paces - I'm going to use heart rate to dictate my training runs and races.  Unless it's a tempo or threshold run - I need to make sure I don't go above a HR of 145.  For recovery runs - I need to keep it below 125.  This will ensure that I recover and can then get the most out of my quality workouts.

- I need to experiment more with gels.  I have to learn to take at least 2 / hour in a marathon and keep them down.  That would give me 200 more calories from carbs / hour and should safely get me to the finish.  I learned from the nutritionalist that the gel I was using (stinger) only had 1 type of carbohydrate.  She said tests had shown that gels with a mixture - could be absorbed better.  When I take gels they seem to sit in my stomach and make me feel nauseous, so improved absorption sounded interesting.  Research had been done with some of the powerbar gels for instance that had a mixture of glucose and fructose and lead to increased absorption (Powerbar study ) - so I'll try some of these and by the time I run Berlin - I've hopefully found a gel that my stomach can handle and that can give me an energy boost.

All in all - an interesting afternoon, and hopefully one that will lead me to train smarter and improve my performances.  

If ever you get a chance to do a similar test - I'd highly recommend it.  And if you happen to live in Colorado - or even are visiting.  Go along to the Hudson Sunday open run.  You won't regret it.