By the way, this run was pretty hard (STraM called it "overreaching"). No guilt needed for missing the 10K on the schedule. In fact, this was hard enough I think I'll remember it during the 16 miler tomorrow. (Yesterday's back pain seems to have disappeared though thankfully.)
The experiment. As I planned earlier, I attempted to find my lactate threshold by running a series of 1200 meter intervals of increasing pace while wearing my suunto t6. A picture is worth a thousand words
It doesn't look like I controlled my pace too well, but I think I did a pretty good job. The first hundred meters or so I would usually jump out too fast on each step up by then I settled in. The wind was a factor though.
The 15 mph wind was along the long axis of the track so in my face down one straightaway and at my back for another.I ran 7 x 1200-meter intervals with the following paces and heart rates: 9:51 min/mi (146 bpm), 9:12 (157), 8:41 (166), 8:20 (172), 7:57 (177), 7:33 (183), 7:05 (189)
Analysis. I used Willem Minten's t6 Swiss Army Knife (SAK) version v2.3.0, which can be downloaded from the WristopTrainers yahoo group files section. I imported my sdf file in and looked at the fitness thresholds tab. This is the graph I got.
It looks like it found the elbows in VE versus VO2 pretty well. It looks like the elbow occurs at VO2 = 39.5 liters/minute.The HR versus VO2 line, however, seems wrong. I guess its confused by the low heart rate from the slow jogs to the track and back (and stopping at the red light). Should I split the log, including only the 7x1200 intervals, and try again? If the only purpose of the line is to fit the heart rates, then I can do that by eye. It looks to me like the red dots at VO2 = 39.5 are at about 176 bpm.
I can then use 176 to interpolate between 8:20 min/mi or 7.20 mph @ 172 bpm and 7:57 min/mi or 7.55 mph @ 177 bpm. 7.20 + (176-172)*(7.55-7.20)/(177-172) = 7.48 mph or 8:01 min/mi pace.
My marathon pace should then be .95 * 7.48 mph = 8:26 min/mi. If I use the book Lactate Threshold's 94.3%, I get a slightly slower 8:30 min/mi.
Before, I looked at various marathon pace calculations based on my 10K race time of 47:21 and they came between 8:29 and 8:35 min/mi. So everything seems to line up. Of course today's run was on a track, so maybe my pace at LT is a little slower on a road course (although my marathon should be pretty flat and hopefully less windy).
While the pace at LT seemed to confirm what I knew, I did pick up my heart rate at lactate threshold (if I did this right): 176 bpm. If my max heart rate is still ~200 bpm then that's 88% MaxHR. I'm no longer sure of my Max HR though.
Is my MaxHR lower now? I felt like the last 1200 meters was close to redline and I tried to sprint down the straightaway to see if I could get my max. I got about 60 meters before deciding I wasn't going to get much higher. The most I saw was 191. In last fall's 5 miler I averaged 186 bpm and maxed at 199 crossing the finish link. I noted that my 10K heartrate seem much lower and topped out at 190 near the end. Is the 190 a result of the greater distance and just being too tired to max out or has my Max HR actually dropped? Here's a graph comparing today, the 10K two weeks ago, and the 5 miler last fall. I have EPOC on there just to show that today was a tough run!
You can see my sprint effort at the end of the 10K (the drop off is me forgetting to turn the watch off after the finish line) and today's workout. It certainly looks like 190-191 bpm is my max. But look at the 5 miler. I was above 190 for a lot of the time.Update: Pete Pfitzinger says here that the max hr of an untrained person can decrease by 7% with training. Now, having finished a marathon 3 weeks before the 5 miler (and having run a 10K in between), I wouldn't say I was untrained, but is it possible it's gone down since because I'm in better shape?
Should I retune STram and try again? Besides my max hr potentially being wrong, my METS and respitory rate could use tuning. I played with the STraM tuning page and using my 10K time from two weeks ago I get a METS of 13.5. I had 13.1 in STraM based on my 5 miler last fall. My breathing topped out 55 bpm (as I've seen in other max efforts). SAK suggests using 57 bpm. I still have the (strangely low) default value of 41 bpm in STraM. I believe changing these will alter VO2 and VE at lactate threshold, but unless the shape of the curves change significantly I don't think the values I care about, heart rate and speed, will change much.
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