An introduction in to muscle fibre types.
So in the previous two parts of the VO2 max series we talked about how the oxygen gets delivered in the cells as efficiently as possible and also how oxygen is utilised in the cell.
Today we're going to talk about the different characteristics in muscle fibre type. Some muscle fibres are very efficient with energy. Some are not. Why is this important, and what underlying functions do these differences have? And also, can you get an idea of what your muscle fibre types your muscles are made of?
The two muscle fibre types at both ends of the spectrum are slow twitch and fast twitch muscle fibres. Slow twitch fibres are more energy efficient in comparison to their fast twitch counterparts.
Now this whole series we've been talking about creating energy for the body to use. How do you classify the two above mentioned muscle fibre types?
Since we've talked about endurance a lot, let's delve in to the powerhouses amongst the muscle fibres.
Fast twitch fibres are more power based. Usually lighter in colour due to the lack of myoglobin (a red coloured protein). Fast twitch fibres are usually found in muscles that are not involved in maintaining posture and can produce a lot more force.
Now how do these fast twitch fibres produce more force? By keeping things simple.
A motor unit is a neuron that innervates multiple muscle fibres. The more motor units, the more potential there is for a higher level of coordination. For instance: the muscles in your fingers have a vast amount of motor units, allowing for fine movement.
However, fast twitch fibres are often innervated by very few motor units, allowing for a simple but powerful contraction.
The Fast twitch fibres not only lack myoglobin but also lack mitochondria (the powerhouse of the cell.). Due to this they are more reliant on glycogen to fuel the anaerobic system.
Slow twitch fibres are quite the opposite.
They're weaker, (usually) have more motor units, more mitochondria and are more reliant on fats as means of acquiring energy. You'll find these fibre types in muscles that are responsible for posture such as the spinal erectors.
To get an idea of how these muscle fibre types look in real life. Compare a chicken breast to a chicken thigh. You'll find that the chicken breast's colour will be a lot lighter (fast twitch) and the thigh meat a lot darker (slow twitch).
So how can you find out which muscle group is comprised of which fibre type?
Find your 1RM in say a leg extension, a movement to isolate the Quadriceps. Then use 80% of that 1RM to do as many leg extensions as possible. If your repetitions stay in the lower range (say, 3-5 reps) your probably more fast twitch dominant. If it's in the higher range (say 10-15) probably more slow twitch dominant. Intermediate rep ranges would mean it's 50/50.
Important to note it is there are some studies that suggest that Fast twitch fibres can contain more mitochondria therefore increasing the output, but this could give you at least a "guestamation".
I hope that now you've got a general idea of muscle fibre characteristics. Realise the slow and fast twitch fibres are on opposite ends of the spectrum with a lot of grey area in between.
Thanks for reading:)
So in the previous two parts of the VO2 max series we talked about how the oxygen gets delivered in the cells as efficiently as possible and also how oxygen is utilised in the cell.
Today we're going to talk about the different characteristics in muscle fibre type. Some muscle fibres are very efficient with energy. Some are not. Why is this important, and what underlying functions do these differences have? And also, can you get an idea of what your muscle fibre types your muscles are made of?
The two muscle fibre types at both ends of the spectrum are slow twitch and fast twitch muscle fibres. Slow twitch fibres are more energy efficient in comparison to their fast twitch counterparts.
Now this whole series we've been talking about creating energy for the body to use. How do you classify the two above mentioned muscle fibre types?
Since we've talked about endurance a lot, let's delve in to the powerhouses amongst the muscle fibres.
Fast twitch fibres are more power based. Usually lighter in colour due to the lack of myoglobin (a red coloured protein). Fast twitch fibres are usually found in muscles that are not involved in maintaining posture and can produce a lot more force.
Now how do these fast twitch fibres produce more force? By keeping things simple.
A motor unit is a neuron that innervates multiple muscle fibres. The more motor units, the more potential there is for a higher level of coordination. For instance: the muscles in your fingers have a vast amount of motor units, allowing for fine movement.
However, fast twitch fibres are often innervated by very few motor units, allowing for a simple but powerful contraction.
The Fast twitch fibres not only lack myoglobin but also lack mitochondria (the powerhouse of the cell.). Due to this they are more reliant on glycogen to fuel the anaerobic system.
Slow twitch fibres are quite the opposite.
They're weaker, (usually) have more motor units, more mitochondria and are more reliant on fats as means of acquiring energy. You'll find these fibre types in muscles that are responsible for posture such as the spinal erectors.
To get an idea of how these muscle fibre types look in real life. Compare a chicken breast to a chicken thigh. You'll find that the chicken breast's colour will be a lot lighter (fast twitch) and the thigh meat a lot darker (slow twitch).
So how can you find out which muscle group is comprised of which fibre type?
Find your 1RM in say a leg extension, a movement to isolate the Quadriceps. Then use 80% of that 1RM to do as many leg extensions as possible. If your repetitions stay in the lower range (say, 3-5 reps) your probably more fast twitch dominant. If it's in the higher range (say 10-15) probably more slow twitch dominant. Intermediate rep ranges would mean it's 50/50.
Important to note it is there are some studies that suggest that Fast twitch fibres can contain more mitochondria therefore increasing the output, but this could give you at least a "guestamation".
I hope that now you've got a general idea of muscle fibre characteristics. Realise the slow and fast twitch fibres are on opposite ends of the spectrum with a lot of grey area in between.
Thanks for reading:)
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