Analysis Paralysis
Monday, January 10, 2011 at 06:01PM 
I'm starting to get a tick thinking about the data generated by my new toy, the Suunto T6 wrist computer. Be careful what you wish for, right? Don't get me wrong, seeing the performance data is crazy interesting to a geek like me but crunching the information and generating some direction afterwards is overwhelming. Fortunately, I have solicited advice from Mark Twight at Gym Jones and Matthew Weatherley-White from Restwise to help make some sense of it all.
I have a lot to learn about utilizing the information generated by the device and it will be a fascinating trip, to be sure. I also feel that, to fully understand the Guinea pig that is my body right now, I should get into a lab and go through the usual battery of performance testing that will provide me the basic numbers from which to build a program. Coincidentally, I was the graduate assistant at the Boise State University Human Performance Lab back in '91-'92. I definitely know a thing or two about this kind of testing having run most of my friends through the torture protocols. I was also the subject more times than I can count. These efforts are unpleasant to say the least, made even more so by having a gas analyzer tube rammed into your mouth and your nose plugged to keep the precious gasses from escaping unanalyzed. But now that I have had a glimpse into my current physiology with the T6, I want to know more.
Although I have resisted this kind of data-based training, I am intrigued enough to experiment with it for awhile. I may find it too cumbersome in the long run but for now I will play with it and share my impressions on these pages. Honestly, the device has already been revealing in that I'm probably going too hard on my "easy" days. According to the gurus who set the parameters for the various "zones", I'm spending too much time working "hard". And to think I thought I was above needing some sort of regulator, believing my own sense of discipline would see me through. Apparently, not so much.
For sure, though, I need to get into a lab before I go too far down this road. If you don't have a baseline, a maximum heart rate, as an example, it's hard to work backward to determine various work loads. That said, more advanced coaches have discarded some of these out-dated concepts in favor of recommendations based upon substrate oxidation (sub ox) analysis. Using a blood lactate analyzer, work levels can be determined based upon intensities that use varying degrees of carbohydrate and fat. Clearly, the athlete that can burn fat, nearly an unlimited fuel source, at a high level of work will last longer and go farther than the athlete that uses predominantly carbohydrate. This kind of testing is more complicated, of course, requiring multiple finger sticks and blood analysis during the testing. But the information gleaned provides a far more accurate picture of what is happening metabolically as an athlete's output increases.
Along with the T6, Suunto has developed Movescount, a web-based software program that downloads and analyzes the performance data gathered by the wrist computer. Movescount also generates some very attractive graphics from the data which makes the information more easily digested. I'm sure it will take me some time to be able to fully utilize all the features and data analysis of the program. Until then, I will gather the information with the watch, download it to Movescount and try to make something out of what's going on.
Below is my T6 recorded output from the Jackson skimo race last weekend. I started recording about a minute before the gun went off and stopped recording several minutes after the finish. Heart rate (HR) is depicted in the first graphic and altitude in the second.
Heart Rate Data - U.S. Ski Mountaineering Championships, January 8, 2011
The most striking feature of the HR graph is the steady, downward trend over the course of the first half of the race. I can honestly say the my rate of perceived exertion (RPE) remained the same, meaning I was going as hard as I could for the duration of the effort. In spite of this, my output steadily dropped until around the 90 minute mark where things stabilized until the end. The sharp drops in HR represent transitions and descents.
So, what caused the decrease in my power output during the event? Uhh, I got tired? Well, yeah, that's true. But really, in a steady state event like a skimo race, a well-trained, well-paced athlete should survive the effort without cratering too bad. Arguably, I did not "crater" per say, but the data does reveal some over reaching in my pacing early on. The consensus suggests that I was probably supra-threshold for the first 50 minutes of the race, causing a huge reliance on carbohydrate as an energy substrate. Carbs, of course, are our priority fuel source at high intensities but we only possess a limited quantity. Once we deplete our glycogen stores, we shift to free fatty acid (FFA) oxidation which, although nearly unlimited in quantity, requires a more involved metabolic pathway requiring lower power outputs as a result.
Mark Twight at Gym Jones speculates that my "ideal" race pace HR may be more like 160 bpm, allowing for a more sustainable output. The drop off and shift to FFA as the primary energy substrate eventually happens but can be delayed by appropriate pacing and food intake. If you can delay the shift through the event, you can go harder longer.
The take home here is that I probably should have started out at 160 bpm and tried to hold it there to the end. I may have lost some ground initially but may have been able to rally later. It's a tough call. The psychological impact of "letting them go" early on could be high. I just don't know. But the tradeoff of being able to hammer the later climbs would probably make up for it. There is nothing like savagely reeling in and then dropping competitors at the end of a race to propel one to the finish line.
One other indication that my self-selected initial pace may be too high is that it is not uncommon for me to hear other competitors around me conversing a little. One thing is for sure, I cannot speak when I'm charging uphill on skis. I always thought that that was just me - I breathe hard. Apparently, however, I just go too hard. Perhaps I can look forward to some witty banter at my next race!
The other thing that has to happen is eating earlier in the event. It is well-known that ingesting carbohydrate early in a race spares glycogen stores in the muscle and liver. Once those are depleted the dreaded bonk comes on so delaying this depletion is key. I distinctly remember leaving the first skins-off transition without getting anything down and almost forgot again at the first skins-on transition. This is not hard to do early in an event when energy and psych are high. You're simply concentrating on racing. But eating IS part of racing and it's key to start feeding as early as possible. There is no penalty. Aim for 300 calories an hour. The fact that I waited an hour before getting anything meaningful down is another reason for the decline in my output.
The next race on my calendar is Bozeman's Skin to Win on January 29th. I will try and tone it down some at the start and see what happens. I mean, let's be real here. I'm not going to be charging for the win these days so I might as well use these races like lab experiments and report my results here, right? Stay tuned. - Brian
Altitude and Speed Data - US Skimo Championships - January 8, 2011
Reader Comments (2)
Reading the part about your HR over the course of the race was interesting.....mostly because, to me, it shows the value in NOT getting too caught up in the numbers in a race (I'm speaking for this sport). From my experience in these races you have to go hard on the first climb (maybe too hard even) to get a solid position for the rest of the race. This isn't like biking racing where there are more opportunities tor, at least, SEEMS like it to me) to gain positions. I've found that where you come out after the first climb will largely reflect where you finish.......but maybe that's just me and the fact that I'm a "middle of the pack" racer. Most of the position changes seem to occur in the descents and transitions once the first climb is over with. Could the arguement be made that the drop in HR over the course of the race is reflecting your body's "adapting" to the race intensity? When I was running long distance in college it was well known that your HR would spike at the start of races and drop when you "settled in".......I don't think that is a bad thing or something that should necessarrily change. Would like to hear your thoughts.....
This analysis is consistent with what I have found. Your graph shows a classic example of going out too fast. I would greatly disagree with the above comment. I actually think because there are so many mtn bike racers in the sport that the thought is to go out hard to get position and then try to hold on. But it is important to understand that a racer in a 2+ hour race really should not be exceeding Lactate Threshold early in the race, especially races at altitude. And position in a ski mo race is not as critical because it is easy to pass once things settle out.
When I got a LT test last year I learned that I was going out way too fast (also learned my LT was at a lower heart rate than I thought). Just as an example, last year at Nationals (couldn't make this year's race unfortunately) I changed my strategy and started below LT pace. I had to hold off the urge to go with the leaders. Halfway up GV I was in about 20th place. At the top of the first climb in about 12th place. By the Corbetts' boot pack, 7th place. And ended in 5th, quickly gaining on 4th. It felt great too. By comparison, the 6th place racer was ahead of Pete halfway up the first climb.
On the eating front I was watching a 50K world cup nordic race last year (winner finishes in about 2 hours.) The leaders took their first water bottle 17 minutes into the race. I figure if the fittest aerobic athletes in the world are taking in fluids and calories that early, I better be.