Mobility and Flexibility Quiz

Study Notes

Mobility and Flexibility

Mobility is the ability of body structures to move. Range of motion (ROM) is essential for functioning.
Flexibility is the smooth, pain-free movement of one or more joints through their full ROM. It depends on muscle length, joint integrity, and surrounding tissue extensibility.
Dynamic flexibility (active ROM) is the range a body segment can achieve via muscle contraction. It depends on the muscle's ability to move the joint and the tissue resistance during movement.
Passive flexibility (passive ROM) is the segment's movement range when assisted, relying on muscle and connective tissue extensibility. Dynamic flexibility is dependent on it, but not the other way around.

Hypomobility

Hypomobility is decreased mobility or restricted motion.
Factors causing hypomobility include:
- Prolonged immobilization (casts, splints).
- Sedentary lifestyle, poor posture.
- Postural malalignment (scoliosis, kyphosis).
- Impaired muscle performance (weakness, spasticity, flaccidity).
- Tissue trauma, inflammation, pain, or disease.

Contractures

Contracture is the adaptive shortening of muscle-tendon units and surrounding tissues, limiting ROM and functional ability. It's significant resistance to passive or active stretching.
Shortness is partial loss of motion, while tightness describes mild muscle shortening.
A contracture is almost complete loss of motion.
Contracture is different from contraction (muscle tension).

Soft Tissue Properties

Soft tissues respond to stretching differently:
- Elasticity: Return to resting length after brief stretch.
- Viscoelasticity: Resistance to initial deformation, but gradual return to resting length with sustained stretch.
- Plasticity: Assumes a greater length after stretch force is removed, often permanent. (Non-contractile tissue)
Contractile tissue (muscles) has elasticity and plasticity, but not viscoelasticity. Noncontractile tissue (tendons, ligaments, etc.) has all three.
Connective tissue surrounding the muscle (endomysium, perimysium, epimysium) provides resistance to passive stretch, and adhesions in connective tissues restrict movement.

Mechanical Properties of Contractile Tissue

Muscles consist of parallel muscle fibers, comprised of myofibrils, which in turn are made up of contractile units called sarcomeres.
Sarcomeres' actin and myosin filaments interact during contraction. Sarcomere shortening occurs; relaxations slide apart.
Stretch force to muscle fibers is passed via connective tissue (endomysium, perimysium) surrounding the fibers.

Response to Stretch and Immobilization

Stretch Response:
- Initial lengthening of the connective tissue component (series elastic component) causes immediate tension increase.
- Further lengthening leads to mechanical disruption (filaments sliding apart), abrupt lengthening of sarcomeres, and elasticity response.
Immobilization Response:
- Prolonged immobilization can result in muscle atrophy (decay of contractile proteins, decreased fiber diameter, decreased myofibrils, and intramuscular capillaries).
- Immobilization in a shortened position leads to faster atrophy and weakness than lengthened positions.
Role of sensory organs. Muscle spindles sense quick stretch, Golgi tendon organs (GTO) monitor tension.

Neurophysiological Response

Stretch reflex: Quick stretch activates the stretch reflex, increasing tension and resisting lengthening. Low-intensity, prolonged stretch minimizes this.
GTOs (Golgi tendon organs) inhibit muscle tension and encourage relaxation and lengthening when stretch is sustained.

Mechanical Properties of Non-contractile Soft Tissue

Non-contractile tissues (ligaments, tendons, etc) impact tissue flexibility.
Connective tissue consists of collagen, elastin, reticulin, and ground substance.
- Collagen: Strength, stiffness
- Elastin: Extensibility, flexibility
- Reticulin: Tissue bulk
- Ground substance: Hydration, stability, reduce friction

Effects of Immobilization and Inactivity

Immobilization weakens tissue due to collagen turnover and reduced ground substance.
Inactivity reduces collagen and increase elastin, leading to decreased strength and increased compliance.
Cyclic loading is beneficial for connective tissue strengthening and flexibility improvement.

Stress-Strain Curve and Tissue Deformation

Stress-strain curves analyze connective tissue deformation under stress.
Toe region: Minimal force for significant deformation (mostly in functional activities).
Plastic range: Permanent deformation occurs as fibrils rupture.
Ultimate strength: Maximum load the tissue can sustain. Necking signals tissue weakening.
Failure: Rupture of tissue integrity, which can be from repeated microfailures.
Stretching procedures often cause microfailure to increase length and improve range of motion, but time between stretching bouts allows recovery and tissue remodeling.

Description

Test your knowledge on mobility and flexibility concepts, including range of motion, dynamic and passive flexibility, and hypomobility. Understand how these factors affect joint function and overall health. Learn what contributes to mobility and how to address issues like hypomobility.