The reason they get referred to as fast and slow twitch muscle fibres is due to the speed of the contraction when the muscle activates, but they can also be known as by different names, such as red or white muscle fibres.
When it comes to strength and power everyone associates fast twitch and the ACTN3 gene with being the most important, and whilst this in many instances is true…its not the only truth.
Slow twitch fibres have still got their part to play for improving performance, and whilst slow twitch fibres do not get as big as their fast twitch cousins, they will be just as strong.
Slow twitch fibres take longer to contact, but can hold a contraction for an extended period of time which makes them ideal for endurance events where you’re working for an extended period of time.
Slow twitch fibres are also full of myoglobin, which is used to transfer oxygen from inside your muscle tissue to provide energy for the muscle to contract, which is an extremely important aspect in their endurance capability and makes them suitable for aerobic exercise