Friday, February 5, 2010

Quandrant Analysis

I just discovered quadrant analysis in WKO+.  I've used WKO+ for several years, but QA is a new feature in the latest version, and I hadn't gotten around to looking at it until recently.  It's pretty damn cool, but really it's a little more sophisticated than I need.  The gist of it is that there are four ways you can pedal your bike:
  1. Fast and Hard: high cadence, lots of power (Sprints)
  2. Slow and Hard: low cadence, lots of power (Strength workouts, hill climbing)
  3. Slow and Easy: low cadence, little power  (Recovery ride, Warmup and Cooldown)
  4. Fast and Easy: high cadence, little power (Criteriums, long distance rides, technique drills)
So they take information about your ride from your power meter (force, cadence) and figure out for each second of your ride in which category you were in, and plot it.  Technically I just lied to you.  They don't really plot power vs. cadence - it's actually force vs. pedal velocity.  There are legitimate reasons why they do this (read here) but they derive force and velocity from power and cadence - which is easier for my brain to wrap itself around.  The plot looks like this:

  This graph is from my hill repeat workout this week which consisted of six climbs up Torrey Pines (400 ft climb over 1.4 miles, 5% grade).  The red dots are samples from my first trip up the hill, which was a strength building climb using my big chainring.  The yellow dots are from my 4th trip up, which just happened to result in a similar power figure than the big chainring climb (258 vs. 263).  The blue dots are "everything else" in the workout and can be ignored for this discussion.  The sweeping brown/yellow/grey arcs just indicate my threshold power and can also be ignored.
So looking at the red and yellow dots, it's clear that they are all grouped together.  The red dots are significantly further up and to the left of the yellow dots.  This equates to the first trip (big chainring) being at a lower cadence (left) and higher power (up) than the other trip.  Same power output (258 vs. 263), same distance (1.47 miles) yet accomplished in drastically different ways.
I guess none of this was news to me, of course there's two ways to climb a hill: spin up it in an easy gear, or power up it like a weightlifter.  But it's kind of cool to see it graphically.  Plus, it might be good for planning future workouts.  Got a flat, short race coming up?  You're going to want to do a lot of Quadrant 1 (top right) workouts to prepare.  Recovery ride today?  Stay in Quadrant 3 (bottom left).  Working on perfecting your pedal stroke?  Maybe Quadrant 4 is right for you.  Instinctively I think most people already know this - but here's a tool that lets you (or your coach) go back and verify that you did it right.  I think this is more of a "isn't that interesting" feature than a "I have to use this daily" thing - but I must say I like graphs :)
Just in case you're interested, here is the graph from one of my CP30 tests.  This was done on Fiesta Island here in San Diego, which is a pancake flat ride.

The red dots are the ones to look at here, blue are from warmup and cooldown laps.  First, you'll notice that almost all the red dots are above my threshold power of 223 watts (yellow line).  I was going as hard as I could, as you can see on the right side it was 254 watts for 31 minutes.  You'll also notice that horizontally the dots mostly fall in Quadrants 1 and 4 (right side) meaning my cadence was high.  In fact, it's listed in the bottom right corner as 96 RPM for this test.  I would qualify this as a "Hard and Fast" Quadrant 1 workout - which is exactly what it was supposed to be.  Of course, I'd love to move my dots up and to the right as far as I can go!
I'm doing hilly IM courses in St. George and Wisconsin this season, and when I climb hills I end up in Quadrant 2.  So it looks like Q2 will be my new home for the next 7 months.

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