Updated: Mar 14
I am (un)healthily obsessed with type 2 muscle fibres. My inner nerd dreams of shrinking down to a subcellular size and going on an expedition into someones bicep to explore the inner machinations of these fibres. The main way to develop type 2b/x muscle fibres is through plyometric training. Plyometrics make you hit fatigue in seconds. There is a terrible misconception that as we age we should not do plyometric movements. I theorise that this misconception is the main contributor to type 2 fibre wastage with age. Do not give up! I have more Type 2 fibre at 48 years old than I did in my twenties! Even though this is a very simple introduction to type 2 fibres, I am hoping it will kickstart or reinvent your health and fitness regime!
Even amongst those who are perceived to be the fittest people in the world, or regular gym goers, type 2 muscle fibres are neglected. Over the last 16 years of study and practise, I have learnt and theorised that type 2 muscle fibre activation is one of a few keys to unlocking the majority of health benefits to human health and longevity. As dungeon master, I implore you to recover this key as a primary quest. The key unlocks the chest containing the frost-axe of hypertrophy. As usual I will try to summarise the knowledge that would fill a Tolkien-esque anthology.
What are type 2 muscle fibres?
To answer this we need to look at the main fibre types.
Type 1 = slow endurance muscle (mainly skeletal).
Type 2 = Fast & power muscle.
The long answer
Type I fibres aka slow-twitch. Red in colour because of high myoglobin and mitochondria. Responsible for repetitive low intensity contractions from aerobic pathways. More of this fibre is present in postural muscles unless you do plyometric training. Unfortunately most of the western population, even fitness fanatics are dominated by this fibre type.
Type 2a aka fast twitch fibres are also high in mitochondria and myoglobin. They are different to type 1 in that they make and use ATP faster by aerobic and anaerobic metabolism. Strong and fast but they fatigue quicker unless you are conditioned for peak fitness.
Type IIb and 2x muscle fibres. I like to call these 'super fast twitch'. Low in myoglobin and mitochondria. Hence they are white. They are totally anaerobic slower ATP producers but break it down ultra quick. Short fast pings of power!
The exercise science regarding these muscle fibre types is still very much a growth area. For me, the take-home message is that the combination of all the fibre types can potentially create muscle contraction over a smoothly increasing range of speed. The all round fitness, agility and coordination this can generate is self-explanatory.
Movements and training styles that hit type 2 fibres.
Basically all explosive, 'shocking', fast and randomised movements e.g. Burpees, jumping push ups, going from one plyometric movement into another so the brain cannot work out a pattern. Modern dancing, boxing etc.
You do activate type 2's with classical resistance training and other activities but this has to be supplemented by the above to have a full impact on health and fitness.
Anything medium to long distance or dynamically repetitive just forget it. You will never get the benefits. You won't get the ice-axe!
I want to take this a step further. Even amongst fitness practitioners who do plyometric training it is nearly always on the legs. The whole body needs to be trained explosively. In the same way that we can train the whole body dynamically or isometrically, you need to find plyometric solutions for your whole body. e.g. jumping push ups for the chest and shoulders. jumping tricep dips etc.
Think about a fit runner who puts in 60km a week who does not do much supplementary training. Their upper body is neglected and virtually none of their body is trained with plyometrics. They are at a fraction of their health potential and will undoubtedly suffer injury at some point.
Genetic changes (epigenetics) from activating type 2 fibres. Some study examples. Huge amounts of work needs to be done in this area which I hypothesise will discover some ground-breaking shizzle.
Researchers have found that targeted acute explosive exercise can slow, pause and even lengthen telomeres. HIIT (high intensity interval training), plyometric sequences (jumping push ups, box jumps and burpees etc), really do the trick here. Telomeres are like a biological egg timer of death. They are on the ends of your chromosomes. This appears to tie in with muscle atrophy with ageing being the loss of type 2 fibres. Even though the cause in studies is assigned to a natural process, I theorise that it is more to do with a sedentary western lifestyle, particularly from ages 25 to 60. I have clients in their mid 70s doing plyometrics and strength moves they didnt do before they were 65 that has seen a reversal in their muscular atrophy. Also pushing back sarcopenia and a myriad of other health risk factors including obesity due to an increased muscle mass. Also practical health benefits like surviving falls with less injury, increased reaction times etc. All contributing to higher survivability.
Tendon & ligament strengthening.
Studies have shown that the combination of muscle and tendon working together (muscle-tendon complex) have greater strength and suppleness from plyometric training than weight training or more 'normal' types of exercise. People tend(on) to think that explosive movements make you more stiff but the opposite is actually true. It is an area I would love to study more. I have definitely become more flexible, agile and faster through explosive training and increasing my type 2 muscle fibre, than through light exercise or stretching.
Plyometric induced hormonal activation.
HGH (Human Growth Hormone) is one of the firecrackers that has been studied in explosive training. Type 2b/x fibre hungry training increases HGH. This is called an exercise-induced growth hormone response (EIGR).
1) Help to metabolise fat.
2) Increase the insulin like growth factor 1.
3) Promote the growth of bone, skin and cartilage.
4) Boost protein production.
5) Increase lean muscle mass.
6) Reduce the risk of heart disease.
7) Increase physical performance.
8) Increase skin thickness.
9) Aid faster injury recuperation.
To name but a few
From one bout of intense or acute exercise over 10-20 minutes studies have shown increases in HGH of 500-1000%. This can peak up to an hour after training. This is massive! You could have a 2 hour period with HGH levels beyond that of a 16 year old. The amount secreted has a greater association with peak intensity of the exercise, not the duration (endurance).
There is more work to do! There is a huge amount more to study in this area and I will add more information as the studies roll in!
In conclusion.....Add fast explosive movements into your weekly routines so that they are at least 50% of your output. Trust me you will reap huge benefits at a muscular, organ, metabolic and genetic level!
ALWAYS CONSULT A DOCTOR BEFORE UNDERGOING ANY NEW DIET OR FITNESS REGIME.