Factors Affecting Strength

Affecting Strength

By Chad Tackett

I am often asked why one person develops strength and muscle
faster than another when he or she is performing the same exercises, following
the same training program. Many people feel that they must be doing something
wrong because they aren’t getting the same results as another person. It’s
important to realize that there are six primary factors affecting every
individual’s ability to achieve strength and muscle development, and we have
little or no control over most of them.

Type of Muscle Fiber

One of the most influential factors is muscle fiber type. We have two basic
types of muscle fibers, often referred to as “slow twitch” and “fast twitch.”
Slow twitch muscle fibers are best used for cardiovascular (aerobic) activities.
They produce small levels of force for long periods of time and thus are
better suited for endurance activities. Fast twitch fibers are best used
for anaerobic activities. They produce high levels of force for short periods
of time and are best suited for power activities such as weightlifting.

Most men and women have an equal combination of both slow twitch and fast
twitch fibers. However, some people inherit a high percentage of slow twitch
fibers that enhance their performance in endurance activities, such as long
distance runners. Most world class marathon runners have a very high amount
of slow twitch fibers. World class sprinters or football players, for example,
have relatively more fast twitch muscle fibers. Although both fiber types
respond positively to strength training exercises, the fast twitch types
experience greater increases in muscle size and strength, and thus may obtain
greater and/or faster results from a strength training program.


Another factor over which we have little control is age. Studies show that
people of all ages can increase their muscle size and strength as a result
of a safe and effective strength training program. However, the rate of strength
and muscle gain appears to be greater from age 10-20, the years of rapid
growth and development. After reaching normal physical maturity, muscular
improvements usually don’t come as quickly.


Gender does not affect the quality of our muscle, but does influence the
quantity. Although men’s and women’s muscle tissue are characteristically
the same, men generally have more muscle tissue than women do because muscle
size is increased by the presence of testosterone, the male sex hormone.
The larger the muscles, the stronger the person; this is why most men are
stronger than most women.

Limb and Muscle Length

Another strength factor that is naturally determined is limb length. Persons
with short limbs tend to be able to lift more weight because of advantageous
leverage factors (arms and legs). Similarly, differences in strength development
may come about because of variation in muscle length. Some people have long
muscles, and some people have short muscles. Persons with relatively long
muscles have greater potential for developing size and strength than persons
with relatively short muscles.

Point of Tendon Insertion

Muscle strength is also influenced by the point of tendon insertion. For
example, let’s say Jim and John both have the same arm and muscle length.
However, Jim’s biceps tendon attaches to his forearm farther from his elbow
joint than John’s does. This gives Jim a biomechanical advantage: he is able
to lift more weight than John in biceps exercises such as the Biceps Curl.

Other Important Factors

All of these factors affect our ability to gain strength and muscle development
through training. Keep in mind, however, that the most influential factor
in achieving good results is using a very slow, controlled lifting movement
and lifting to the point of muscle fatigue.

In addition to using good lifting technique, it is absolutely imperative
that you not only train with intensity on a well-balanced program, but also
give your muscles enough resting time between training sessions. Overtraining
is a common mistake people make; it happens not only when you don’t allow
your muscles enough rest, but also when you train with too many sets and
exercises for each muscle group.

Another mistake people make is doing the same program over and over again
even after they have reached a plateau. Any time you 1) stop gaining strength
or muscle size or 2) get bored, it is crucial that you change the program,
so that you can go through a whole new phase achieving new results.

We inherit most of these factors affecting strength from our parents, and
they have a big impact on our size, strength, and appearance. It is very
important that you not become obsessed with trying to look like a world-class
body builder–or any other body type that is not your own. We are not all
meant to look the same. It is very important that you learn about and accept
your own body’s characteristics and type, so you can develop a reasonable
program specific to realistic goals and personal interests.

Genetics does clearly play a role in your health and appearance, but they
certainly do not determine how often or well you train. Even if you are born
with a genetic predisposition to being overweight or weak, the way you live
is what will ultimately determine whether you become fit and strong or fat
and weak.

Weightlifting provides many important benefits that cannot be achieved by
any other exercise or activity. Physiologically, the benefits of consistent
strength training include an increase in muscle size and tone, increased
muscle strength, and increases in tendon, bone, and ligament strength.
Strength-training has also been shown to improve psychological health as
well, by increasing self-esteem, confidence and self-worth. If you understand
and accept your body, you will be able to work with it, not against it. Everyone
can improve their strength, appearance, and performance level by consistently
implementing an effective strength training program. Good luck: I hope you
enjoy all the many benefits of strength training.

– Bio: Chad Tackett has degrees in Exercise and Heath Science and
Nutrition, is a Certified Personal Trainer, and is a regular guest lecturer
to both professional and lay audiences on the principles of effective exercise
and good nutrition.

last update: February 2009

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