JOINT RANGE OF MOTION In addition to joint integrity, adequate muscle length and other soft tissue extensibility must be The amount of motion available at a synovial joint maintained to optimize joint function.3 Most muscles is called the range of motion (ROM). Normal cross more than one joint to allow for shortening ROM varies among individuals and is influenced by over one joint and lengthening over the other during age, gender, body habitus, and whether motion is movement. However, there is potential for a muscle performed actively or passively.1 The type and amount or muscle group to become excessively lengthened of movement that occurs throughout the ROM is or shortened when it crosses more than one joint. If unique to each joint of the body and is dependent a muscle is rendered weak because it is shortened as primarily upon the shape of the articular surfaces. much as it can be as it crosses each joint, it is said to Other factors include the integrity and flexibility of be actively insufficient. An example of this occurs the periarticular soft tissues. when an individual lies prone with the hip extended Joint motion involves rotation or translation of or in neutral, and the individual is asked to perform one articular surface relative to the other about an a “leg curl” to flex the knee as much as possible. axis known as the instantaneous, helical, or screw axis. Active insufficiency occurs in the hamstrings in this Both rotation around the joint axis and translation example because they are shortened over the knee along the instantaneous axis must occur to provide and hip at the same time, and full flexion of the knee normal joint kinematics.2 Joint movements that are may be difficult. The hamstring muscles may even produced actively through voluntary activation of spasm when such a maneuver is attempted without muscles or passively through an external moment allowing hip flexion to occur to lengthen the applied by a clinician to simulate active motions are hamstrings as they cross the hip joint. Figure 1 known as physiological movements. Physiological illustrates this principle. Passive insufficiency occurs movements occur around and along the instanta- when a muscle limits joint motion by being neous axis. For example, reaching overhead prima- stretched or lengthened as an antagonistic muscle is rily involves the physiological movement of flexion contracting. If we use the example of the individual at the shoulder. The majority of actual movement that occurs with shoulder flexion is rotation, which is a turning movement, about the instantaneous axis of the glenohumeral joint. However, some transla- tion or a straight glide occurs to a lesser degree along the axis for most synovial joints. (i.e., rotation is the primary movement, while translation to a lesser degree along the axis). ROM activities are prescribed to prevent loss of physiological movements. Isolated translational movements are known as accessory movements and they cannot normally be produced through volitional effort. Just as some translation occurs with physiological movements, some degree of rotation is produced when perform- ing accessory movements. These translational move- ments are used in manual therapy procedures known as joint mobilizations and are used in combination with ROM exercises to restore joint kinematics. Figure 1 Therapist must be aware of patient positioning to prevent muscle insufficiency when addressing strengthening or stretching of two joint BOX 1 STOP and THINK muscles. In this example, the patient is flexing his Why are both physiological and accessory knee while his hip is maintained in extension, the movements important to restore following joint hamstring muscle group will become pro- injury? gressively less effective as it reaches maximum shortness with contraction (active insufficiency). lying prone again, as the hamstring muscles act to of muscle (myostatic contractures) or other soft tis- flex the knee joint, the rectus femoris muscle of the sue shortening. Fibrous changes in periarticular quadriceps femoris group can limit knee flexion tissue respond to stretching as well. However, the because of passive insufficiency. Both active and longer the periarticular contracture exists, the more passive insufficiencies occur in healthy, nonpatho- difficult it is to reestablish ROM and tissue length. logical muscles, but ROM loss because of these is Once the tissue is replaced with scar tissue that does temporary. That is, as soon as the joint positions not respond, the contracture becomes irreversible. change to prevent active or passive insufficiency of This lesson will focus on the ROM and stretching the muscles, full joint ROM can be achieved. techniques used to maintain and restore physiolo- gical joint movements. The reader should keep in mind that these should be used in combination with BOX 2 STOP and THINK manual therapy techniques (joint mobilizations) Why should passive insufficiency be promoted when necessary to restore accessory movements. at the hand and wrist (extrinsic flexors) in a patient with quadriparesis? Impairments in ROM Disease, injury, immobilization, overuse, and aging Conditions that may cause adaptive shortening of may result in pathological joint ROM. Excess motion muscle, periarticular connective tissue, and skin will beyond the physiological motion expected is known result in a more permanent loss of ROM. These as hypermobility and may be caused by an inability conditions include prolonged immobilization, of bone or soft tissue to limit motion. Hypermobile restricted mobility, connective tissue or neuromus- joints are not necessarily pathological, but are more cular diseases, tissue pathology because of trauma, susceptible to injury and pain because there are and congenital or acquired bony deformities.4 increased tensile and shear forces. Increased rotation Limitation of joint ROM because of soft tissue ad- and translation contribute to the tension and shear aptive shortening is known as contracture (Table 1). forces generated. Management of hyper-mobility is Contractures involving musculotendinous units are therefore aimed at joint protection. For example, a known as myostatic contractures. Pseudomyostatic person with a total knee arthroplasty who complains contractures occur when there is hypertonicity from of a feeling of instability while walking and whose a lesion involving the central nervous system. The knee demonstrates hypermobility in an anteriopos- muscles in this situation are resistant to passive terior direction when examined, may benefit from stretch and thus give the appearance of a myostatic the use of exercises and functional activities that contracture. Periarticular contractures result from encourage co-contractions of the knee extensors and intraarticular pathology, such as adhesions, chronic flexors. The co-contractions may help stabilize the joint effusions, arthritis, or arthrosis. knee in the anterior-posterior direction. Since the While ROM activities are prescribed to maintain focus of this lesson is to apply the concepts of ROM existing joint and soft tissue mobility, stretching and stretching, treatment of hypermobility will not activities are used to treat joint contractures because be discussed further. TABLE 1 ■ Common Conditions That Affect Joint Range of Motion ADAPTIVE MUSCLE SHORTENING PERIARTICULAR DISEASE SKIN Tight hamstrings associated with Adhesive capsulitis Burns posterior pelvic tilt Tight trunk extensors associated with Systemic lupus erythematosus Scleroderma increased lordosis and anterior pelvic tilt Hip and knee flexion contractures with tight Rheumatoid arthritis hip adductors, flexors, and hamstrings BOX 3 STOP and THINK defined as “normal” for a given joint. A joint with an “abnormal” end-feel means that the “normal” end- What are the clinical concerns of a feel that should be expected for that particular joint hypermobile joint? is not present. The use of the end-feel assessment can help classify the stage or severity of pathology for a particular joint and also provide prognostic inform- Limited motion or hypomobility may be caused ation (Table 2). by bony or cartilaginous blocks or by the inability of the soft tissues (joint capsule, ligaments, tendon, muscle) to elongate sufficiently to allow physiolo- BOX 4 STOP and THINK gical ROM (Figure 2). Motion may be limited either Why are end-feels important? when the patient or individual performs the move- ment independently (active motion) or when the examiner performs the movement (passive motion). Capsular Pattern Muscle contraction or spasm, muscle weakness, neurological deficit or pain may cause differences A specific pattern of limitation or restriction may be in joint range of motion between active and passive found when the clinician examines passive range of motions. motion of the joint. This pattern is unique to a given joint (e.g., shoulder vs. hip) and usually represents Joint End-Feel capsular contraction, but may also represent muscle spasm, generalized osteophyte formation, or chon- Passive joint motion is normally halted by tissue drocalcinosis. The pattern is described with the most tension at end range or by tissue approximation, limited movement listed first, followed by the next such as contact of one bone to another or by one limited movement or movements. For example, at body segment touching another body segment. the glenohumeral joint, the capsular pattern is extern- When performing an examination of passive al rotation - abduction - internal rotation. This motion,