Question concerning 2x20 and HR

London knight

Hello:

I am new to this forum and I have a question concerning the relationship between power output and HR when performing 2x20 intervals. I am using a combination of HR monitoring and gear ratios rather than actual wattage measurements in order to gauge my work output which is obviously not as accurate. When I begin the interval I find it takes several minutes to bring my heart rate up to L4. Once I reach L4 (while maintaining a cadence of ~ 80rpm) I find I need to gear down as the interval progresses in order to stay in L4. If I were to stay in the gear ratio in which I began the interval there is no way I could maintain the intensity for the entire interval. However, once I have geared down, my HR stays in the correct zone but my wattage has actually dropped by the second half of the interval. Should I be performing the 20 minute interval based on perceived effort (ie use a gear ratio that I know I can maintain for the entire interval ) and pay less attention to my heart rate? (Does that make any sense?)

Alex Simmons

Do them based on wattage and forget your HR. HR will drift naturally upwards over time when riding at a quasi steady state power level (and not just at L4). Adjusting your effort down to maintain a HR is far less optimal training. If you are unable to complete the 2x20s at the same/similar power then you are either too fatigued to start with or the wattage level chosen was too high, so knock it down a touch.

You don't need to ride at maximum effort level for 2x20s in order to gain the LT improvement benefits though. Riding at a power level of at least 90% of that level will have almost exactly the same physiological impact.

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POGATA

Link to article.

Sillyoldtwit

+1 Alex. Forget you HR. Tyson

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cnudell

I do exactly that. I do not have a power meter so I use gear ratio and cadence to simulate exactly the power-based training effect (without knowing the power number. I do know my TT / LT / HR numbers and stay at that desired 82% level for 2x20.

Yes, you have to start in a lower gear to sustain it for the whole 20min. This will come with experience.

I do not see anything wrong with it.

cnudell

This article states (quote):
"Don’t despair if you haven’t ponied up for a powermeter. Even conceptual understanding of the graphical analysis below will help you conduct your intervals by “feel”."

"Feel" to me means exertion estimate and experience therefore it is OK to use gear ration and cadence to simulate the 2x20 power training.
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London knight

Thanks for the info. The article was very useful. Based on my limited experience with these type of workouts It seems to me that performing 2x20s on a home trainer can be effective based on feel. However, on the road this might be more difficult because of other factors such as terrain/ wind conditions etc. I can see where a powermeter would certainly take the guesswork out of the interval workout

bing181

My 2c.

I have a trainer with power, and my HR takes most of the first 20 mins to get up to where I need it. Even after 10 mins it can still be 5-10 bpm lower. The telltale signs are with the second interval (same power, same cadence), where HR "gets up to speed" in the first 2 or 3 minutes, and pretty well stays there - though there's often still a drift upwards of 2-5 bpm over the remainder of the interval.

As has been said, do a few and you'll find the cadence/gears that work for you. Based on my experience, I would be looking at what happens in the second 20 to find what you need.

B

bing181

My 2c.

I have a trainer with power, and my HR takes most of the first 20 mins to get up to where I need it. Even after 10 mins it can still be 5-10 bpm lower. The telltale signs are with the second interval (same power, same cadence), where HR "gets up to speed" in the first 2 or 3 minutes, and pretty well stays there - though there's often still a drift upwards of 2-5 bpm over the remainder of the interval.

As has been said, do a few and you'll find the cadence/gears that work for you. Based on my experience, I would be looking at what happens in the second 20 to find what you need.

B

Ade Merckx

Hey LK like you last year I trained quite a bit on the trainer by heart rate/feel. It was ok. but Peceived Exertion can really throw a spanner into the works on trainer only rides.
Ouite often I'd change down from 53/17 to 53/19 and it would feel just as hard, due to heat, lack of road feel etc. The rear wheel speedometer wasn't the best at always picking up speed/power changes. Coupled by the fact it was a cheap £70 trainer probably didn't help much. So I'd say continue but be warned trying to assess just small improvements accurately on a turbo based on feel alone is difficult. Sometimes its those small improvements that you want to see because they drive you on to train a bit harder and make bigger fitness gains. See SillyOldTwit's use of the gym trainer in his recent training stint from Aug -Oct for his big race - Inspirational !!I can evaluate my improvements much more accurately now too cause I have a KK

Sillyoldtwit

Ade, what powermeter are you using?

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Ade Merckx

I've got a Kurt Kinetic and its excellent. I bought it from Planet X

Sillyoldtwit

Thanks for that. Tyson

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cnudell

Perfect timing for this post as I was going to describe the following training session but now all I have to do is post the picture...note the second 20...

If you really want, you can even estimate the power using some calculations/tools such as: http://www.kreuzotter.de/english/espeed.htm
You will need to know the gears, cadence, calculated speed, and bunch of other assumptions.

Progress to me is: cadence or gear ratio: over time I am looking to increase cadence for the same gear ratio or higher gear ratio for the same cadence for the duration of the 2x20.