Most people would have heard of slow vs fast twitch muscle fibres. In the fitness world they are often talked about in regards to power, strength and endurance. When it comes to your gains in the gym understanding what muscle fibres are, what category you fall under and how to train them is a step you must take to go to the next level!
Basically there are 2 types of muscle fibres – Slow twitch and fast twitch, depending largely on genetics an individual is typically either slow twitch dominant or fast twitch dominant; however there are cases in which a person may be a combination of both.
Slow-twitch muscle fibers known as type 1 generate less power and strength than fast-twitch fibers, but they can sustain activity for longer. The cells within these muscles excel at clearing waste and using oxygen as fuel and, within the muscles, there’s a high-density of capillaries, which helps bring blood to the muscles. These muscle fibres are typically associated with long distance or endurance athletes such as marathon runners or cyclists. In the gym slow twitch dominant people will revel in higher reps, slower tempo and time under tension.
Fast-twitch muscle fibers known as type 2 generate far more power and strength, but they fatigue much faster and require more time for recovery. There are also two types of fast-twitch fibers: Type IIa and Type IIb. Type IIa yields more endurance but produces slightly less strength; Type IIb creates the most strength, but yields less endurance. Bursts of power, speed and strength are what fast twitch people excel at, Olympic lifts, box jumps and sled base pulls are all examples of fast twitch dominant exercises.
How to Train Your Muscle Type
The goal in any strength or weights training should be to train as many as muscle fibres as possible - A fast twitch person should never train the same way as a slow twitch person. Different training methods affect both slow and fast twitch muscle differently.
Training Slow Twitch Muscle Fibres
In order to affect the greatest number of slow twitch muscle fibers, you need to train that muscle with higher reps, shorter rest periods and higher volume. This is because they take longer to fatigue, they recover quickly and they require more work to maximize growth.
If you find you have a hard time gaining size in a particular muscle, it could be because it has a predominance of slow twitch muscle fibres. 12 to 15 reps, higher set numbers and 30 seconds to a minute between sets can help you to maximize those muscles.
It is still important to lift heavy and train hard, with an aim to fatigue muscles to failure – You must give your muscles a reason to GROW!
This doesn’t mean you can’t target fast twitch muscle groups because there is still some fast twitch fibres floating around! Power exercises and HIIT are great options.
Training Fast Twitch Muscle Fibres
Some describe fast twitch predominant individuals as the ‘lucky ones’, because of their ability of to develop size and strength, with a low rep range.
Optimal training for fast twitch muscle fibre groups to maximise includes low to moderate reps - 4 to 8 reps, rest periods of around 1 to 2 minutes and a moderate training volume (shorter workouts).
Personally I would recommend everyone strike a balance in training both fast and slow twitch fibres. For example, a fast twitch predominant individual should aim to train 75% fast twitch and 25% slow twitch.
Understanding muscle fibres will enable you to tailor your training according to the exact specifications of your muscle group and get the absolute most out of every minute you spend in the gym. Make it count!