ho trovato sul sito power2max a questo indirizzo:
http://www.power2max.de/europe/en/leistungstests-teil-2-berechnung-der-schwelle/
2 metodi di calcolo FTP che non ricordo di aver letto sul libro...
Estimating from short duration tests
If you have a recent 5 and 20-minute best effort, you can estimate your FTP. Some sources suggest that simply taking 95% of your 20 minute value offers a reasonable estimate. I have found that this significantly over-estimates the FTP in most circumstances and offer this alternative method:
- Identify the % drop off from your 5 to 20 minute test
e.g. if 5 minute = 400W & 20minute = 300W, the drop is 100W or in % terms, 100/400 = 25%.
2. Multiply this % by 0.75 = 18.75%
3. Take this % off the athlete’s 20 minute value to get a good estimate of FTP.
So, for this athlete, we would multiply his 20 min test of 300W by 18.75% = 56W and subtract this from 300W to get a good estimate of FTP, in this case, 244W.
This method takes into account the very real differences in each athlete’s power-duration or ‘fatigue’ curve, a concept we’ll explore in future articles.
Estimating from aerobic tests
Even a 20 minute best effort test can be excessively stressful for certain athletes at certain points in the year. However, even at these times, a relatively accurate, ‘real
time’ estimate of FTP is required in order for training metrics to be valid. Fortunately, threshold can also be estimated from the ‘bottom up’ just as accurately as from the ‘top down’.
If you know your actual threshold heart rate, max heart rate and resting heart rate and you have a good number of data samples from the sub-maximal tests outlined above, you can do this with a good deal of precision. However, even if you don’t know your exact threshold heart rate, you can get a good estimate for FTP with the following method:
Threshold heart rate tends to lie approximately 20 beats below max heart rate (85-92% of max). You’ll remember from the heart rate test that I outlined above, I recommended an interval at ~40BBM and another at ~30BBM. This lends itself easily to the extrapolation of 20BBM a little further up the curve.
For example:
Power at maximum – 40 bpm = 200W,
Power at maximum – 30 bpm = 230W (a 30W jump for 10 bpm)
We would expect a similar jump when increasing heart rade leading to an estimated FTP of 260W.
Of course, this is a heart rate measure, so you’d probably want to do this test a few times before ‘going firm’ on your FTP. However, the good news is, you can! This is a very low stress test that can be done very frequently to assess changes in fitness. It is an estimate to be sure, however, an up to date estimate is far more valuable than an
expired ‘true’ 1 hour test. Fitness changes more quickly and more significantly than most athletes realize over the course of a season.
In my next article we’ll take a closer look at critical power testing and what it can tell you about your strengths and weaknesses as an athlete.
che ne pensate?! (e che ne pensa Roberto)?