Does exercise-induced muscle damage play a role in skeletal muscle hypertrophy?
Posted: 26 February 2012 06:36 PM   [ Ignore ]  
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Exercise-induced muscle damage (EIMD) occurs primarily from the performance of unaccustomed exercise, and its severity is modulated by the type, intensity, and/or duration of training. Although concentric and isometric actions contribute to EIMD, the greatest damage to muscle tissue is seen with eccentric exercise, where muscles are forcibly lengthened. Damage can be specific to just a few macromolecules of tissue or result in large tears in the sarcolemma, basal lamina, and supportive connective tissue, as well as inducing injury to contractile elements and the cytoskeleton. Although EIMD can have detrimental short-term effects on markers of performance and pain, it has been hypothesized that the associated skeletal muscle inflammation and increased protein turnover are necessary for long-term hypertrophic adaptations. A theoretical basis for this belief has been proposed, whereby the structural changes associated with EIMD influence gene expression, resulting in a strengthening of the tissue and thus protection of the muscle against further injury. Other researchers, however, have questioned this hypothesis, noting that hypertrophy can occur in the relative absence of muscle damage. Therefore, the purpose f this paper will be twofold: 1) to extensively review the literature and attempt to determine what, if any, role EIMD plays in promoting skeletal muscle hypertrophy, and; 2) to make applicable recommendations for resistance training program design.

This one looks interesting

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Posted: 27 February 2012 03:15 AM   [ Ignore ]   [ # 1 ]  
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yea. Brad had emailed me the paper. The interesting question is how much damage is too little or too much.

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Posted: 27 February 2012 03:54 PM   [ Ignore ]   [ # 2 ]  
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Hi Anatoly and Anoop,

What were their exact recommendations?

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Posted: 28 February 2012 01:01 AM   [ Ignore ]   [ # 3 ]  
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Here are the practical reccommendations:

Practical Applications
There is a sound theoretical rationale supporting a potential role for EIMD in the
hypertrophic response. While it appears that muscle growth can occur in the relative absence of muscle damage, potential mechanisms exist whereby EIMD may enhance the accretion of
muscle proteins including the release of inflammatory agents, activation of satellite cells, and upregulation of the IGF-1 system, or at least set in motion the signaling pathways that lead to hypertrophy. Although research suggests that eccentric exercise has greater hypertophic effects compared to other types of actions, however, a cause-effect relationship directly linking these gains to EIMD has yet to be established. Moreover, if such a relationship does in fact exist, it is not clear what extent of damage is optimal for inducing maximum muscle growth.

Evidence does seem to show that a threshold exists beyond which damage does not further augment muscle remodeling and may in fact interfere with the process. Given that a high degree of EIMD causes a reduction in the force-producing ability of the affected muscle, excessive damage can impair an individual’s ability to train, which necessarily would have a detrimental effect on muscle growth. Moreover, while training in the early recovery phase of EIMD does not seem to exacerbate muscle damage, it may interfere with the recovery process (83, 111). Thus, current research indicates that a protocol that elicits a moderate amount of damage would be most appropriate for maximizing the hypertrophic response.

Future research should seek to clarify whether a causal relationship exists between EIMD
and muscle hypertrophy and, if so, evaluate optimal levels of damage to maximize the response.
Furthermore, the vast majority of studies have been carried out on untrained subjects.
Considering that a ceiling effect slows the rate of muscle growth as one gains training
experience, it is possible that myodamage may become an increasingly important mediator of
hypertrophy in highly trained individuals. Elucidating these issues will help to increase our
understanding of the mechanisms of muscle development and allow for the optimization
hypertrophy-oriented training programs

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Posted: 28 February 2012 04:30 PM   [ Ignore ]   [ # 4 ]  
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Thanks for posting.

So what is a moderate amount of damage and how does someone measure that? Still a bit vague.

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Posted: 01 March 2012 03:26 AM   [ Ignore ]   [ # 5 ]  
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FullDeplex - 28 February 2012 04:30 PM

Thanks for posting.

So what is a moderate amount of damage and how does someone measure that? Still a bit vague.

No clue. We know around 8-10 sets are good starting number for one muscle group.We also know volume is beneficial and too much volume can hurt things.

Now use your intuition and judgement to fine tune the number.

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Posted: 01 March 2012 12:11 PM   [ Ignore ]   [ # 6 ]  
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Anoop - 01 March 2012 03:26 AM
FullDeplex - 28 February 2012 04:30 PM

Thanks for posting.

So what is a moderate amount of damage and how does someone measure that? Still a bit vague.

No clue. We know around 8-10 sets are good starting number for one muscle group.We also know volume is beneficial and too much volume can hurt things.

Now use your intuition and judgement to fine tune the number.

Agreed, I was just hoping for some specifics, but it appears the research is unclear on this topic.

sorry for going of topic:
Talking about 8-10 sets per muscle group being a good starting point, how about the 20 rep breathing squat routine that a lot of people are fanatic about? I myself haven’t tried it yet, but I have heard about a lot of good results resulting from it. Seems almost too good to be true sometimes, with no really good reason why this low volume routine would work so well for building muscle mass, which is the reason I haven’t tried it.

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Posted: 01 March 2012 12:22 PM   [ Ignore ]   [ # 7 ]  
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FullDeplex - 01 March 2012 12:11 PM

sorry for going of topic:
Talking about 8-10 sets per muscle group being a good starting point, how about the 20 rep breathing squat routine that a lot of people are fanatic about? I myself haven’t tried it yet, but I have heard about a lot of good results resulting from it. Seems almost too good to be true sometimes, with no really good reason why this low volume routine would work so well for building muscle mass, which is the reason I haven’t tried it.

Are you talking about super-squat program by Shtrossen?

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Posted: 01 March 2012 06:09 PM   [ Ignore ]   [ # 8 ]  
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Anatoly - 26 February 2012 06:36 PM

Exercise-induced muscle damage (EIMD) occurs primarily from the performance of unaccustomed exercise, and its severity is modulated by the type, intensity, and/or duration of training. Although concentric and isometric actions contribute to EIMD, the greatest damage to muscle tissue is seen with eccentric exercise, where muscles are forcibly lengthened. Damage can be specific to just a few macromolecules of tissue or result in large tears in the sarcolemma, basal lamina, and supportive connective tissue, as well as inducing injury to contractile elements and the cytoskeleton. Although EIMD can have detrimental short-term effects on markers of performance and pain, it has been hypothesized that the associated skeletal muscle inflammation and increased protein turnover are necessary for long-term hypertrophic adaptations. A theoretical basis for this belief has been proposed, whereby the structural changes associated with EIMD influence gene expression, resulting in a strengthening of the tissue and thus protection of the muscle against further injury. Other researchers, however, have questioned this hypothesis, noting that hypertrophy can occur in the relative absence of muscle damage. Therefore, the purpose f this paper will be twofold: 1) to extensively review the literature and attempt to determine what, if any, role EIMD plays in promoting skeletal muscle hypertrophy, and; 2) to make applicable recommendations for resistance training program design.

This one looks interesting

this would explain while rotating/switching exercises a la DC is a useful tool.

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Posted: 01 March 2012 07:12 PM   [ Ignore ]   [ # 9 ]  
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Anatoly - 01 March 2012 12:22 PM
FullDeplex - 01 March 2012 12:11 PM

sorry for going of topic:
Talking about 8-10 sets per muscle group being a good starting point, how about the 20 rep breathing squat routine that a lot of people are fanatic about? I myself haven’t tried it yet, but I have heard about a lot of good results resulting from it. Seems almost too good to be true sometimes, with no really good reason why this low volume routine would work so well for building muscle mass, which is the reason I haven’t tried it.

Are you talking about super-squat program by Shtrossen?

There are several variations: http://startingstrength.wikia.com/wiki/20_Rep_Squats

Have you tried it?

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Posted: 01 March 2012 07:13 PM   [ Ignore ]   [ # 10 ]  
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FullDeplex - 01 March 2012 07:12 PM

Have you tried it?

Nope

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Posted: 01 March 2012 07:16 PM   [ Ignore ]   [ # 11 ]  
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Anatoly - 01 March 2012 07:13 PM
FullDeplex - 01 March 2012 07:12 PM

Have you tried it?

Nope

Because?

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Posted: 02 March 2012 03:33 AM   [ Ignore ]   [ # 12 ]  
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Agreed, I was just hoping for some specifics, but it appears the research is unclear on this topic.

sorry for going of topic:
Talking about 8-10 sets per muscle group being a good starting point, how about the 20 rep breathing squat routine that a lot of people are fanatic about? I myself haven’t tried it yet, but I have heard about a lot of good results resulting from it. Seems almost too good to be true sometimes, with no really good reason why this low volume routine would work so well for building muscle mass, which is the reason I haven’t tried it.

And it will be never clear.

It always depends on your goals, risk factors, your recovery ability, age, skill level and such. This is where the trainer expertise comes in.

Unless we do study comparing a 20 rep breathing squat with regular squats, I don’t think we can say much.

And is the risk of going through all that pain with a 20 rep squat worth the gains? Can you do eat more or do a higher volume and gain better? Some question to ponder about.

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Posted: 02 March 2012 07:44 AM   [ Ignore ]   [ # 13 ]  
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FullDeplex - 01 March 2012 07:16 PM
Anatoly - 01 March 2012 07:13 PM
FullDeplex - 01 March 2012 07:12 PM

Have you tried it?

Nope

Because?

I don’t believe in magics

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Posted: 02 March 2012 12:10 PM   [ Ignore ]   [ # 14 ]  
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Anatoly - 02 March 2012 07:44 AM
FullDeplex - 01 March 2012 07:16 PM
Anatoly - 01 March 2012 07:13 PM
FullDeplex - 01 March 2012 07:12 PM

Have you tried it?

Nope

Because?

I don’t believe in magics

The same problem I am having. It sounds to good to be true and as Anoop said, there is still research needed to compare the 20 rep squat routine with more sets of heavy squats.

I personally am going to try breathing squats as part of a high volume squating routine I am already doing and see how my body responds. At least I will get some extra conditioning and maybe some magical muscle growth. wink

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