Adapting your workout to suit
your muscle fibre type
There is no single workout that can be labelled as the best workout. There are a couple of reasons for this, the first being the law of individuality, which states that each individual is different on a physical as well as a mental level, and the second is the law of adaptability, which states that once the body adapts to a specific stimulus, it no longer derives the same benefits as it did before adaptation occurred. These two factors make it impossible for there to be one magic workout.
Muscle Fibres
Each individual will react to a workout differently. A 6-foot 200-pound person has different physical
attributes than a 5-foot 200-pound person. More than likely, these two
individuals have a different muscle fibre makeup as well as a difference in
limb and muscle length. Muscle fibre makeup is one of the most important
factors to consider when deciding which workout will produce better results.
Each muscle contains three different types of muscle fibres.
These include
slow, intermediate, and fast-twitch. Slow-twitch fibres, also known as red
fibres due to their abundant supply of blood, are active during endurance
activities such as running. They are highly oxidative and are not likely to hypertrophy very much. Fast-twitch fibres have little blood supply, causing them
to be white in appearance. They are power-oriented and fatigue quickly. These
fibres tend to hypertrophy more than the slow-twitch fibres. Intermediate fibres have
properties of both of the previously mentioned fibres.
About 60% of people have intermediate muscle fibres.
The remaining 40% is equally divided among the people between slow and fast-twitch. To ensure maximum growth, low, medium, and high repetitions
must be performed. Each muscle in the body has all three muscle properties, but
the ratio of muscle fibre types can vary with each muscle.
Dr F. Hatfield's test for fibre type
Dr Hatfield has devised a test to determine the fibre
composition of each muscle group. The first step is determining your
1-repetition max (RM) on a particular exercise. Use 80% of the 1RM on each
exercise to determine your fibre composition. Remember, one muscle can be
fast-twitch while another is slow-twitch. For this reason, a
variety of exercises should be performed using this test.
Hatfield has found a wide variety of repetition ranges with
his 80% of 1RM test. While some athletes can perform 4 to 6 repetitions with
80%, others can perform 15 to 20 repetitions. The reason this occurs is that
people performing the lower repetitions have mostly fast-twitch muscle fibres,
which have weak endurance capabilities. The people performing 15 to 20
repetitions have more slow-twitch fibres due to their greater endurance
abilities. People performing 7 to 13 repetitions usually have mostly
intermediate fibres.
Test protocol
- Determine your one-repetition maximum (1RM) on an
exercise.
- Perform as many repetitions as possible with 80% of your
1RM.
- Use your result to determine your fibre type:
- Less than seven repetitions - fast-twitch (FT) dominant.
- 7 or 8 repetitions - mixed fibre type.
- more than eight repetitions - slow-twitch (ST) dominant.
This test indicates whether you should perform high, medium,
or low reps on a particular exercise. For instance, if you are FT dominant,
then you should use heavier loads and lower repetitions in your
training. ST dominant individuals, on the other hand, will respond better to
lighter loads and higher repetitions.
The ratio of muscle fibre type
By determining muscle fibre ratios, we are better able to
personalize our training style. A person with mostly fast-twitch fibres
should spend the majority of their time training with lower repetitions. In contrast, the
person with mostly slow-twitch fibres should spend the majority of time in the
higher repetition range. The athlete with mostly intermediate fibres should
spend the majority of time training in the medium repetition range.
To optimise
the size of the muscle, the trainee must recruit as many muscle fibres as
possible. Even if you have mostly fast-twitch fibres, you still must stress the
intermediate and slow-twitch fibres because no muscle has 100% fast or slow-twitch. All muscles have a mixture of both; therefore, all fibres must be
stressed through a variety of repetition ranges.
Grip width
The angle of exercise also plays an important role in recruiting
specific muscle fibres. If you change the angle of an exercise, you create a
different pattern of recruitment, which stimulates different muscle fibres. If
we perform a lat pull-down using a wide grip or a lat pull-down using a closer
grip, we stimulate the same muscle, but by changing the width of the grip, we now
have a different recruitment pattern of muscle fibres within the muscle. By
altering the angle of exercise, we can expect other muscle fibres to be
activated.
Speed of movement
Variations in the speed of exercise also result in different
muscle fibre recruitment. Individual fibres are stimulated with high-velocity
training that is not used when moving heavier weights slowly. It is also a
good idea to use super slow training, which could involve a tempo of 5-0-5. No
matter what type of program you use, after a while, you will adapt to this
specific stimulus, and gains will come to a halt. By continuously varying your
routines, your body does not have a chance to adjust. No routine is immune to
the law of adaptation.
Conclusion
In conclusion, have an open mind about your workouts. Vary your
training protocols and find out what works best for you. Also, do not forget the
importance of nutrition, rest-recovery, and a good supplement program. No
matter how hard you train, if the factors mentioned above are not optimised,
you will never reach your full potential.
Article Reference
This article first appeared in:
- HALE, J. (2006) Adapting your workout to suit your muscle fibre type. Brian Mackenzie's Successful Coaching, (ISSN 1745-7513/ 37/ November), p. 6-7
Page Reference
If you quote information from this page in your work, then the reference for this page is:
- HALE, J. (2006) Adapting your workout to suit your muscle fibre type [WWW] Available from: https://www.brianmac.co.uk/articles/scni37a4.htm [Accessed
About the Author
Jamie Hale is a Sports Conditioning Coach in the USA, a member of the World Martial Arts Hall of Fame, and a contributor to numerous exercise and sports journals.