Objectives of Functional Rehabilitation

The overall objective of a functional exercise program is to return patients to their preinjury level as quickly and as safely as possible by resolving or reducing the measurable dysfunction within fundamental and functional movement patterns. Specific training activities are designed to restore both dynamic joint stability and ADL skills. To accomplish this objective, a basic tenet of exercise physiology is used. The SAID (specific adaptations to imposed demands) principle states that the body will adapt to the stress and strain placed on it. Athletes cannot succeed if they have not been prepared to meet all the demands of their specific activity. Reactive neuromuscular training (RNT) helps bridge the gap from traditional rehabilitation via proprioceptive and balance training to promote a more functional return to activity. The SAID principle provides constructive stress, and RNT creates opportunities for input and integration. The main objective of the RNT program is to facilitate the unconscious process of interpreting and integrating the peripheral sensations received by the central nervous system (CNS) into appropriate motor responses. This approach is enhanced by the unique clinical focus on pathologic orthopedic and neurologic states and their functional representation. This special focus forces the clinician to consider evaluation of human movement as a complex multisystem interaction and the logical starting point for exercise prescription. Sometimes this will require a breakdown of the supporting mobility and stability within a pattern. Regardless of the specific nature of the corrective needs, all the functional exercises follow a simple but very specific path. First, the functional exercise program is driven by a functional screening or assessment that produces a baseline of movement (see Chapter 22 ). The process of screening and assessment will rate and rank patterns. It will provide valuable information about dysfunction in movement patterns such as asymmetry, difficulty with movement, and pain. Screening and assessment will therefore identify faulty movement patterns that should not be exercised or trained until corrected. Second, the functional framework will assist in making the best possible choices for corrective categories and exercises. No single exercise is best for a movement problem, but there is an appropriate category of corrective exercises to choose from. Third, following the initial session of corrective exercises, the movement pattern should be rechecked for changes against the original baseline. Fourth, when an obvious change is noted in the key pattern, the screening or assessment is repeated to survey other changes in movement and identify the next priority. By working on the most fundamental pattern, it is possible to see other positive changes. Therefore, these four steps provide the framework that makes corrective exercise successful:

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  The screening and assessment direct the clinician to the most fundamental movement dysfunction.

  
  
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  One or two of the most practical corrective exercises from the appropriate category should be chosen and applied.

  
  
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  When the exercise has been taught and is being performed correctly, check for improvement in the dysfunctional basic movement pattern as revealed by specific tests in the screening or assessment.

This concept is called the functional continuum . Most patients seek care because of an obvious source of pain or dysfunction. What is not obvious is the true cause of the pain or dysfunction, ascertainment of which is the purpose of functional movement assessment (see Chapter 22 ). By looking at movement as a whole, all the compensations and conscious sources of pain and dysfunction can be highlighted and addressed. Patients fall into one of four phases on a functional continuum ( Table 23-1 ).

Exercise prescription choices must continually represent the specialized training of the clinician through a consistent and centralized focus on human function and consideration of the fundamentals that make function possible. Exercise applied at any given therapeutic level must refine movement, not simply create general exertion in the hope of increased tolerance of movement. Moore and Durstine state, “Unfortunately, exercise training to optimize functional capacity has not been well studied in the context of most chronic diseases or disabilities. As a result, many exercise professionals have used clinical experience to develop their own methods for prescribing exercise.” Experience, self-critique, and specialization produce seasoned clinicians with intuitive evaluation abilities and innovations in exercise that are sometimes difficult to follow and even harder to ascertain; however, common characteristics do exist. Clinical experts use parallel (simultaneous) consideration of all factors influencing functional movement. RNT as a treatment philosophy is inclusive and adaptable and has the ability to address a variety of clinical situations. It should also be understood that a clinical philosophy is designed to serve, not to be served. The treatment design demonstrates specific attention to the parts (clinical measurements and isolated details) with continual consideration of the whole (restoration of function). Moore and Durstine follow their previous statement by acknowledging that “experience is an acceptable way to guide exercise management, but a systematic approach would be better.” We use the three Rs as a way to understand the type of treatment phases that a patient will undergo ( Table 23-2 ).

The Three-Phase Model for Prescription of Exercise

The purpose of this chapter is to demonstrate a practical model designed to promote the systematic thinking required for effective prescription of therapeutic exercise and progression at each phase of rehabilitation. The approach is a serial (consecutive) step-by-step method that will, with practice and experience, lead to parallel thinking and multilevel problem solving. The (redundant) purpose of this method is to reduce arbitrary trial-and-error attempts at prescribing effective exercise and lessen protocol-based thinking. It will give the novice clinician a framework that will guide but not confine clinical exercise prescription. It will provide experienced clinicians with a system to observe their particular strengths and weaknesses in dosage and design of exercise. Inexperienced and experienced clinicians alike will develop practical insight by applying the model and observing the interaction of the systems that produce human movement. The focus is specifically geared to orthopedic rehabilitation and the clinical problem-solving strategies used to develop an exercise prescription through an outcome-based goal-setting process. All considerations for therapeutic exercise prescription will give equal importance to conventional orthopedic exercise standards (biomechanical and physiologic parameters) and neurophysiologic strategies (motor learning, proprioceptive feedback, and synergistic recruitment principles). This three-phase model ( Box 23-1 ) will create a mechanism that necessitates interaction between orthopedic exercise approaches and optimal neurophysiologic techniques. It includes a four-principle foundation that demonstrates the hierarchy and interaction of the founding concepts used in rehabilitation (both orthopedic and neurologic). For all practical purposes, these four categories help demonstrate the efficient and effective continuity necessary for formulation of a treatment plan and prompt the clinician to maintain an inclusive, open-minded clinical approach.

This chapter is written with the clinic-based practitioner in mind. It will help the clinician formulate an exercise philosophy. Some clinicians will discover reasons for success that were intuitive and therefore hard to communicate to other professionals. Others will discover a missing step in the therapeutic exercise design process. Much of the confusion and frustration encountered by rehabilitation specialists is due to the vast variety of treatment options afforded by ever improving technology and accessibility to emerging research evidence. To effectively use the wealth of current information and what the future has yet to bestow, clinicians must adopt an operational framework or personal philosophy about therapeutic exercise. If a clinical exercise philosophy is based on technology, equipment, or protocols, the scope of problem solving is strictly confined. It would continually change because no universal standard or gauge exists. However, a philosophy based solely on the structure and function of the human body will keep the focus ( Box 23-2 ) uncorrupted and centralized. Technologic developments can enhance the effectiveness of exercise only as long as the technology, system, or protocol remains true to a holistic functional standard. Known functional standards should serve as governing factors that improve the clinical consistency of the clinician and rehabilitation team for prescription and progression of training methods. The four principles for exercise prescription (see Table 23-3 ) are based on human movement and the systems on which it is constructed (see Box 23-2 ). The intent of these four distinct categories is to break down and reconstruct the factors that influence functional movement and to stimulate inductive reasoning, deductive reasoning, and the critical thinking needed to develop a therapeutic exercise progression. It is hoped that these factors will serve the intended purpose of organization and clarity, thereby giving due respect to the many insightful clinicians who have provided the foundation and substance for construction of this practical framework.

Joints: Support and Sensory Function

In a normal healthy joint, both static and dynamic stabilizers provide support. The role of capsuloligamentous tissues in the dynamic restraint of joints has been well established in the literature. Although the primary role of these structures is mechanical in nature by providing structural support and stabilization to the joint, the capsuloligamentous tissues also play an important sensory role by detecting joint position and motion. Sensory afferent feedback from receptors in the capsuloligamentous structures projects directly to the reflex and cortical pathways, thereby mediating reactive muscle activity for dynamic restraint. The efferent motor response that ensues from the sensory information is called neuromuscular control . Sensory information is sent to the CNS to be processed, and appropriate motor strategies are executed.

Physiology of Proprioception

Sherrington first described the term proprioception in the early 1900s when he noted the presence of receptors in the joint capsular structures that were primarily reflexive in nature. Since that time, mechanoreceptors have been morphohistologically identified around articular structures in both animal and human models. In addition, the well-described muscle spindle and Golgi tendon organs are powerful mechanoreceptors. Mechanoreceptors are specialized end-organs that function as biologic transducers for conversion of the mechanical energy of physical deformation (elongation, compression, and pressure) into action nerve potentials yielding proprioceptive information. Although receptor discharge varies according to the intensity of the distortion, mechanoreceptors can also be described in terms of their discharge rates. Quickly adapting receptors cease discharging shortly after the onset of a stimulus, whereas slowly adapting receptors continue to discharge while the stimulus is present. Around a healthy joint, quickly adapting receptors are responsible for providing conscious and unconscious kinesthetic sensations in response to joint movement or acceleration, whereas slowly adapting mechanoreceptors provide continuous feedback and thus proprioceptive information related to joint position (see Chapter 24 for examples of quickly and slowly adapting receptors).

When stimulated, mechanoreceptors are able to adapt. With constant stimulation, the frequency of the neural impulses decreases. The functional implication is that mechanoreceptors detect change and rates of change, as opposed to steady-state conditions. This input is then analyzed in the CNS to determine joint position and movement. The status of the musculoskeletal structures is sent to the CNS so that information about static versus dynamic conditions, equilibrium versus disequilibrium, or biomechanical stress and strain relationships can be evaluated. When processed and evaluated, this proprioceptive information becomes capable of influencing muscle tone, motor execution programs, and cognitive somatic perceptions or kinesthetic awareness. Proprioceptive information also protects the joint from damage caused by movement exceeding the normal physiologic range of motion (ROM) and helps determine the appropriate balance of synergistic and antagonistic forces. This information generates a somatosensory image within the CNS. Therefore, the soft tissues surrounding a joint serve a double purpose: they provide biomechanical support to the bony partners making up the joint by keeping them in relative anatomic alignment, and through an extensive afferent neurologic network, they provide valuable proprioceptive information.

First-Level Response: Muscle

When faced with an unexpected load, the first reflexive muscle response is a burst of electromyographic (EMG) activity that occurs between 30 and 50 msec. The afferent fibers of both the muscle spindle and the Golgi tendon organ mechanoreceptors synapse with the spinal interneurons and produce a reflexive facilitation or inhibition of the motor neurons. The monosynaptic stretch reflex is one of the most rapid reflexes underlying limb control. The stretch reflex occurs at an unconscious level and is not affected by extrinsic factors. These responses can occur simultaneously to control limb position and posture. Because they can occur at the same time, are in parallel, are subconscious, and are not subject to cortical interference, they do not require attention and are thus automatic.

At this level of motor control, activities to encourage short-loop reflex joint stabilization should dominate. These activities are characterized by sudden alterations in joint position that require reflex muscle stabilization. With sudden alterations or perturbations, both the articular and muscular mechanoreceptors will be stimulated to produce reflex stabilization. Rhythmic stabilization exercises encourage monosynaptic cocontraction of the musculature, thereby producing dynamic neuromuscular stabilization. These exercises serve to build a foundation for dynamic stability.

Second-Level Response: Brainstem

The second level of motor control interaction is at the level of the brainstem. At this level, afferent mechanoreceptors interact with the vestibular system and visual input from the eyes to control or facilitate postural stability and equilibrium of the body. Afferent mechanoreceptor input also works in concert with the muscle spindle complex by inhibiting antagonistic muscle activity under conditions of rapid lengthening and periarticular distortion, both of which accompany postural disruption. In conditions of disequilibrium in which simultaneous neural input exists, a neural pattern is generated that affects the muscular stabilizers and thereby returns equilibrium to the body’s center of gravity. Therefore, balance is influenced by the same peripheral afferent mechanism that mediates joint proprioception and is at least partially dependent on an individual’s inherent ability to integrate joint position sense with neuromuscular control.

It is important that these activities remain specific to the types of activities or skills that will be required of the athlete on return to sport. Static balance activities should be used as a precursor to more dynamic skill activity. Static balance skills can be initiated when the individual is able to bear weight on the lower extremity. The general progression of static balance activities is to move from bilateral to unilateral and from eyes open to eyes closed. With balance training, it is important to remember that the sensory systems respond to environmental manipulation. To stimulate or facilitate the proprioceptive system, vision must be disadvantaged, which can be accomplished in several ways ( Box 23-3 ).

Third-Level Response: Central Nervous System/Cognitive

Appreciation of joint position at the highest or cognitive level needs to be included in an RNT program. These types of activities are initiated on the cognitive level and include programming motor commands for voluntary movement. Repetitions of these movements will maximally stimulate the conversion of conscious programming to unconscious programming. The term for this type of training is the forced-use paradigm . By making a task significantly more difficult or asking for multiple tasks, the CNS is bombarded with input. The CNS attempts to sort and process this overload information by opening additional neural pathways. When the individual goes back to a basic ADL task, the task becomes easier. This information can then be stored as a central command and ultimately be performed without continuous reference to conscious thought as a triggered response. As with all training, the single greatest obstacle to motor learning is the conscious mind. We must get the conscious mind out of the act!

Closed-Loop, Open-Loop, and Feedforward Integration

Why is a coordinated motor response important? When an unexpected load is placed on a joint, ligamentous damage occurs in 70 to 90 msec unless an appropriate response ensues. Therefore, reactive muscle activity that provides sufficient magnitude in the 40- to 80-msec time frame must occur after loading begins to protect the capsuloligamentous structures. The closed-loop system of CNS integration may not be fast enough to produce a response to increase muscle stiffness. There is simply no time for the system to process the information and provide feedback about the condition. Failure of the dynamic restraint system to control abnormal force will expose the static structures to excessive force. In this case, the open-loop system of anticipation becomes more important in producing the desired response. Preparatory muscle activity in anticipation of joint loading can influence the reactive muscle activation patterns. Anticipatory activation increases the sensitivity of the muscle spindles, thereby allowing the unexpected perturbations to be detected more quickly.

Very quick movements are completed before feedback can be used to produce an action to alter the course of movement. Therefore, if the movement is fast enough, a mechanism such as a motor program would have to be used to control the entire action, with the movement being carried out without any feedback. Fortunately, the open-loop control system allows the motor control system to organize an entire action ahead of time. For this to occur, previous knowledge needs to be preprogrammed into the primary sensory cortex ( Box 23-4 ).

In the open-loop system, a program that sets up some kind of neural mechanism or network that is preprogrammed organizes movement in advance. A classic example of this occurs in the body as postural adjustments are made before the intended movement. When an arm is raised into forward flexion, the first muscle groups to fire are not even in the shoulder girdle region. The first muscles to contract are those in the lower part of the back and legs (approximately 80 msec passes before noticeable activity occurs in the shoulder) to provide a stable base for movement. Because the shoulder muscles are linked to the rest of the body, their contraction affects posture. If no preparatory compensations in posture were made, raising the arm would shift the center of gravity forward and cause a slight loss of balance. The feedforward motor control system takes care of this potential problem by preprogramming the appropriate postural modification first rather than requiring the body to make adjustments after the arm begins to move.

Lee demonstrated that these preparatory postural adjustments are not independent of the arm movement but rather are part of the total motor pattern. When the arm movements are organized, the motor instructions are preprogrammed to adjust posture first and then move the arm. Therefore, arm movement and postural control are not separate events but instead are different parts of an integrated action that raises the arm while maintaining balance. Lee showed that these EMG preparatory postural adjustments disappear when the individual leans against some type of support before raising the arm. The motor control system recognizes that advance preparation for postural control is not needed when the body is supported against the wall.

It is important to remember that most motor tasks are a complex blend of both open- and closed-loop operations. Therefore, both types of control are often at work simultaneously. Both feedforward and feedback neuromuscular control can enhance dynamic stability if the sensory and motor pathways are frequently stimulated. Each time that a signal passes through a sequence of synapses, the synapses become more capable of transmitting the same signal. When these pathways are “facilitated” regularly, memory of that signal is created and can be recalled to program future movements.

Conclusion: Relationship to Rehabilitation

A rehabilitation program that addresses the need for restoring normal joint stability and proprioception cannot be constructed until one has total appreciation of both the mechanical and sensory functions of the articular structures. Knowledge of the basic physiology of how these muscular and joint mechanoreceptors work together in the production of smooth, controlled coordinated motion is critical in developing a rehabilitation training program. This is because the role of the joint musculature extends well beyond absolute strength and the capacity to resist fatigue. With simple restoration of mechanical restraints or strengthening of the associated muscles, the smooth coordinated neuromuscular controlling mechanisms required for joint stability are neglected. The complexity of joint motion necessitates synergy and synchrony of muscle firing patterns, thereby permitting proper joint stabilization, especially during sudden changes in joint position, which is common in functional activities. Understanding of these relationships and functional implications will allow the clinician greater variability and success in returning patients safely back to their playing environment.

The Four Ps

The four Ps represent the four principles for therapeutic exercise: purpose, posture, position, and pattern ( Table 23-4 ). They serve as quick reminders of the hierarchy, interaction, and application of each principle. The questions of what, when, where, and how for functional movement assessment and exercise prescription are addressed in the appropriate order (see Table 23-4 ).

Purpose

The word purpose is simply a cue to be used during both the evaluation process and the exercise prescription process to keep the clinician intently focused on the greatest single factor limiting function. The primary questions to ask for this principle appear in Table 23-4 . It is not uncommon for clinicians to attempt to resolve multiple problems with the initial exercise prescription. However, the practice of identifying the single greatest limiting factor will reduce frustration and also not overwhelm the patient. Other factors may have been identified in the evaluation, but a major limiting factor or a single weak link should stand out and be the focus of the initial therapeutic exercise intervention. Alterations in the limiting factor may produce positive changes elsewhere, which can be identified and considered before the next exercise progression.

The functional evaluation process should take on three distinct layers or levels ( Table 23-5 ). Each of the three levels should involve qualitative observations followed by quantitative documentation when possible. Normative data are helpful, but bilateral comparison is also effective and demonstrates the functional problem to the patient at each level. Many patients think that the problem is simply symptomatic and structural in nature and have no example of dysfunction outside of pain with movement. Moffroid and Zimny suggest that “Muscle strength of the right and left sides is more similar in the proximal muscles whereas we accept a 10% to 15% difference in strength of the distal muscles.… With joint flexibility, we accept a 5% difference between goniometric measurements of the right and left sides.”

Table 23-5

Three Levels of Functional Evaluation

Level	Name	Description
I	Functional activity assessment	Combined movements common to the patient’s lifestyle and occupation are reproduced. They usually fit the definition of a general or specific skill.
II	Functional or fundamental movement assessment	The clinician takes what is learned through the observation of functional movements and breaks the movements down to the static and transitional postures seen in the normal developmental sequence.
III	Specific clinical measurement	Clinical measurements are used to identify and quantify specific problems that contribute to limitations in motion or control.

 

The functional activity assessment involves a reproduction of combined movements common to the patient’s lifestyle and occupation. These movements usually fit the definition of a general or specific skill. The clinician must have the patient demonstrate a variety of positions and not just positions that correspond to the reproduction of symptoms. Static postural assessment is included, as well as assessment of dynamic activity. The quality of control and movement is assessed. Specific measurement of bilateral differences is difficult, but demonstration and observation are helpful for the patient. The clinician should note the positions and activities that provoke symptoms, as well as the activities that illustrate poor body mechanics, poor alignment, right-left asymmetries, and inappropriate weight shifting. When the clinician has observed gross movement quality, it may be necessary to also quantify movement performance. Repetition of the activity for evaluation of endurance, reproduction of symptoms, or demonstration of rapidly declining quality will create a functional baseline for bilateral comparison and documentation.

Next is the functional or fundamental movement assessment. The clinician must take what is learned through the observation of functional movements and break the movements down into the static and transitional postures seen in the normal developmental sequence. This breakdown will reduce activities to the many underlying mobilizing and stabilizing actions and reactions that constitute the functional activity. More simply stated, the activity is broken down into a sequence of primary movements that can be observed independently. It must be noted that these movements still involve multiple joints and muscles. Assessment of individual joints and muscle groups will be performed during clinical measurements. Martin notes, “The developmental sequence has provided the most consistent base for almost all approaches used by physical therapists.” This is a powerful statement, and because true qualitative measurements of normal movement in adult populations are limited, the clinician must look for universal similarities in movement. Changes in fundamental movements can effect significant and prompt changes in function and must therefore be considered functional as well. Because the movement patterns of most adults are habitual and specific and thus are not representative of a full or optimal movement spectrum, the clinician must first consider the nonspecific basic movement patterns common to all individuals during growth and development. The developmental sequence is predictable and universal in the first 2 years of life, with individual differences seen in the rate and quality of the progression. The differences are minimal in comparison to the variations seen in the adult population with their many habits, occupations, and lifestyles. In addition to diverse movement patterns, the adult population has the consequential complicating factor of a previous medical and injury history. Each medical problem or injury has had some degree of influence on activity and movement. Thus, evaluation of functional activities alone may hide many uneconomical movement patterns, compensations, and asymmetries that when integrated into functional activities, are not readily obvious to the clinician. By using the fundamental movements of the developmental progression, the clinician can view mobility and static and dynamic stability problems in a more isolated setting. Although enormous variations in functional movement quality and quantity are seen in specific adult patient populations, most individuals have the developmental sequence in common. The movements used in normal motor development are the building blocks of skill and function. Many of these building blocks can be lost while the skill is maintained or retained at some level (though rarely optimal). We will refer to these movement building blocks as fundamental movements and consider them precursors to higher function. Bilateral comparison is helpful when the clinician identifies qualitative differences between the right and left sides. These movements (like functional activities) can be compared quantitatively as well.

Finally, clinical measurements will be used to identify and quantify specific problems that are contributing to limitation of motion or limitation of control. Clinical measurements will first classify a patient through qualitative assessment. The parameters that define that classification must then be quantified to reveal impairment. These classifications are called hypermobility and hypomobility and help create guides for treatment that consider the functional status, anatomic structures, and the severity of symptoms. The clinician should not proceed into exercise prescription without proper identification of one of these general categories. The success or failure of a particular exercise treatment regimen probably depends more on this classification than on the choice of exercise technique or protocol.

When the appropriate clinical classification is determined, specific quantitative measurements will define the level of involvement within the classification and set a baseline for exercise treatment. Periodic reassessment may identify a different major limiting factor or a weak link that may require reclassification, followed by specific measurement. The new problem or limitation would then be inserted as the purpose for a new exercise intervention. A simple diagram ( Fig. 23-1 ) will help the clinician separate the different levels of function so that intervention and purpose will always be at the appropriate level and assist in the clinical decision making related to exercise prescription.

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