Running is the basis for many sports and has an explosive quality common to other movements. However, most sports require much more than sprinting in a straight line at top speed.
The ability to change direction and maintain stability is often more important. Changing direction and speed, without falling, for the purposes of this article, is agility and balance. Changing speed and direction requires the muscles to shorten, immediately after lengthening. The above muscle function is called a stretch reflex, which is protective to the muscle and tendon. In order to train the muscle to react quickly enough to avoid injury neuromuscular training is essential. One example of how to train the neuromuscular system is by using plyometrics and/or explosive weight training exercises.
While playing a sport the athlete is focused on winning or outperforming the opponent. Therefore the athlete reacts without a conscious effort. Most coaches refer to the above movement as reflexes. In order to improve these unconscious movements the athlete needs to train the neuromuscular system. The neuromuscular system is the connection of the muscles to the Proprioceptors, which are nerve ending within soft tissue structures surrounding our joints that give the muscles information in order to react quickly to protect the ligaments and tendons from injury. In other words, as we are running our foot may land on an uneven surface. Special Proprioceptors within the soft tissue structures surrounding the ankle joint informs the muscles that if they do not react to make adjustments to the uneven surface the ligament will be torn.
Before we describe how to train the Proprioceptors, which are important to the neuromuscular system, let us define some of the terminology we will use.
Balance: Three sensory systems contribute to maintenance of balance, visual (eyes), vestibular (inner ear), and the proprioceptor (ligaments and tendon), systems.
Perturbation: The definition of perturbation is an unconscious reaction to a sudden unexpected out side force or movement. For example, while running down a football field suddenly a defender attempted to tackle the ball carrier. The ball carrier reacts by cutting, sidestepping, stopping, and quickly starting again. These are all a reflex activity that occurs within seconds. Training the athlete in restoring or improve reaction times, is referred to as perturbation training.
Balance is a conscious effort to hold a position without falling. For example one leg stance is a basic test for balance. Injury to the vestibular system secondary may occur as a result of a blow to the head or ear and/or, ear infections. In addition, visual defects may also affect balance. Two simple tests, to evaluate the vestibular and visual systems are, close your eyes while standing one leg, then open your eyes and try turning your head from right to left while trying to maintain your balance on one leg.
Perturbation exercises have recently been proven to enhance the ability of the proprioceptor signals to the muscle and prevent injuries and to enhance performance. Perturbation exercises are performed on an unstable surface. The athlete can jump on to a proprioceptive disk, which is soft and unstable. The goal is for the athlete to jump on to the disk and maintain their balance. A more basic exercise to enhance balance and provide a perturbing force is standing with both feet on proprioceptive disks while performing a squat. The athlete may also hold a weight to increase the difficulty
Agility is defined as quick and nimble. To an athlete agility means that during running they can create quick changes in direction while maintaining their balance. Training to improve your agility should include perturbation, balance, and plyometric training exercises. It is important before starting a challenging program of the above exercises the athlete be evaluated by a physical therapist specializing in sports rehabilitation. The evaluation will determine the deficits in the neuromuscular systems and help design a specific program for the athlete. Furthermore, advanced exercises involving the perturbation, balance and plyometric exercises should be performed under the supervision of a physical therapist.