Lab #3 Quiz - MLS & Fatigue

Eccentric Muscle Action

• muscle at length (or lengthening) under tension

• applied external load is greater than the force the muscle is producing

Concentric Muscle Action

• muscle shortening (contraction) & moving a joint

• external load is less than muscle force generation; muscle force is greater than the external load

Isometric Muscle Action

• NO muscle length change

• static contraction where a muscle generates tension without changing length or causing visible movement

• NO joint rotation

What does a HHD measure

objectively tests peak muscle force

Effort involved in a make test

purely isometric effort

Effort involved in a break test

subject applies isometric effort that ends with eccentric effort

Does a make or break test yield significantly higher strength values?

break test

The longer the lever arm for the examiner = _______

the less force required to break the subject because leverage multiples force

In a break test, how does moving the HHD further down the limb affect the measured resistive force (Fr)? How does this generally apply?

• the farther down the limb you go the greater the advantage the examiner has

• he longer the lever arm (MAr) the more advantage is given to the outside force

What muscles & manual muscle tests were associated with this lab?

• Shoulder abduction tested at 90^o - deltoid & supraspinatus

• Hip flexion tested in both supine & seated positions - iliopsoas (iliacus & psoas major) & rectus femoris

Deltoid tuberosity location

the midpoint between the acromion process and olecranon process

MA_e “bony landmarks”

distance from acromion process to deltoid tuberosity

Definition of F_e & name its counterpart

effort force from the muscle of the subject; MA_e - movement arm for the effort force

Definition of F_r & name its counterpart

resistive force of HHD by the examiner; MA_r - movement arm for the resistive force

MA_r “bony landmarks”

distance from acromion process to ulna head

Isolation

targeting a specific single muscle group/joint action by minimizing the involvement of surrounding muscles

Substitution

“cheating” or using a secondary muscle/body momentum to help perform a movement when the primary muscle is weak or fatigued

Recruitment

activation of additional motor units & muscle fibers to generate more force as demand increases or primary fibers fatigue

Isometric fatigue definition & example

• Decreased ability to produce speed

• increased ability to produce force

Ex: 90^o static hold shoulder abduction w/ DB

Isotonic fatigue definition & example

• lessened fatigue on speed

• Increased fatigue on force

Ex: 0^o to 90^o shoulder abduction aka lateral raises 3×15

Standardization

assuring that each subject receives the same treatment or opportunity

Normalization

adjusting a score to make it relative to an individual subject in a study (anything that makes things specific to each person)

Diving peak force by BW to establish relative force each subject is an example of what?

normalization

Ensuring that each subject in our lab used their dominant arm for the test is an example of (standardization/normalization)?

normalization

Measuring leg length specific to each subject by bony landmark location is an example of?

normalization

How did we prevent substitution (“cheating”) during the lateral raises?

By leaning the subjects torso against the wall

What is a RS/RS_c

• reduction score

• it is the quantitative (data driven) way to measure fatigue

• 
  

What does a steeper RS_c mean?

fatigue occurred quickly &/or at an increased level

What does a flatter reduction score slope (RS_c) mean?

greater muscular endurance &/or a slower progression of fatigue

What does this graph show? Give a brief elaboration.

Orange (male): negative slope; demonstrates classic fatigue

Blue (female): positive slope; demonstrates fatigue resistance & easy recovery