Monday, November 22, 2010

Test Lab Results

Went up to TWU today were a grad student (Eric) offered to run a bunch of running tests on me hooked up to his machines at the university. I wish I'd taken a picture - Hooked up to an ECG via 10 probes spread around my chest (which now looks like a checkerboard from the shaved spots btw), a helmet that holds the snorkle I keep in my mouth and running on a treadmill while every 10 minutes getting pricks to my finger for blood - good times!

I love all the data - if I ever do this again I'm wearing my Garmin HRM and footpod to get cadence and a full HR trend instead of just at a few spots.

Test Description - After a baselining period taking readings at rest and a slow walk - the test goes 8 min at each speed, each row has the readings at the end of this 8 minutes, 2 minute rest then start next speed. At the end there were 1 minute intervals harder and harder until I was done to get to VO2max.

Min...Road Eq..vo2 ...HR ....Lactate... Breath/min...Notes
0................... 5.0 .... 47 .....0.9.... 25
8/2....9:55.... 29.7 .... 85 .....1.2.... 33.........50% mile Pace
8/2....8:20.... 36.2 .... 122 ....1.1.... 35.........60% mile Pace
8/2....7:11.... 44.2 .... 140 ....1.4.... 39.........70% mile Pace
8/2....6:20.... 49.8 .... 153 ....2.6.... 46.........80% mile Pace
8/2....5:58.... 54.2 .... 160 ....3.8.... 48.........85% mile Pace
8/2....5:38.... 59.4 .... 169 ....6.6.... 50.........90% mile Pace
1......5:58.... 42.6 .... 160 ........... 51
1......5:37.... 56.3 .... 167 ........... 51
1......5:19.... 62.4 .... 171 ........... 51
1......5:04.... 64.8 .... 174 ....9.3.... 55..........VO2max

My initial thoughts looking at it:
- VO2max ~65 seems about right - looking up my last (and only other) VO2max test (9/2007) my VO2max was measured to be 64 - max VE 126.7 l/m in 2007 vs 128.7 today so 1.5% more O2.

- 2:2 breathing pattern would be 45 breaths/minute assuming 90 cadence - that would sure be running slow - don't think I'll be using that as a speed indicator in racing. I find it interesting the breaths/minute changes very slight between 6:20 and 5:58 pace - not so precise an indicator at all.

- Using some benchmarks from Daniels Running Formula for Threshold speed:
Threshold Lactate ~4.0 = 5:56.
88% VO2max - 57 VO2 = 5:47.

- MP lactate I understand from Eric is typically in the 2.5 to 3.0 range which makes 6:12-6:21 mpm range for me (2:42.5-2:46.5) - short of my goal 2:40 marathon pace of 6:06.

- Heartrate data doesn't seem to correlate to my training heartrates. Big disconnects. The HR in the lab showed around what I see at Marathon Pace for what appears to be Threshold and what I use at Threshold (170ish) is far above Lactate 4.0. Guess I'm discounting the heartrate data as useful until I can find some explanation that makes sense why it is so different from what I see on the road.

- As I happenned to have the Daniels Running Formula open I'm noting "individuals show vast variation from this 4.0 threshold value. One runner might maintain a steady blood lactate concentration of 2.8 and feel same degre of stress as another runner who has a steady 7.2." So I'll take it all with a grain of salt. Still interesting stuff..

Error Analysis

- On scale after the ECG cable was hooked up - adds ~1 lb - so actual weight closer to 157 vs 158.
- On treadmill probably supporting 1/2 the ECG cable as well as a helmet tube holder - total together ~1 lbs extra weight.

Impact - pretty small - typically 1 lb ~ 2 sec/mile so MP potential 6:10-6:19. Also VO2max would be ~0.5 higher.

- Lab temperature was recorded on the test results to be 72°F. Per runworks/calculator (6th option down) at colder than 60°F the equivalent marathon speed would drop 6 sec/mile - so MP potential at less than 60°F would be 6:04-6:13.

- Each segment was 8 minutes. Looking at my most recent training run at ~Threshold pace (3x3 miles at ~170 bpm with 5 min rest between on 11/26) - the heartrate flattens out after about 1.5 miles or 7 minutes, about 1/4 mile quicker for the 2nd and 3rd intervals. Conclusion: taking the HR readings 8 minutes into a constant pace should be pretty representative.

- Another time-lag issue I heard discussed while I was on the treadmill - there is a 2 minute lag between lactate levels from the muscles to lactate levels in the finger where the blood is drawn - I think this explains the very last Lactate datapoint - although taken after VO2max - the lactate level probably corresponds to a couple minutes earlier or 2 data points to the left - then it kinda lines up with the rest of the curve.

Still the HR levels are a mystery. I can hold 170 HR for 10-13 miles in races so that heartrate should be around threshhold pace (by the 1 hour race pace definition approximation of threshhold pace) - but this test shows 7+ lactate at that HR and the 4.0 lactate points is far lower than this - closer to 160 HR. Makes the heartrate data suspect - but I don't know how to get better HR data than an ECG. It could be that I run my marathon pace with lactate levels in the 3.5-4.0 range - that would be a bit of an outlier but not unheard of - as mentioned above Daniels has seen 7.2 for Lactate Threshold - could be I'm THAT guy.
Eric's anaysis:
I went back and looked at your data, and the only thing I can think of why the data was off is that possibly the machines were not properly calibrated. The information just doesn't make sense to me. I have attached your VO2/CO2 data and the cross over point is known as your ventilatory threshold. This with lactates can give a good estimate on lactate threshold. But your lactates correlated with the metabolic data so I don't know why they seemed so low. The treadmill also has a calibration which we did not do prior to testing but found out later. VO2 max was found similar to your previous testing so I am confident that we got that correct.

Based on the lactates I would have predicted from 2.5-3.0mM for marathon pace. That had you at around 6:40ish pace. What I found interesting, knowing the at least the VO2 data was correct, was that your cross over data of fuel usage was on the low end for an experienced endurance runner. Maybe heat stress you do improves CHO metabolism? I don't know. But the information tells that you were using less fats as fuel at lower and higher intensities. This seemed to correlate well with the metabolic data and lactate samples. I have included someone that is an average female runner. Highly trained runners show a cross over point shift further to the right.

My only other explanation is that that you were not fully recovered from any previous training. I do think you must have done really well with carbo-loading and fueling during the marathon to keep pace with the increase in carbohydrates at the 6 min pace. Someone did tell me that the CIM course is downhill, do you think that it's that much of an aided course?
If you are in the area and want to get tested again let me know and we can set something up.


Anonymous said...

I wish I understood a quarter of the stuff in here. WOW.

Anonymous said...

from waidt
- Look at the lactate level at 92% of HRmax or at 166, it corresponds to ~6.3 mMol.
- Joe Friel has a newer book for Ironman distance training called "Going Long". I don't have this book but I have two other books, Triathlete Training Bible, Cyclists Training Bible from Joe. Content are similar between two books.
- my 10/half PR was 35:33 and 1:19:32 from almost two decades but my marathon time was nowhere near VDOT 59-60. Your body seems to be very efficient at long distance.
- Look at Loreen Cordain and Joe Friel's Paleo Diet for Athletes. I remember reading that a lot of Ironman elites are using this diet to force the body to burn fat during base training cycle.