Powercranks Status – The First 11 Weeks

As I sit here in Japan for work, giving my body a short respite from training, I have time to reflect on my use of Powercranks. I’ve got 75 hours of riding on them now since the Texas State TTs in early August. While I haven’t been using them exclusively, I have been using them as my primary crank. I’m a firm believer in the Coggan quote – “Testing is training, training is testing.” In that context, I want to get out on the race bike with regular cranks for each Saturday blitzfest to put myself in a situation where I have to push to the maximum. I want to see if the PC training is paying off. Those Saturday rides provide both the training and testing stimuli needed to verify the role of PCs in my daily training. Likewise, midweek workouts provide additional test points.

First, let’s look at the facts of my situation prior to starting with Powercranks. The figure below shows my max normalized power (10 minutes is actually average power) for a variety of time durations. The data covers late 2003 up until August 4 of this year, the Monday after a successful weekend at the State TT champs (first in M35-39 individual and first in Cat 3 team).

What is evident from the graph is that 2006 appears to be my best year considering efforts of 70 minutes and under. 2007 looks to be my best for longer durations. However, while the curves above look like they are distant from one another, it’s important to read the magnitude of the y-axis. For a given time, the powers from year-to-year are all within 10-20 watts of each other. One note about 2006 is that the big hump around 60 minutes was set in December of that year. I had just gotten off a HUGE block of training load. I was riding 18 or so hours per week for a few weeks and appeared to benefit from that training load. Further, December is a cool month in Houston, so my power is naturally better and you can’t discount thermal issues with the Powertap. Unfortunately it was a one-off performance. I haven’t been able to match that performance since. Indeed, if you look at my other best performances, the 287 W performance sticks out like a sore thumb. The rest are all 275 W and below. For the 275 W number to be real, I want it to be repeatable. Given that comment, I would say that the thick green line, which represents the 2007 training year (October 2006 to October 2007) envelopes my more realistic best yearly performances.

Let’s examine my best normalized powers in the months leading up to the State TT and in early August and a month beyond. Heat load during the summer was a serious concern, and it shows up in my data.

Date	20 min	30 min	60 min
3/17 to 4/13	280	275	257
4/14 to 5/11	270	267	263
5/12 to 6/8	267	261	250
6/9 to 7/6	270	267	255
7/7 to 8/3	285	273	258
8/4 to 8/31	266	257	248

What we see is some pathetic 60 minute numbers. Going into my “A” event I wasn’t putting out much power, despite hours and hours of threshold training. Nonetheless, the power numbers were fairly consistent. What is also seen is that after the TT, my power took a small dip, owing to the fact I was riding for fun as well as starting up the PC riding in full swing.

Starting from August 4, let’s look at how my training volume has been divided. I’ve charted time in each zone, regardless of whether it was on PCs or regular cranks. Further, I was really struggling the first weeks with stamina on the PCs. Nonetheless, the times in zone are based on an estimated 275 W threshold (perhaps a little high even with regular cranks). When on the PCs in those early weeks, endurance felt like tempo, and tempo felt like threshold. The things hurt. My training volume over the last 11 weeks has averaged just under 10 hours per week.

In the 11 week period, the plot represents 6577 minutes of training, with 98 minutes of L6, 230 minutes of L5, 736 minutes lf L4, 1579 minutes of L3, and the rest L1/L2. Compare this with the 11 weeks leading up to the State TT, which saw 124 minutes of L6, 278 minutes in L5, 826 minutes in L4, 1171 minutes of L3, and a total volume of 6946 minutes. What isn’t accounted for in this time period, however, is time spent racing and training on the TT bike without a powermeter. Nonetheless, there wasn’t a significant increase in training load nor in composition. The compositions of these two periods are shown below. The main difference between the two 11 week blocks is that the pre-PC time was 100% on regular cranks, whereas the post-PC time was 66% on Powercranks.

So, now that we know the training load’s pre- and post-Powercranks are similar in both composition and total volume, have there been any benefits to riding with PCs? Yes and no. As mentioned, the first few weeks were rough. It took time for the hip flexors to be accustomed to longer rides. With time I was able to ride them for several hours on end, and now a two hour ride on the PCs is just like a two hour ride on regular cranks. In time, I’ve been able to maintain the same power for a given duration on the PCs as I have on regular cranks. One thing I have noticed, however, is a perceived benefit for durations lasting longer than an hour. My hour power hasn’t budged much, but the longer efforts have improved. Whether this is due solely to PCs versus cooler temperatures is debatable. Nonetheless, something is causing my long term power to increase. If we now roll in my normalized powers in the 11 weeks of using PCs and compare against my 2008 training year before PCs, my all-time bests, and last year (2007 training year), we have the plot below.

I’ve hit my best 60 minute power of the year since using PCs, but honestly the difference between what was and what is now my best is only a few watts. If I had seen 290 W rather than 270 W, there’d be reason for rejoicing. But for now, all I can say is that my threshold is in line with my seasonal variations and within the expected range. However, I have been hitting yearly best numbers for the 120 minute and beyond range. Indeed, since riding PCs I’ve hit some all-time bests in the 150 minute and beyond range. We are talking a few watts, so again, it’s not a significant change.

At this point, if I look at PCs objectively with my Ph.D. glasses on (my doctorate is in mechanical engineering, and I have some background in testing and the influence of test variables on outcome), I would conclude that given similar training stimuli (the composition and duration of my training), training with Powercranks offers no benefit compared to regular cranks for durations lasting under 90 minutes. Seasonal variations in temperature and humidity appear to be the more logical reason for a slight uptick in power for 90 minutes and under. I do however, feel that Powercranks may have a minor benefit for durations lasting longer than 2 hours. There may be some benefit in reducing overall muscle fatigue for longer durations.

Since I’m only 3-4 months into this year long study, I won’t come to solid conclusions yet. I still have plenty of training ahead of me. November will be spent primarily on threshold training, and December will introduce even greater volumes of VO2 work. The work will be performed on PCs with continued Saturday testing on regular cranks.