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"Medicina Sportiva" No.14 - 2008 The 15-th Sports Medicine Balkan Congress


Ankara University School of Medicine, Sports Medicine Department, Ankara, Turkey
Sometimes the proper management of sport injuries can be complex and challenging to sports medicine clinician and team members. In order to prevent athletic injuries and programming the rehabilitation after a joint lesion, understanding the role of proprioception (or as sometimes called neuromuscular properties) is important. Proprioception is one of the main clinical goals and serve to regain functional goals. Therefore, after an injury, proprioception training should be incorporated with all other elements of fitness.
Many researchers have defined proprioception as the afferent input of joint position sense (for example awareness of position or movement). Some others explain proprioception in a broader sense that includes neuromuscular control. Most contemporary authorities define proprioception as a specialized variation of the sensory modality of touch that includes the sensation of joint movement (kinesthesia) and joint position (joint position sense).
During any voluntary movements or perturbations occurring in gait, running or jumping, due to rapid responses of lower and to some extent upper extremities, musculature of these parts play an important role in keeping desirable posture. This is executed with a reflex mechanism to maintain the body’s center of mass over the feet (a static or dynamic balance). Any sudden change of the foot or feet position stimulates a sequence of muscle firing that is dependent upon central generators and programs interacting with peripheral reflexes. Afferent information for necessary fine tuning of motor control is provided by proprioceptive, visual, vestibular, and somatosensorial receptors. This function altogether is dynamic or so called functional joint stability. Functional stability helps to protect joints from injuries and contribute to performance via mastering certain necessary movements.
Through receptors proprioceptive information is conveyed to upper centers. Proprioception is mediated by peripheral somato sensorial reseptors in articular, muscular and cutaneous structures. In addition, vestibular and visual organs also serve to send signals related to the body position. Articular structures include nociceptive free-nerve endings and proprioceptive mechanoreceptors consist of Pacinian, Ruffinian corpuscules and GTO. Muscle spindles send messages about the tension of fibres in relation to loading in certain position. Mechanoreseptors do play an important role and a little bid of more pronounced than others. These are specialized neurons traducing mechanical deformation (for example during joint rotation) into electrical signals. Mechanoreceptors all appear to contribute to the transmission of peripheral information related to joint position and motion as well as muscle tension. They are involved in regulating muscle activation. Ruffini endings are quick whereas pacinian corpuscule, muscle spindle and golgi tendon organs are slow adapting receptors.
The clinical importance of proprioception is related to functional (dynamic) stability. Functional (dynamic) joint stability can be defined as the ability of appropriately activated muscles to stabilize a joint together with the support of mechanical stabilizers. In essence, dynamic joint stability is the "product" of the proprioceptive system plus mechanical properties. In relation to dynamic (functional) joint stability, cognitive programming plays a role in the neuromuscular control mechanism. This function refers to voluntary movements that are repeated and stored as central commands. The awareness of body position and movement allows various skills to be performed without continuous reference to consciousness. Proprioceptive feedback is crucial in the conscious and unconscious awareness of a joint or limb in motion. Therefore, enhancement of dynamic (functional) joint stability is important both in prevention and rehabilitation of athletic injuries. This requires a constant and appropriate flow of sensory information, integrated with motor output, in a coordinated manner.
Trauma to tissues may result in partial deafferentation by causing mechanoreceptor damage, which can lead to proprioceptive deficits. Consequently, susceptibility to reinjury, may become a possibility because of this decrease in proprioceptive feedback.
If the question is how to train or reeducate proprioception, the key element appears here as “controlled early motion”.
There are several advantages of early motion following to injury:
1.There is a decreased disuse effects
2.Stimulation of collagen fiber growth is attained
3.The adhesions (contracture formation) is limited
4.Maintenance of articular cartilage is obtained
5.And better maintenance of joint proprioception is provided.
Following proprioceptive exercises could be involved during a rehabilitation program;
These are: Standing; Balancing; Stepping; Walking; Hopping; Jumping. They all should be progressive.
Along with proprioceptive exercises, the program should include a work on strength development of muscles around the involved joint  (e.g. in ankle) especially peronealis, gastrosoleus and tibialis anterior muscles.
General training principles: The number of exercises can be around 2-5; The number of repetitions is less in the beginning and more towards later phases; This applies to the number of sets as well; Total duration of a program can be 5 minutes for preventive and up to 15 minutes for rehabilitative purposes; The patients are recommended to do these exercises daily and continue for about 6-10 weeks in order to gain good results.
Evaluation of proprioceptive progression is important. Therefore, objective analysis methods are necessary.
1.Kinesthesia and joint position sense
2.Balance and postural control
3.Muscular latency
4.Non-instrumented methods
Kinesthesia and joint position sensibility are the two major assessment methods of joint proprioception. Kinesthesia is assessed by measuring threshold to detection of passive motion (TTDPM) while joint position sense is assessed by measuring reproduction of passive positioning (RPP) and reproduction of active positioning (RAP). These later tests are performed at slow angular velocities (0,5 to 2,5 degrees/second) to selectively stimulate Ruffini or Golgi-type mechanoreceptors, and because the test is performed passively, it is believed to maximally stimulate joint receptors while minimally stimulating muscle receptors.
Several researchers utilized PTDs similar in action and design. A device having a moving arm rotating the limb through the axis of the joint is used. A rotational transducer interfaced with a digital microprocessor counter provides the angular displacement values. Pneumatic compression cuffs are placed on each limb distal to the tested joints to reduce cutaneous input. The subjects are blindfolded to eliminate visual cues and headphones with white noise are used to eliminate auditory cues. The subjects are holding an on-off switch to press when they detect the threshold of passive motion or the pre-positioned angle.
The active angle-reproduction test for ankle joint. For the test of active reproduction, an isokinetik dynamometer can be used. The foot is placed in the neutral position. Subjects are blindfolded so that they won’t be distracted. The tester passively moves the test limb into the test position and maintains that position for 10s. Then, the ankle is moved back passively to the reference angle. The subject is asked to actively reproduce the previously given test position angle. This is done twice. In case the subject may not bring his ankle back to its test position. This is called subject error and it is recorded. (This can be two to  three degrees or more). The average error score is calculated. If the score is high, the subject has proprioception deficit.
 The Evaluation of Passive Movement Sense for Ankle joint. A device (simple box) with a movable platform that rotates around a single axis is used. Ankle is placed on the platform. The platform is moved by an electric motor that rotates the foot on an axis at a  rate of 0.50/sec. Movement can be stopped any time by a hand-held switch. The subject is blindfolded and wears a head­set so that he won’t be distracted by sight and sound.  The same procedure as the previous test is applied to produce the angle set by the patient himself. Isokinetic devices and  KAT 2000 are other methods that help for evaluation of neuromuscular properties.
Noninstrumented, clinically applicable tests to assess neuromuscular and functional deficits are reliable and valid for both research and clinical purposes. Limb matching tasks are examples to evaluate proprioception without utilizing an electromechanical device. Providing different angles joint movements, the patients are asked to reproduce the given angle with the other limb. Although various hop tests have been used to measure the lower limb power and functional ability of the athletes, they are assumed to be useful in the evaluation of proprioceptive status of the injured athlete at the end of the rehabilitation periods. These tests are performed either for distance or time to evaluate lower extremity symmetry.

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