Intensity and MPS

Discussion in 'Hypertrophy Research' started by dkm1987, Jun 12, 2009.

  1. dkm1987

    dkm1987 New Member

    Influence Of Muscle Contraction Intensity And Fatigue On Muscle Protein Synthesis (MPS) Following Resistance Exercise

    Burd, Nicholas A.; West, Daniel WD; Staples, Aaron W.; Holwerda, Andrew M.; Moore, Daniel R.; Tang, Jason E.; Baker, Steven K.; Phillips, Stuart M.

    Volume 41(5) Supplement 1, May 2009, p 149

    PURPOSE: To determine how changes in mixed skeletal muscle protein synthetic rate (MPS) are influenced by training load (90 vs. 30% maximal strength) or exercise intensity (failure vs. work matched) over 24h of recovery.
    METHODS: Six male subjects (21±1y, 176±1cm, 74.5±2.7kg) were counterbalanced and randomly assigned to two of three unilateral exercise conditions (n = 4 each group) consisting of 4 sets at 90% 1RM to failure (90RM), 30% 1RM worked matched to 90% 1RM (30WM), or 30% 1RM to failure (30FAIL). Exercise at 90RM, 30WM, and 30FAIL differed in total contractions performed (5 ± 0, 14 ± 1 and 23 ± 1, respectively; all P<0.05) and time under tension (16.4 ± 1, 27.1 ± 2, 42.1 ± 1 seconds, respectively; all P<0.05).

    RESULTS: Mixed MPS was elevated to a greater extent (241%, P<0.05) in the 90RM (0.112 ± 0.020%/hr) compared to 30WM group (0.066 ±.020%/hr) at 4h post-exercise. No difference (P>0.05) was found at 4h between 30FAIL (0.093 ± 0.007%/hr) and 90RM (Figure 1.). The elevation in MPS at 4h post-exercise was greater than 24h (main effect, P<0.05).

    CONCLUSION: These data suggest that training to maximal failure, independent of training load, induces a greater acute rise in mixed MPS compared to a work-matched control. The greater acute increase in mixed MPS after exercise at 90RM and 30FAIL is likely related to recruitment of more type II muscle fibres not activated in 30WM. These findings support the notion that heavy and light training loads may elicit similar training-induced increases in muscle hypertrophy provided exercise is performed to maximal failure.

    Supported by NSERC


    So what does this all mean?

    In a nutshell the mixed muscle protein synthesis changes were about the same for the 2 failure routines while the worked matched 30% 1RM not to failure was less.

    Also notice the total time under tension, the 90% 1RM got it done in a lot less time than the 30% 1RM to failure but both produced about the same MPS response.

    Now the drawbacks of the study. They only compared two intensity extremes 30% vs 90. What would the results have been if they measured 30, 75, 90?

    Also it doesn't state the training experience of the subjects.

    So even though it begins to paint a picture of recruitment being a necessity it doesn't quite give all the answers yet, but it is a step in the right direction.
     
  2. omega99

    omega99 Member

    <div>
    (Dan Moore @ Jun. 12 2009,11:16)</div><div id="QUOTEHEAD">QUOTE</div><div id="QUOTE">In a nutshell the mixed muscle protein synthesis changes were about the same for the 2 failure routines while the worked matched 30% 1RM not to failure was less.</div>
    Interesting. This should certainly stir things up a bit, although not entirely conclusive. Thanks for posting, Dan.
     
  3. dkm1987

    dkm1987 New Member

    I am sure the &quot;Go to failure&quot; group is going to jump all over this and say &quot;told ya so&quot; but in reality since they didn't test routines with a respectable load without failure but matched work it doesn't quite paint that picture either.

    What it does tell us is that in low load training going to failure on several sets is a viable option in an untrained state (I can only assusme these were untrained subjects because of the MPS magnitudal response).
     
  4. abanger

    abanger Member

    Komi @ ECSS

     
  5. anoop

    anoop New Member

  6. dkm1987

    dkm1987 New Member

    Hey Anoop how ya been?

    The only disagreement I would make is the idea that high rep (lower load) sets would show a lessened damage response as this hasn't been justified and in fact the recent paper by Zanchi would give one the opposite impression but until this is duplicated on humans, it's hard to say. Everything else though is spot on and nice blog as well.
     
  7. anoop

    anoop New Member

    Hello Dan,

    It's been a long time since I have posted here. i lost my username and my I don't have that email, hence the new username.

    How is your Max-Stimulation coming? Any updates?

    And great to hear the HST forum being redone. I think it is time that Bryan came out with the book. HST still has enough science to topple any other routine.

    And what are your thoughts about the protein article Dan? The amount of protein needed after your workout.

    Thanks about the blog comment. Not sure how long I can keep it going since i am not making much of out it besides spending a lot of time on reading stuff.
     
  8. dkm1987

    dkm1987 New Member

    Anoop,

    The Cribb study even though better in looking at timing still left a little to be desired in that the additional creatine in the mix added confounding variables. Also they did not compare to a control group who RT'd but did not ingest the protein at all. There wasn't any means used to isolate the effects pre vs. post and lastly Cribb's desire was to sell the products he was involved in so having a study behind him only added to the marketing appeal. The good thing is they actually used RT'd subjects. Your article though is very nice and I love your graphs.
     
  9. anoop

    anoop New Member

    Hi Dan

    Thanks. I wasn't talking about that article in fact.

    I was talking about the recent one I wrote.

    http://www.exercisebiology.com/inde..._much_protein_do_you_need_after_your_workout/

    I think the Cribb study had a lot of good things but I would have done it with a double-blinded fashion, especially when the author has a conflict of interest. And good point about the creatine.
     
  10. dkm1987

    dkm1987 New Member

  11. anoop

    anoop New Member

    Thanks, Dan.

    I though the study was very well done but I didn't hear much about the study. People still take and belive in 40-60 gms of protein post workout. I had asked what Alan to comment. He said the authors conclusion/speculation that 5-6 times of 20-25 gms off protein a day is sufficient doesn't agree with other research. And I agree considering the study only tested post workout they just cannot extrapolate it outside the post workout times.

    Have you come across any protein refractory studies( continuous AA levels blunting protein synthesis). The one study came out in 2001 and I didn't see anything after that.
     
  12. anoop

    anoop New Member

  13. jvroig

    jvroig Super Moderator

    Interesting, thanks for the link, and great site by the way.

    It has been a source of contention before. The single set camp has believed that anything beyond a single set just consumes more calories, with no evidence of any additional benefit. I suppose this study appears to support multiple sets.

    How were the total results gathered? There are 8 participants, and 2 legs, so there is a total of 16 results. Then there are 2 measurements of reach result, making for a total of 32 individual measurements. The graph only shows PS levels at 5H and 29H for 1 set and 3 set results - I assume these are averages? The sample size is rather small (8), so it would be helpful to know the variance. In statistical analysis, averages always need to be presented with standard deviation. Without knowing the variance / std deviation, or the individual results of all participants, there's a lot of wiggle room left on the study.
     
  14. anoop

    anoop New Member

    Thanks for the comments, Jvorig.

    Usually, they don't show all the results of each individual participant. They usually show just the group averages.

    They had the error bars in the graph like in any graph. I just didn't copy it into my graph. My bad. The error bars looked fine and it didn't overlap across groups showing that the results were significant.

    And all good questions. And no study will ever get published in journal of physiology if they get these basic things wrong. So it usually helps to look at the journal published and the author of the study.

    And do register in the forum when you get a chance.
     
  15. dkm1987

    dkm1987 New Member

    Last edited by a moderator: Aug 12, 2010
  16. Greenlantern11B

    Greenlantern11B New Member

    thought HST was against training to failure?
     
  17. CDB

    CDB New Member

    No, HST principles just tell us it's not necessary to train to failure all the time or even frequently for muscles to grow. You can still do it if you want, just don't burn yourself out doing it.
     
  18. abanger

    abanger Member

    Leangains Blog

     

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