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Strength Training
Strength can be defined as the ability to apply force.
This relies on the neuro-muscular capability to overcome an external and
internal resistance. Therefore, strength training involves using training
techniques that help to increase the athlete ability to apply force. The
development of strength should be of prime importance for anyone seeking to
improve athletic performance. Even athletes that competed in the ancients
Olympic Games realized the importance of strength training, and used primitive
strength training techniques to take advantage of it's benefits. However,
it is still common for many coaches, particularly endurance coaches, to overlook
the benefits that can be gained from strength training.
There are several types of strength that can be considered:
-
General Strength refers to the strength of the
whole muscular system. general Strength provides the foundation for
the whole strength programme and a low level of general strength may be a
limiting factor for an athletes overall progress.
-
Specific Strength refers to the strength of
the particular muscles that will be used in that activity and can be
referred to as Sport Specific Strength.
-
Maximum Strength refers to the highest force
that can be performed during an activity. This will often be measured
through an athletes one repetition maximum (1RM).
-
Muscular Endurance refers to a muscles ability
to perform work over a prolonged period of time.
-
Power refers to the maximum amount of force
that can be applied in the shortest time. Power is the product of both
strength and speed.
-
Absolute Strength refers to the maximum amount
of force that can be applied regardless of body weight.
-
Relative Strength refers to a ratio between an
athletes absolute strength and his or her body weight. Relative
Strength is important when considering athletic performance in sports such
as cycling, boxing etc.
Strength is one of the most important biomotor abilities.
It has an effect on both speed and endurance. Strength training can result
in improvements in any one, or all, of the different types of measurable
strengths. The large improvements that occur in strength, initially
following training, are due all most entirely to improve neuro-muscular
co-ordination, rather than any increase in muscle size. We know that this
is the case since it takes, normally, at least four weeks before there is any
significant increase in muscle size (muscular hypertrophy) It is only
after this initial period that the increase in muscle size also acts to improve
muscular strength. However, the increase in muscular strength due to
muscular hypertrophy is lower than the improved strength due to improvements in
neuro-muscular co-ordination. Muscular hypertrophy results from the
following factors:
-
An increase the number of myofibrils (slender threads of a
muscle fibre) per muscle fibre
-
An increase in the amount of capillaries per muscle fibre
(Capillary density)
-
An increase in the amount of protein per muscle fibre
-
An increase in the total number of muscle fibres
(hyperplasia)
These factors result in a general increase the muscle's cross
sectional area.
Neuro-muscular co-ordination can be divided into three parts:
-
Inter-muscular co-ordination is the
interaction of a number of muscle groups during a muscular activity.
The greater the level of co-ordination between different muscle groups the
better. This can be easily understood when considering the bicep curl.
Although the biceps provide the main force for the movement - assisted by
the brachiallis - there must be co-ordination with the triceps muscle which
must be relaxed to allow proper lifting of the dumbbell. A low level
of inter-muscular co-ordination will therefore adversely affect performance.
This becomes increasingly important with more co-ordinated movements
such as sprinting and is why elite sprinters will concentrate on relaxation
techniques to relax the non-working muscles (antagonist) and thus allow the
working muscles (agonists) to function to their maximum potential.
-
Intra-muscular co-ordination is the
interaction of individual neuro-muscular units within a muscle fibre.
The greater the number of neuro-muscular units recruited during a task the
greater the force that is applied. The level of intra-muscular
co-ordination, and hence, the number of neuro-muscular units recruited, can
be increased through specific training such as maximum load training.
-
Force Generated Through A Nervous Impulse
- Muscles
react to a training stimulus with only about 30% of their potential.
This means that when an athlete lifts a weight only about 30% of the muscle fibres are recruited when lifting that weight. A strength training
program aims to increase the amount of neuro-muscular units recruited during
physical activity. It also aims to allow muscle fibre groups to
alternate, so when one muscle fibre group exhausts, another is still able to
contract.
Since strength training will lead to improvements in all three
of these factors it is clear that strength training will lead to a greater level
of neuro-muscular co-ordination in the strength trained muscles.
Strength and Athletic Performance - An athletes strength
depends on three main factors:
-
Muscle Potential is the amount of force that
could be generated, if all of an athletes muscle-fibres were recruited at
the same time.
-
The Use of Muscle Potential refers to the
athletes ability to recruit muscle fibres at the same time. The
greater the amount of muscle fibres recruitment the greater the use of the
athletes full potential.
-
Technique refers to the level of co-ordination
between different muscles during an activity. The greater the level of
co-ordination the greater the use of the athletes potential.
Types of Muscular Contarction - A strength training
programme can include the use of any of three types of muscular contraction:
-
Dynamic contractions occur with the use of
free weights. When an athlete lifts a free weight they are exerting a force
against gravity. This contraction is sometimes wrongly called an
isotonic contraction. However, Isotonic implies that there is equal tension
throughout the movement. This is inaccurate however, as the muscle
tension changes in relation to the angle of flexion. The phase in
which the weight is lifted, against gravity, is called the concentric phase.
During the concentric phase the muscle shortens as the individual muscle
fibres contract in order to overcome the force of gravity. The
lowering phase is called the eccentric phase. In this phase the muscle
fibre lengthens during the phase of stimulation.
-
Isokinetic Contractions occur when athletes
use machines to perform strength training. When using a weight machine
there is a constant force throughout the range of motion. During an
isokinetic contraction the athlete will still perform concentric and
eccentric contractions.
-
Isometric Contractions occur when a muscle is
contracted under static conditions (i.e. there is no lengthening or
shortening of the muscle fibres). With these contractions the
resulting force is often greater than developed during a dynamic
contraction. In this contraction a high force is developed without the
muscle altering it's length.
Defining The Strength Training Load:
-
Supermaximum is a load that exceeds the
maximum strength of the athlete (typically 100-175% of maximum). This
can only be performed using eccentric contractions, which are stronger than
concentric contractions, and require the help of a spotter.
-
Maximum Load Training involves training with a
resistance that is 90-100% of maximum.
-
Heavy Load Training is where the training load
is 80-90% of maximum.
-
Medium Load Training refers to a load that is
50-80% of maximum.
-
Low Load Training is where the training load
is less than 50% of maximum.
Types of Strength Training - There are four main
categories of strength training:
-
Maximum Strength Training is used to develop
maximum strength. This involves performing 1-3 repetitions of a weight
that is 90-175% of maximum and the movement is be performed at a slow speed.
-
Power development training involves completing
5-10 repetitions of a weight that is 30-80% of maximum. When training
for power the speed of movement is normally fast and explosive.
-
Muscular Endurance Training involves the use
of much higher repetitions (normally 25 up to 250) and uses a weight that is
20-60% of maximum. The pace of each repetition is fairly moderate and
controlled.
-
Hypertrophy Training is used to increase
muscular size and is the main method used for bodybuilding and recreational
athletes. This involves the use of a medium load (70-80% of maximum) with
approximately 8-12 repetitions.
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