Stretching Interventions

Question 1

What is stretching

Answer 1

• any therapeutic maneuver designed to increase soft tissue extensibility & to improve flexibility & ROM (functional excursion) by elongating (lengthening) structures that have adaptively shortened & have become hypomobile

Question 2

Difference between dynamic flexibility and passive flexibility

Answer 2

• Dynamic: AROM (motion + control)
• Passive: PROM (motion) prerequisite for dynamic flexibility

Question 3

Difference between hypo-mobility & contracture

Answer 3

• Hypo-mobility: decreased mobility
• Contracture: maladaptive shortening of the muscle tendon unit & other soft tissues that cross or surround the joint resulting in resistance to stretch (if the flexors are tight = flexion contracture)

Question 4

Types of contractures & clinical implications

Answer 4

• Myostatic: no specific muscle pathology, shortened musculoteninous unit, no decrease in sarcomere length = amendable to stretching
• Pseudomyostatic: CNS pathology resulting in hypertonicity & resistance to passive stretch = amendable to PNF stretching (temporary)
• Arthrogenic/Periarticular: intra-articular pathology, connective tissues that cross a joint or attach to the joint capsule = abnormal arthrokinematics (mobilization/prolonged stretching)
• Fibrotic/irreversible: fibrous changes in connective tissue potentially resulting in non-reversible ROM loss (possibly would require a manipulation under anesthesia)

Question 5

Describe selective stretching

Answer 5

• applying stretching techniques to some muscles & joints while allowing motion limitations to develop in other muscles or joints to improve overall function

Question 6

Describe overstretching & hyper-mobility

Answer 6

• overstretching is a stretch well beyond the normal length of muscle & ROM of joint & the surrounding tissues resulting in hyper-mobility

Question 7

Indications for stretching

Answer 7

• primary impairment: soft tissue loss of extensibility due to adhesion, contracture, scar resulting in impaired activity/participation
• secondary impairment: restricted motion can lead to postural deformities, muscle imbalances/weakness can lead can lead to limited ROM, & muscle spasm/trigger points

Question 8

Effects of “life” on soft tissue

Answer 8

• Immobilization: decreased stiffness, weakening bonds, greater disorganization or collagen, ground substance is ineffective resulting in poor space, lubrication & further adhesive formation
• Inactivity (decrease of normal activity): decreases size & amount of collage fibers, increased elastin fibers, recover can take up to 5 months
• Age: increased stiffness, decrease tensile strength, more susceptible to overuse syndromes
• Corticosteriod use: catabolic effects, destroys collagen, type I to type type III, decrease in tensile strength of tissue
• Injury: new injury +type III collagen, not as structurally as strong, as mature type I collagen
• Other: nutrition, hormones, dialysis

Question 9

Properties of soft tissues/response to stretch

Answer 9

• movement requires active neuromuscular control & passive extensibility of the soft tissues
• decreased extensibility of connective tissue is the primary cause of restricted mobility in healthy people & those with injury, disease, or surgery
• immobilization often leads to morphological changes to soft tissues

Question 10

Interventions to increase mobility

Answer 10

• different modes of stretch
• self stretching
• neuromuscular facilitation & inhibition techniques (neural techniques)
• muscle energy
• joint mobilization/manipulation
• soft tissue mobilization/manipulation
• neural tissue mobilization

Question 11

Contraindications for stretching

Answer 11

• bony block that limits joint motion
• recent fracture with incomplete bony union
• evidence of acute inflammatory or infectious process
• sharp/acute pain with joint movement/muscle elongation
• hematoma/other trauma
• joint hypermobility already exists
• shortened tissues that enable necessary joint stability

Question 12

Theories of stretch

Answer 12

• Mechanical model: viscoelastic deformation = viscoelastic stress relaxation & plastic deformation = stress/strain curve & creep
• Sensory models: neuromuscular relaxation & sensory theroy

Question 13

Describe viscoelastic deformation

Answer 13

• elastic, viscoelastic, & plastic changes occur to non contractile tissues
• elastic = tissue returns to pre-stretch resting length after force is removed
• viscoelastically is a time dependent property
• plasticity = tissue assumes a new & greater length after a stretch force is applied
• Application: the direction, velocity, intensity (magnitude), duration, & frequency of the stretch force, as well as tissue temperature, tension, and stiffness, all interact to affect the unique soft tissue responses & outcomes
• an increase in muscle length can occur due to the viscous behavior of muscle undergoing a stretch of sufficient magnitude, duration, or frequency

Question 14

Describe the stress strain curve

Answer 14

• illustrates the mechanical strength of soft tissue & demonstrates what happens to connective tissue under stress from an externally applied load
• Stress = force/load per unit area (internal reaction to applied load), can be tension, compression, shear
• Strain = amount of deformation/lengthening that occurs when load is applied
• Clinical implications: structural stiffness is defined by the elastic range & high stiffness = steep elastic region (contracture/scar tissue)

Question 15

Parts of the stress strain curve

Answer 15

• Toe region: activity occurs here, collagen straightens, but there is no elongation of the tissues “take up slack” phase
• Elastic range: collagen aligns parallel along stress, will lengthen, but return to original size/shape
• Elastic limit: point beyond which tissue does not return to original shape & size
• Plastic range: permanent tissue deformation occurs after load is released
• Ultimate strength: the maximum strain a tissue can sustain, resulting in “necking”
• Failure: tissue ruptures & loses its integrity

Question 16

Time & rate influence on tissue deformation

Answer 16

• Rate dependence (influences stiffness): rapid load creates a steep stress strain curve and makes the tissue stiff for protection
• Time dependence (influences creep): viscoelastic tissue will continue to slowly elongate with a sustained external load (prolonged static stretch or low load long duration/LLLD)
• Stress relaxation (influences force): sub-failure load applied to viscoelastic tissue & kept constant = gradual decrease in the force required to maintain the amount of deformation

Question 17

Difference between a muscle spindle and a Golgi tendon organ (GTO)

Answer 17

• Muscle spindle: prevents overstretching of the muscle, major sensory organ of the muscle sensitive to quick (velocity change) & sustained stretch (length change)
• Golgi tendon organ (GTO): major sensory organ of the muscultendinous junction (MTJ) that senses tension, muscle tension increases which activates the GTO to inhibit alpha motor neuron activity to decrease tension in the MTJ (prevent injury)

Question 18

Difference between agonist muscle and antagonist muscle

Answer 18

• Agonist: prime mover, muscle opposite the range limiting muscle
• Antagonist: muscle opposite of the prime mover, the range limiting muscle

Question 19

Difference between reciprocal inhibition and autogenic inhibition

Answer 19

• Reciprocal: the relaxation of muscles on one side of a joint to accommodate contraction on the other side of that joint (muscle spindle)
• Autogenic: the ability of a muscle to relax when it experiences a stretch/increased tension (GTO)

Question 20

Describe proprioceptive neuromuscular facilitation (PNF) stretching

Answer 20

• used to facilitate or inhibit muscle activation to increase likelihood the muscle lengthened stays relaxed as it is stretched
• patient must have normal innervation & voluntary control, cannot be used effectively with patient’s with paralysis or spasticity from neuromuscular disease or injury
• most appropriate for contractile ROM deficits as seen in muscle spasm

Question 21

Describe hold-relax with passive movement PNF stretching

Answer 21

• therapist moves the extremity to reach end ROM/resistance
• at this resistance point an isometric contraction is performed by the shortened muscle/antagonist muscle for 5 secs
• the therapist then moves the extremity passively to reach a new end ROM/resistance & this is repeated multiple reps
• favors autogenic inhibition

Question 22

Describe hold-relax with active movement PNF stretching

Answer 22

• same as with passive movement but this time the patient will actively move the extremity through use of the prime mover/agonist into the newly acquired ROM until reaching a point of resistance again, this is repeated multiple reps
• reciprocal inhibition

Question 23

Describe the sensory theory

Answer 23

• these studies suggest that increases in muscle extensibility observed immediately after stretching & after short term (3-8 week) stretching programs are due to an alteration of sensation only & not to an increase in muscle length

Question 24

Describe manual stretching

Answer 24

• most appropriate in early stages of a stretching program to determine how a patient will respond to intensity & durations of stretch
• passive manual stretching by a therapist is appropriate when a patient lacks neuromuscular control
• if the patient has adequate neuromuscular control, have the patient become active & use the principle of reciprocal inhibition (hold-relax w/active movement)

Question 25

Describe mechanical stretching

Answer 25

- application of a low load long duration (LLLD) stretch over a prolonged period of time to create relatively permanent lengthening of soft tissues (plasticity principle) - use of equipment: cuff weight, weight pulley system, orthotic device, serial casting, or automated stretching machine - 15-20 minutes to as long as 8-10 hours per session - longer for more chronic contractures due to neurologic injury or musculoskeletal disorders

Question 26

Describe dynamic stretching

Answer 26

- involves active movements of joint through normal ROM to loosen tissues & increase blood flow - most often mimics sport specific activity (start light & becomes more intensive)

Question 27

Describe ballistic stretching

Answer 27

- avoided in therapeutic stretching due to high velocity & short duration of stretching causes repeated firing of the muscle spindles & GTO that increase muscle hypertonicity & overall resistance to elongation - primarily used in the sports population prior to athletic event - "bouncing" (essentially is an explosive type of dynamic stretching)

Question 28

Uncontrolled AROM risk from dynamic stretching

Answer 28

- tearing of soft tissue - hyperflexibility of targeted joints - worsening go hyperextensibility in pregnancy - increased rigidity of muscultendinous structures during rapid growth - decreased explosive muscle force immediately after stretching

Question 29

Describe a dynamic warm up

Answer 29

- increase body temp. - use of dynamic stretches to reduce muscle stiffness - increase speed & intensity as the warm-up progresses - complete movements that will be used during exercise/activity

Question 30

Describe a dynamic cool down

Answer 30

- decrease body temp. - decrease intensity & speed of activity (run to walk) - use static stretches to stretch warm tissues - prevents blood pooling

Question 31

Integration of function

Answer 31

- after immobilization, important to include low load resistance exercises to improve muscle performance - this will help the patient develop neuromuscular control for the new ROM acquired as well as provide further stretch opportunities to the hypomobile musculature - without development of neuromuscular control in the new ROM the gains will only last 4 weeks max

Question 32

Important final thoughts on stretching

Answer 32

- low intensity active exercise should be completed prior to stretching program - stretching does not prevent injury prior ro activity & can decrease performance in some power events - stretching is contraindicated in acute inflammatory stage of tissue healing - stretching programs for the general population should include all major muscle groups - should be performed 2-3 days/week for many weeks (gradual process) - intensity of mild discomfort or if using isometric contractions this is sub maximal - hold time can vary but good results with 15-60 second bouts - dynamic stretching should be used prior to more vigorous activities, should be specific to task, avoid unwarranted "bouncing", & avoid extreme stretching - stretch gains must be maintained with functional activities into the new ROM

Question 33

ACSM's key points about stretching

Answer 33

- most effective when muscles are warm - should be performed before/after conditioning phase - stretching following exercise may be preferable for sports - may not prevent injury - should be performed 2-3 days per week -static, dynamic, ballistic, PNF, & dynamic ROM improve flexibility - should involve the major muscle tendon groups - 4 or more reps per muscle group -ballistic stretching may be considered for persons whose sports involve ballistic movements - static stretches should be held for 15-60 secs - 6 sec contraction followed by 10-30 sec assisted stretch is recommended for PNF techniques