(Exam 1) Stretching and Flexibility

Measuring Flexibility

1. Measuring Joint ROM: with a universal goniometer (Fig. 4-7) which is a protractor with degree measurements. Other types of goniometers are inclinometer, pendulum goniometer, and fluid goniometer. 2. Measuring joint stability with Special Tests. Assesses ligament stability, joint capsule flexibility etc. Person may have normal AROM but may have a joint that is unstable, tight, or unyielding to pressure.

Types of stretching techniques: Dynamic Stretching

A muscular contraction is used to stretch a muscle. Effect is to increase or decrease the joint angle where the muscle crosses, thereby elongating the musculotendinous unit as the end ROM is obtained. Uses activity-specific movements, preparing muscles for a specific sport. (ie, sprinter -exaggerated strides) Subsequently actively contracts and stretches mm. All movements are under control. Does not incorporate ballistic movements at end ROM.

Benefits of a Warm-Up

Blood Flow to working muscles is increased. Temperature in working muscles is increased Cardiovascular response to sudden dynamic exercise is improved Breakdown of oxyhemoglobin for the delivery of oxygen to the working muscles is increased. Warm-up protocols usually last 10-25 minutes and should be intense enough to cause an increase in body temp but not so intense to cause fatigue.

Muscle Spindle

Changes in length in the intrafusal fibers within the muscle spindle (via extrafusal fiber stretch) stimulate primary (Ia) and secondary (II) sensory nerve endings, sending information about the stretch to the higher brain centers and to the alpha motor neurons of the same muscle, activating the muscle to contract.

Types of PNF stretches

Contract Relax- (4-17) At end ROM- pt is instructed to actively contract restricted mm against manual resistance for 5-8 seconds. Pt relaxes and therapist passively moves to new ROM holding 10-30 seconds. Hold Relax- similar to contract-relax, except pt actively moves limb to its end ROM, does isometric hold for 5-8 sec. then relaxes and pt actively stretches limb to new limit of motion 10-30 seconds. (4-19)

Stretching Soft Tissue Contractures

Contracture- permanent of transient limitation of movement or shortening of mm or other soft tissues. A contracture is the result of healed tissue that forms a fixed rigid scar and causes cosmetic deformity deformity of functional deficits. Scar Tissue- union or two injured or torn parts. Replaces normal tissue. Happens after surgery/injury. Adhesion- development of scar tissue between two or more structures that causes limitation of motion. Fig 4-21 . Sometimes adhesions are desirable if the MD is trying to add stability to a hypermobile joint.

Stretching

Definition: elongating the muscles and tendons to the end of the available ROM. Applying a tensile force to a muscle results in a transient deformation, which elongates the musculotendinous unit, resulting in a stretch. The amount of stretching that takes place depends on the type of connective tissue present

Duration, Frequency, and Intensity

Depends on the joint targeted, flexibility goal, and type of stretching technique used. Duration- Hold in fully elongated position 10-60 seconds. (we will do 30 seconds). ACSM recommends 3-5 reps for each stretch exercise. Approximately 6 weeks of stretching is necessary for change and lasting improvement. At least 3x/week to improve ROM, 1x/week to maintain flexibility. intensity- low load (pain free) long duration.

Types of stretching techniques: Ballistic Stretching

Dynamic, high velocity and motions at the end ROM to stretch but also facilitate a muscle contraction. Often used before and during sporting events by athletes Cannot be used on injured tissue because it potentially places the tissue at risk due to the bouncing, jerking movements at the end of the ROM to stretch mm. Increased risk of injury and difficult for patients to perform correctly Ballistic stretches are considered undesirable is that they stimulate the mm spindles during the stretch. This results in a continuous resistance to further stretch, which causes a high rate of tension strong enough to potentially injure the musculotendinous unit.

Stress-Strain Curve

Elastic region: -strain is directly proportional to the ability of tissue to resist the force. Occurs when tissue is taken to the end of its ROM and gentle stretch is applied. Complete recovery from the deformation occurs and tissue returns to its original shape and size when load is released. Stretch experienced during many body movements. Like a rubber band. -The slope in this elastic zone is indicative of the relative stiffness of the tissue. The stiffer the tissue, the steeper (more vertical) the slope. Plastic region: -the range beyond the elastic region extending to the point of rupture. Permanent deformation occurs, rupturing of fibers increase length. -Increasing levels of stress on the tissue results in proportionately increased changes in tissue length, probably due to microscopic failure of tissue. -The plastic energy is not recoverable when the load is removed, and there is a change in the tissues resting length.

Benefits of Stretching

Enhanced Flexibility: A long term, routine stretching program can result in ↑ long-term flexibility. Relief of Muscle Soreness: Conflicting research- some studies show that ballistic and static stretching can cause DOMS. Muscle Relaxation: Chronic tension has many negative effects on muscle. Other negative side effects- high BP, HA, ulcers, mm and joint pain. ie. Yoga, biofeedback. Injury Prevention: Research is unclear about what is more beneficial- Stretching before or after exercise to ↓ injury, but can ↓ occurrence of re-injury. Performance Enhancement: conflicting studies but most agree that a warm-up and stretching are necessary to perform an activity safely and successfully. However, some studies show that stretching beforehand has negative effects probably because the muscle-tendon unit becomes weaker after acute stretching & is unable to produce high-intensity force. It has been suggested that low-intensity mm contractions (dynamic stretching) should be done immediately before sport performances.

Scar tissue Healing

Immature Scar tissue is adaptable for up to 8 weeks and becomes mature and unadaptable for up to 14 weeks. Immature Scar tissue is adaptable, highly vascular and has a high rate of remodeling, which is the process of tissue restructuring in response to stress or immobilization. Scar becomes quite inextensible or inadaptable after 14 weeks and is then termed as a mature scar.

Stretching Principles

Mechanical Effects: The muscle-tendon unit responds viscoelastically during stretching. Neurophysiologic Effects: Some stretches resulting a neural inhibition of the muscle being stretched, resulting in ↓ resistance to stretch. Researchers believe that both have an important role in the ability of stretching to increase flexibility. Stiffness relates to a tissue's ability to resist stretch and indicates the amount deformation proportional to the load applied. Stiffer tissue= less compliance.

Sensory Receptors

Muscle Spindle a. Excitatory fibers located within the muscle belly b. Sensitive to rapid changes in muscle length c. When a mm is stretched quickly, the mm spindle sends a message to higher brain centers and the spinal cord which signals that muscle to contract. Agonist contracts. i.e. Deep Tendon Reflex Ballistic stretching

Warm -Up

Necessary to help prepare the tissue for activity. Stretching alone before exercise is not recommended. Purpose of the warm-up is to increase the core body temperature and intramuscular temperature. A warmed up muscle is able to contract more forcefully and relax more quickly. ROM increases with warmed tissue. The risk of CT and contractile tissue damage is ↓

Types of stretching techniques: PNF stretches

Proprioceptive neuromuscular facilitation uses different techniques to promote neuromuscular responses via stimulation of the proprioceptive system. Found to be more effective than static stretching. Based on the stretch reflex- using mm spindle/GTO. Disadvantages: more time consuming, requires a skilled professional to perform it for it to be effective, may lead to mild complaints or muscle soreness. PNF Stretches appear to increase ROM through the stimulation of proprioceptors. In some cases PNF stretches provided greater increases in ROM than static stretching. It uses the muscles spindle and GTO to get a better relaxation of the muscle.

General Flexibility tests

Sit and reach test - sit in long sitting with UE's in 90 degree of shoulder flexion-reach toes (Fig. 4-9 A & B) Standing toe touch for back and hamstrings Stand- bend at hips to touch toes (Fig 4-9 C). Seated hip external rotation test -(Fig. 4-9 D) Butterfly stretch: hips in ER, feet together Standing recurvatum test- These can also be used as stretching techniques.

Types of stretching techniques: Static

Static- The most common type of stretching used to safely increase joint ROM. PT sustains a controlled stretch by placing a muscle in a fully elongated position and holding the position for a period of time (at least 30 seconds). (Fig. 4-11) Passive Static Stretch- force is applied externally. (4-12) Active Static Stretch- an opposing muscle action is used to aid the stretch. Advantages: -↓ chance of exceeding strain limits -↓ energy requirements, -↓ potential for muscle soreness easy to teach patients -Safe for patients to perform independently Goals: -Prevent or minimize the risk of soft-tissue injury from participation in sports of physical activity -Improve movement and increase flexibility -Prevent contracture.

Stress relaxation

Stress-relaxation occurs when a viscoelastic material experiences a constant strain (no deformation occurs). A high initial stress placed on a tissue decreases over time until equilibrium is reached and the stress equals zero, resulting in relaxation of the tissue. No change in length is produced.

Stress and Strain

Stress: defined as the amount of tension/load placed on tissues, given in units of force/area. (pounds/square inch or Newtons/square cm) 3 types are tension, compression and shear stress. Strain (deformation): the proportional degree of elongation of tissue that occurs during the stress. Affected by the rate of the stress. (fast/slow) Recovery: the ability of tissues to return to their previous resting state Toe region: The minimal amount of tissue tension, to take up the slack in the tissue with no stretch being encountered. Collagen fibers must first be pulled tight Stress and strain curve

Effects of heating with Stretching

Temperatures from 98.6 F (37 C) - 104 F (40 C) affect the viscoelastic properties of CT causing a greater degree of elongation when stress is applied before tissue failure. Because plastic changes in CT occur at higher temperatures, there is less microscopic damage tissue damage at stress under higher tissue temperatures. Active Exercise can ↑ intramuscular temperature Heating modalities are also used to increase CT temps When the temperature of the muscle is cold, there is less flexibility and higher risk for injury

Definition of Flexibility

The ability of a muscle to relax and yield to a stretch force (Kisner & Colby). The ability to move muscles and joint through a full ROM. Muscles, tendons, ligaments, skin, joint capsule and bone geometry all influence joint motion and flexibility.

Stretch Tolerance

This is an accommodation to the discomfort of stretching over time. With this philosophy, the aim of stretching is to inhibit the reflex activity, subsequently decreasing the resistance and improving ROM .

Critical components of stretching

Time - Amount of time since injury or surgery and type of immobilization. Fragility of immature adaptable scar ( 5 days = 10% of its maximal potential stretngth, 40 days 40%, 60 days 70%, 12 months close to 100%) Appropriately applied stress for remodeling unorganized scar- new scar tissue aligns itself along lines of stress. Most effective technique is low- load , long duration stretching with thermal agents to preheat tissues

Elastic Deformation:

Tissue rapidly conforms to a new length and is able to return to its resting length when the stress is removed. Steepness of slope in Elastic Region is related to how stiff the tissue is. Ligament stretch would have steeper slope than loose CT stretch. ie, Rubberband (Fig. 4-3). The rubberband will break if the stress exceeds the strain capabilities.

Splinting

Used for low-load prolonged stretch. Must be comfortable enough for a patient to wear for long periods of time. Gradually increase wear time. Check for skin breakdown Many brands- find one that is best for your patient. Dynasplint and Pro-glide are examples of dynamic splints used for progressive loading to gain ROM

Viscoelasticity

Viscoelasticity of CT is the combination of its properties of elasticity and viscosity. Elasticity: a material's ability to return to its original state following strain or deformation after a removal of a stress or load. Viscosity : a material's ability to resist a change in form or to dampen shearing forces. Tissues exhibiting viscosity have time dependent and rate dependent properties when forces are applied to them.

Creep phenomenon

When a load is applied to a viscoelastic tissue for an extended time and permanent deformation in tissue occurs Gradual increase in tissue length that occurs when maintaining a constant stress or force. (Fig 4-4). The longer the duration of the applied force, the greater the deformation or stretching of the tissue. Creep-plastic deformation occurs with low-load, long duration stretching

The Golgi Tendon Organ (GTO)

a. Inhibitory sensory receptors located in series with the muscle fibers and within the myotendinous junction. b. Function is to monitor muscle contraction. Activated by excessive and prolonged stretches and by muscle contractions. c. When a muscle is stretched the GTO sends a message to the spinal cord to inhibit contraction. This causes a reflex response which protects against damage to the tissue. Agonist shuts off, antagonist contracts.