Muscle And Tendon

Question 1

what are the tissues involved with the musculotendon unit?

Answer 1

-ligaments (bone to bone)
-tendon (muscle to bone)

*It is important to view these structures together. They work as a unit and are woven together sort of like ropes

Question 2

What area of muscle/tendon are prone to injury?

Answer 2

Junction areas (muscle tendon/ tendon bone)

Question 3

Muscle tone

Answer 3

The tension of a muscle while it is at rest. Without the tone, the muscle can’t keep joints together. (Ex. Shoulder)

Question 4

How is a muscle arranged

Answer 4

Myofilaments, myofibrils, muscle fibers, fascicles, muscle

Question 5

Characteristics of a tendon

Answer 5

-crimp at rest, when muscle is contracted they are parallel
-resists tensions
-does not handle twisting or compression (why we have sesamoids/bursae)

Question 6

The contractile unit of muscle

Answer 6

-Sarcomeres: multiple bands that allow tension generation via sliding or cross bridge formation
-ATP/ADP use for function
-they lie between z-disks
-they are added or deleted with immobility or lack of drive (when a person is flexed for too long, muscle starts to delete)
-Sarcomerogenesis

Question 7

Which type of movement can we generate the most muscle tension

Answer 7

Eccentric movement

Question 8

Titin

Answer 8

Functions as a molecular spring that is responsible for passive elasticity in the muscle cell

Question 9

Isometric

Answer 9

Muscle contraction where the filaments generate tension but the units do not move

Question 10

Concentric

Answer 10

Muscle contraction where the muscle units generate enough tension that the muscle unit pulls together

Question 11

Eccentric

Answer 11

Muscle contraction where there is tension, but the muscle unit is moving farther apart (most tension can occur here than concentric)

Question 12

Muscle contusion

Answer 12

-disruption of tissue
-bleeding (the bleeding is what usually causes pain, due to the large inflammatory response)
-regeneration is usually not a factor

Question 13

Muscle strain

Answer 13

-Stretching or tearing of a muscle or tendon
-muscle tendon junction (most commonly the distal MTJ last sarcomere or two)
-associated with eccentric activation (heavy loads)

Question 14

What often causes DOMS

Answer 14

Related to eccentric activation in naive subjects (peaks 48-72 hours)

Question 15

Tendon- injury/pathology

Answer 15

-Macrotrauma: a single event, you know you have done it, often an itis-inflamed

-Microtrauma: part of repetitive cycles-submaximal, often leading to digerati events processes (osis-degeneration) “it hurts when…”

-can be tendon sheath related (inflammation)

Question 16

Tendonitis

Answer 16

-Macrotrauma and inflammatory
-single event
-extrinsic overload
-macroscopic injury
-significant event

-Acute: less than 2 weeks
-Subacute: 2-6 weeks
-Chronic: 6 or more weeks

Question 17

Tendonosis (tendinopathy)

Answer 17

-microtraumatic and degenerative
-Repetitive action
-intrinsic trauma
-often eccentric demand
-stabilizing/absorbing
-focal area of intratendinous degeneration that is initially asymptomatic and may remain unless a specific stress is brought forth

*may be related to aging and significant use (accumulative microtrauma) -> amount of elastic in tissue decreases causing them to become more rigid

Question 18

Tenosynovitis

Answer 18

-inflammation of paratendon “sheath restriction”
-abuse (overuse) or septic (infection)

Question 19

Tendon structure

Answer 19

-macroscopic appearance: crimp at rest, longitudinal orientation
-microscopic appearance: tightly arranged parallel fibers organized sequence of structures

-tropocollagen, microfibrils, subfibril, fibril, fascicle, tendon

Question 20

Recruitment and fiber types

Answer 20

-Slow Oxidative (SO): always first, smaller nerve fibers, fewer/smaller MU recruited
-Fast oxidative glycolytic: Next fibers to be recruited, intermediate
-Fast glycolytic: Least fatigue resistant

*Ideally you have a training program that trains the system you use the most

Question 21

Impact of shape and structure of muscle fibers

Answer 21

-muscle fiber orientation directly impacts tension generation capacity (the higher the number of fibers in cross section the greater tension generation capacity)
-if not perpendicular, less generating capacity

Question 22

Impact of training on muscular strength

Answer 22

-neural comes first (neurological response)
-muscular strength next (6-8 weeks) (muscle changes)
-tendon strength last (10-12 weeks) (tendon response)

Question 23

Length tension ratio

Answer 23

-optimal length tension ration is where best cross bridge formation occurs
-in rehab, you can use a quick stretch and different portions of the ROM

Question 24

Force velocity rules

Answer 24

-concentric: as you increase speed, you decrease force/torque output
-eccentric: as you increase speed, you increase/keep constant force/torque output

Question 25

What is flexibility

Answer 25

-connective tissue is the limiting factor (perimysium and endomysium) -ROM through which the joint can move -Stretching will only increase flexibility if it is constantly worked (otherwise it will be reversed) -Increase in flexibility does not necessarily result in a decrease in injuries (previous injury is the best way to predict a future injury)

Question 26

Muscle Strain

Answer 26

-Usually multi joint muscles (inarticulate) -eccentric load to an activated muscle -injury is at MTJ (usually distal) -Reaction is inflammatory

Question 27

Strain Levels

Answer 27

-Mild: 1st, few fibers, limited response, no loss of strength in MTU, moderate pain -moderate: 2nd, larger number of fibers, significant inflammatory response, many weeks, loss of muscle strength in MTU, but intact -Avulsion: 3rd, complete disruption, often from insertion rather than muscle from tendon, may be surgical

Question 28

How do we treat contusions

Answer 28

-benign neglect -donut pad if area that may receive impact (load around it not on it) -often looks worse as it moves to the surface (looks do not correlate to severity) -self limiting/ed unless underlying contribution (ex. Clotting disorder)

Question 29

how do we treat strains

Answer 29

-recognize limiting factors: pain from inflammation, decreased MT output or decreased strength early post injury -may use modalities to increase blood flow after initial phase -NSAID’s from MD 2-3 days - PRICE initial care -no aggressive stretching- progressive strengthening (eccentric works well) (slow and heavy) -Progressive function

Question 30

Good exercises for hamstrings

Answer 30

-Nordic hamstrings -hip hinges

Question 31

How do we treat tenosynovitis

Answer 31

-remember it is usually a result of repetitive overuse (repetitive wrist/thumb action) -put it at rest: sometimes just leave it alone -NSAIDs from MD (3-5 days) -PRICE: rest it at night in splint if needed, if really uncomfortable can use iontophoresis