When we lift a weight with the sole purpose of increasing
the size of the muscle we have different muscle contractions to consider. There
is the eccentric which means the negative portion and the concentric which means
the lifting of the weight. However, there is another contraction which I see so
many people over looking during their workouts which is often the reason why
their efforts in the gym yield very little to zero results!! This is of course
the isometric contraction and I am a huge advocator of paying special attention
to this area of the repetition – here is why.
What Is An Isometric Contraction?
This is the contraction which follows the eccentric and concentric
muscle contraction. However, I want to focus on the isometric contraction which
follows the concentric contraction, for example holding the bar in a ‘’flexed’’
position having just bicep curled it. At this point you would agree most would
let the weight drop back down – but I want you to hold the weight in the same
Motor Unit Recruitment
Within the muscle you have motor units, both small and
large. When you place a level of force against a resistance your motor units
become excitable, leading to recruitment of muscle fibres. Without exception it
is your small motor units which first become engaged when your muscles act
against a resistance. However, to optimise muscle growth it is imperative that
you force the large motor units to become stimulated because they can lead to
the recruitment of 10 times the amount of muscle fibres!! This occurs when the
body feels it is necessary to recruit the larger motor units, in a way you need
to view them as being lazy.
To force the recruitment of large motor units the muscle
needs to come under immense levels of stress where the body feels it MUST
activate the larger motor units. Focussing on the isometric muscle contraction
does just this because it drastically increases the level of tension the target
muscle experiences. It takes the momentum out of any repetition leading to
immense volumes of resistance against the muscle, of course leading to greater
motor unit recruitment.
Muscle fibre Recruitment
As a result of a bigger number of large motor units becoming
involved it inevitably leads to more muscle fibres becoming recruited. This in
turn means that a greater percentage of your overall muscle fibre population is
now working harder through each repetition. As well as the muscle becoming
larger in size and stronger it also leads to a more developed looking muscle. The
muscle groups become noticeably more separated and you often experience more
drastic striations in the muscle.
Mind & Muscle Connection
The mind to muscle connection theory works in my opinion. In
short, by focusing on high quality muscle contractions you are able to carve a
more prominent pathway between your CNS and muscle. As a result you will be
able to stimulate more muscle fibres with each and every repetition. By incorporating
isometric muscle contractions in each and every repetition you are going to
have a massively positive effect on this.
How Can I Do it?
Putting this into practise is relatively simple yet I would only
ever use this when I am not going beyond 8-10 repetitions. At the ‘’top’’ of
each repetition hold the movement in place for 2 seconds, forcing the target
muscle to work over time to apply adequate levels of force to hold the weight
in place. As you do this make sure you squeeze the target muscle as this
reinforces the engagement of the muscle!
After trying this I guarantee you there will be no going
back, the results you experience will be mind blowing!