Flexibility involves working with a muscle’s defense mechanism in the form of the myotonic or stretch reflex. Stretching a muscle activates nerve receptors in the muscle belly, which, in response, attempt to contract the stretched muscle in order to prevent potential damage from too great a range of motion.
Flexibility can be broken down into 3 specific types:
- Static Flexibility involves ‘holding’ a specific exercise for more than 15 seconds. If there is severe pain, the muscle is being stretched beyond its capacity – STOP! Warming up is to prevent injuries, not create them.
- Proprioceptive Neuro-muscular Facilitation (PNF) is a form of stretching where a joint is moved to its maximum (or near maximum) stretch. At this point the athlete offers a resistance in the opposite direction of the initial force by contracting the muscle being stretched. When this contraction is released, the muscle is able to stretch further. This is usually done with a partner: good cooperation is required. This is in order to respect the difference between the resistance provided by the muscle itself (which the PNF technique can safely overcome) and the greater the resistance offered by the connective tissues which stabilize the joint. This greater resistance should be recognized as marking the safe limit to stretch. All stretching movements are done slowly.
- Dynamic Flexibility involves repeated stretching movements with swinging, or other kinetic actions. Strongly correlated with speed of body movement, dynamic flexibility leads directly into skill or technique development where the body is educated to ‘feel’ correct movements. This ‘feeling’ is known as ‘kinesthesis’. This brings together the technical skills of the event with the neuromuscular patterns necessary to stimulate correctly the muscle pairing. These are made up of protagonist and antagonist muscles, respectively those which cause the desired action.
The four fundamental principles of training apply to flexibility as:
- Specificity: Exercises must focus on specific joint actions and the demands of each event.
- Overload: Gains in flexibility occur when the limits of the existing range of movement are reached regularly.
- At this point, Adaptation occurs, allowing new limits to be set.
- Reversibility: Improvements in flexibility will be lost if regular work is not maintained. The flexibility of an elite athlete begins to deteriorate after three days if some form of flexibility is not maintained; deterioration occurs as quickly as the gains.
For more information on speed and similar articles, “The Sciences of SAC” by Brent McFarlane