Tuesday, August 27, 2013

An Introduction to Power Analysis

By Hunter Allen, PCG Founder/CEO and Master Coach

If you’re the new owner of a power meter, you probably have the same question everyone else does when just getting started training with power: What are the most important things I should be looking at every day? Power meter data is complex, and there’s a lot of it to analyze. Sometimes it can be so overwhelming that you can feel like you’re searching for a needle in a haystack. Which is the magic chart? Where in the graph should I focus my attention? What is my blue line doing?

Over the years I have refined my custom charts and how I approach analysis. I’ve also shortened the time it takes me to get to the most important data. So pull up a chair; I’d like to show you how I analyze power data from my clients using the TrainingPeaks WKO+ software.

1. Review the graph. Open your ride file and click on the Graph tab to view the graph of your workout, which gives you a second-by-second overview of it. This graph is the most complete picture of your workout, but it’s also the most confusing, with squiggly lines running everywhere. The first thing to do is get rid of some of those squiggly lines that aren’t very helpful, such as temperature, elevation, and possibly cadence. Cadence might be important to you; if your training included some type of cadence drill, maybe you’ll want to zoom in on that area and confirm that you executed the drills correctly and hit the cadences you wanted to hit. After that, turn off the cadence line. After turning off those three lines, you’re left with power, speed, and heart rate.

The next thing to do is view the graph in horizontal mode (un-zoomed) so you can get the big picture of your ride. Identify the intervals, climbs, hard efforts, and any area that was clearly a difficult part of the workout; mark these by left-clicking and dragging to highlight the area and create a range to review the precise metrics for it. You might want to zoom in on a particular area to be more precise in your selection of data, as it’s important to select just the absolute area that will give you the most accurate data. For example, if you did a five-minute effort but select the ten seconds before your interval commenced, your averages will be lower than they would if you started your selection the exact second when the interval began.

Once you’ve marked up your file, it’s easy to view the exact metrics for each area of interest and assess your success in hitting your goal wattages.

2. Review the quadrant analysis graph. Quadrant analysis tells you how you created the watts. 300 watts is always 300 watts (the same amount of work), but that 300 watts can be created by a different percentage of force and cadence every time. Since wattage is torque (force) multiplied by angular velocity (cadence), you can create 300 watts in your 39:21 gear by pedaling very quickly but using little force, or you can create 300 watts in your 53:12 gear by pushing hard on the pedals but pedaling slowly. Quadrant analysis is a scatterplot that graphs all your power data on an X and Y axes to show exactly how you created the wattage.

Why is this graph important? First, it begins to give you an understanding of the muscular and cardiovascular demands each ride creates. Second, it can help you determine whether you are creating wattage in training in the same quadrants that you would in a race or hard event. If not, you can change the way you create the wattage so you’re training just as specifically as you race. For example, the quadrant analysis below compares a training ride (in red) to a race (in yellow). The points are largely the same, which means that this athlete’s training ride closely mimicked his goal race for the year. Creating wattage the same way in training as you’ll have to in racing means that you’re training for the actual demands of racing, which is super important.

3. Review the cadence distribution chart. This chart tells you how much time you spent pedaling within different cadence “bins.” For example, many people spend most of the time pedaling in the “bin” between 90-95 rpm. This provides further insight into how you create power, but one thing many people miss is how much time they spend not pedaling. The amount of time between 0-5 rpm represents the amount of time you spend coasting or not creating power. This is important because cycling is a game of energy conservation; the more time you spend coasting (the less time you spend pedaling), the more energy you’ll have for later in the race. The winningest road racers pedal only 85% of the time, which means that a full 15% of the race they’re coasting, resting, eating, drinking, and staying out of the wind to conserve energy.

4. Glance at your power zones/levels chart. How much time did you spend in each power training zone? Did you spend most of the time in your threshold zone? Endurance zone? What was the dominant training zone that you rode in for the training? This is important to know because it can confirm that you completed the workout in the correct training zone or level.

One thing to remember when looking at this chart is that the time spent in each zone is not consecutive but cumulative. This could skew your view of your training ride. For example, I live in a very hilly area with lots of short, ten- to thirty-second hills that require me to get out of the saddle and ride in my anaerobic capacity zone. However, you need at least thirty seconds of effort in that zone to really stress it enough to cause adaptation and improvement. After every ride this chart makes it look like I spent a ton of time in my anaerobic capacity zone, but in reality it was a lot of short forays into the zone that accumulated throughout the ride. Even with this caveat in mind, you’ll want to regularly review this chart to give you confidence you’re training properly.

5. Review your mean maximal power periodic chart. The mean maximal power chart shows all your bests, or peaks of wattage, for certain time periods. I recommend looking at your best five seconds, best one minute, best five minutes, best twenty minutes, and best sixty minutes (normalized power) to get a clear understanding of how each physiological zone is changing. The MMP chart shows instantly if you’ve set a new personal best in any of these important time periods. This will probably be your favorite chart since it truly shows your improvements over time, and it’s always exciting when those lines move up! Look at this chart daily to keep you motivated!

6. Follow the blue line on the performance manager chart. The performance manager chart is one of the most important charts to study after the mean maximal power chart. This chart tells you how much training you can handle, when you need to rest, and when you might come on form or create a peak of fitness. I’ve written about this one extensively elsewhere, so I won’t spend too much time on this one here, other than to tell you that following your blue line (represents your chronic training load, or your training load over the last forty-two days) closely is a critical part of improvement, as that blue line represents your fitness. The higher the blue line goes, the higher your fitness goes. Of course, there’s a lot more to it than this over-simplification, but training smart and continuing to give your body additional training stress will keep that blue line climbing.

Hunter Allen is a USA Cycling Level 1 coach and former professional cyclist. He is the coauthor of Training and Racing with a Power Meter, co-developer of TrainingPeaks’ WKO software, and CEO and founder of Peaks Coaching Group. He and his coaches create custom training plans for all levels of athletes. Hunter can be contacted directly through www.PeaksCoachingGroup.com.