Strength gains after training are specific
to the type of training that we do. And there are at least eight different ways
in which strength gains are specific after training. These are: contraction mode, the velocity,
the point on the strength-endurance continuum, the joint angle or range of motion that we
use, the amount of stability that the exercise has, the muscle group that we use, the force
vector that the exercise involves, and the type of external resistance that the exercise
involves. Contraction mode refers to whether the muscle
is lengthening or shortening. When the muscle is lengthening, we refer to
that as eccentric training. When the muscle is shortening, we refer to
that as concentric training. Now, normal strength training involves both
lengthening and shortening muscle actions. But that doesn’t mean that we obtain equal
benefits from both of those muscle actions. In fact, if we use the same load for both
eccentric and concentric muscle actions during normal strength training – which is typically
what happens – then the relative load (the percentage of our maximum strength) is far
smaller in the lengthening phase compared to in the shortening phase, because our maximum
strength while the muscle is lengthening (the maximum force we can produce) is far greater
than when the muscle is shortening. And that means that the adaptations that result
will be far smaller in response to the lengthening phase, than in response to the shortening
phase. After eccentric training (that is strength
training that only involves the lengthening phase of a given exercise), we tend to find
that our eccentric strength (or the maximum force we can produce while the muscle is lengthening)
is increased to a much greater extent than our concentric strength (or the maximum force
we can produce while the muscle is shortening). Conversely, when we perform concentric training
(or in fact normal strength training, because that is a type of strength training in which
the concentric phase is the limiting factor), we tend to find that our concentric strength
increases more than our eccentric strength. In the context of strength training for sport,
the velocity of a muscular contraction primarily relates to the load that we use, because the
load that we use determines the speed that we can move, because of the force-velocity
relationship. Now, after strength training with heavy loads,
which require us to use a slow bar speed to move the weight, we tend to find that our
ability to produce force is greatly increased at slow speeds, but it is increased much less
at high speeds. Conversely, after strength training with light
loads and therefore with high speeds, we find that our ability to produce force is greatly
increased at high speeds, and much less at slow speeds. The strength-endurance continuum also refers
to the load that we use, but in a different context. In this context, the load determines the rep
range that we use for a given set, assuming that set is performed under fatiguing conditions. When we train with heavy loads, we can only
perform a small number of reps. And we improve the ability to produce force
at the strength end of the strength-endurance continuum. Conversely, when we train with light loads
under fatiguing conditions, and for a great number of reps, we improve the ability to
produce force repeatedly at the endurance end of the strength-endurance continuum, which
is often called muscular endurance. Exercises that we perform in the gym can be
done with varying different degrees of stability. For example, the bench press can be performed
in the Smith machine, which is a very stable set-up, it can be done on a bench with a barbell,
which is a relatively stable set-up, it can be done on a bench with dumbbells, which is
a slightly less stable set-up, or it can be done with dumbbells while resting on a Swiss
ball instead of a bench, which is a very unstable set-up. Now, if we do long-term strength training
programs with a bench press, then the type of stability that we choose determines the
type of strength gains that we achieve. If we do a training program using a very stable
bench press, then we will improve our strength on the very stable bench press more than the
other types of bench press. And if we perform a training program involving
a very unstable bench press, then we will improve our strength on that particular bench
press variation much more than on all the others. Exercises can also be done with different
ranges of motion. If we perform an exercise with a full range
of motion, then the end of the lowering phase involves quite a long muscle length. If we perform an exercise with a partial range
of motion, then the end of the lowering phase tends to be a slightly shorter muscle length. After long-term strength training with a full
range of motion, we tend to improve our ability to produce force at a full range of motion
(or a long muscle length) to a greater extent than we do at a partial range of motion (or
at a shorter muscle length). Conversely, after a long-term strength training
program involving a partial range of motion exercise, we tend to improve our ability to
produce force in that partial range of motion, or that shorter muscle length, more than we
do in a full range of motion, or at a longer muscle length. Exercises can be performed with different
force vectors. Force vectors can be either vertical, they
can be horizontal, they can be lateral, or they can be rotational. And the type of force vector that the exercise
involves determines the results that we see after a long-term strength training program. And the strength gains that we achieve tend
to be specific to the force vector used in the exercise. Exercises can be done with different types
of external resistance. The two most common types of external resistance
are weight and accommodating resistance in the form of either elastic bands or chains. And the type of external resistance that we
use determines the strength curve of the exercise over its range of motion. When we use weight, we tend to find that the
exercise becomes slightly more difficult at the beginning and easier towards the end of
the lifting range of motion. Conversely, when we use accommodating resistance,
we find that the exercise becomes harder towards the end of its range of motion, and is slightly
easier at the beginning. And this has quite a large effect on the type
of strength gains that result, such that our strength gains when using weight are greater
when tested with weight, than they are when tested with accommodating resistance, and
our strength gains after training with accommodating resistance are greater when tested with accommodating
resistance than they are when tested with weight. Strength gains are specific to the type of
training performed because of the unique adaptations that each type of training causes. So for example, eccentric training (which
is strength training only involving the lowering phase of a movement, which involves lengthening
the muscle) causes much greater gains in eccentric strength, than in concentric strength. And this happens because of unique adaptations
that eccentric training causes. And these include: certain specific changes
in the motor cortex, changes in spinal reflexes, and adaptations inside the muscle fibers themselves,
including (probably) changes to the giant molecule titin (which is partly responsible
for the greater forces that are produced during lengthening muscle actions), and perhaps also
to the surrounding collagen layer of the muscle fiber, called the endomysium. Similarly, high-velocity strength training
produces very different adaptations from heavy strength training, and this is why it produces
large increases in the ability to produce force at high speeds, and only small increases
at slow speeds. And heavy strength training produces the opposite
effect. High-velocity strength training tends to increase
the rate coding of the motor units, so the rate at which the signal is sent from the
central nervous system to the muscle, whereas heavy strength training seems to improve the
motor unit recruitment level, so the number of muscle fibers that are actually active
at the point when maximum force is being exerted. Similarly, inside the muscle, high-velocity
strength training seems to improve the maximum shortening speed of the muscle fibers, whereas
heavy strength training seems to reduce it. The ability to produce force is a key determinant
of our performance in any sporting movement. And force is produced in different sporting
movements in very different ways – often at different points in the movement, and by
different muscles. Therefore, if we want to understand how best
to use strength training to transfer to a sporting movement, then we need to understand
the ways in which force is produced in the sporting movement that determine its performance,
and then we need to program our strength training exercises and loading types in a way that
matches those demands. However, we always need to remember that it
is the adaptation that is produced during strength training that allows us to exert
greater force in the sporting movement. And this means that sometimes the type of
strength training we do will not match perfectly to the sporting movement, in some respects. And yet it will actually improve performance
in that movement quite substantially. Everything depends on whether the adaptation
(produced during strength training) is appropriate for an improved ability to produce force in
the sporting movement. It is not valid that say “this type of strength
training looks like this sporting movement, and therefore it is the right type of strength
training to perform” because what a strength training exercise looks like (and whether
it has some superficial characteristics that are similar) is irrelevant. The only thing that matters is whether the
adaptations that are produced by that type of strength training are beneficial for force
production in the sporting movement, in the context in which force is being produced.

One thought on “Transfer to sport

  1. Hi, in your opinion the strength training for tennis it is usefull to use olynpic weightlifting? The force vector in this exercises are from down to up and in tennis we have rotational, back to front and up to down in service.

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