Muscles

Question 1

Patterns of muscular imbalance (tightness/weakness) can impact…

Answer 1

joint motion, stability, posture, etc.

Question 2

What is isometric contraction?

Answer 2

No movement takes place, load on the muscle exceeds the tension generated by the contracting muscle

Question 3

What is concentric contraction?

Answer 3

Muscle shortens against an opposing load

Question 4

What is eccentric contraction?

Answer 4

Muscle lengthens as it resists a load

Question 5

Initiation of movement involves what type of muscle contraction?

Answer 5

Concentric contraction; origin and insertion approximate during contraction

Question 6

Control of movement involves what type of muscle contraction?

Answer 6

Eccentric contraction; origin and insertion separate during contraction

Question 7

Which muscles initiate extension from upright position?

Answer 7

Erector spinae

Question 8

Which muscle control extension from upright position?

Answer 8

Abdominals

Question 9

What are the limitations of extension from upright position?

Answer 9

• Bony impaction (SPs, facets)
• Smaller contribution from ligaments (ALL, anterior annulus)

Question 10

Which muscles initiate flexion from upright position?

Answer 10

Iliopsoas (when femur is fixed)
Abdominals (if pelvis is fixed, as in a sit up from supine)

Question 11

Which muscles control flexion from upright position?

Answer 11

Mostly gluteus maximus and hamstrings early, then after 60 degrees, erector spinae primarily (until 90 degrees)

Question 12

What are the limitations of flexion from upright position?

Answer 12

• Facet joints and capsule
• Disc and ligaments (LF, PLL, interspinous ligaments)

Question 13

What muscle initiates lateral flexion from upright?

Answer 13

Ipsilateral quadratus lumborum

Question 14

What muscles control lateral flexion from upright?

Answer 14

Contralateral quadratus lumborum and contralateral psoas major

Question 15

What are the limitations of lateral flexion from upright?

Answer 15

• Ipsilateral facet impaction
• Contralateral facet capsule
• Lumbar facets
• Intertransverse ligaments

Question 16

What muscles initiate rotation?

Answer 16

Concentric contraction of contralateral external abdominal obliques, multifidi, and rotatores

Question 17

What muscles control rotation?

Answer 17

Eccentric contraction of ipsilateral multifidi and rotatores

Question 18

What are the limitations of rotation?

Answer 18

• Shape and orientation of facets, facet capsules, and interspinous ligaments
• Disc (annulus)

Question 19

What is an agonist?

Answer 19

Muscle that is the prime mover

Question 20

What is an antagonist?

Answer 20

Stabilizer, allows extremity to return to normal position

Question 21

What is a synergists?

Answer 21

Help agonists with desired motion

Question 22

What is a stabilizer?

Answer 22

Maintain body position to allow motion to occur

Question 23

What are four examples of agonist/antagonist pairs?

Answer 23

• Biceps/triceps
• Abdominals/spinal erectors
• Quadriceps/hamstrings
• Grastrocnemius/tibialis anterior

Question 24

What is Sherrington’s law?

Answer 24

“Law of reciprocal inhibition”
When contraction of a muscle is stimulated there is simultaneous inhibition of its antagonist

Question 25

How do agonist/antagonist pairs often present clinically?

Answer 25

Patterns of over/under activation create faulty movement patterns

Question 26

Some muscles tend toward hyperactivity/hypertonicity, others toward...

Answer 26

inhibition/hypotonicity

Question 27

Both hyperactivity/hypertonicity and inhibition/hypotonicity can be caused by...

Answer 27

repetitive use, stress, neurological coordination, postural strain, trauma, etc.

Question 28

If muscle imbalance is not addressed, what is likely to happen?

Answer 28

Self-perpetuating, will continue to progress if not addressed

Question 29

Muscle imbalance can in turn affect...

Answer 29

joint movement

Question 30

Describe patterns of hypertonicity

Answer 30

Varies between patients Patterns are common based on typical movement/positional stresses in most patient populations BUT may differ based on specific activities

Question 31

How is muscle tone determined?

Answer 31

* Ability of the muscle to lengthen (movement based assessment) * Deformation of the muscle at rest

Question 32

What is normal muscle tone?

Answer 32

* Relative not absolute * Compare side to side * Compare agonist/antagonist

Question 33

What is a myofascial trigger point?

Answer 33

A focus of hyperirritability in muscular or fascial tissue. When compressed, it is locally tender, and gives rise to **referred** pain and tenderness.