# Thread: Aerobic threshold coupling workout

1. ## Aerobic threshold coupling workout

There is a section in Joe Friels Cyclist Training Bible about measuring fitness during base training which he calls an aerobic threshold coupling workout, which involves completing an aerobic zone 2 ride, 30mins > 120mins, keeping the heart rate steady and seeing what happens to power.

Some number crunching is then done to the avg HR and power for the first and second half of the zone 2 portion of the ride. If the shift between HR & power is less than 5% then this is considered good and that you have a low level of cardic drift, when you can complete a ride like this for 2hrs with a shift of less than 5% then you can consider your aerobic thershold fitness fully developed i.e.base training.

Not having a power meter Would it be possible to adapt this kind of workout using HR & cadence on an indoor trainer. I completed a ride this morning on the trainer where I kept my HR as steady as I could midway within zone 2 for 30mins, pressing the lap button at the 15 & 30min point, without looking at the cadence, noting the resitance, gearing and also the warmup routine for future similar rides. The data from my Garmin shows somthing like this, a steady HR and a slight cadence drift as I slowed slightly to maintain a steady HR. Overall the HR remains close to parallel to the cadence for the aerobic portion of the ride.

I then entered the avg's of HR & cadence as required into a speadsheet I put together to do all the maths, and it looks like this. Which indicates a drift of just under 5%

Am I correct in substituting power for cadence for this type of work out? What are your thoughts on this?

2. Cadence doesn't equal power but I see what you're saying about staying in the same gear and maintaining the same cadence should equal a constant power output. I don't know that the math is working right but it seems that if you are maintaining the same gear and cadence that it should suffice for measuring HR drift. I would look at the inability to maintain cadence as a loss of power though and there's no way to determine the power loss there so I don't see it as a good indicator of power output.

3. Originally Posted by ACDC
Am I correct in substituting power for cadence for this type of work out? What are your thoughts on this?
The premise seems sound to me as long as the resistance stays the same and you don't shift gears. The catch is that the resistance on a trainer will increase with speed. So your cadence is not directly proportional to power, but has some exponential relationship instead. However, I would expect the effect to be small since you are going at a fairly constant cadence.

4. Thanks for the replies, just thought it would be interesting to have some way to measure gains during winter base training, I might complete the test gain, this time maintaining a steady cadence and seeing what happens to HR.

5. If you have the power curve of your trainer, you have a speed to power equation and can use software to get your power from speed with reasonable precision, especially for such a ride where heat buildup in the trainer is not much of a concern. If you use a Kurt trainer, heat drift is very limited so it's pretty good too.

Check out this SportTracks plugin : SportTracks &bull; Plugin Catalog &bull; Trainer Power Track

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•