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A new area of PC controversy, your thoughts ...
Quote | Reply
Frank Day
Feb 17, 03 8:46
Post #1 of 10 (2310 views)
I was recently having a back and forth with one of the coaches who has been using PC's exclusively for over a year when he wrote me this:

"(We) originally got on this topic (metabolic efficiency changes by use of the pc's) when I noticed that, on a 63mile mountainous loop that I use to require 750calories (@ 146bpm)...............that, now with the pc's..........i require ALMOST HALF THOSE CALORIES (370) @ a workload that's 2bpm higher?!?!

This confounded us..........until we spoke to Chris (a human performance lab researcher) and he reminded us that muscle glycogen is depleted in the 'primary mover 1st'. And with the pc's...............that primary muscle mover NO LONGER bears
the SOLE burden of work. Because the wattage output (& hence, fuel usage) is spread MUCH more evenly

FINALLY..........I can see why RACING on them is advantageous (@ least from a metabolic standpoint). AND why running off the bike is even improved by using them in a race.

These things keep getting better and better!!"

I can see that "glycogen sparing" could be a potential benefit of using the PC's but the degree that he has noticed seems way to much to me. Further, this is very unscientific so cannot be used as proof of anything. However, I though I would put this out to see if any of you have noticed anything similar. If so, maybe this should be studied sooner rather than later.

Also, are there any other comments about his observation?

Frank
--------------
Frank,
An original Ironman and the Inventor of PowerCranks
Quote Reply
Re: A new area of PC controversy, your thoughts ... [Frank Day] [ In reply to ]
Quote | Reply
Fred
Feb 17, 03 9:06
Post #2 of 10 (2291 views)
In Reply To:
"(We) originally got on this topic (metabolic efficiency changes by use of the pc's) when I noticed that, on a 63mile mountainous loop that I use to require 750calories (@ 146bpm)...............that, now with the pc's..........i require ALMOST HALF THOSE CALORIES (370) (snip) Also, are there any other comments about his observation?
Quote Reply
Re: how is he counting calories [ In reply to ]
Quote | Reply
tom
Feb 17, 03 11:56
Post #3 of 10 (2205 views)
What method is he using to count calories? A slightly higher HR yet 1/2 the caliories? There is some part of this story we are not getting. What di the speed look like between the 2 rides? What differences were there in cadence? How has he changed in body weight and fitness? What where the weather differences?
Quote Reply
Re: A new area of PC controversy, your thoughts ... [Frank Day] [ In reply to ]
Quote | Reply
andrew-t
Feb 17, 03 12:32
Post #4 of 10 (2176 views)
Is "the coach" using a power tap to measure work done and then determining calories from that? (my guess) I would think that there are possibly a few problems with this approach. First, you are not always going to perform the same amount of work on a given course. You can put out more ave watts and go slower than if you put out the "right watts" at the right time. Secondly, is glycogen depletion really the major cause of fatigue?? Inorganic phosphates, Noakes' central governer hypothesis??

andrew

In Reply To:
I was recently having a back and forth with one of the coaches who has been using PC's exclusively for over a year when he wrote me this:

"(We) originally got on this topic (metabolic efficiency changes by use of the pc's) when I noticed that, on a 63mile mountainous loop that I use to require 750calories (@ 146bpm)...............that, now with the pc's..........i require ALMOST HALF THOSE CALORIES (370) @ a workload that's 2bpm higher?!?!

This confounded us..........until we spoke to Chris (a human performance lab researcher) and he reminded us that muscle glycogen is depleted in the 'primary mover 1st'. And with the pc's...............that primary muscle mover NO LONGER bears
the SOLE burden of work. Because the wattage output (& hence, fuel usage) is spread MUCH more evenly

FINALLY..........I can see why RACING on them is advantageous (@ least from a metabolic standpoint). AND why running off the bike is even improved by using them in a race.

These things keep getting better and better!!"

I can see that "glycogen sparing" could be a potential benefit of using the PC's but the degree that he has noticed seems way to much to me. Further, this is very unscientific so cannot be used as proof of anything. However, I though I would put this out to see if any of you have noticed anything similar. If so, maybe this should be studied sooner rather than later.

Also, are there any other comments about his observation?

Frank
Quote Reply
Re: A new area of PC controversy, your thoughts ... [andrew-taft] [ In reply to ]
Quote | Reply
Frank Day
Feb 17, 03 12:53
Post #5 of 10 (2154 views)
Tom and Andrew,

I told you the report was not scientific. he was not measuring power but using perceived exertion over the same course. His speed was similar but slower with the PC's even though his HR was higher. He did not measure calories expended but caloric intake but assessed calories expended (or available glycogen reserves) based upon how he felt after the ride compared to his usual.

the only way to "prove" such a thesis is to measure calories expended using a calorimeter or oxygen consumption on PC's and non-PC's and do muscle biopsy glycogen assessments. Something fairly "easy" to do.

I guess the question is, have any of the PC'ers out there noticed a similar "post-ride freshness" suggesting improved glycogen stores that would facilitate improved endurance on the bike or improved effort on the run. Or, for you non-PC'ers academic types, does it make sense that "spreading the load" would result in improved glycogen utilization? Or, as Andrew suggests would there be another mechanism that might be at play here (assuming there is something actually to this anectodal observation).

BTW, I didn't think I was ever going to get a response to this question. It would have been a first, a PC post that resulted in no controversy whatsoever.
--------------
Frank,
An original Ironman and the Inventor of PowerCranks
Quote Reply
Re: A new area of PC controversy, your thoughts ... [Frank Day] [ In reply to ]
Quote | Reply
andrew-t
Feb 17, 03 15:25
Post #6 of 10 (2082 views)
Yes, I would say that is an "un-scientific" study. So the question that you are trying to address is, whether Powercranks are more metabolically efficient than standard cranks. To do the study properly you would need calorimetry tools. How is this for an un-scientific study... take some people who have been using PCs and get them to do a 30' or 60' time-trial with their PCs and NCs (normal cranks) on their trainers. See which one is faster.

andrew



In Reply To:
Tom and Andrew,

I told you the report was not scientific. he was not measuring power but using perceived exertion over the same course. His speed was similar but slower with the PC's even though his HR was higher. He did not measure calories expended but caloric intake but assessed calories expended (or available glycogen reserves) based upon how he felt after the ride compared to his usual.

the only way to "prove" such a thesis is to measure calories expended using a calorimeter or oxygen consumption on PC's and non-PC's and do muscle biopsy glycogen assessments. Something fairly "easy" to do.

I guess the question is, have any of the PC'ers out there noticed a similar "post-ride freshness" suggesting improved glycogen stores that would facilitate improved endurance on the bike or improved effort on the run. Or, for you non-PC'ers academic types, does it make sense that "spreading the load" would result in improved glycogen utilization? Or, as Andrew suggests would there be another mechanism that might be at play here (assuming there is something actually to this anectodal observation).

BTW, I didn't think I was ever going to get a response to this question. It would have been a first, a PC post that resulted in no controversy whatsoever.
Quote Reply
Re: A new area of PC controversy, your thoughts ... [Frank Day] [ In reply to ]
Quote | Reply
gj
Feb 17, 03 15:38
Post #7 of 10 (2072 views)
The problem with accessing how many calories he used with pc's v.s without...seems a bit of a stretch based on the idea that he felt the need to eat less...this could be explained many other factors like maybe he had been eating more for a few days before and felt fine...maybe he had placed his food breaks more evenly so he felt less need to eat...did he then go for a long run and continue to feel great? I have often gone for a 60+ mile ride and basically ate a powerbar and bottle of cytomax and felt fine...especially if I had previously been putting in quite a few longer rides. Also he could have drank more water giving him the feeling of being full....I don't know...I rarely eat that much going on a 3 hour ride...and I ride regular cranks (not trying to bash PC's) and don't think I could make the claim that I eat less on those rides because my pedaling is more efficient....

But if through further testing you prove this is true it could really change the way people think about metabolism/efficiency but I think that so far its kind of making a quantum leap....
Quote Reply
anyone who has trained on them ... [andrew-taft] [ In reply to ]
Quote | Reply
Frank Day
Feb 17, 03 15:44
Post #8 of 10 (2069 views)
knows the outcome of your proposed "study". Clearly, the observations of this one person on himself does not constitute a "study". but he has made some observations and proposed a theory that he had confirmed as possible by someone who should know.

Let me state the question again. This person has surmised a mechanism to explain his "energy requirement" observations pre and post PC that goes beyond simple mechanical efficiency improvements. In this he is surmising, also, metabolic efficiency improvements resulting in glycogen sparing that may have significant impact for triathletes running off the bike or, for cyclists, improving sprinting ability at the end of a long day.

I had never conidered this before and I wanted to get the thoughts of others on this possibility.

Frank
--------------
Frank,
An original Ironman and the Inventor of PowerCranks
Quote Reply
Re: A new area of PC controversy, your thoughts ... [gj] [ In reply to ]
Quote | Reply
Frank Day
Feb 17, 03 16:10
Post #9 of 10 (2054 views)
I agree with your criticism of his assessment of caloric expenditure. I don't mean to say this is proof of anything (it barely suggests it) but it got him, and then me, thinking about this, which is why I raised the question.
--------------
Frank,
An original Ironman and the Inventor of PowerCranks
Quote Reply
Alan Lim made the same observation [ In reply to ]
Quote | Reply
Andrewmc
Feb 18, 03 15:36
Post #10 of 10 (1926 views)
when we talked about PC's. Not the calorie part specifically but the spread of glycogen depletion over a greater range of muscles.
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