Stretching for Improved Mobility: A Clinical Briefing
Mobility is a fundamental component of physical function, defined as the ability of body structures to move through a range of motion (ROM) sufficient for functional activities. This briefing outlines the clinical definitions, pathological restrictions, and therapeutic interventions associated with mobility and stretching.
- Functional Mobility: Mobility is not merely "normal" ROM but the specific range required to perform motor tasks and functional activities. It is dependent on both joint integrity and soft tissue flexibility.
- Hypomobility and Contractures: Restricted motion results from adaptive shortening of soft tissues. While "hypomobility" refers to general restricted motion, "contracture" denotes a significant, often pathological, resistance to mobility.
- Therapeutic Stretching: Stretching serves as a primary intervention to increase soft tissue extensibility, improve flexibility, and reduce injury risk. Effectiveness is determined by specific parameters such as alignment, intensity, duration, and frequency.
- Clinical Decision-Making: Interventions must be based on a systematic evaluation. This includes the strategic use of "selective stretching," where certain tissues are allowed to remain tight to maintain stability or improve specific functional outcomes for the patient.
Fundamental Concepts of Mobility and Flexibility
- Mobility is the capacity of an individual to initiate, control, or sustain active body movements to perform motor tasks. It is inextricably linked to:
- Joint Integrity: The health and structure of the joint itself.
- Soft Tissue Flexibility: The extensibility of the muscles and connective tissues crossing or surrounding the joints.
Flexibility: Dynamic vs. Passive
- Flexibility is the ability to rotate a joint smoothly through an unrestricted, pain-free ROM. It is categorized into two distinct types:
1. Dynamic Flexibility (Active Mobility): The extent to which an active muscle contraction can rotate a joint. This depends on muscle strength and the quality of tissue extensibility.
2. Passive Flexibility (Passive Mobility): The extent to which a joint can be rotated through its available ROM by an external force. Passive flexibility is a prerequisite for, but does not guarantee, dynamic flexibility.
Hypomobility and the Pathophysiology of Contractures
- Hypomobility: refers to decreased mobility or restricted motion at a single joint or a series of joints. It can lead to significant activity limitations and participation restrictions.
Classification of Contractures
- A contracture is the adaptive shortening of the muscle-tendon unit and other soft tissues, resulting in significant resistance to stretch and limited ROM. They are classified by their underlying cause and tissue involvement:
1. Myostatic: The musculotendinous unit is shortened with no specific muscle pathology. There is a reduction in the number of sarcomere units, but individual sarcomere length is unchanged. This is usually resolvable in a short time with stretching.
2. Pseudomyostatic: Limited ROM caused by hypertonicity (spasticity or rigidity) from Central Nervous System (CNS) lesions (e.g., stroke, spinal cord injury). Muscles appear to be in a constant state of contraction.
3. Arthrogenic: Result of intra-articular pathology, such as adhesions, joint effusion, synovial proliferation, or irregularities in articular cartilage.
4. Periarticular: Occurs when connective tissues that cross or attach to a joint capsule lose extensibility, restricting normal arthrokinematic motion.
5. Fibrotic / Irreversible: Permanent loss of extensibility due to normal tissue being replaced by inextensible fibrotic tissue or scar tissue. Often occurs after long-term immobilization or severe trauma.
Factors Contributing to Restricted Motion
Various extrinsic and intrinsic factors lead to hypomobility and the development of contractures: