# Threshold test question...



## soulfly_nyc (Feb 16, 2007)

So i want to do a field test for lactate threshold. In other words, to see what kind of wattage i can sustain for 20 minutes on a computrainer.

2 questions:

1) On tonight's workout on the computrainer my average wattage after 20 minutes of riding was 298w. * Is that my threshold?*

The course program was basically a slight incline for the first 20 minutes with maybe a 2% incline on average.

2) Regarding the calibration of the computrainer: the shop employee asked for my weight + 20lbs which he typed into the computrainer. Then he asked me to pedal hard enough to get the LCD readout over 25 and then coast down....*Does this sound like it was calibrated correctly?*

I'm asking because the employee was self-admittedly "new" to the system.

Thanks for all the info.


----------



## Guest (Feb 11, 2009)

soulfly_nyc said:


> So i want to do a field test for lactate threshold. In other words, to see what kind of wattage i can sustain for 20 minutes on a computrainer.
> 
> 2 questions:
> 
> ...


I don't know how to do the calibration on the CT so I won't touch that but as for the rest assuming it was an accurate measurement:

Your threshold or functional threshold power (FTP or CP60 in some text) is over an hour so the 298 might be a bit high. In Coggan and Allen's book they take 95% of that 20 minute interval.

However there are a couple of things that might affect how truly that represents your threshold. First, if you don't train indoors regularly or if it was warm in there without much airflow it can cause you to under perform. If properly cooled you can get to where your stationary trainer performances are about the same as outside but it does take a little adaptation for many. The other thing would be something you would have to judge and that is how you felt at the end of the 20 minutes and how well you paced the 20 minutes. 

Thus if you paced evenly, feel that is the best 20 minutes you could've ridden and are used to training like that on a stationary trainer then about 95% of that 298 is your threshold. Any deviation from that could effect the accuracy of the numbers, but its still probably a good place to start.


----------



## soulfly_nyc (Feb 16, 2007)

Thanks a lot for this info.

I started off strong, the first 5 minutes was an average of 330w. Then the next 12 minutes was around 270-280. Last 5 was around 300-350w...continued on the training ride for another 20 minutes at which point my average was indicated at 275. Total ride was about 1h20m and wattage average was around 260.

I'm guessing i can push the first 20 minutes a little harder next time. I definitely was not at max heart rate at any point in the session.


----------



## Guest (Feb 11, 2009)

soulfly_nyc said:


> Thanks a lot for this info.
> 
> I started off strong, the first 5 minutes was an average of 330w. Then the next 12 minutes was around 270-280. Last 5 was around 300-350w...continued on the training ride for another 20 minutes at which point my average was indicated at 275. Total ride was about 1h20m and wattage average was around 260.
> 
> I'm guessing i can push the first 20 minutes a little harder next time. I definitely was not at max heart rate at any point in the session.



After warming up (and I would use the same one each time) try to pace the 20 minute effort pretty evenly, you can ramp it all the way to the end if you feel like you have a little more in you but don't start to hard.


----------



## sabre104 (Dec 14, 2006)

I hope you warmed up the CT properly first. The magnets inside the load generator that simulates the wattage require a 10 to 15 minute warm-up period. Ride at 100 watts( what's shown on the controller) and every 30 seconds increase the load by 5 watts until the 5 minute mark. You should be at 150 watts by then. Do a run down test and set the controller at what comes up on the controller ( for now). Ride a additional 5-10 minutes and do another run down test and you will have the final setting( and you will notice a different number) and your CT will be warmed up and calibrated properly. 

Hope this helps.


----------



## allison (Apr 19, 2006)

This may or may not help you, but Jason Hilimire has been posting up links to the article recently (and I saw it on VeloNews yesterday):

What to do with your new power meter

I realize all of it may not specifically apply as you didn't just get a power meter, and already did the test, but maybe it can answer a few Q's or set you up better for next time around.


----------



## MontyCrisco (Sep 21, 2008)

It seems important to re-test at a later date, and on an ongoing basis - in addition to gauging progress, it also helps you be sure you're getting reliable test results. If your average comes back wildly different each time, you're not doing it right. I'll leave it to the pros to tell you how often to re-test though. 

Also, one way to figure out how reliable your measurement is on a given day would be to use a measure of variance like standard deviation (e.g., dump your power over time into an Excel column then calculate STDEV). In plain English this gives you how variable your measurements were for a given test session. (It's the mean difference of all measurements from the actual mean, if that makes sense.) The STDEV from a single test tells you how much you tended to vary in terms of power from your average power. And over the course of multiple tests you will see that the STDEV is smaller in tests when you are more consistently riding at your optimal power, and it will be bigger if your power is inconsistent throughout the 20 minutes.

Just a thought...


----------



## Alex_Simmons/RST (Jan 12, 2008)

Are you using a power meter in training?

If not, then the CT result is basically a one-off benchmark, which you can compare yourself to on another ride on the CT but that's about it.

If you are, then use the power meter while on the CT.

Just a point of clarification:
The power you can sustain at Lactate Threshold is some way below (~10-15%) the power you could sustain for a ~1-hr TT (aka Functional Threshold Power) which is typically ~4%-10% below what you can maximally sustain for ~20-min.

If it's FTP you are interested in estimating, then here are some thoughts on the topic:
http://alex-cycle.blogspot.com/2008/05/seven-deadly-sins.html


----------

