Fat burning myths

124

Comments

  • jp1985
    jp1985 Posts: 434
    edited June 2009
    OK I would like to address a few points from this thread – I’ll do this over a couple of posts as I can’t help but write a bit about this topic. Most of this info comes from a presentation I made in order to gain funding for a PhD to investigate the effects of training on cycling efficiency

    1st point– cycling efficiency is not related to performance - I would suggest that there is evidence that it is, and I find it quite worrying that individuals working as cycling coaches seem to have dismissed this out of hand (if I have interpreted there statements correctly).
    Here are a few studies which have shown performance to be correlated to efficiency

    Horowitz et al (1994) assessed average power in a 1 hour cycling performance test in two groups of cyclists matched for VO2max but different gross cycling efficiencies (20.4% vs. 21.9%). The higher efficiency group displayed a 9% higher average power output in the performance test (342 vs. 315watts)
    http://www.ncbi.nlm.nih.gov/pubmed/8005729?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    Passfield and Doust (2000) showed gross efficiency was attenuated following prolonged moderate intensity endurance. This attenuation of gross cycling efficiency was significantly related to a 4% (approx -0.56km/hr) reduction in 5minute performance power output (r= 0.91, P<0.01)
    http://www.ncbi.nlm.nih.gov/pubmed/11079525?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    Lucia et al 1998 also observed VO2max to be comparable between top level amateur and professional cyclists with the groups distinguished by different cycling efficiencies
    http://www.ncbi.nlm.nih.gov/pubmed/9721058?ordinalpos=&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.SmartSearch&log$=citationsensor

    Computer modelling studies have predicted that for a 26km TT would be improved by 3% with a 1SD change in gross efficiency (Moseley and Jeukendrup 2001)
    http://www.ncbi.nlm.nih.gov/pubmed/11283439?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    A cyclist with a 1hour sustainable power output of 400 watts a 1% improvement in efficiency would improve performance by 48 seconds (Jeukendrup et al 2000)
    http://www.ncbi.nlm.nih.gov/pubmed/11235007?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    However all of this is relatively unimportant if efficiency cannot be trained as Alex asserts. – Which is the second point
  • jp1985
    jp1985 Posts: 434
    2nd point - Cyling efficiency cannot be trained - Again i would suggest that it can be, however it is relatively difficult to reccomend how this may be done due to limitted research. Which is where Alex may have a point in saying that it isnt worth focussing on as at the minute as we dont really know what may or may not work to best effect. However I think this is one of the biggest areas where performance improvements may be gained in the future.

    Several studies have failed to observe differences in gross efficiency between trained and untrained cyclists and have used this to support the argument that efficiency cannot be trained. However these studies tend to measure gross efficiency at absolute intensities e.g. 100 watts for both trained and untrained subjects; however this is likely to represent different relative intensities between the groups. As GE is significantly influenced by exercise intensity this may explain these findings. Further the trained status of participants in some studies may be questioned as well as the impact of sample size

    Some studies have in fact observed differences between trained and untrained cyclists as well as variation of the GE of individual cyclists over the course of a season.

    Hopker et al 2007 observed 5.1%, 8.7% and 8.9% greater efficiency at 150 watts, 50% and 60% work max respectively between trained and recreational cyclists (not the greater effect at the relative intensities of 50 and 60% work max)
    http://www.ncbi.nlm.nih.gov/pubmed/18059575?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=3&log$=relatedarticles&logdbfrom=pubmed

    However there are relatively few longitudinal studies so it is difficult to tell whether the relationship is causal or coincidental

    Chris mentioned the study by Ed Coyle on Lance Armstrong. This has largely been discredited as it is riddled with floors.
    A couple of responses to the paper can be found here
    http://www.ncbi.nlm.nih.gov/pubmed/16160031?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus
    http://www.ncbi.nlm.nih.gov/pubmed/16160032?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlus


    If I’m not mistaken it was written in response to the court case brought by his insurance company to avoid paying out after he won his 5th Tour de France until he could prove he didn’t dope so Coyle botched the paper together from old findings which introduces considerable bias. (I could be very wrong on this point – but it’s a story I’ve heard)

    Hopker et al 2009 have also just looked at the variation of physiological parameters during the competitive season. They found GE to change significantly over the course of the season, increasing over the pre-competition phase, maintained during the competition phase and decreasing during post-competition phase. The pre competition phase changes were related to the total time spent training and also the time spent above OBLA intensity (blood lactate of 4mmol/l)(r = 0.84 and 0.80) and riders who spent the most time above OBLA were better able to maintain GE (r = 0.87,Pp <0.05). An inverse relationship was also observed between % change in training duration below LT over the competition phase and GE, e.g. less time below LT = Higher GE.
    http://www.ncbi.nlm.nih.gov/pubmed/19276841?ordinalpos=25&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    Additionally I think Alex mentioned the paper by Sassi at Mapei.
    http://www.ncbi.nlm.nih.gov/pubmed/18641717?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed

    While findings were not significant the authors did state that there were within subject seasonal waves in GE and economy

    Several other methods of training have also been seen to improve efficiency

    Resistance Training

    http://www.ncbi.nlm.nih.gov/pubmed/11820327?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    http://www.ncbi.nlm.nih.gov/pubmed/10378917?ordinalpos=&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.SmartSearch&log$=citationsensor

    http://www.ncbi.nlm.nih.gov/pubmed/16287351?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=3&log$=relatedarticles&logdbfrom=pubmed

    Altitude Training

    http://www.ncbi.nlm.nih.gov/pubmed/17805094?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2&log$=relatedreviews&logdbfrom=pubmed

    http://www.ncbi.nlm.nih.gov/pubmed/11428690?ordinalpos=7&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

    Power cranks

    http://www.ncbi.nlm.nih.gov/pubmed/14666944?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=4&log$=relatedarticles&logdbfrom=pubmed
  • jp1985
    jp1985 Posts: 434
    And in an attempt to bring this thread back on topic...

    I think an important point to consider is the post exercise oxygen consumption which is far far greater with high intensity exercise. I've seen research that would actually advocate a resistance training program over endurance/ aerobic based training programme for weight/ fat loss.
  • Alex_Simmons/RST
    Alex_Simmons/RST Posts: 4,161
    jp1985 wrote:
    1st point– cycling efficiency is not related to performance - I would suggest that there is evidence that it is, and I find it quite worrying that individuals working as cycling coaches seem to have dismissed this out of hand (if I have interpreted there statements correctly).
    No, that's not what I'm saying. What I'm saying (at least what I think I'm saying LOL) is that considering efficiency in isolation from other factors that influence performance can be misleading. e.g. it is obvious that an improvement in efficiency, if all else remains the same, will result in an increase in power. But "all else remains the same" is a theoretical construct.
    jp1985 wrote:
    However all of this is relatively unimportant if efficiency cannot be trained as Alex asserts. – Which is the second point
    My point is more about making significant long term changes to efficiency, not short-medium term fluctuations that one would expect to see as a matter of course.

    I have acknowledged that this may indeed be possible and provided one speculated mechanism via which this may occur (e.g. long term conversion of muscle fibre types through years of high volume training) but that overall the evidence is equivocal on the matter.

    Shorter term efficiency can change simply due to variations in fuel substrate mix being utilised amogst a whole range of possible reasons (e.g. I can imagine variances due to environmental condition changes) as well as some of those mentioned in the links you provided.
    RST Sport : Coaching - Training Plans - Powermeters -- My blog -- AeroCoach Australia
  • Alex_Simmons/RST
    Alex_Simmons/RST Posts: 4,161
    chrisw12 wrote:
    So Alex, where do you stand on the debate about Amstrong and the professor (Ed Colyle) who determined that Armstrong's efficiency had increased and that was one of the reasons why he became so dominant after cancer. Against your compatriot (Ashenden) who stated that efficiency would never increase by as much stated.
    My limited understanding is that perhaps the methodologies or equipment used to make the measurements may not have provided sufficiently consistent or accurate data and so the conclusions may not be valid as a result - but I am not sufficiently well read on the topic to know for sure.

    In that Martin paper I posted earlier in this thread - there was a paragraph emphasising the importantance of checking the calibration of such equipment and methodologies especially when attempting to make longitudinal analyses.
    chrisw12 wrote:
    I don't mind if you don't answer that as it might be a too contravessial a question for one working in sport science, but have I got the jist of the arguments right?
    I am not a sports scientist. I am a coach who uses evidence based principles (as opposed to belief based ones). Our head coach, Ric Stern, is a sports scientist and a coach.
    chrisw12 wrote:
    Apologies for taking this thread way off topic.
    I think given the topic that it was inevitable. Hence why I posted the pocorn muncher early on :)


    But it has been good to have a relatively sensible debate/discussion and having information like that presented by jp1985.

    I have no problem if my arguments are shown to be incorrect or not supported by evidence or other evidence is brought to my attention that would change my interpretation of how to apply the knowledge to cycle coaching for performance. I've been wrong before and I'm sure I'll be wrong again in the future.
    RST Sport : Coaching - Training Plans - Powermeters -- My blog -- AeroCoach Australia
  • BeaconRuth
    BeaconRuth Posts: 2,086
    jp1985 wrote:
    1st point– cycling efficiency is not related to performance - I would suggest that there is evidence that it is, and I find it quite worrying that individuals working as cycling coaches seem to have dismissed this out of hand (if I have interpreted there statements correctly).
    Here are a few studies which have shown performance to be correlated to efficiency.....
    I'm not a sports scientist either but I find your 'evidence' in the form of your quoted papers pretty weak. For instance this one:
    Computer modelling studies have predicted that for a 26km TT would be improved by 3% with a 1SD change in gross efficiency (Moseley and Jeukendrup 2001)
    http://www.ncbi.nlm.nih.gov/pubmed/11283439?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
    draws the conclusion "We conclude that a graded exercise test with 3-min stages and 35-W increments is a method by which reproducible measurements of both GE and EC can be obtained, whereas measurements of DE seemed slightly more variable." which is nothing to do with any link between efficiency and performance. What am I missing? I'm happy to be put right, but your summary doesn't seem to be connected with the paper you have referenced?

    Ruth
    http://www.rutheyles.co.uk/
  • jp1985
    jp1985 Posts: 434
    edited June 2009
    Hi Ruth

    Sorry, I've made a mistake there. The information quoted was a secondary reference as I couldn't get hold of the original paper. The quote is not related to the actual findings of that specific study mereley presented in the introduction to support the importance of efficiency. This was the original paper:

    Olds, T.S., Norton, K., Craig, N.P., Olive, S. and Lowe, E. (1995). The limits of the possible: Models of power supply and demand in cycling. The Australian Journal of Science and Medicine in Sport; 27: 29-33

    If anyone woud like any of the full references pm me and i can e-mail them to you.

    Which other papers do you see as weak?

    Do you actually believe that efficiency is irrelevant to performance?
  • jp1985
    jp1985 Posts: 434
    edited June 2009
    Shorter term efficiency can change simply due to variations in fuel substrate mix being utilised amogst a whole range of possible reasons (e.g. I can imagine variances due to environmental condition changes) as well as some of those mentioned in the links you provided

    However if the study is controlled as those i quoted were then such factors can be ruled out as a causal factors for the improvements in efficiency. In a controled study designs the only factor that differs between groups is that of the training intervention (resistance/ altitude/ power crank training) and therefore that is the only factor that improvements in efficiency can be atrributed to.

    Even if changes are short to medium term (weeks) i would still suggest that they are extremely important.
  • jp1985
    jp1985 Posts: 434
    I am not a sports scientist. I am a coach who uses evidence based principles

    That is what i would call a sports scientist.

    I would say that if you work as a coach it is important that you are a sports scientist. This is not to say you have to be tucked away in a lab conducting research but that you need a sound understanding of the undelying physiology and parameters that you are attempting to influence through your training program as well as being up to date with current research relating to these areas.
  • Alex_Simmons/RST
    Alex_Simmons/RST Posts: 4,161
    jp1985 wrote:
    I am not a sports scientist. I am a coach who uses evidence based principles
    That is what i would call a sports scientist.
    I think you have a low threshold for what qualifies as a scientist.

    I know I have contributed to exploring ways to improve performance, e.g. my paper on Optimal Time Trial Pacing Strategies and developed associated models to quantify it, but I am hardly a scientist. If I can get my stuff together, I might have a crack at re-writing it in a manner suitable for publishing in an appropriate science journal.
    jp1985 wrote:
    I would say that if you work as a coach it is important that you are a sports scientist. This is not to say you have to be tucked away in a lab conducting research but that you need a sound understanding of the undelying physiology and parameters that you are attempting to influence through your training program as well as being up to date with current research relating to these areas.
    Not sure I agree with the first sentence but I agree with the second.

    I certainly try and one never stops learning but in reality, I need help from real scientists in interpreting some of the information and assesing the practical implications, if any, of such information. Fortunately I know some good ones who are generous with their time but I probably don't know enough (do we ever?). But that's part of what a coach does, not necessarily try to be an expert in everything but to seek out expert assistance as and when needed.

    From a practical POV, looking for methods to improve efficiency might be nice, but it's performance I'm interested in and I will always assess implications of such information against that criteria. If I can improve performance, and that happens to come about because of a change in efficiency, all well and good.

    But as far as I can tell, chasing efficiency improvement specifically on a bike is not a particularly productive quest versus simply chasing (legal/ethical) methods to improve performance, certainly not in the same way that a focus on efficiency in other more technique oriented events such as swimming has. But of course the impacts of training are multi-factoral, so isolating elements isn't always easy.

    Now you quoted one example study - the (God forbid) reference to Powercranks. I haven't read the full study but the abstract talks about changes in GE but does not mention any changes in performance. What's the point of reporting one without the other?

    And how does it stack up against this study published this year:
    Cycling efficiency and performance following short-term training using uncoupled cranks abstract here:
    http://www.ncbi.nlm.nih.gov/pubmed/19417225
    which finds no changes to performance compared to using normal cranks after the set training protocol.

    Of course the manufacturer would tell you that the protocol was insufficient to detect such improvements. He may be right, but I somehow doubt it. At least I remain highly skeptical.

    Here's an example of a 2007 study on chasing efficiency which turned out to be pretty fruitless:
    Effect of pedaling technique on mechanical effectiveness and efficiency in cyclists.
    http://www.ncbi.nlm.nih.gov/pubmed/17545890


    Like I said, not ruling out chasing cycling efficiency for it's own end but I need to be convinced.
    RST Sport : Coaching - Training Plans - Powermeters -- My blog -- AeroCoach Australia
  • BeaconRuth
    BeaconRuth Posts: 2,086
    jp1985 wrote:
    Which other papers do you see as weak?
    Just for clarification I don't see the papers as weak. It was your evidence for the link between efficiency and performance which I saw as weak, which is a different thing entirely.
    Do you actually believe that efficiency is irrelevant to performance?
    No, I don't. It would be possible to deliberately cycle inefficiently (say, by using a stupidly high cadence) and show that your performance was impaired. So if you take my statement at face value, of course it's rubbish. However, as a coach, given the vagueness of the relatively recent paper you quoted:
    Hopker et al 2007 observed 5.1%, 8.7% and 8.9% greater efficiency at 150 watts, 50% and 60% work max respectively between trained and recreational cyclists (not the greater effect at the relative intensities of 50 and 60% work max)
    http://www.ncbi.nlm.nih.gov/pubmed/1805 ... rom=pubmed
    .......... on the topic of efficiency, I'm not about to start worrying about improving efficiency for myself or the riders I coach, as, from a purely practical POV, there are other far more beneficial aspects of performance to go after. (I paraphrase the paper: Differences in efficiency between trained and untrained individuals do exist - but need further investigation.) Incidentally, the abstract quotes a +1.4% difference, not the much larger numbers you have quoted? Admittedly I haven't read the whole paper, but, again, that doesn't tie in with your own summary of it. Am I missing something this time or is that another mistake on your part?

    Ruth
    http://www.rutheyles.co.uk/
  • jp1985
    jp1985 Posts: 434
    edited July 2009
    No Mistake this time. 1.4% is the absolute difference in efficiency between groups (e.g. 20.91% for a trained athlete vs. 19.89% for an untrained athlete - for those who dont know efficiency is measured as a percentage) and was the average across the 3 work loads. The differences between trained and untrained as a proportion of the untrained efficiency were 5.1, 8.8 and 8.9% respectivley at 150 watts and 50% and 60% wmax.
    No - the efficiency of the 'fuel consumption' is not a limiting factor in cycle race performances
    Horse power is what you need in a TT, not fuel efficiency (or economy). Improving fuel efficiency without improving horse power will not help in a TT one iota

    How else should i take these statements??
  • jp1985
    jp1985 Posts: 434
    efficiency doesn't just mean fuel economy.
    I'm afraid it does just mean (human) fuel ecomomy in the way Alex, Liversedge and I have been using it. It has a very precise definition in exercise physiology.

    Ruth
    Fuel economy is a major aspect of efficiency but by no means the only aspect. Central activation, frequency of motor unit firing, coordination of motor unit firing, transmission of force through tendons amd joint stability may all also play a part.
  • jp1985
    jp1985 Posts: 434
    Now you quoted one example study - the (God forbid) reference to Powercranks. I haven't read the full study but the abstract talks about changes in GE but does not mention any changes in performance. What's the point of reporting one without the other?

    I would agree that this is a weakness of the study. However the study reported that there was no change in VO2max or anaerobic threshold so it is logical to assume that performance would have been improved.

    In general I am wary of investigations that look at training products rather than training methods and im by no means convinced by the use of power cranks but i do believe that there are avenues through which efficiency can be improved.
    Here's an example of a 2007 study on chasing efficiency which turned out to be pretty fruitless:
    Effect of pedaling technique on mechanical effectiveness and efficiency in cyclists.
    http://www.ncbi.nlm.nih.gov/pubmed/17545890

    Well its not fruitless, even negative outcomes have worth. From that paper and others like it you can assume that trying to improve efficiency through changes in pedalling technique (e.g. pedalling circles, pulling upwards on the crank) doesn't change efficiency or performance which is important to know. But this does not mean that studies looking at other areas are not of value or that they will not produce positive findings that may influence training programme design.

    You and Ruth are entirely justified in taking the stance that from a coaching standpoint it is better to focus on other areas of performance. All my arguements stem from the fact that efficiency does effect performance and can be manipulated to improve performance. How this is achieved to best effect is unknown. Compared to the body of evidence ion training VO2max and threshold values efficiency research is thin on the ground but this does not mean efficency is unimportant or should be dirsregarded.
  • Alex_Simmons/RST
    Alex_Simmons/RST Posts: 4,161
    jp1985 wrote:
    Now you quoted one example study - the (God forbid) reference to Powercranks. I haven't read the full study but the abstract talks about changes in GE but does not mention any changes in performance. What's the point of reporting one without the other?

    I would agree that this is a weakness of the study. However the study reported that there was no change in VO2max or anaerobic threshold so it is logical to assume that performance would have been improved.
    You'll have explain why this is a logical assumption (givn that there isn't supporting evidence that performance/power has actually improved).

    Not sure if this example is relevant to where you are heading - e.g. I can pedal at a low cadence and be more efficient but it doesn't help me to generate more power. My LT and VO2 Max haven't changed though. In fact, I can produce more power at higher (less efficient) cadences.
    jp1985 wrote:
    Here's an example of a 2007 study on chasing efficiency which turned out to be pretty fruitless:
    Effect of pedaling technique on mechanical effectiveness and efficiency in cyclists.
    http://www.ncbi.nlm.nih.gov/pubmed/17545890

    Well its not fruitless, even negative outcomes have worth. From that paper and others like it you can assume that trying to improve efficiency through changes in pedalling technique (e.g. pedalling circles, pulling upwards on the crank) doesn't change efficiency or performance which is important to know. But this does not mean that studies looking at other areas are not of value or that they will not produce positive findings that may influence training programme design.

    You and Ruth are entirely justified in taking the stance that from a coaching standpoint it is better to focus on other areas of performance. All my arguements stem from the fact that efficiency does effect performance and can be manipulated to improve performance. How this is achieved to best effect is unknown. Compared to the body of evidence ion training VO2max and threshold values efficiency research is thin on the ground but this does not mean efficency is unimportant or should be dirsregarded.
    Maybe fruitless was a poor choice of word. I meant fruitless in the sense that the negative outcome (which is useful information) demonstrated that such techniques (in this case trialling various pedalling techniques) for chasing efficiency improvements as a performance enhancer were "fruitless". IOW the information is useful to me as it suggests I not bother with such pedalling drills, since there is nothing much to be gained.

    And I don't mean that enhancing our understanding of the underlying mechanisms or ways in which efficiency changes can be induced and any subsequent ties to improving performance (or not as the case may be) shouldn't be done or are fruitless. Just that it's not turning up much that can be usefully applied - rather it seems to be demonstrating what not to bother with (e.g. powercranks, pedalling in "circles" etc).
    RST Sport : Coaching - Training Plans - Powermeters -- My blog -- AeroCoach Australia
  • jp1985
    jp1985 Posts: 434
    You'll have explain why this is a logical assumption (givn that there isn't supporting evidence that performance/power has actually improved).

    Well as you have previously eluded to in your posts the three major determinants of performance are VO2max, lactate threshold and efficiency. If two are held constant and one improves then it is logical to assume performance (sustainable power output) will be enhanced.
    Not sure if this example is relevant to where you are heading - e.g. I can pedal at a low cadence and be more efficient but it doesn't help me to generate more power. My LT and VO2 Max haven't changed though. In fact, I can produce more power at higher (less efficient) cadences.

    If you change efficiency while VO2max and lactate threshold are held constant then power output for a set intensity would be higher or relative intensity for a set power output would be lower. The statemnet about higher cadences leads to other debates. Chavarren and calbet (1999) actuall found that delta efficiency ( a more valid but less reliable measure of efficiency) increased with pedalling rate. While they also observed that gross efficiency decreased with pedallling rate this effct was attenuated at higher power outputs.
    http://www.ncbi.nlm.nih.gov/pubmed/10541922?ordinalpos=2&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum
    Just that it's not turning up much that can be usefully applied - rather it seems to be demonstrating what not to bother with (e.g. powercranks, pedalling in "circles" etc).

    I would suggest that it is. For instance I think that the intensity of training is likely to be very important. If you look at other endurance sports ( running, cross country skiing) resistance training has consistently been seen to improve both efficiency and performance. Studies looking at the effect of resistance training on cycling are now poducing similar results. The Hopker et al 2009 i linked to earlier also observed a link between training intensity and efficiency. So if working as a coach i would be prescribing very high intensity interval work.
  • Alex_Simmons/RST
    Alex_Simmons/RST Posts: 4,161
    jp1985 wrote:
    You'll have explain why this is a logical assumption (givn that there isn't supporting evidence that performance/power has actually improved).

    Well as you have previously eluded to in your posts the three major determinants of performance are VO2max, lactate threshold and efficiency. If two are held constant and one improves then it is logical to assume performance (sustainable power output) will be enhanced.
    Except that it's % of VO2 Max at LT that matters in the context of that physiological performance trilogy, and I don't know whether the % of VO2 Max at LT has remained constant. But maybe that's what you meant? Hence my asking.

    Simply telling us their power at LT, or for an actual performance such as a standardised time trial would have been far more useful.
    jp1985 wrote:
    Just that it's not turning up much that can be usefully applied - rather it seems to be demonstrating what not to bother with (e.g. powercranks, pedalling in "circles" etc).

    I would suggest that it is. For instance I think that the intensity of training is likely to be very important. If you look at other endurance sports ( running, cross country skiing) resistance training has consistently been seen to improve both efficiency and performance. Studies looking at the effect of resistance training on cycling are now poducing similar results. The Hopker et al 2009 i linked to earlier also observed a link between training intensity and efficiency. So if working as a coach i would be prescribing very high intensity interval work.
    I'm interested in cycling performance, not other sports. The greater the freedom of motion (e.g. runing, swimming, X-C skiing), the greater technique can affect efficiency. In cycling we have a very much more contrained freedom of motion, which tends to narrow down the impact of modifying technique on efficiency.

    So examination of information from other sports needs to be appropriately relevant. I think one needs to be somewhat more careful when examing techniques to changes to efficiency when it's being applied to other sports which don't have the same level of physical constraints on joint angles and muscle velocities as experienced in cycling.

    Again, prescribing HIT (or any other training method/mechnism) needs to be considered for it's impact on performance, not efficiency. It may well have a positive impact on efficiency but if a focussed regime of HIT has other less desireable impacts, such as bringing on a peak too early, then just doing it without due consideration of all the impacts would be foolish.

    I do of course prescribe HIT, at times, when appropriate to the extent of my knowledge. But it isn't for the purposes of improving efficiency, but if that also happens, then great.

    All I am suggesting is that unless an outcome is considered for its impact on performance, it makes it harder to assess its usefulness for practical implementation. Doesn't make it useless or uninteresting or unhelpful.

    One thing I do know - there's sure no escaping hard work in the right doses if one wants to improve! :D
    RST Sport : Coaching - Training Plans - Powermeters -- My blog -- AeroCoach Australia
  • Homer J
    Homer J Posts: 920
    :?
  • Surf-Matt
    Surf-Matt Posts: 5,952
    I have a very complex training technique that I have used over the years with several top 10 (and two top 5) 10k trail race (run) results and an off road Sprint (my first) tri win to date.

    I run and cycle as fast as I can.
    I then try and go faster the next time.
    And try and eat sensibly.

    No HRM, no V02 Max, no calorie counting, no abstinance from booze. Just hard training.
  • sandbag
    sandbag Posts: 429
    edited July 2009
    Alex_Simmons/RST wrote:
    Again, prescribing HIT (or any other training method/mechnism) needs to be considered for it's impact on performance, not efficiency. It may well have a positive impact on efficiency but if a focussed regime of HIT has other less desireable impacts, such as bringing on a peak too early, then just doing it without due consideration of all the impacts would be foolish.

    I do of course prescribe HIT, at times, when appropriate to the extent of my knowledge. But it isn't for the purposes of improving efficiency, but if that also happens, then great.

    HIIT improves efficiency, you training the slow twitch muscles to move very quickly, use less oxygen and improve circular motion. There is suggestion some fast twitch muscles are recruited to use as slow twitch, even if they do not, you making the existing slow twitch more efficient. The cyclists who had the most efficiency were the ones with the most slow twitch fibres High cadence spinning teaches your leg muscles to fire more efficiently and quickly, which helps improve economy.

    Efficiency will improve if you never done the following: HIIT. Improve pedal stroke. Lose body weight. Improve saddle position. Make your bike lighter, aerodynamic. Improve your VO2 max. Improve your muscle efficiency. Improve strength/flexibility. Use a rotor crank(better than a powercrank).
  • sandbag
    sandbag Posts: 429
    There are a few specific body systems that directly affect endurance. Among them are the cardiovascular system, respiratory system and most notably the muscular system. Without a doubt, a large percentage of the endurance gains that you see in your training are due to muscular adaptation. Muscle is where energy metabolism takes place and muscular contraction is the end result if a series of a very complicated physiological and biological process.

    There are basically three types of muscle fibers that produce the different ranges of power you use on the bike:

    “Slow twitch” slow glycolytic (endurance)
    “Fast twitch” fast-oxidative glycolytic (sustained power, maximal aerobic efforts)
    “Fast glycolytic” (non oxygen use used for bursts power).

    Your genetic make up strongly influences the composition of the muscle you use on the bike. With specific training, you can increase the size and capacity (hypertrophy) of all the cycling muscles. However, it is virtually impossible to convert say “slow” twitch fibers into “fast” twitch and vice versa. However, you can train each of these groups of muscles to be more efficient and effectively re-balance the ration between the fibers. The ratio of fibers will be a strong determiner of your event specialty in cycling, from track sprinter, to ITT specialist to high endurance road racer.

    Along with hypertrophy effects, aerobic training will cause many chemical adaptations in the muscles. Sustained aerobic training has been shown to increase the size and number of mitochondria in the muscle cells by as much as 200%. Mitochondria are the “power plants” of all living cells and where energy metabolism takes place. The mitochondria receive the oxygen carried in your blood and mixed it with glycogen (from either the blood, or stores in the muscle or liver) to produce adenosine tri-phosphate (ATP), the basic unit of energy for the cell that fuels muscular contraction to create movement. Another chemical adaptation is the increase in production and efficiency of metabolic enzymes in the mitochondria. Metabolic enzymes fuel glycolysis (that breaking down carbohydrates) and beta-oxidation (the breaking down fats) to produce ATP more efficiently during exercise.

    Endurance Training and the effects on Blood Flow and Oxygen
    The delivery of fuel to the cells in your body and the processes by which your body maximizes the use of this energy is a truly remarkable process. To put it simply, when you breathe air into your lunges, oxygen is exchanged with carbon dioxide in the blood through the small air sacs in the lunges called alveoli. When you exhale you are expelling the carbon dioxide along with water vapor (both are byproducts of aerobic energy metabolism in the muscles) with each breath.

    The next breath delivers a fresh load of oxygen to the lungs for another round of gas exchange and the blood stream delivers it to the cells in your body for energy production. This involuntary process continues 24 hours a day 7 days a week.

    Oxygen is transported in the blood as a gas attached to a carrier compound called hemoglobin. Hemoglobin is carried by the red blood cells. The amount of red blood cells is regulated by the amount of oxygen that reaches the tissues in the body. If a lack of oxygen is detected, the kidneys will produce the compound erythopoetin (EPO), which stimulates the bone marrow to produce more red blood cells. The amount of red blood cells in the blood is measured in terms of hematocrit levels (the % of blood volume made up of red blood cells). Normal hematocrit levels can range from 39-54% for men and 35-48% for women.

    Upon delivery to the muscle oxygen is transferred from the hemoglobin to the carrier compound in the muscle cell called myoglobin. The stresses of aerobic training cause adaptations that make this process more efficient by increasing the level of hemoglobin in the blood and increasing the total blood volume.

    The increase in blood volume causes another adaptation in the heart muscle. The heart must now develop the capacity to pump more blood per stroke (heart beat). Hypertrophy (increased size) of the heart muscle allows more blood to be pumped per stroke. This is called increasing cardiac output. Cardiac stroke volume (the pumping capacity of the heart) is represented in the following equation.

    Cardiac Output = Stroke Volume x Heart Rate (in beats per minute)

    So, as the stroke volume increases, the heart has to beat fewer times per minute to maintain blood flow during all levels of activity. This is why during the off-season, your resting heart rate might be 56 beats per minute, but as your stroke volume increases as a result of increased aerobic training your resting heart rate may be somewhere in the range of 45-50 beats per minute (or lower!). This adaptation is also felt during high-level exercise when the heart has to do less work to keep the muscles properly fueled and flushed out and you see a lower HR response to the work being done.

    One last adaptation in the cardiovascular system is the growth of new blood vessels and capillaries, known as “neovascularization”. Every year that you train, your body develops new networks of blood vessels to carry blood and nutrients and fuels to your muscles, specifically the ones we use the most during training. Once these vessels are “built” they are easy to maintain with light exercise in the off-season that keeps the pathways open and flowing. The bonus of neovascularization is that every season your body remodels and builds onto the vascular network, enhancing your capacity for endurance and power.

    Endurance Training and Energy
    Remember ATP, the main molecule of energy for muscle contraction? It can be derived from three different sources in your diet, Carbohydrates (sugars), Protein and Fat (fatty acids). Carbohydrates (sugars) are converted to a more easily consumed form called glucose. Glucose is in turn converted to ATP through a metabolic process called glycolysis (breaking down the glucose molecule). This produces 19 ATP molecules per molecule of glucose. In contrast, one molecule of fatty acid goes through a different process called beta-oxidation (breaking down the fatty acid molecule) and produces 441 molecules of ATP.
    Endurance level training increases both the activity and efficiency of beta-oxidation and increases the use of fatty acids for fuel at sub-maximal intensities. The dramatic differences in yield of ATP molecule makes fatty acids the preferable choice of fuel for sustainable endurance level work.

    Aerobic training also effects lactic acid, the chemical that causes your legs to burn and your strength to fade during extended hard efforts. Lactate is produced in the muscles, in large concentrations, during anaerobic level efforts. When the levels of lactate are too high in the muscles and blood stream for the body to deal with you get the burn and have to back off to recover. It has been shown that an enzyme called lactate dehydrogenase increases with aerobic level training. This enzyme helps your body convert Lactate into a chemical called (AcetyLcoA) that easily produces more ATP, allowing you to beat the burn. This process is called lactate turnover and can be trained effectively through aerobic/endurance exercise.
  • sandbag
    sandbag Posts: 429
    Within a given population, muscular efficiency and thus work rate typically vary by as much as 20–30% when comparing individuals with low vs. high efficiency individuals despite controlling for oxygen consumption, training status, diet and other factors.

    This represents a large amount of biological difference between individuals, which directly influences physical stress and work productivity.

    Work efficiency represents the product of two phenomena: (a) the efficiency with which the chemical energy of glucose and/or fat is converted to ATP through oxidative phosphorylation; and (b) the efficiency with which the chemical energy of ATP hydrolysis is converted to work.

    The large differences among individuals in cycling efficiency appear to be due largely to the efficiency of transferring the chemical energy from ATP hydrolysis into physical work.
  • liversedge
    liversedge Posts: 1,003
    jp1985 wrote:
    efficiency doesn't just mean fuel economy.
    I'm afraid it does just mean (human) fuel ecomomy in the way Alex, Liversedge and I have been using it. It has a very precise definition in exercise physiology.

    Ruth
    Fuel economy is a major aspect of efficiency but by no means the only aspect. Central activation, frequency of motor unit firing, coordination of motor unit firing, transmission of force through tendons amd joint stability may all also play a part.

    I'm struggling with this statement. It strikes me that if we were talking about fuel economy in a car you'd say
    Fuel economy is a major aspect of efficiency but by no means the only aspect. Central processing logic, spark plugs per cylinder, cylinder timing and pattern, and loss of power through the gear box and transmission may all also play a part.

    It begs the question "So what?" are you saying you can train these to make substantial gains in efficiency or that efficiency is a marker of performance in other areas?

    Or perhaps more simply (I am quite simple :lol: ) What is your point with that statement?
    --
    Obsessed is just a word elephants use to describe the dedicated. http://markliversedge.blogspot.com
  • jp1985
    jp1985 Posts: 434
    Efficiency is simply the ratio of work done to energy expended. We measure work done via power output at the pedals so we can only look at cycling efficiency as a whole body measurement. There are many more areas than just fuel economy that contribute to efficiency.

    The comments prior to mine seemed to suggest that fuel efficiency was the only aspect that influences cycling efficiency. I was pointing out that these factors also contribute to cycling efficiency and need to be considered in the debate (can efficiency be trained).

    Yes I'm saying that these areas could be trained and if improved may increase efficiency.
  • liversedge
    liversedge Posts: 1,003
    jp1985 wrote:
    Yes I'm saying that these areas could be trained and if improved may increase efficiency.
    But doesn't the research suggest that gains from training are pretty negligible?
    --
    Obsessed is just a word elephants use to describe the dedicated. http://markliversedge.blogspot.com
  • jp1985
    jp1985 Posts: 434
    liversedge wrote:
    jp1985 wrote:
    Yes I'm saying that these areas could be trained and if improved may increase efficiency.
    But doesn't the research suggest that gains from training are pretty negligible?

    Read my first and second posts for the long version.

    The short version is this:

    There is very little actual research that has looked at the effect of training on efficiency.
    Cross Sectional Studies comparing trained and untrained individuals tend to be equivocal some finding an effect others not.
    Of the longitudinal studies looking at how efficiency changes in individuals over there is and indication that efficiency changes in relation to the stage in the season and is related to the type of training performed.
    Of those studies that have looked at interventions there is evidence to state that altitude training and very high intensity/ resistance training may improve efficiency.
    Alot more ressearch needs to be done.
  • sandbag
    sandbag Posts: 429
    edited July 2009
    Why don't you let the efficiency/economy debate die and contribute on other realistic improvements. It has been proven several posts back, that efficiency doesn't substantially improve, until after several years of training. That's taking into consideration you been training optimally already and monitored your progress. Of course if you never done proper training, then do so, then you going to see a change in efficiency sooner. You get more efficient at anything you do regularly.

    Here is more proof.

    Has Armstrong's cycle efficiency improved?

    This case describes the physiological maturation from ages 21 to 28 yr of the bicyclist who has now become the six-time consecutive Grand Champion of the Tour de France, at ages 27-32 yr. Maximal oxygen uptake (Vo(2max)) in the trained state remained at approximately 6 l/min, lean body weight remained at approximately 70 kg, and maximal heart rate declined from 207 to 200 beats/min. Blood lactate threshold was typical of competitive cyclists in that it occurred at 76-85% Vo(2max), yet maximal blood lactate concentration was remarkably low in the trained state. It appears that an 8% improvement in muscular efficiency and thus power production when cycling at a given oxygen uptake (Vo(2)) is the characteristic that improved most as this athlete matured from ages 21 to 28 yr. It is noteworthy that at age 25 yr, this champion developed advanced cancer, requiring surgeries and chemotherapy. During the months leading up to each of his Tour de France victories, he reduced body weight and body fat by 4-7 kg (i.e., approximately 7%). Therefore, over the 7-yr period, an improvement in muscular efficiency and reduced body fat contributed equally to a remarkable 18% improvement in his steady-state power per kilogram body weight when cycling at a given Vo(2) (e.g., 5 l/min). It is hypothesized that the improved muscular efficiency probably reflects changes in muscle myosin type stimulated from years of training intensely for 3-6 h on most days.

    Tracked over approximately 7 years of training, Lance improved his efficiency by a whopping 8%. Or roughly 1% / year. Three to six hours of cycling per day everyday to get a 1% efficiency increase / year :cry:.

    There are now accusations that Coyle mis-analyzed the data; the re-intrepretation suggests that Lance actually did not improve his efficiency much at all.
  • sandbag
    sandbag Posts: 429
    edited July 2009
    Alot of the body energy generated is lost as heat.
    Approximately 60% of the Caloric energy from the food we eat is lost as heat during the fabrication of ATP (adenosine triphosphate), the high energy, intermediary molecule actually used by the muscle cell to power muscle contraction. Additional energy, again reflected as heat production, is lost when ATP is metabolized in the actual mechanical work of muscle fiber contraction. The net result - only 25% of the Caloric energy in the food we eat is actually used to power the mechanical work of the muscle cells. The initial heat loss associated with the conversion of Calories in food into ATP occurs slowly over several hours and is easily compensated for by our body's temperature control mechanisms, but the heat produced with the metabolism of ATP to power muscle contraction is concentrated over a shorter period of time and is why our body temperature rises (and we sweat to compensate) when we are exercising.
  • jp1985
    jp1985 Posts: 434
    sandbag wrote:
    Why don't you let the efficiency/economy debate die and contribute on other realistic improvements. It has been proven several posts back, that efficiency doesn't substantially improve until after several years of training.

    Here is more proof.

    Has Armstrong's cycle efficiency improved?

    This case describes the physiological maturation from ages 21 to 28 yr of the bicyclist who has now become the six-time consecutive Grand Champion of the Tour de France, at ages 27-32 yr. Maximal oxygen uptake (Vo(2max)) in the trained state remained at approximately 6 l/min, lean body weight remained at approximately 70 kg, and maximal heart rate declined from 207 to 200 beats/min. Blood lactate threshold was typical of competitive cyclists in that it occurred at 76-85% Vo(2max), yet maximal blood lactate concentration was remarkably low in the trained state. It appears that an 8% improvement in muscular efficiency and thus power production when cycling at a given oxygen uptake (Vo(2)) is the characteristic that improved most as this athlete matured from ages 21 to 28 yr. It is noteworthy that at age 25 yr, this champion developed advanced cancer, requiring surgeries and chemotherapy. During the months leading up to each of his Tour de France victories, he reduced body weight and body fat by 4-7 kg (i.e., approximately 7%). Therefore, over the 7-yr period, an improvement in muscular efficiency and reduced body fat contributed equally to a remarkable 18% improvement in his steady-state power per kilogram body weight when cycling at a given Vo(2) (e.g., 5 l/min). It is hypothesized that the improved muscular efficiency probably reflects changes in muscle myosin type stimulated from years of training intensely for 3-6 h on most days.

    This thread has become a debate on whether efficiency can improve performance so i am debating this topic. Liversedge asked a question about my post so i replied.

    Where has this been proven?
    One study does not constitute proof no matter what its findings. Proof can only come from a large body of research observing replicable findings. This body of research doesn't exist for the effects of training on efficiency. But the research that does exist indicates that it certain methods may be a viable mechanism for improving performance and warrants further investigation.

    That paper you have put forward as "proof" has been discredited by a number of researchers. With questions arising about the timing of testing, accuracy and reliability of the testing procedure and equipment used during testing and the equations used to calculate efficiency.

    http://jap.physiology.org/cgi/reprint/99/4/1628
    http://jap.physiology.org/cgi/reprint/99/4/1630
    http://jap.physiology.org/cgi/pdf_extract/105/3/1020
  • jp1985
    jp1985 Posts: 434
    Tracked over approximately 7 years of training, Lance improved his efficiency by a whopping 8%. Or roughly 1% / year. Three to six hours of cycling per day everyday to get a 1% efficiency increase / year

    If the finding were reliable (there not but I'm playing devils advocate) I would suggest that an 8% improvement in efficiency would lead to a significant increase in performance and would very much be worthwhile.
    There are now accusations that Coyle mis-analyzed the data; the re-intrepretation suggests that Lance actually did not improve his efficiency much at all.

    If you assume that the findings were wrong (which they were) and his efficiency didn't change. The conclusion would be that over 7 years of training with no training specifically dedicated to improving efficiency, efficiency did not improve. Thats a shock.

    Longitudinal studies only assess the effect of the cyclist current training, if that training is not designed to enhance efficiency is it a shock that efficiency is not shown to improve?
    It has been proven several posts back, that efficiency doesn't substantially improve, until after several years of training. That's taking into consideration you been training optimally already and monitored your progress. Of course if you never done proper training, then you going to see a change in efficiency sooner. You get more efficient at anything you do regularly. Alot of the energy generated is lost as heat.

    Taking the second part of this quote... I would actually say that specific training for efficiency is more likely to be of benefit to the already very highly trained who are reaching the limits of improving performance via enhancing vo2max or lactate threshold.

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