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Thursday
Oct132011

Quadrant Analysis: What You Need to Know About the 'Other Quad'

This is the first in a three-part series where Hunter Allen discusses Quadrant Analysis and how to apply the theories behind this science to your cycling training.  In the first post, he explains what QA actually measures and takes a look at an example of QA for a crit.

 

Let’s think about those leg muscles and all that they do, especially the quadriceps muscles (the big ones on top of your upper leg).  The ‘quads’ tend to be the leg muscles that get the most work, and also the most sore and the quads contribute a significant amount of work toward propelling you forward on a bicycle as they are the muscles that help to push the pedal downward on each stroke.  As you know, sometimes you have to contract your quads more forcefully when your cadence is slower and when you are going up a steep hill for example and other times you don’t have to push down very forcefully at all, but your cadence is very quick.   The quadriceps, along with the rest of the lower body muscles, need to be able to contract forcefully and slowly and also contract lightly and quickly in order for you to become a successful cyclist.   To me, it’s another one of the great things that makes cycling so challenging: You need to have the ability to pedal both hard and slow, along with easy and fast.  The best cyclists can do a bit of each and while even the best cyclists have strength in one or the other, they also train these skills as well to improve the weaker of the two skills.   You see, the rider that feels more comfortable mashing a bigger gear most likely has more ‘fast’ twitch muscle fibers (type II), whereas the rider that likes to ‘spin’ typically uses more slow twitch fibers (type I) and this is important because if your event is going to require you to pedal hard and slow, but in training you always pedal easy and quick, then you might not be ready for your event.

                This is where the ‘other’ quad comes into play.  That other quad is called Quadrant Analysis.  Quadrant Analysis is a tool that allows you to understand whether or not you are indeed pedaling correctly for your given event.  What does ‘correct’ pedaling mean?   Well, thinking back to this idea that “training to the specific demands of the sport is paramount to succeeding in that sport” and of course you would agree that practicing basketball all day is not going to help you win a 100 mile road race,  and the same applies within the sport as well.   Riding at a cadence of 100 rpm for 3 hours is not going to prepare you well for a race that is going demand that you ride at 80 rpm for 2 hours and then 100rpm for the last hour.  You just simply are not training specifically for the demands of the event.  This is where quadrant analysis comes into play.  

Scientific studies using a variety of techniques  have found that threshold power (FTP) represents not only a threshold in terms of the power that an athlete can sustain, but also somewhat of a threshold in terms of fast-twitch fiber recruitment.  To state it another way: When pedaling at a typical self-selected cadence, functional threshold power appears to occur at the power (and thus force) at which significant fast-twitch fiber recruitment first begins.  Thus, not only does cardiovascular fitness play a role in your success, but so does your neuromuscular function.  Neuromuscular function sounds complicated, but it simply means how fast you can contract a muscle, how strongly you can contract it, and how long you can keep it contracted before relaxing it again.  Even though no commercial power meter has the ability to directly measure the forces applied to the pedals, it’s possible to derive the Average (over 360 degrees) Effective (tangential to the cranks) Pedal Force (both legs combined) or AEPF from the power and cadence data. (Refer to page 132- Training and Racing with a Power Meter book for more info).   One must also understand the relationship to velocity in order to really get a better understanding of this and Circumferential Pedal Velocity (how fast the pedal moves around the circle it makes) or CPV can also be derived from cadence and crank length.

What does this mean to you as a cyclist?   Well, it means that with your power meter and quadrant analysis, you can make sure that you are indeed training properly for the cardiovascular AND neuromuscular demands of your event.  Enough of this physiology speak; let’s examine some different quadrant analysis plots so you can understand how to apply this in your own training.   

The first plot is a plot showing you what a typical criterium would look like.  Quadrant Analysis is incorporated into both WKO+ and TrainingPeaks software, so if you're using a powermeter, you can look at this data from your own workouts and races.  Figure 1 shows how most of this race was spent in Quadrant IV (low force, fast pedaling ) and Quadrant I (high force, fast pedaling) and this is characteristic of a criterium in which the rider has to keep a high cadence to respond quickly to changes in speed, along with hard sprints which come relatively often either out of turns, for premes or for hard attacks.   

 

 

Over the next two posts, we'll take a look at more examples of what Quadrant Analysis looks like for different races and talk more about how to apply it to your training.  Stay tuned for part 2 tomorrow!

 

 

Hunter Allen is the co-author of “Training and Racing with a Power Meter," co-developer of TrainingPeaks WKO+ Software, and is the CEO and Founder of the Peaks Coaching Group.   He has online training programs available at www.TrainingPeaks.com/hunter   and you can contact Hunter or any of his coaches about a custom training plan directly www.PeaksCoachingGroup.com

References (2)

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Reader Comments (4)

In your writing you explain the graph as " most of this race was spent in Quadrant II (low force, fast pedaling )" but in the picture you have the low force, fast pedaling int Quadrant IV. Or am I reading this wrong?

October 13, 2011 | Unregistered CommenterJeff K

Hunter, I've been thinking a lot about quadrant analysis and observed that in criteriums and road races, I tend to get a reverse trend which is a direct mirror of the expected curve ... I've got an example from a criterium here - http://toonecycling.files.wordpress.com/2011/08/critpf.gif (race - red circles, warm-up/cool-down - black circles). Can you address source of the reverse trend in one of your future articles? I would assume drafting somehow plays a role.

October 14, 2011 | Unregistered CommenterBrian Toone

Thanks Hunter. It is good to know when and where "fast" twitch muscles take over. I can sure notice the differences during my races. It is a bit counter intuitive though: "fast" twitch muscles taking over when cadence slows, with power held constant. I'll check your book for more on the subject. I appreciate the information. Ciao.

October 15, 2011 | Unregistered CommenterPeter

Hey Brian- Great to hear from you! I am not sure what you mean by reverse trend because your screenshot shows exactly what a criterium should represent. tons of time in QI and QIV. Fast pedaling and either hard or not so hard pedaling, so that makes perfect sense in how a crit should be. Warm-up? That's QIII always, not so hard pedaling and not so fast either... Just warming up the muscles. I think you are dead on there. The key that you need to use here is that it asks the question: Are you training in QI and QIV enough(in your training rides) so that you are ready for those tough crits?
Hunter

October 22, 2011 | Unregistered CommenterHunter Allen

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