Flexibility
Definition: Flexibility is the range of movement around a joint (as
in the hip), or series of joints (vertebrae).
This is the basic definition we used in GCSE. At A2 we divide
flexibility into two types:
Static flexibility
Def: The range of motion around a joint without accounting for
speed.
Static flexibility is important in sports such as gymnastics or dance,
where there is a need to hold static balances.
Dynamic flexibility
Def: The range of motion around a joint which occurs in the
performance of a physical activity at normal speed or rapid speed.
Dynamic flexibility is important in sports where high speed
movements are required, such as sprinting, kicking, stretching,
throwing and landing. Gymnastics would need dynamic flexibility also.
Flexibility is:
Joint specific for the individual. e.g. An individual could have good
shoulder flexibility, but poor hip flexibility.
Sport specific. e.g A rugby player needs less flexibility in the
shoulder than a gymnast. A rugby players shoulder needs stability –
too much flexibility would compromise the stability.
Factors affecting flexibility
Type of joint – A ball and socket joint has a greater range of
motion than a hinge which only allows flexion and extension.
Shape/structure of joint – The shoulder has a greater range of
motion than the hip joint due to the ball being set much deeper in
the socket of the joint.
Length of muscle – The longer the resting muscle the greater the
range of motion is likely to be – the muscle spindles (stretch
receptors) initiation point is greater.
Elasticity of muscle – Allows a greater stretch (as above).
Temperature of muscle – The muscle tendons and ligaments
elasticity increases when muscle temperature increases by 2-3
degrees. Part of the reason we should warm-up.
Muscle mass – Excess muscle mass around a joint restricts the
range of motion.
Nerves – nerves running through joints are stretched or
compressed as the joint is taken through its full range of motion.
This triggers a stretch reflex in the muscle stopping further
movement.
Gender – Generally females are more flexible than males.
Age – Flexibility is greatest in children. It decreases as you get
older as the muscle, tendons and ligaments lose their elasticity.
Genetic hypermobility – Some people have extreme range of motion.
This can be inherited (double jointed) or through training. This can
lead to the joints being very unstable and an increase in risk of
injury.
Training – Incorporating flexibility training within a training
programme will increase the range of motion within the joints that
are stretched.
Flexibility tests
Sit and reach – lumbar/hamstring
Lumbar stretch - vertebrae
Shoulder stretch – shoulder
You should be familiar with these tests – see notes in files.
The problem with these is that they only measure the range of
motion at the one joint through one type of movement e.g. flexion
Flexibility needs are very sport specific so general flexibility tests
may be of little use.
Goniometer – This is the most valid, accurate and specific method
of testing.
It uses a two armed angle finder, with one arm starting at a neutral
point and the second arm moving with the limb through its full range
of motion. This will give the angle measured in degrees of the range
of motion. ( see pictures on p449 of textbook.) The advantage of
this method is that all types of movement can be measured at all
joints.
Flexibility training
The aim of this training is to prepare for physical activity, increasing
performance and minimising the risk of injury.
The muscle is stretched just beyond its end point of resistance
(range of motion).
To bring about a longer term adaptation in the length of the muscle,
a more extreme stretch is used, pushing the muscle further past the
end point of resistance.
There are two methods of stretching
Maintenance stretching – stretching performed as part of a warm
up or cool down. This does not cause a long term adaptation to the
range of motion, only a short term one in preparation for physical
activity.
Developmental stretching – This involves sessions or significant part
(in terms of time-at least 15 min) of a session given over to
stretching. This will increase the range of motion log term.
Types of stretching
There are four types of stretches that you can use within a training
programme. These are:
Static - This can be divided into passive and active.
Active is where the performer contracts the agonist to create a
stretch in the agonist just beyond its end point of resistance. Held
for 6-20 secs.
Passive is where the stretch is created by an external force, for
example a partner, gravity or apparatus such as a stretch band.
Again the stretch takes the joint just beyond its end point of
resistance.
Key points
- Safest and most effective form of stretching to increase the
length of the muscle/tendons/ligaments.
- It is questioned whether this method prepares the muscles for
activities involving explosive or dynamic movements.
- As a result it is now thought that this method is best used at
the end of activity to aid muscle relaxation.
- Either use maintenance stretches to return muscle to preactivity length or developmental stretches to increase range
of movement (as muscles are very warm and elastic it is very
receptive to these extreme stretches).
- More appropriate in muscles around joints with poor range of
motion.
- Stretches should be limited to less than 20 secs. It is now
believed that any longer will have a detrimental effect on
speed, power and strength.
Ballistic
This involves using momentum to force a joint through to its
extreme end point of resistance.
It involves fast swinging or bouncing movements.
Movements should replicate the dynamic movements of the activity.
Key points
- Thought to be the least effective method as there is not
adequate time for the tissue to adapt to the stretch.
- There is a greater risk of injury.
- Believed to produce limited long term adaptations to muscle
length.
- Should only be used by athletes who already have a good range
of motion.
Dynamic
This involves taking the muscle the joints full range of motion
controlling muscle tension at the entry and exit point of the stretch.
This control prevents the muscle being stretched in the extreme
manner as in ballistic stretching.
Dynamic stretching can be active or passive as with static
stretching.
Key points
- More controlled version of ballistic stretching.
- Suitable only for athletes who already have a good range of
motion in the joints of the muscles being stretched.
- Develops a higher level of dynamic flexibility (great for
activities involving dynamic movement)
- More appropriate than static stretching for warm ups, as
dynamic stretching increases speed, power and strength within
the subsequent activity.
- Developed as research started to show detrimental effect of
static stretching on speed, power and strength.
PNF (Static- contract- relax)
Static – the muscle is moved past end point of resistance either
by actively contracting the agonist to stretch the antagonist or
more commonly passively with a partner taking the muscle past its
end point of resistance.
Contract – The muscle contracts isometrically and held for at
least 10 seconds.
Relax – The muscle is relaxed and movement reversed.
This three phase process is repeated at least three times.
Partner is required to resist movement when the muscle is
contracted.
Key points
- Prior to PNF stretching, dynamic stretching was the most
complex and thought to be the most effective form of
stretching.
- Most effective in muscles around joints with poor range of
motion.
- PNF works by preventing the stretch receptors from inhibiting
movement at the joint.
- The isometric contraction stretches the muscle further than
the stretch reflex would normally allow. With each subsequent
three phase process the muscle stretches further.
- PNF is more complex and a toleration of greater discomfort is
necessary.
- PNF should be used by those who regularly take part in
physical activity. ( muscle tissue is more elastic – less prone to
injury.)
- Stretches should be limited to less than 20 seconds to prevent
a loss in – You should know what by now!
Above is an example of PNF stretching the hamstring
Adaptations to flexibility training
- Increased elasticity of connective tissue (muscles, tendons and
ligaments.
- Increased resting length of muscle.
- Muscle spindles adapt to increased length so stretch reflex is
inhibited.
- Increased range of motion before stretch reflex is initiated.
- Increased potential for static and dynamic flexibility
(remember these from the beginning – check the definitions
and examples!)
- Increased range of motion reduces potential for injury to
muscle/connective tissue.
- Increased distance (and efficiency) for the muscle to create
force and acceleration.
Importance of flexibility
Important for both sports performance and for good health.
Benefits:
- Reduced risk of injury
- Improved posture, alignment and ergonomics.
- Reduction in DOMS and muscle soreness
Performance enhancement:
- Flexible muscles perform better than tight ones
- Improved range of motion at joints
- Greater potential force (power) applied due to greater range
of motion.
- Improved economy of motion – greater gain from less energy
(good for strength endurance and aerobic capacity.
- Improved motor performance/skills. (sporting skills e.g.
sprinting/backstroke)
Flexibility and its effect on Posture and overall health
Health related questions are more and more becoming a focus for
examiners. Be able to describe the positive effects of good
flexibility (and how it prevents the negative effects of poor
flexibility) in relation to good health.
See p455 in textbook or p209 in revision book for more details.