Static flexibility -the maximum range of motion a muscle or connective tissue will allow with an external force, not taking into account the speed of the movement.
Dynamic flexibility -the range of motion which takes into account the speed of movement and reflects the joints resistance to movement e.g. a straddle jump.
Benefits of flexibility training:
- Reduced risk of injury
- Improved posture, alignment and ergonomics
- Reduction of DOMS
- Performance enchancement due to an improve RoM normally and when applying a force, therefore making movements more efficient.
Factors affecting flexibility:
- The type of joint - a ball and socket has a full range of motion whereas a hinge joint only allows flexion or extension.
- Joint shape - the shoulder joint has increased RoM due to its shallow joint cavity compared to the hip's deeper cavity.
- Length/elasticity of connective tissues - tendons, ligaments and the joint capsule all limit RoM
- Muscle length/elasticity - the muscle spindles activation point before it initiates the stretch reflex
- Gender - females are generally more flexible than men
- Age - flexibility is greater in children and decreases as a person gets older due to decreased elasicity
- Elasticity - the suppleness of skin and adipose tissue
- Temperature - elasticity is increased as temperature increased by 1-2 degress Celsius
- Muscle mass - excess muscle mass around a joint restricts RoM
- Nerves - nerves pass through joints, so the more present the nerves, the smaller the RoM
- Training - stretching within a training programme may maintain/increase RoM
Sit and Reach Test -
Using a sit and reach box, with shoes removed, the subject places their feet against the box with legs straight. The subject then reaches forward and over the box, pushing a straight object (ruler) as far as possible along the scale on the box with extended fingertips. This position is held for 2-3 seconds and a score is recorded.
Goniometyr uses a double-armed goniometer to measure the number of degrees from a neutral starting position to the position at the end of the full RoM. For example for hip flexion:
Lay flat on your back, keeping your left leg straight and flat on the ground, Move the opposite leg as close as possible to your chest while flexing the knee.
- Static active stretches are unassisted, voluntary static contractions of the agonist muscle to create a force to stretch the antagonist,
- Static passive stretches are assisted by an external force, for example gravity or a partner, to help move the joint just beyond its end point to stretch the muscle/connective tissues.
- Static stretching has long been thought to be the safest method and, despite being the slowest, the most effective form of stretching to increase the length of muscle.connective tissues.
- On the other hand, static stretching fails to prepare the joints for the more dynamic/powerful range of motions that are involved in actual activity.
- Involved the use of momentum to move a joint forcibly through to its extreme end of point of resistance.
- It involved fast, swinging, active or bouncing movements.
- Long been thought as the least effective as it fails to allow adequate time for the tissues to adapt.
- Therefore it carries a gretaer risk of muscle soreness/injury so should only be performed by athletes with a good flexibility.
- Ballistic stretching is thought to produce limited long-term adaptations.
- Dynamic stretching is a more controlled version of ballistic stretching.
- It takes the msucles through a joint's full RoM, with the muscle but with the entry and exit under more control and therefore not the extreme end point of resistance as with ballistic stretching.
- Dynamic stretching can be performed both actively and passively.
- As with ballistic stretching, dynamic stretching should only be performed by athletes who already have a good range of flexibility in the muscle/connective tissues being stretched.
Proprioreceptive Neuromuscular Facilitation (PNF)
Until recent arguments in favour of dynamic, PNF was thought the most effective, and also the most complex, type of stretching.
- PNF attempts to inhibit the stretch reflex mechanism to increase flexibility by allowing a greater stretch of the muscle/connective tissues.
- It usually consists of three stages:
- Static - muscle stretched just beyod point of resistance
- Contract - isometric muscle contraction held for a minimum of 10 seconds
- Relax - muscle relaxed and sequence repeated at least 3 times
- The isometric contraction inhibits the stretch reflex, allowing the muscle to be stretched further in each consecutive PNF stretch.
- Although PNF is a more complex technique, requiring more time to learn and to tolerate the greater discomfort and therefore risks, most research has shown PNF to produce quicker and better flexibility gains.
Flexibility Training Adaptations
- Increased elasticity/length of muscle/connective tissues.
- Increased resting length of muscle/connective tissues.
- Muscle spindles adapt to the increased length reducing the stimulus to the stretch reflex.
- Increased RoM at a joint before the stretch reflex is initiated.
- Increased potential for static and dynamic flexibility (RoM).
- Increased distance and efficiency for muscles to create force and acceleration.
- Increased RoM reduces potential for injury to muscle/connective tissues during dynamic sports movements.