Saturday, July 26, 2008

2 weeks in Japan

I was PC-less for the last 2 weeks. I had to go to Japan for work. The bad news is that my trip started 3 weeks before one of my target events, The Texas State TT Championships. The good news is that I at least took my road bike. Cycling around Tsukuba, Japan is always enjoyable to me. Once you get on the quieter roads you are met with some beautiful scenery and traditional Japanese architecture. Plus there's something Houston doesn't have - hills! Tsukuba-yama (mountain) is just 30 minutes from the hotel, and I often head up the 8-10% slopes. Did that again this year and cranked out some yearly best powers in the 6-30 minute range. I won't claim a couple of weeks of PCs before the trip was the reason. In my opinion, it was more due to slightly cooler temperatures in the mornings (typically on the road by 5 AM) than Houston for the equivalent humidity, REALLY fueling up (I put on a few lbs - love that Japanese food), and grinding it up the mountain (much easier to hold pace up the steep grade than gusty conditions typically found at home). I packed a 11-28 cassette to keep the cadence high and at least simulate my TT cadence.

I'm a week out from the TT event, so my use of PCs will be somewhat limited. I'll be on them several times this week, but the real exclusive use comes in one more week.

Tuesday, July 8, 2008

Crank comparison – PowerCranks versus regular cranks

As part of a study I’ve been selected to train on PowerCranks for a year. I’ve got plenty of historical power data, so I think any potential gains from PowerCranks will stick out like a sore thumb. Nonetheless, I’m always looking for ways to crunch data. As an engineer, it’s what I do. I’m a number cruncher. So with that in mind, Monday was a scheduled recovery ride. I had planned on a 60 minute PC ride, but after 30 minutes I was getting some pain on the outside of my left hip. Still no hip flexor soreness, but the outside hip pain was troubling. I know it well as it sometimes rears its ugly head when I load up on L3 miles. Not wanting to cause injury, I headed home, switched to my race bike with regular cranks, and did another 30 minutes of riding. I was trying to ride both rides in the same manner so I could potentially get a comparison of the two crank systems.

The first plot shows how similar the rides were in terms of speed. Towards the end of the ride I felt my average power was a little higher with regular cranks, so I was slowing down to compensate. I overcompensated a little too much, however, as power averages were lower with regular cranks.

The second plot shows that in general the course rode the same with PCs and regular cranks. Note the higher power in the PC ride, particularly late in the game.

One thing I’ve noticed with PCs is that my heart rate has been higher when using them. This is clearly indicated in the third plot which shows PCs always riding high. Of interest is that from the plot it appears my heart rate is a consistent 10 beats per minute higher with PCs for areas where the power is similar. The last plot clearly (or not so clearly) shows how much more effort PCs require compared to regular cranks. I’ve plotted a ratio of power to heart rate reserve (HR-HR_resting), where I’ve assumed my resting heart rate is 36 beats per minute. The plot is certainly noisy, but does show that normal cranks are easier than PowerCranks.

A summary of the ride is in the table below. Average power, normalized power, heart rate, and various ratios are computed. Average and normalized power for the PowerCrank portion are higher, but only by 4 and 3 watts, respectively. However, average heart rate was a good 10 bpm higher with PCs. Computing ratios of power (average and normalized) to average heart rate or heart rate reserve show that across the board regular cranks give a bigger bang for the buck (i.e., more power for the same heart rate).

AP (Avg Power)154150
NP (Norm Power)166163
HR (Heart Rate)120110
AP/HR (Heart Rate)1.281.36
AP/HRR (Heart Rate)1.832.03
NP/HR (Heart Rate)1.381.48
NP/HRR (Heart Rate)1.982.20

What will be interesting is if these ratios converge on each other with time or if there will always be some difference associated with the two crank systems. Clearly the principles of specificity and adapting to a different way of pedaling take time, and using slightly different muscles does alter the physiological response (i.e., heart rate response).

Time on PCs – 30 minutes
Time to date – 2.5 hours

Sunday, July 6, 2008

Getting Dropped

Getting dropped is no fun, but it's especially demoralizing when it happens in the warmup of a group ride. That's how it went this morning while riding the PowerCranks. First off, a little prelude. Friday night was spent at the track. It's been almost two months since my last track race, so I was a little rusty. My training this week was also lousy, and I was hoping some hard racing in the Masters and 123 fields would wake my legs up. I'll spare all the details, but bottom line is that the racing did indeed provide a spark to my legs. That was followed up less than 12 hours later with my best Saturday group ride in months (ride was without PCs, since my small training group treats these like road races). My legs were back! Of course, they were also tired from the intense riding over the last 2 days.

Nonetheless, Sunday brings the "easy" group ride. I headed out with the intent of doing the full 38 or so miles on PCs. Of course, with pal Dan on his Specialized Transition TT bike, and his claim that "I'll just put it at an easy 250 or so on the front" I knew that it was going to be a fast "easy" ride. That 250 W or so would be 25-26 mph, and doing that after just a couple of days with PCs would be tough. I was dropped (would never happen with regular cranks), so I just tried to ride a consistent pace. My pedaling with PCs has certainly improved, but my legs were ablaze with pain. The PCs were kicking my butt this morning. I decided to make it a bit of an interval session - turn the cranks 100 revolutions, feel my legs burn, get the heart rate up, stop pedaling, recover by dropping HR by 30+ bpm, and repeat. I did this for an hour, so I doubled my longest ride with PCs. That's 2 30 minute rides and now an hour long ride with the things, and yes, they hurt.

Average HR for the hour was 120 bpm, and that was with a fair amount of coasting. By comparison, Saturday's "hammerfest" portion of the group ride (about 2.5 hours) was 131 bpm average and 233 W normalized. It didn't feel nearly as hard as the PC ride. I came home after an hour, switched bikes, and headed back out to intercept the group. Perceived effort on the non-PC bike was SO MUCH easier. The hardest part of that portion (not very hard), was 117 bpm average and 194 watts normalized, a true recovery pace for me. But honestly, the PCs just kicked my tail today.

Time on PCs - 60 minutes
Total time on PCs - 120 minutes

Friday, July 4, 2008

PCs, day 2

Did a quick 30 minute "easy" ride this morning. Was planning to do 60 minutes, but I noticed my perceived effort was way too high. I'm planning on racing track tonight so I didn't want to wear myself out. The PCs really force me to push, so recovery rides with them are a challenge. Currently I don't have either of my Powertap wheels on the training bike (one on the TT bike, the other on the race bike, and I'm too lazy to swap out cassettes today), but I was wearing a heart rate monitor. Normal practice for me is to ride without heart rate, but when I don't have power, it's a nice feedback. I know how my power zones correlate to my heart rate zones in the absence of cardiac drift due to heat/dehydration. My heart rate was much too high for a recovery ride. My threshold is in the 270 W range (~4 W/kg), and heart rate typically is in the upper 150s/lower 160s for that power. With the PCs, I was trying to take it easy (but kept accelerating) and was in the 130s.

I did a completely unscientific test where I cycled one loop of a neighboorhood block on both my training bike with PCs and race bike with normal cranks. Times were identical. Perceived effort was higher with the PCs, and my heart rate for the loop was a consistent 15-20 bpm higher with PCs. That 15-20 bpm equates to around 40-50 watts for me. That's too much to be accounted for by rolling resistance (virtually identical tires) and aero (was on the tops on both bikes).

Next week or as soon as I get back from Japan, I'll do some back-to-back testing on the two bikes again, but this time with power.

Time on PCs - 30 minutes
Year to day - ~65 minutes

Thursday, July 3, 2008

The PowerCrank experiment begins

As part of Frank Day's "long-term" PowerCranks study, for which I was chosen as a participant, the cranks finally arrived today. They were waiting for me when I got home from work, and I immediately set upon the task of installing them on my training bike (a hefty 22+ lb steel beast). After a quick installation, I was all set to take them for a spin but dinner called. An hour or so after eating it was time for a light spin. My intent was to have a light recovery ride after a 2 hour ride before work this morning on the time trial bike. Instantly I felt awkward on these things, partly because my shoes were hitting the cranks with each revolution. The last pair of Look cleats I bought had no float, so while I have clearance on my fixed cranks, the PowerCranks don't leave me with that luxury. Nonetheless I made it through a 30 minute ride. After cursing the shoes, I came home, switched to my Time ATAC pedals, switched to my MTB shoes, and had more than enough clearance for comfortable riding (a 5 minute test proved this out). For now, it will be MTB shoes on the training bike.

I was cautious at first since I've heard plenty of stories regarding sore hip flexors with PCs. My 35+ minutes of riding was a breeze. No pain whatsoever. I felt I could have easily gone over an hour the first time out (and may do that July 4th in the morning as a warmup ride for Friday night track racing). Now the pedaling style was certainly odd. I definitely need practice pedaling with the PCs. My left and right legs were not in synch. Part of that was due to the pedal issue; once switching to the Time pedals, my pedal stroke was much more efficient. One thing I noticed was that I had no difficulty bringing the pedals over the top on the upstroke. I'm wondering if 10,000+ miles a year on completely flat roads has simply refined my stroke to that "perfect circle". I haven't been on my Computrainer in over a year for a Spin Scan test, so maybe it's time. I also found that to make a more even stroke, I tended to increase my cadence and push harder on the pedals. Maintaining a consistent pace was tough; my legs felt like they wanted to push into zone 3 to 4 just to stay balanced. I'll have to monitor that more closely.

The only bummer is that I can only use the PCs for another few rides before I hang them up for 2 weeks. I have to head to Japan for work, and I'm not lugging the beast with me. That honor goes to my road race bike, which at under 16 lbs, is a nice match for the local mountains there. I'd fall flat on my face trying to use PCs up 8-10% grades, and they won't match my Specialized BB anyway. Sorry Frank - it's hard enough remembering to ride on the left side of the road without worrying about my pedal stroke in the mountains. But once I get back I'll be on them probably every day.

To date time with PCs - ~35 minutes