|
|
Thread Tools | Display Modes |
#61
|
|||
|
|||
Beware of PowerCranks
On Jun 6, 12:42 am, "Phil Holman" piholmanc@yourservice wrote:
BTW, do you ever discuss the gastric freezing debacle in your class? When I used to teach intro I used that as my cautionary tale for RCTs (I used tuberculous meningitis as my counter-example). No, and searching through some articles it looks to be very controversial. Is it universally resolved yet? You mean gastric freezing? Yup. One of the side-effects is that nowadays it's generally required that medical researchers declare their potential conflicts of interest, like whether they own the company making the gastric freezing machines. Or did you mean the ethical line of when to do placebo controls? That's not universally resolved. Remember the fast-tracking that HIV activists wanted the FDA to do? Much of that fast-tracking was about whether placebo controls were necessary. |
Ads |
#62
|
|||
|
|||
Beware of PowerCranks
Tim McNamara wrote:
Ummm. What? Ah. Circumcision. Cosmetic ? Don't tell me this is another helmet thread. |
#63
|
|||
|
|||
Beware of PowerCranks
Tim McNamara wrote:
In article , Bill wrote: Now, sneaking in a question, does one full blast run per day make any difference compared to a few hours on the bike? I'm thinking heart condition mainly on this. The literature I have seen in the last year or two has indicated that sprint training has significant benefits for endurance. I don't think your heart can tell if you're running or riding a bike. Probably not, but my legs sure feel the difference. It could be geometry related since I ride 3 different bikes. They all fit pretty good but none is a custom fit. I think I can stay heart healthy with my 2 minute blasts as opposed to watching television or sitting here at the computer. I guess anything that raises you heart rate for a while is a good thing. I try to get the run in first and then do the bike ride and when I get home I sometimes do the run again. I just hope that is a good plan. Bill Baka |
#64
|
|||
|
|||
Beware of PowerCranks
In article
, Bill wrote: I don't want to make a 'me' thing out of this post Yes, you do. -- Michael Press |
#65
|
|||
|
|||
Beware of PowerCranks
In article
, "Phil Holman" piholmanc@yourservice wrote: wrote in message ... Phil Holman writes: Wouldn't that argument mean that if you did observe a change in VO2Max (in ml/kg/min) then the previous value was faulty and shouldn't be used as a basis for comparison? If one subscribed to that argument, both the improvement and VO2Max and the improvement in power should be discounted. It depends on the definition of VO2max. I don't see how something like this could be so fixed. Yeah, I was engaging in Socratic dialog. I don't think VO2Max is that fixed, either -- in part because of the kg vs. "lean" kg issue. OTOH, one does have to worry about how well the initial tests were done. Which sort of argues in favor of RCTs. BTW, do you ever discuss the gastric freezing debacle in your class? When I used to teach intro I used that as my cautionary tale for RCTs (I used tuberculous meningitis as my counter-example). No, and searching through some articles it looks to be very controversial. Is it universally resolved yet? For the success stories we do the Linus Pauling vitamin C to prevent colds and the largest medical experiment of all time with the Salk vaccine. It's a shock to students when they see the higher contracted numbers of polio in the placebo group. "You mean, if they had given the vaccine to everyone there would be a couple of hundred less children who contracted polio." Errrm. This whole subject reappear under new guises because people do not want to believe that there is a direct relationship between aerobic capacity and performance on a bicycle. Here we go again. I spent years reading how ankling would improve climbing and top speed and that it needed to be practiced diligently. That went away only to be replaced by other beliefs that we can fabricate power by trickery. In recent times, steam RR locomotives, although not rated in Horse Power (but rather "tractive effort", the pull at which the wheels would spin) had a conversion chart to HP based on grate area in the fire box which governs how much heat can be transferred to steam in the boiler. Grate area is closely similar to lung displacement for physically fit racers. That is what limits climbing or TT ability, not ankling, pedaling style or other external means. You continue to repeat this misconception. Lung displacement or lung capacity is not the limiting factor in climbing or TTing or cycling in general. If you understood the cause and effect elements you would understand that extreme "out of breath" is caused by excess CO2 in the blood stream as a result of lactic buffering. That is, the limits of aerobic capacity were reached upstream (cardiac output, blood muscle interface limitations etc) and no further limitations are imposed by the lungs. It wouldn't matter if you doubled lung capacity, blood lactate concentrations wouldn't change and this is the culminating event in limiting aerobic performance. Heavy breathing is an effect not a cause. As I understand it the proximate cause is mitochondrial respiration rate overload. Cellular ATP hydrolysis in excess of the mitochondrial respiration rate increases H+ in the cell. -- Michael Press |
#66
|
|||
|
|||
Beware of PowerCranks
In article
.net , "Tom Kunich" cyclintom@yahoo. com wrote: "Phil Holman" piholmanc@yourservice wrote in message . .. wrote in message ... Phil Holman writes: Wouldn't that argument mean that if you did observe a change in VO2Max (in ml/kg/min) then the previous value was faulty and shouldn't be used as a basis for comparison? If one subscribed to that argument, both the improvement and VO2Max and the improvement in power should be discounted. It depends on the definition of VO2max. I don't see how something like this could be so fixed. Yeah, I was engaging in Socratic dialog. I don't think VO2Max is that fixed, either -- in part because of the kg vs. "lean" kg issue. OTOH, one does have to worry about how well the initial tests were done. Which sort of argues in favor of RCTs. BTW, do you ever discuss the gastric freezing debacle in your class? When I used to teach intro I used that as my cautionary tale for RCTs (I used tuberculous meningitis as my counter-example). No, and searching through some articles it looks to be very controversial. Is it universally resolved yet? For the success stories we do the Linus Pauling vitamin C to prevent colds and the largest medical experiment of all time with the Salk vaccine. It's a shock to students when they see the higher contracted numbers of polio in the placebo group. "You mean, if they had given the vaccine to everyone there would be a couple of hundred less children who contracted polio." Errrm. This whole subject reappear under new guises because people do not want to believe that there is a direct relationship between aerobic capacity and performance on a bicycle. Here we go again. I spent years reading how ankling would improve climbing and top speed and that it needed to be practiced diligently. That went away only to be replaced by other beliefs that we can fabricate power by trickery. In recent times, steam RR locomotives, although not rated in Horse Power (but rather "tractive effort", the pull at which the wheels would spin) had a conversion chart to HP based on grate area in the fire box which governs how much heat can be transferred to steam in the boiler. Grate area is closely similar to lung displacement for physically fit racers. That is what limits climbing or TT ability, not ankling, pedaling style or other external means. You continue to repeat this misconception. Lung displacement or lung capacity is not the limiting factor in climbing or TTing or cycling in general. If you understood the cause and effect elements you would understand that extreme "out of breath" is caused by excess CO2 in the blood stream as a result of lactic buffering. That is, the limits of aerobic capacity were reached upstream (cardiac output, blood muscle interface limitations etc) and no further limitations are imposed by the lungs. It wouldn't matter if you doubled lung capacity, blood lactate concentrations wouldn't change and this is the culminating event in limiting aerobic performance. Heavy breathing is an effect not a cause. As proof of what Phil has to say about this - when you're staggeringly out of breath and can hardly move your blood oxygen is still more than 90%. Normal blood oxygen runs about 98%. I have an ex-brother in law who was the longest surviving person without a main coronary artery. Until he got a partial heart transplant in 1999 his blood oxygen was normally 70% or less. Proof that blood oxygen is NOT the problem in climbing - rather lactac and excess CO2 is. BTW - he's still alive at about 55 years old now. No, lactate is not the problem. You should know because you posted this URL: URL:http://ajpregu.physiology.org/cgi/content/full/287/3/R502 -- Michael Press |
#67
|
|||
|
|||
Beware of PowerCranks
Michael Press wrote:
In article , Bill wrote: I don't want to make a 'me' thing out of this post Yes, you do. There's no "me" in "team". |
#68
|
|||
|
|||
Beware of PowerCranks
|
#69
|
|||
|
|||
Beware of PowerCranks
In article ,
Donald Munro wrote: Tim McNamara wrote: Ummm. What? Ah. Circumcision. Cosmetic ? Don't tell me this is another helmet thread. LOL! Circumcision is actually a controversial procedure even though it's taken for granted. For one thing, it is generally done without anesthesia under the myth that infants don't feel pain. For another, the owner of the penis is not consulted before the procedure is done. And for a third, the procedure is really quite unnecessary. It's done mainly out of mindless tradition, although there are of course multiple religions that practice circumcision for various hygienic or other faith-based reasons. Some people get quite perturbed about the subject and consider it to be genital mutilation and a human rights issue. Some of the threads I have seen on the topic are far more intense than any helmet thread. |
#70
|
|||
|
|||
Beware of PowerCranks
"Tim McNamara" wrote in message news:timmcn-
.... Some people get quite perturbed about the subject and consider it to be genital mutilation and a human rights issue. Some of the threads I have seen on the topic are far more intense than any helmet thread. Think how intense it would be if infants could post. Probably talk like it was all about them... -- Curtis L. Russell Odenton, MD (USA) Just someone on two wheels... |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Beware of PowerCranks | [email protected] | Racing | 205 | August 4th 07 07:23 PM |
Beware of PowerCranks | [email protected] | Techniques | 202 | August 4th 07 07:23 PM |
FS: POwerCranks- | Mike | Marketplace | 0 | December 24th 05 04:52 AM |
FS: Powercranks | steve | Marketplace | 0 | December 19th 05 04:53 AM |
POWERCRANKS | Marketplace | 0 | January 20th 04 01:33 AM |