First 90" of an interval: why does this feel so bad?
Say you're in a session that includes two or three FT bike intervals. Are you able to go to goal watts immediately in your second or third interval and stay at it, or do you need to build to it? For years, I've found that at about 90 seconds into the second or third FT -type interval of a w/o, I get this terrible feeling in my legs. It's not the same feeling as lactic acid build up late into a hard set - i know what that feels like - but actually feels much much worse. On more than one occassion (okay, pretty much always) it causes me to just back out, recover another 2' or so, and get back at it.
1) physically, what's happening here? There's some metabolic process going down, I would guess, but what exactly is it? I can't see any markers - like a rise in HR or RPE - that correspond.
2) my workaround is to build up to the goal watts ... so if the set is calling for 2 x 20 (4) @ 275, the first set can be a solid 275, but set two ends up being ~245 for the first two minutes, and then 275 for the remainder (the NP typically ends up being close enough). Any reason to change or rethink this?
3) is the recovery interval the culprit? Is this sensation telling me that despite the RI, I still haven't flushed out the lactic acid from my muscles, and take a few more minutes to stand down?
Dave
ps apolgies if this gets covered in basic 'training with power" EN resources - I remember coming across a good discussion of it a few years ago, but can't remember if it was in EN, CF or Gordoworld.
Comments
This is an interesting physiologic question which I don't have the answer to, but I have experienced it in a different form and also wondered about. I'll offer an few theoretical thoughts that may or may not have validity, but certainly make me feel better about the phenomenom. Whenever I start a run (not a brick), the first 60-90" always induce a feeling of "This is really hard, and I don't want to do it." Then, it's almost as if I feel a gear click internally, and I'm into run mode, instead of I-don't-want-to mode. What I imagine happening is that somehow my internal homeostatic mechanisms take some time to get the message that I'm actually going to be working harder for a sustained period, and so changes in blood flow (increase to muscles, decrease to gut, etc), heart rate, hormone release etc occur which allow for the harder level of sustained activity.
Similarly, whenever I do a hard swim after rest, like a race, the first 75 meters seems effortless (about 45-60"), as if I could do it without taking a breath, and then all of a sudden, it starts to become work. I had always envisioned that as switching from anaerobic to aerobic energy sources, and maybe that's also at work here.
I don't get this doing bike intervals. Note the times I get this feeling are after I am starting up from a complete rest, say with an HR of <50, rather than after a good warm up of 15-20 minutes.</p>
For the bike, when I'm tired, I also face Dave's issue, and for me the solution is - as you suggest - to warm into the hard interval over a few 10s of seconds if necessary. For whatever reason, this somewhat slower change of effort is less troublesome, and as long as the interval is of a reasonable length, I think it's inconsequential.
But here's another one:
Running, I sometimes get a very obvious anomolous HR response when just getting going. Starting out near resting HR, I go quickly to above LT (without actually running very hard). I feel bad, but maybe not quite as bad as when I've "earned" that HR through faster pace. Then, a few min later, and just as quickly, the HR drops down to the normal level and everything is fine. I associate it with warmup at some level, but don't know the physiology. Fortunately, I've learned to recognize this and just run through it, waiting for it to pass before doing whatever hard set I have in mind.
@ William - after reading this month's Inside Triathlon article on Ventricular Tacycardia (e.g., what led to Greg Welch's retirement), I wonder if you should get a stress test or some sort of cardio eval. Even supremely fit people, apparently, can get conduction anomalies triggered by small areas of heart fibrosis. A heart rate going that high that soon sounds like some kind of an arrythmia to me. I'm not suggesting you have a problem, but it doesn't sound normal, and (if you have insurance), it can't hurt to at least ask a doc about it. Of course, you should rule out HR monitor malfunction first!
Usually when that happens, it is a heart rate monitor thing, not an actual heart rate thing. Sometimes it takes a minute or two for enough sweat to accumulate and make good contact, and while that ie happening, the friction of the strap can cause faulty high readings. Used to happen to me all the time with my polar unit. Seems to happen a little less with my garmin, though it still happens.
Have you checked your pulse with a finger just to double check?
Mike