What % of lactate threshold heart rate should I use for 2x20's? (My LTHR is 167.)
IMHO, the only accurate power readings will be from some sort of power meter. Unfortunately, even the best mag and fluid trainers will vary. I have a very good fluid trainer at home, and depending on temp, etc, the resistance will feel differently.tyro said:Can you use a gearing/rpm combination and calculate a power output?
I could see how rollers might be a different story, but I am assuming you are using some kind of tension like a fan or somthing. Honestly a fan would be better than fluid. Magnets are better as well. Like I stated, my trainer is a fluid trainer and it seems to be slightly different everyday.yz_387 said:I do 2x20s without a power meter by finding the speed that gets my HR to 90% of LTHR, then I hold that speed for the entire 20 min. I figure holding the speed constant means I am putting out approx the same power throughout the interval even though my HR rises as time passes. FYI, I have been doing them on rollers, so I figure if my tire pressure is constant then the power output for a given speed is pretty constant from one day to the next. If you are doing them on a trainer however, you have the added variable of how hard you tighten the resistance mechanism to the tire. It is not perfect, but it works for those of us who are not fortunate enough to have a PM.
You need to explain what you mean by or how you arrived at LTHR.tyro said:What % of lactate threshold heart rate should I use for 2x20's? (My LTHR is 167.)
I had it tested in a physiology lab. I rode on a trainer and they pricked my finger, etc...Alex_Simmons/RST said:You need to explain what you mean by or how you arrived at LTHR.
If that is a measure of your HR for long duration pace (lactate threshold), then you'll need to ride harder than that for typical 2x20 workout. You'll need to test yourself in a TT like effort to find out what range of HR makes sense. It won't be one value, but a range.
If you mean that's your HR when you are doing a threshold/time trial effort, then there's your answer - ride at/near that value but start a little below. It'll most likely drift upwards through the effort and take a few minutes to get up to near that level, if you maintain a consistent pace/effort that is.
If you see it flat line or drop, then you probably started too hard and faded.
You should be aware that tire rolling resistance, which is a major component of the resistance you have on most rollers, drops as the tire heats up. The odds are good that your tires heat up when you go into an interval, so that is throwing your numbers off a little. How to correct for it, I do not know. It's just something to keep the OCD among us awake at night.yz_387 said:IFYI, I have been doing them on rollers, so I figure if my tire pressure is constant then the power output for a given speed is pretty constant from one day to the next.