What do we really know definitively about building muscle or what is known as muscle hypertrophy? This is a short excerpt from Chris Beardsley and Bret Contreras.
Chris Beardsley says…
Hypertrophy is one of the most sought-afer outcomes that
resistance-training programs are intended to achieve.
However, in spite of the great interest in this area, relatively
few long-term training studies have been performed to
assess how the diferent variables within a resistancetraining
program can be manipulated to alter the amount of
hypertrophy that occurs.
What are long-term studies important?
Most of the studies that are discussed in popular forums
relating to hypertrophy are actually acute investigations of
physiological variables. For example, studies are ofen
performed to assess how diferent molecular signaling
pathways are activated in response to diferent training
protocols. Ofen, these are taken as evidence of the
efectiveness of a particular protocol for achieving increases
in muscular size. However, in reality, physiology is so
complex that it is incredibly hard to be sure that such acute
investigations will actually lead to meaningful changes over
longer periods. A great reminder of this fact is the recent
demise of the “hormone hypothesis” which stated that the
level of the post-exercise anabolic hormone response was
able to predict the amount of hypertrophy that occurred.
For many years, researchers believed that if a workout led
to a greater post-exercise anabolic hormone release, it
would cause more hypertrophy. This led some strength and
conditioning coaches to structure their programs around
ways of increasing this post-exercise hormone response.
However, recently, this has been found to be incorrect.
There may certainly be some benefts of acute elevated
hormone levels, but their overall importance for
hypertrophy appears to be greatly over-exaggerated. This
error underscores how dangerous it is to base our
guidelines for resistance-training on acute studies and
emphasizes the importance of knowing exactly what the
long-term studies say.
What do long-term studies investigate?
Long-term studies tend to investigate how diferent training
variables can be manipulated in order to alter the degree of
hypertrophy that occurs. Training variables are those
factors that can be altered within a resistance-training
program in an efort to maximize hypertrophy. Such
variables include relative load (i.e. percentage of 1RM),
volume (i.e. number of sets and reps at a given load),
whether muscular failure is reached, frequency (i.e. number
of times per week), rest periods, range-of-motion,
repetition speed (or duration), and muscle action (i.e.
eccentric or concentric). Unlike the underlying mechanisms
by which hypertrophy is thought to occur (mechanical
loading, metabolic stress, and muscle damage), these
factors can be very easily measured from one intervention
to the next simply by altering programming and monitoring
What is the point of reviewing long-term studies?
Given that many researchers have already performed
reviews of the literature relating to hypertrophy, it is fair to
ask what a limited review of the long-term studies can add.
Importantly, few previous reviews have limited themselves
to an exclusive discussion of the chronic, long-term training
literature. Inevitably, this means that the conclusions of the
reviews are colored by the acute literature, which as we
noted above, leads to less reliable fndings and could
potentially cause coaches to make programming errors as
the “hormone hypothesis” previously did.
What does this review add?
This particular review was performed in order to show what
we know about how hypertrophy is afected by training
variables. As you will see, our understanding is very much
less complete than many would lead you to believe. In fact,
amazing as it may seem, we actually know very litle about
how to structure a resistance-training program so that it
causes signifcantly more hypertrophy than any other
What factors do have an effect?
Overall, it seems that the only factors for which we can
make even the most tentative statements are: volume,
range-of-motion and muscular failure. It seems that training
with a higher volume, a greater range of motion and to
muscular failure all seem to lead to greater hypertrophy.
With a still smaller degree of confdence, we might also
assert that a higher training frequency (in trained subjects
only) and the use of eccentric muscle actions could also
lead to greater hypertrophy. Finally, however, it is very
difcult to see whether or how relative load, rest periods,
and repetition speed afect the extent to which hypertrophy
occurs following strength training programs.
Therefore, it seems logical that for developing muscle mass,
training programs should focus on increasing volume (either
in individual workouts or by increasing frequency), the use
of full ranges of motion, and training to muscular failure
where possible, acknowledging that recovery requirements
may necessitate switching between periods of training to
failure and not training to failure. Additionally, it is likely
most benefcial to use exercises that involve an eccentric
component as well as a concentric component.
This document is copyright Strength and Conditioning Research Limited, 2014. Bret and Chris both work very hard to bring you this information.
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