I started training with PowerCranks in April of this year and have been using them regularly for the past 6 months.  To sum up my experience: They work.

 

The adaptation phase was slow, and it took me about a month to get acclimated and able to sustain an outdoor workout on the cranks.  In retrospect, it would have been better to begin PowerCrank training in the winter.  By May, base building was finished, racing season was in full swing, and my training plan called for a lot of short high intensity workouts each week.  PowerCranks really excel at isolating the minor cycling muscles — especially the hip flexors, outer hamstring (semitendinosus), and claves.  These are muscles that aren’t well trained, and until you build up the necessary muscular endurance, it is difficult to jump right into weekday intervals.   For that reason, I think it’s best to begin Powercranking in the strength building phase of an annual periodization plan.  Since I was starting in April, I had to gradually work my way up to being able to complete my workouts on the PCs.  Each week, I did a little more of my training on the PowerCranks until I was riding them 5-6 days per week by mid-summer.  At that point, I started to notice some real improvements.

 

The two things you can do to increase power output on the bike are 1) apply more force through the pedal stroke and 2) spin at a higher cadence (power = torque x velocity).  I approached PowerCrank training by trying to attack these variables one at a time – building strength first, and speed second.  I started with high gear, low cadence pedaling, focusing on maintaining power through the upstroke.  Given that my hip flexors were underdeveloped, I could only handle short workouts at first, lasting 30-45 minutes with a cadence under 75 rpm.  As my muscles adapted to the PCs over the first month, I was able to complete 60-70 minute workouts, at a cadence of around 80.  Low cadences allow you to recover between repetitions, which kept me from going anaerobic.  My initial goal was to complete a Central Park lap without coasting, and soon I was doing 4 consecutive laps this way.  I focused on increasing my cadence each week as my workouts got a little longer.  After two months, I could sustain a 90 rpm cadence for about 2.5-3 hours, and began riding the PowerCranks on 9W to Piermont and doing River Rd repeats on them.

 

By July and August, I was feeling a noticeable difference when riding my standard cranks and there were definite improvements in my time trialing ability.  I was summoning extra power from previously underdeveloped muscles, and riding above my previous threshold.  My max 20 minute average power went from 310 watts early in the season, to 350 watts, and my 5 minute average improved from 375 to 430 watts.  In field test workouts, I saw my best Central Park lap time improve from 15:10 early in the year to 14:23 by August.  I was also getting better race results than I ever did before, too (1^st at Silvermine, 2^nd at FBF TT, 9^th at GMSR Prologue).

 

One of my weaknesses is the ability to recruit fast-twitch muscles to generate short-term power, and as a result, I’ve yet to be competitive in a field sprint.  However, I’ve made definite progress by working high cadence drills into my PowerCrank training.  High cadence drills on PowerCranks are essentially plyometric excercises on the bike, where you are training the ability of your hip flexors and hamstrings to put out explosive power in short amounts of time by doing a bunch of repetitions in rapid succession.  Also, the cranks themselves are very heavy, which accentuates the upstroke since it feels like you have weights tied to your feet.  The plyometric aspect comes from each leg working independently so the upstroke is distinctly the harder (concentric) phase of the movement and the downstroke is the easier (eccentric) phase.  By contrast, your quads tend to do more of the work on normal cranks, as the upstroke is assisted by the downstroke of the opposite leg.  I still need a lot of improvement before I can be an above-average sprinter, but my power numbers have increased substantially.  At the end of last season, I would consistently max out at 1100 watts in a sprint.  By September of this year, I could regularly hit 1265 watts.

 

Next season, I’m going to continue with the PowerCranks with the goal of achieving further improvements.  I’m planning to work with a coach this winter to build PowerCrank-specific workouts into my training schedule, and will ride them consistently throughout the year.