The 2 Primary
Training Related Reasons Why A Muscle Won’t Grow
1.
One has difficulty recruiting a specific muscle group (likely because
it’s the weak link in the chain, and stronger muscles take over during
movements that are ‘supposed’ to target a specific muscle)
2.
One has difficulty recruiting the high threshold motor units/fast-twitch
fibers of the targeted muscle (which have the greatest potential for growth and
are only recruited only when the tension is high enough – which is maximized with
the use of heavy loads, explosive movements, or at the end of a set taken to
failure with lighter loads)
Excitation
Thresholds – What You Know About That?
The greatest factor
that is missed, or misunderstood, by most experts is that of excitation
thresholds – motor units and recruitment patterns. Literature suggests that the
nervous system has a marked ability to selectively preferentially recruit
segments of a muscle over the targeted intention. This would indicate that the
joint angle, and angle of contraction, play a larger role when it comes to
recruiting the desired segments of a muscle group than the amount of weight
used, thus making these variables (angle of contraction and exercise order) of
greater significance when it comes to building muscle.
Motor units (muscle
fibers and the motor neuron that innervates them) with lower excitation
thresholds are always preferentially recruited during a given movement,
regardless of the intent. This is why it’s not uncommon to have a seemingly
unresponsive bodypart located right next to a highly responsive bodypart.
What’s happening is the more neurologically dominant and responsive muscles,
those with lower excitation thresholds, act first and basically take over
exercises that are ‘designed’ to target other muscle groups. This goes beyond
what most experts address when explaining why muscles are unresponsive and/or weak,
and is why certain exercises can be especially effective at stimulating growth
for one individual, while having little to no effect for another, and why exercise
prescription must be personalized, irrespective of the goal.
The ability to not
only recruit selective segments of a muscle, but to recruit the fast-twitch
muscle fibers of that muscle, is very often a limiting factor as it relates to the
capacity to build muscle. If ones nervous system fails, or is unable, to
efficiently recruit these muscle fibers within the targeted muscle, then growth
of that particular muscle is limited. Therefore, as it relates to training, maximal
growth potential can be defined as the sum of one’s ability to stimulate maximum
muscle fibers.
Insanity – Doing The
Same Thing Over And Over, And Expecting A Different Outcome
When a muscle is
seemingly resistant to grow, the common solution is to do more work. This is
done by performing more frequent workouts for the targeted muscle group, or
adding sets and reps to what is already being done. While this approach may seem
logical, in reality it is extremely flawed considering that doing more of the
same will not make up for the underlying problem regarding innervation, in fact,
it will only make it worse.
A muscle with
suboptimal innervation can never fully be under maximal loading, which is
necessary for the fast-twitch fibers are to be recruited, as other highly
responsive nearby muscles will interfere. Increasing the volume in these
situations only ends up creating a greater reliance on the highly responsive
nearby muscle groups, or slow twitch muscle fibers of the targeted muscle. As a
result, the fast-twitch fibers of the targeted muscle group remain untrained,
and over time the nervous system becomes better, and better, at relying on the
highly responsive nearby muscle groups, or slow twitch muscle fibers of the
targeted muscle group, and this cycle takes on a life of its own and feeds
itself.
Break The Cycle
Only once the
nervous system is able to recruit the targeted muscle, including the fast
twitch muscle fibers of that muscle, is increasing the training volume an
effective solution. At that point in time is when the volume can be increased without
ill effect. Until then, training smarter is needed to break the cycle, not
harder.
Training Smarter
Some effective and
practical strategies in regards to taking an unresponsive, high excitation
threshold muscle group, and reducing its excitation threshold so that it is
more responsive to training, are:
·
Pre-exhaust the dominant/responsive muscles at the onset of the
workout to avoid having them take over throughout the rest of the workout. This
is self-explanatory - simply fatigue the low excitation threshold, highly
responsive muscle groups, so that their contribution during the rest of the
workout is minimal, and by default the high excitation threshold, low
responsive muscle(s) are left with bearing the load.
·
Pre-exhaust the unresponsive muscle at the onset of the workout to
ensure it is maximally stimulated throughout the rest of the workout. By
isolating and exhausting the targeted muscle(s) early on, they become the
limiting factor which ensures the highly responsive, low excitation threshold
muscle groups are essentially undertrained by comparison, which lessens the discrepancy
between the relatively weak, and relatively strong muscle groups.
·
Chain together compound and isolation exercises as part of a
superset to enhance the mind-muscle connection which facilitates the
recruitment of the high-threshold motor units of the targeted muscle(s). The
innervation threshold of the targeted muscle should determine where in sequence
the isolation movement is placed. If recruiting the targeted muscle is
problematic, and nearby muscle groups are overpowering during exercises designated
for the targeted muscle, then performing the isolated movement first in
sequence is preferred (to pre-exhaust). If however, stimulating the fast-twitch
fibers is problematic, then performing the isolated movement second in sequence
is preferred (to post-exhaust).
Pre-Exhaustion
If recruiting the
targeted muscle group is problematic, the pre-exhaustion method offers two
distinct benefits:
·
It can improve the capacity to recruit the targeted muscle during
other movements, which allow for the use of greater loads, by enhancing the
mind-muscle connection. The localized ‘pump’ and fatigue created by
pre-exhausting a muscle allows the working muscle to be felt to a much greater
degree than under normal conditions, and this carries over to other movements,
thus increasing their overall value in a training program, all of which contributes
to reducing the excitation threshold of the targeted muscle, thus improving its
responsiveness to training.
·
Fatiguing the targeted muscle ensures that it is fully stimulated
during movements in which nearby, low excitation threshold, highly responsive
muscles, are involved. This is especially true for larger muscle groups which
do not get fully stimulated as a result of the smaller, albeit more responsive
muscle groups, being the limiting factor.
To reiterate, the
goal with the pre-exhaust superset is to learn to integrate the targeted muscle
into other movements in which other muscles generally take over.
Post-Exhaustion
Before being able to
fully stimulate a muscle to grow, one must be able to recruit it – that’s where
the pre-exhaustion method is of greater value than the post-exhaustion method. When
innervation is optimal, the post-exhaustion method offers one primary benefit:
·
All things being equal in terms of innervation thresholds, a
greater load is indicative of greater recruitment, and since a major contributing
muscle is not pre-fatigued, greater loads can be handled during the compound
movement.
To maximize
recruitment during the compound movement, select movements that place the
targeted muscle in a relatively stretched position, as muscles that are
stretched the most, are recruited the most, and always aim to lift with as much
acceleration as possible as fast-twitch fiber recruitment is proportionate to
force production. The greater the muscle is stretched, the more fast-twitch
fibers that are recruited. The more fast-twitch fibers that are recruited, the
more force that is produced. The more force that is produced, the faster the
weight is lifted. As you can see, the process is cyclical, as all of these factors
build upon one another, and contribute to fast-twitch fiber stimulation.
To reiterate, the
goal with the post-exhaust superset is to recruit the targeted muscle with
heavy weights, and further fatigue it with the use of isolation movements.
Complex-Contrast Training
Advanced lifters,
those who have no problem recruiting a muscle at will, can get away with using complex-contrast
training to stimulate newfound growth, without the added risk of injury that
usually accompanies highly intensive techniques. Generally complex-contrast training
is reserved for those looking to increase performance with the goal of
increasing their strength levels, but the same principles can be tailored to
those looking to build muscle.
Complex-contrast training
consists of first performing lifts which allow for supramaximal loads to be
used, to recruit as many muscle fibers as possible, before performing a
traditional movement through a full range of motion with a slightly greater
load than would otherwise be possible. By contrast the weight feels lighter
after lifting the supramaximal load, and therefore it is sometimes possible to perform
more reps with the same amount of weight, or lift slightly more weight for the
same amount of reps.
Up to 10% more
muscle fibers can be recruited during a maximal isometric contraction compared
to a concentric contraction, and muscles are typically capable of lowering 30%
more weight eccentrically, than concentrically, as the fast-twitch fibers are
preferentially recruited during eccentric contractions, and are therefore under
greater stress. This opens the door for a few different combinations:
*A power rack is
required for the following techniques
Overloading a muscle
eccentrically is done by putting more weight on the bar than would be possible
to lift concentrically, and lowered as slow as possible (goal is 4-6 seconds)
until the bar rests on the pins in the power rack.
Overloading a muscle
isometrically is done by either pressing/pulling a bar into the pins in the
power rack (which are strategically placed based on the movement being
performed), or holding a bar at the joint angle in which you are strongest, loaded
up with more weight that would be possible to lift through a full range of
motion concentrically, for roughly 6 seconds.
Immediately after
performing either of the options above, the same movement is performed through
a full range of motion (with a load that allows for 3-5 or 4-6 reps, resting as
long as needed in between, 2 minutes being ideal for most, and repeated for 4-5
complex-contrast sets).
If you have any
questions about excitation thresholds and how they affect building muscle, or
how to stimulate newfound growth, feel free to contact me at ben@paramounttraining.ca. I'm available for
online consulting and personalized program design, as well as one on one
training if you are located in the Greater Toronto Area (GTA).
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