SPORTS
MEDICINE REHABILITATION SECTION
NEUROMUSCULAR
(PROPRIOCEPTIVE)
TRAINING Emin
ERGEN
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.
TTPDM
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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