Stretching Flashcards
The degree to which a body segment can be passively moved through the available ROM and is dependent on the extensibility of muscles and connective tissues that cross and surround a joint
Passive flexibility
-AKA passive mobility or ROM
A sustained or intermittent external, end-range stretch force, applied with overpressure and by manual contact or a mechanical device, elongates a shortened muscle-tendon unit and pariarticular connective tissues by moving a restricted joint just past the available ROM with the pt as relaxed as possible
Passive stretching
refers to the muscle opposite the range-limiting target muscle
agonist
refers to the range-limiting muscle
antagonist
To perform this procedure, the patient concentrically contracts the muscle opposite the range-limiting muscle (agonist) and then holds the end range position for at least several seconds
Agonist contraction stretching technique
What is the physiologic basis of AC procedure?
When the agonist is activated and contracts concentrically, the antagonist is reciprocally inhibited
To perform this procedure, move limb to the point that tissue resistance is felt in the range-limiting target m. Then have the pt perform a resisted, pre stretch isometric contraction of the range limiting muscle followed by voluntary relaxation of that m. and an immediate concentric contraction of the agonist m.
hold relax agonist contraction stretching technique
The range limiting target m is first lengthened to the point of tissue resistance. The pt then performs a pre-stretch, end-range, isometric contraction (~5 s) followed by voluntary relaxation of the range limiting target m. The limb is then passively moved into the new range
Hold relax stretching technique
- note: rotators of the limb (i.e., shoulder m’s) can contract concentrically while all other muscle groups should contract isometrically
What is the physiologic evidence that supports HR stretching technique?
decrease in EMG activity (due to autogenic inhibition) following the sustained pre stretch isometric contraction of the muscle to be lengthened
Area of the stress strain curve where the wavy collagen fibers straighten; a large change in length of the connective tissue occurs with only minimal stress
Toe region
Area of the stress strain curve when tissue is taken to the end of its ROM and a gentle stretch is applied; if load is not maintained for a long time and released, the tissue will return to its original length and shape
elastic range (linear phase)
Area of the stress strain curve that indicates the point beyond which the tissue will not return to its original shape and length; past this, sequential break of collagen occurs, resulting in loss of structure
elastic limit
Area of the stress strain curve where tissue is strained and has a permanent deformation when the stress is released; the greater into this region, the greater resting length upon return; bonds break between collagen fibrils and fibers; eventually collagen fibers rupture
plastic region
Area of the stress strain curve where the PT feels a lessening of the stretch force required for tissue lengthening; occurs just before tissue failure as adhesions release
Region of necking
What does the slope of the curve (in the stress strain curve) represent?
The stiffness of the tissue
What does the slope of stiffer tissue look like in comparison to less stiff tissue? what does i mean?
The slope is higher (greater) in stiffer tissue
- a greater stretch force is required to produce a unit change in length than in less dense tissue
Contractors are an adaptive response to immobilization of soft tissue structures that cross the joint, which include:
- Ligaments
- Joint capsule
- Aponeurosis
- Dermis of the skin
- Skeletal muscle
- Neural tissues - i.e., epineurium
What do contractors or adaptive shortening result in?
- Resistance to passive stretch or active stretch
2. Limitation of joint ROM
What factors cause contractures?
- Prolonged immobilization
- Sedentary lifestyle (i.e., asymmetric/ habitual posture)
- paralysis
- Postural malalignment - congenital or acquired (i.e., scoliosis or kyphosis)
When joint is immobilized, there are specific changes that occur in skeletal m. What is there a decrease in?
- Muscle length
- Length of m. fibers
- Flexibility of soft tissue and incr. fibrous connective tissue
- Number of sarcomeres in series within the myofibrils (i.e., sarcomeres are absorbed)
As a result of the loss of muscle sarcomeres, the muscle weakens and atrophies. The muscle weakens and atrophies at a faster rate if the muscle is immobilized in a _______ position
shortened
Antigravity muscles atrophy and weaken at a ____ rate and to a greater extent than antagonist muscles during immobilization. For example, quadriceps femoris vs. _____.
faster; hamstrings
- quadriceps (antigravity) atrophy faster than hamstrings
- biceps brachii (antigravity) atrophy faster than triceps brachii
What 3 components resist a stretch when a stretch is applied to a muscle?
- Series elastic component (Rse)
- Parallel elastic component (Rpe)
- Contractile component (Rcc)
The contribution of each m component to resisting the stretch depends on the muscle length. What is the length of a normal muscle? How is the total stretch resistance described mathematically?
100-105% of the rest length;
SR = Rse + Rpe + Rcc
What is the length of the sarcomere at 175% rest length? what happens at this length?
- 5 micrometers; over lap of actin and myosin is lost
- at this length, the Rcc does not contribute to total SR; the total resistance is from the Rpe, which is the endomysium, perimysium and epimysium
- main takeaway: at 175% you are stretching CONNECTIVE tissue, not the muscle
What is normal functional excursion of skeletal muscle?
75-105%
Load or force applied on soft tissue
Stress
Change in length of tissue in response to applied load or force
Strain
Does muscle atrophy faster if it is immobilized in a shortened or lengthened position?
Shortened
