Richmond Puke Interval Training - Wednesday evenings?

Getting the intensity right is also really tricky if you're having to guess.

http://www.greenbank.org/misc/int_hr2.jpg

That's a plot of 5 intervals at increasing power outputs (200W, 210W, 220W, 230W, 240W). The later peaks will be slightly skewed by some cardiac drift (usual reasons: overheating, dehydration, etc). I was trying to find out what my HR would be like at the 5 different power outputs. I ended up settling on 5x5 at 230W for future sessions as I doubt I could do 5x5 at 240W without being sick or wimping out before being sick.

And that's part of the problem, without an accurate measure I really can't tell if I'm doing my efforts at 200W (bad), 230W (perfect) or 240W (bad as I'm going to fail to do 5x5 at that).

I was plugging along Embankment this morning feeling like I was riding through molasses and wondering why I was feeling so sluggish. I just felt slow and crap. A glance at the Edge 705 showed I was pushing out 350W at that exact moment; far from crap (and far from maintainable, I can hold that for about a minute max!)

(Power output figures, and associated targets, vary from rider to rider, etc)

According to my PowerTap data from real rides, I've held:-

( http://www.greenbank.org/misc/gc_rp5.jpg )

200W for 23m max
210W for 12m45 max
220W for 8m40 max
230W for 7m8 max
240W for 4m50 max (easier to maintain 240W for 5m on a stationary bike)

So you can see how fine the line is. I can't feel the difference between 230W and 240W yet it's the difference between training just right and too high. I can't feel the difference between 210W and 230W (it's only ~10%) but 5x5 intervals at 210W won't do much at all; they certainly won't replace 2 hours of tempo riding.