Training with LTHR using a HRM

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Training with LTHR using a HRM

Postby stretch » Sat Nov 01, 2008 9:54 am

So I've just picked up a Polar CS600 and Im itching to get into some workouts based upon lactate threshold heart rate. Once a good value for LTHR has been determined it is then possible to train in zones around this value. The problem with the Polar is that it wants to use max HR to base training zones on.

How should I go about entering the data so I can best train as %'s around LTHR?
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by BNA » Sat Nov 01, 2008 11:19 am

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Postby Alex Simmons/RST » Sat Nov 01, 2008 11:19 am

Well since one can sustain riding at LT for several hours, your HR at LT is probably not a good place to start.

There are two broad options:

1. Use training levels/zones based on Max HR (provided you have reasonable confidence on what that is).

2. Use training levels/zones based on your average HR for a well paced time trial of say 25-60 minutes. I say average because for a well paced TT, HR will steadily rise through the course of the ride. If HR remains flat, that typically indicates poor pacing.


Here's a quick summary of HR zones I have, based on % of Max HR and a guide as to the typical duration of efforts:

<70% Recovery (up to 90 min)
75-80% - Core endurance (1 to 6 hours)
80-85% - Tempo (30-120 minutes)
85-92.5% - Sub-TT to TT (5-60 minutes)
>92.5% - Maximal Aerobic (2-8 minutes)

I actually have them broken down a bit more than that but from a basic training guide perspective, these are a reasonable compromise between being broad enough to be simple to use and specific enough to be targeting the major physiological elements of aerobic fitness.

If you want to use your avg HR while TTing as the anchor for zones, rather than reproduce them, they are described as a HR estimation/proxy next to power training levels here:
http://www.cyclingpeakssoftware.com/power411/levels.asp
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Postby stretch » Sat Nov 01, 2008 12:08 pm

Thanks Alex. But isn't it true that different people will go anaerobic at different %'s of max HR. Therefore, if you are training based on max HR you may be riding in an aerobic state when in fact you are attempting to train at an anaerobic intensity (and vice versa)?

I am going to conduct a LTHR test as described by Joe Friel to find a rough estimate. Basically it is the average heart rate in the last 20 mins of a 30 min TT.
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Postby Alex Simmons/RST » Sat Nov 01, 2008 4:13 pm

stretch wrote:Thanks Alex. But isn't it true that different people will go anaerobic at different %'s of max HR.

Well the question really doesn't make sense because HR response is far too slow when talking about anaerobic efforts.

If you mean perhaps when the Onset of Blood Lactate Accumulation (OBLA) occurs, then sure, that will occur at different relative HR to HR Max for different people but even then for an individual it will vary from day to day and upon the protocol of the ramp test used to assess it.

stretch wrote:Therefore, if you are training based on max HR you may be riding in an aerobic state when in fact you are attempting to train at an anaerobic intensity (and vice versa)?

Unlikely. If you were riding anaerobically, you would be forced to slow down significantly after only a very short time.

You can only sustain an anaerobic effort for a couple of minutes at most (and even then quite a lot of your energy is supplied by aerobic sources)*, so I think you are getting confused by what's anaerobic and what's aerobic.

Anaerobic efforts are very short and very hard. HR response is way too slow to be of any value for guiding such training. Even a maximal effort of 90-seconds duration is still dominantly powered by aerobic metabolism.


* how long, for instance, could you swim hard while under water holding your breath?

Here's some data to help explain what I mean. It shows the relative total energy contributions from the three main energy production pathways during maximal efforts at various durations.

Image

stretch wrote:I am going to conduct a LTHR test as described by Joe Friel to find a rough estimate. Basically it is the average heart rate in the last 20 mins of a 30 min TT.

Which is essentially the same thing I suggested in point 2. of my original post.

The exception being that Friel has a tendency to bastardise many terms (e.g. LT and Critical Power).
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