Tuesday, December 30, 2008

PowerCranks – The First 6 Months and an Overly Complicated Data Analysis

Recall a few months ago I gave an “11 week report” on my use of PowerCranks. At the time I had invested some 75 hours of cycling into PowerCranks, but most of the training was in my tempo zone (no more than 245 W) or below. With the passing of November and December I have completed two months of more intense training with PowerCranks and brought my time with PCs to over 150 hours (and some additional hours on regular cranks by way of one weekly group ride). These two months had a focus on threshold (zone 4) and VO2 (zone 5) in an attempt to both raise my functional threshold power and prep myself for the upcoming racing season in Texas, which starts in January.

So did things pan out? Did PowerCranking affect my power positively and satisfy the claims of increasing power? Read on and see for yourself.

Coming in to November my power profile looked like the plot below. The black line represents my all-time best power, and the green line is my power in the one year before taking up PowerCranks. The red line is my power through October 2008. The plot is a combination of mean-maximal power and normalized power. Normalized power is used for durations of 15 minutes and up, and mean maximal (or average) is used for shorter durations. As can be seen, my use of PCs did not generate higher power for durations under 2 hours. Only above 2 hours did I see a boost in power. Was this due to PCs?

First off, the difference between the green and red lines is only about 8 watts, which represents roughly a 3 percent increase in power. It should be noted that in September 2008 my small training group, comprised of my closest pals and teammates, increased the distance of our Saturday training ride by over 8 miles. That added an additional 20 or so minutes to our route and initiated some of the bumps we see in the curve above. Most of my pals are incredible time trialists (55-57 minute range at sea-level). We hurt ourselves on our training ride, and it shows with the high normalized power at the longer durations. Personally, I believe the increase in power from 120-180 minutes is due to the change in our training ride rather than the use of PowerCranks. But honestly, the difference is only 3 percent so even if PCs are the reason for the increase, the increase is minimal.

But that was 2 months ago, and a lot can happen in that time. I approached each bike workout with PowerCranks as I would with regular cranks – I didn’t pussyfoot around. I hit my intervals full tilt. With the race season coming soon, I wasn’t about to sabotage my training. I can honestly say I used PowerCranks as hard as I could.

The plot below shows my training stress in terms of cumulative average TSS. The black curve represents a starting point of August 2007, the pink line a start of August 2006, and the red line August 2008. As can be seen from the graph, my TSS is much higher this training year than the previous two years. With this data and my focus on L4 and L5 work, I would expect to be at least as fit as past training years or even more powerful.
If we plot my power from August to October and compare it to the power over the last 2 months, we have the plot below. The good news is the focus on L4 and L5 is paying off. 20 minute power is up about 10 watts (around 4 percent) and 30 minute power is up 2-3%. So this begs the question; is this increase due to PowerCranks or the focus on L4 and L5?
Plotting my power from August to December of this year (my PC use) to past periods, we get the plot below. I’m ahead of my performance for the same time period as last year, but given the difference in TSS from last year (the plot earlier in this status report), that is somewhat expected. Regardless, I’m still well below (well, not that far) from my all-time best power numbers. I have this huge gap between 20 and 80 minutes to fill, and so far neither more intense training nor PowerCranks has filled that hole.
If I look strictly at mean maximal, or average power, things are even more dire. The plot below shows I’m actually less powerful in some respects compared to the same period as last year.
Now let’s examine 20 and 60 minute normalized power in more detail by looking at a yearly breakdown month-by-month. The next two plots show data going back to 2003. My PowerCrank use would be characterized by the red lines in months 8 to 12. The plots are busy, but one thing is clear - I’m not seeing any significant gains in either 20 or 60 minute power. As a time trialist, I wanted a bump in 60 minute power to cut precious seconds from my 40k efforts. My numbers so far can only be explained as my typical seasonal variances. Yes my 20 minute power is at its highest of the year, but by only a couple (as in single digits) of watts. For 60 minute power, my power has been consistent over the last 3 months, but the max over the 3 months is a mere 1 watt higher than February 2008, well before PowerCrank use.

Finally, let’s look at critical power. I’ve calculated critical power in two approaches. In one case, which I’ll call CP15, I’m using 3, 5, 8, 10, and 15 minute average power to calculate my critical power and anaerobic work capacity. The other case is what I call CP10, which is the same as CP15 but without the 15 minute power number. It is well known that the critical power model can be effective at predicting threshold power (i.e., critical power). One caveat is that for this data I did not go out each month and test to maximize power for each range. It is assumed that I’m hitting a maximum through my normal training and racing. My motivation in training is to push as hard as possible, and likewise in mass start racing the physiological demands push riders to the limit. For the most part, the R^2 values were 0.996 or above (indeed, most were three 9s).

The plot below shows a monthly calculation of critical power. Notice the upswing from September to December. That’s the result of focused training. But also note that my highest critical power was in July 2008, which was the month leading up to the Texas State Time Trial Championships.
At this point I was thinking that perhaps my adaptation to PowerCranks was negatively affecting my critical power calculations. I collected the monthly data and cherry picked over a quarterly basis (that is, picked the peak values over a three-month period). The fourth quarter of 2008 would represent the best time period for PC use. The plot below shows my critical power using this quarterly basis. Using a quarterly basis narrows the gap some, but still my summer power is higher, albeit by only a couple of watts.

So when you take in all this data and puke it out, what is it saying? First, my focus on L4 and L5 is showing a rise in threshold power (but heck, the same can be said for my teammates who are also focusing on these aspects). But more importantly it shows that neither regular cranks nor PowerCranks are a magic bullet when it comes to breaking through a plateau. I consider myself a “well-trained” cyclist based on the historical power data I’ve gathered and my ability to rather quickly maximize my aerobic power to its genetic potential. The plot showing my historical 60 minute power certainly demonstrates my sweet spot is in the 265-275 W range. I had one aberration in January 2006 which I attribute to measurement error rather than really nailing 287 W for an hour. To date I have sufficient data at hand that clearly demonstrates that PowerCranks, once adapted to (and given my ability to ride them for 4+ hours at a high pace or complete critical interval sessions as if they were fixed cranks), have not been able to raise my power.

I really, really, really (you can add some more reallys if you want) want to increase my aerobic power, and I was hoping the PowerCranks experiment would given me just a 5% gain. I’m not greedy; I’m not looking for that 40% power increase or 2-3 mph claim. Just give me 5%, or about 12 watts, which would be about 1/3 mph. Alas, no gains. I have 6 months still ahead of me with PowerCranks (and will be riding a ton this week), but honestly with race season approaching my training volume with PowerCranks will begin to taper off due to race weekends on regular cranks.

Is there merit in using PowerCranks? I think there is, particularly for some riders. I feel many riders don’t know how to truly push themselves on the bike. When the going gets tough, too many riders take the easy way out. For me, VO2 intervals are the absolute worst, yet they are effective at helping get the last few watts out. I have learned to suffer during VO2 workouts, and Powercranks are pain and suffering at the beginning as you adapt to them. The perceived effort I was getting with PCs in the beginning was akin to VO2 and anaerobic intervals, but with more volume. If they can teach a rider how to suffer at a new level and open up their eyes to more intense training, they’ve done their job. You can certainly argue you can achieve the same end state with regular cranks, but I personally feel too many riders take the easy way out when the going gets tough. In that respect, the old axiom “no pain, no gain” is correct.

Monday, December 29, 2008

Week of December 22

Monday – It was too freaking cold (low 30s) for the South, so a great excuse to not ride.

Tuesday – Heck of a 3 hour ride on Powercranks today. The workout started with a brutal VO2 workout. There was a reference posted biketechreview.com regarding an effective VO2 protocol. I typically do traditional VO2 workouts – 10x3, 8x4, 6x5, etc with pretty much equal work:rest ratios. This new protocol, which was shown to give slightly better performance gains than 8x3 with 1:2 work:rest periods, is to ride at max VO2 power for 60% of the time you can hold that power. Recovery is dictated by how long it takes your heart rate (an excuse to wear the HRM!) to drop to 65% of your max heart rate. For me, this all translates to around 330 watts for 3 minutes with the HR target being 110 bpm. Unfortunately for me my HR drops like a rock after the load is removed. Recoveries were between 90 and 120 seconds. The short recovery makes for a more challenging workout. The entire VO2 block of the workout was completed in just over 36 minutes. The plot below, with the line at 330 watts, shows how quickly things came and how well I was hitting my target (not very well as the workout went deeper).

Wednesday – I had limited time this morning as I had to make the drive up to Dallas to see family. I wanted a short and intense workout, which meant I dumped the PCs today in favor of the race bike with regular cranks. I did a quick 75 minute ride with 60 minutes of “surge tempo”.

Thursday – Was hoping for a solid VO2 workout similar to Tuesday, but the mind and body didn’t want to take part. Ended up just doing 65 minutes of PC riding with a variety of zones. A few VO2 efforts, some L6 stuff, threshold. You name it.

Friday – Drove back to Houston and didn’t ride.

Saturday – Usual blitz fest. I really humped it on the way out, but about 1/3 in for the whole ride I got a nasty side stitch which stayed with me the entire day every time I went hard. Still managed some strong numbers despite the limitation. A total of 4 hours on the bike racking up 284 TSS points. A strong day indeed.

Sunday – Given Saturday’s hard ride I wasn’t expecting much today, but I felt really, really good. My pals asked what I was going to do, to which I responded “Not sure. Depends on how the first interval goes.” It went well. I did a “race winning interval” (see the Dec 8 blog entry) of 30 seconds in L6, 4 minutes in L5, 4:30 in L4, then another :30 in L5, and finishing up with :30 in L6. 301 watts for interval number 1. OK. I’m good. 9-10 minutes of rest and go again – 300 watts for interval number 2. Some more rest and I hit interval number 3 at 301 watts. A little more rest and I go into the fourth bit of hell. The wheels came off on that one at only 291 watts, but it was a good workout nonetheless. On the way home it started to rain, which really sucked since there was a headwind and the temperatures were hovering around 50 degrees. My core was cold and it took a warm shower, a cup of coffee, plenty of clothes, and lunch to warm my body. The discomfort was worth it as this was a quality 2:10 workout on the PCs.

A great week overall. The volume wasn’t particularly high, but the intensity was. The average IF for the week was over 0.85 due to the high amount of VO2 work. Things paid off at week’s end with some new yearly bests and bests with the Powercranks. I equaled my 5 and 8 minute bests with the PCs though not beating my yearly best numbers. I set new 30 and 40 minute normalized power numbers by 4 watts.

PC time this week – 6 hours 15 minutes

PC time to date – 150 hours 10 minutes

Weekly status of power progression – I continue to be on a workload pace higher than last year. I’m currently averaging some 60+ TSS points higher per week. I expect this has something to do with the small gains I’m seeing. The plot below shows I’m still running ahead of my performance for the same period as last year but still haven’t bettered my historical power in the durations that count the most in mass start road racing.

Sunday, December 21, 2008

Week of December 15

Monday & Tuesday – Zero riding. I had to go to a conference at work these days, the First International Conference on Laser Peening. Huh? Actually laser peening, which is just like shot peening except a laser is used rather than shot, would have application to bikes. But that’s a story for another day…

Wednesday – Got out of the conference early and went to lunch with some folks. I made the mistake of ordering enchiladas and having a few too many chips. End result was that when I got home and tried to ride my belly was stuffed to the limit and I felt like I wanted to vomit. 50 minutes of torture with the Powercranks due to being full of Tex Mex.

Thursday – First day of Christmas vacation and it was spent on the road. Given I didn’t ride Monday and Tuesday and Wednesday was more of an opener than a real workout I was feeling pretty good. Perhaps a good day for an hour test? Um, nope. 8-10 minutes into an effort I realized things weren’t going to happen for me the way I wanted. I went out a little too hard and was having to pay back the power man. So I rescoped and worked on other threshold and tempo aspects. Unfortunately 68 minutes into my 2:50 ride my PT succumbed to moisture from the 100% humidity. The remainder was mostly tempo on the PCs.

Friday – 85 minutes of endurance/tempo on the PCs.

Saturday – Usual blitz fest but nothing stands out from today’s ride.

Sunday – A strong cold front moved in overnight and brought strong north winds and cooler air. That combination, plus a stomach ache and ankle pain had me cut my ride short at 1:45.

Overall a bit of a bummer week. The good news is I’m on vacation for the next few weeks.

PC time this week – 6 hours 50 minutes

PC time to date – 143 hours 55 minutes

Weekly status of power progression – Nothing new to report this week.

Sunday, December 14, 2008

Week of December 8

Monday – If anyone thinks a recovery ride is impossible on Powercranks, they haven’t tried hard enough (or is that easy enough?). 30 minutes of PCing with an average power of 138 watts. 3 minutes were spent from 0-20 watts, so this wasn’t a lot of coasting to bring the average down.

Tuesday – I’ve got vacation to burn so my plan was to go into work late after a morning workout. It was a little overcast and the radar looked good, but luck wasn’t on my side. After a warmup and a short opener, rain came and effectively shorted out my Powertap. Being wet and with no data, I decided to head home with 30 minutes of riding under my belt. Went to work and came home early to complete the workout I intended to do in the morning. The goal was a VO2 workout but my legs and heart just weren’t in it. It turned into a hodge podge of VO2 and anaerobic efforts. It was a real stinker of a workout, though I still got 20+ minutes of VO2 work in. Overall for the day is was 2:25 on the PCs.

Wednesday – Got home late so no ride.

Thursday – Today was one of those great workout days. I got home a little early and hit the road for my own version of “race winning intervals” as found in the Allen/Coggan book. These intervals are taxing and effectively are longer VO2 efforts. 30 seconds at 140%+ of FTP followed by 3-4 minutes at 110-115% (today was 4 minutes), 4-5 minutes at 100% FTP (today was 4.5 minutes), 30 seconds back into VO2, and finally the last 30 seconds as hard as possible (easier said than done). 10 minutes of hell. See the plot below for actual ride data, where the horizontal lines are at 100%, 115%, and 140% of FTP. The first 30 seconds puts you into debt quickly such that the VO2 effort starts early. Then recovery from the VO2 effort at FTP teaches your body to recover at high intensity.

The first interval went great. A little fist pump when I saw I averaged 300 W. After about 9 minutes of recovery it was time for interval #2. Another 300 W effort. I couldn’t believe I was hitting these kinds of numbers while riding the PCs. Perhaps it was the freshly cleaned and lubed chain on the bike giving me a few extra watts. The third interval was progressing in much the same manner. I was pushing hard and felt really fresh. Then a school bus that was up the road stopped to let kids out with about 1 minute to go in my interval. I had to come to a dead stop and lose all momentum. Aargh! Oh well, the good was done. The first 9 minutes were dead on to the previous intervals first 9 minutes. I was well on my way to another 300 W interval. I rode home at tempo to threshold and was pleased as punch about the effort. A fantastic workout of 1:25.

Friday – Easy 60 minutes on the PCs.

Saturday – Usual blitz fest. I was bringing some of workouts I did this week into the group ride. On one section I tried to a variant of the “race winning interval” but my training pals are simply too strong. Hard to outride guys who are all top 10% in the state when it comes to time trailing. So instead I took the “rinse and repeat” method. Hit it hard for a couple of minutes, make them respond, rest for a minute, do it again. Try to break them down through attrition. The crosswind just wasn’t strong enough to make it effective. Nonetheless, I set a new yearly best normalized power for 15 minutes and just 1 watt short of my best ever. A great 301 W effort for the duration.

Sunday – A good tempo workout of 3:50 on the PCs. It was icing on the cake after a good workout and group ride. Normalized power of 210 for the duration.

PC time this week – 9 hours 10 minutes

PC time to date – 137 hours 5 minutes

Weekly status of power progression – Some new highs to report this week. I hit yearly bests in the 15-20 minute range and some bests on Powercranks in the 8-10 minute range. The moderate progress is shown in the plot below. The “PCs” line is slightly higher this week than last week in the 0-30 minute range. Woo-hoo!
I continue to run ahead of last year in terms of average TSS for the same training period. For grins, I plotted my training volume of 2 years ago on the same plot. See the plot below which shows I’m overtaking my training of a couple of years ago. If I plot my best weekly 20 minute power, you’ll see I was cranking pretty good 2 years ago but then had a 2 week block of no riding due to work travel and the form went to pot. Fortunately I haven’t had to travel this fall for work, so I’ve been on a consistent upswing.

Sunday, December 7, 2008

Week of December 1

Monday – After last week I was totally blitzed. My TSS going into Monday was –34. I was in no mood to ride, so I didn’t.

Tuesday – Still tired but I got out on the bike and managed 66 minutes of L2/L3 riding on the PCs. Legs just didn’t want to go. Last week’s volume really took it’s toll, particularly Saturday and Sunday.

Wednesday – Got home early but I had no motivation to ride. Great week, eh? Seems to be turning into a rest week. It’s my body telling me something – take it EASY!!!

Thursday – Got home late so I threw the bike on the Computrainer with the intent of doing a VO2 workout. Man did I forget how much I hate riding a trainer. I did the workout in the garage where the temperature was in the mid 50s. I was still sweating like a pig. I managed 2 whole VO2 intervals of 3 minutes each before I just had enough. 50 minutes of PC riding on the Computrainer was all I could take.

Friday – No riding.

Saturday – Usual blitz fest. I was apprehensive in how I’d ride. I know that with so much rest this week I often come in flat. On some of the harder efforts the lack of intensity this week certainly got the better of me. My stomach was cramping from intensity and I had to throttle back. Still, it was a good hard ride. Didn’t break any significant records today, and the intensity of the ride was down a few percent for me, but overall it was fun.

Sunday – I started the day thinking I’d do 5+ hours on the PCs. When we hit the road I was feeling pretty fresh despite the Saturday slugfest. I figured I’d try some VO2 efforts and see how that went. To my surprise they went really well. I was pulling off 5 minute VO2 efforts with relative ease, so I just kept up with that. First true VO2 workout on the PCs and it was a good one. Had a yearly best 5 minute power on one of the intervals (OK, by 1 watt) despite not really getting a recovery interval (a teammate was doing threshold intervals at the same time, so it’s hard to really recover at that tempo). I didn’t reach my 5 hour goal (indeed, only half of that at 2:30), but from a workout perspective, today’s ride was better than a long endurance ride.

Overall a pretty light week. My body appreciates it.

PC time this week – 4 hours 25 minutes
PC time to date – 127 hours 55 minutes

Weekly status of power progression – Some new highs to report this week. 280 W normalized for 30 minutes this week is my best yet with PCs and is the best 30 minute power I’ve had since June 2007 (well, by only a couple of watts). Bumped up 40 minute power a watt, and 50 minute went up 4 watts.

Still no significant improvements as a result of Powercranks. If we look at the two plots below, my power since using Powercranks is within the accuracy of the Powertap (around 2.5%) for all but the longest durations (and even then within 3-4%). In general I’m seeing better numbers than I was for the same time period as last year, but if we look at the second plot I’m running a high average TSS. It makes sense that my longer term power is better because of the higher average TSS. It’s not like I’ve been slacking. I’ve been busting my arse each week trying to bump up my power. The big test is December, which is a month focused on VO2 work.