musculoskeletal assessment Flashcards
1
Q
msk assessments
A
- broad term relating to the inter-relationship of muscular strength, power, endurance, flexibility, posture, and balance in health and performance
2
Q
what do msk assessments help with/measure?
A
- guide/monitor RT programs
- to isolate weakness, and muscle balance (bilaterally)
- assess and reduce risk of injuries and disabilities
- monitor/guide rehab programs
- promote healthy aging and maintenance of functional independence
- maintain back health
- mobility and independence
3
Q
strength
A
- the ability of a muscle/group to voluntarily produce a force or torque against an external resistance under specific conditions defined by muscle action, movement velocity and posture
4
Q
architecture of strength
A
- fiber type: type 1, 2a, 2x, and 2b, differences with power output + speed of power output
- pennation
- PCSA
- strength varies across muscle groups and influences magnitude of force produced
- ## more muscles with type 2 fibers have higher force production but fatigue easier
5
Q
assessing fiber type through needle biopsy
A
- best way to assess fiber type
- muscle biopsy
- identify type using chemicals
- least invasive method
- suction from the syringe sucks out tissue
6
Q
how a needle biopsy works
A
- bedside procedure
- local anesthesia for adults, conscious sedation for pediatric patients
- can be done in many populations
- incision of 3-5mm (0.1-0.2 inches) depending on needle size
- success is variable by 95%
- sample side is usually 35-75 mg/pass
- need to get enough tissue
- very safe and low incidence of painful hematomas
- analyze by histochemistry , immunohistochemistry , RNA enzyme analysis, etc.
7
Q
size variables : cross sectional area
A
- indication of how many fibers directly contribute to force production
- bigger muscle = more fibers
volume = length x CSA
8
Q
size variables : length of muscles
A
- long, slender, muscle is more conductive = faster contractions
- shorter, thicker muscle is more conductive for forceful contractions
volume = length x CSA
9
Q
pennation angle
A
- angle of pennation allows muscle to be packed effectively depending on the main function and space available
- shows how muscle fibers attach to a tendon / bone insertion
- increase physiological cross-sectional area (PCSA)
- more force applied for a given CSA
- pennation sacrifices shortening velocity for increase force per volume of muscle
- degrees directly impact sarcomere fiber number per CS of muscle generating considerable force and power
10
Q
velocity and force of pennation angles
A
- for velocity, the optimal angle is 0 degrees , pulls in line with the muscle fibers
- for force, the optimal angle is 45 degrees, start to lose strength / force than you gain
11
Q
joint position and strength
A
- moment arm
- muscle length
- force-length
- joint position generates force differently across ranges of motion
- peak for production of at specific angles at specified load
- target the optimal degree angle to optimize force output
12
Q
moment arm
A
- changes during ROM
- when you start to flex, the moment arm is shorter
- when you fully flex, the moment arm is bigger
13
Q
length tension relationship
A
- depending on when your actin and myosin filaments are cross-bridging
- optimal point where most cross bridges are engaged and overlap
- changes over ROM
14
Q
contraction type and strength
A
- force velocity
- concentric
- eccentric
- isometric
15
Q
force velocity relationship and contraction
A
- strength can be measured at any velocity but maximal (functional) force output will occur at a low velocity or during isometric contractions
- eccentric contractions generate the most force (peak PO)
- however, there are not many movements done in eccentric contraction
16
Q
neural drive and strength
A
- Recruitment
- rate coding
17
Q
recruitment
A
- onion skin model of recruitment
- different layers of how MU are started
- small and large MU
- smallest recruited first because they require the least amount of force
- once recruited, they are fired more often = force over time
- additional firing gains bigger firing of bigger MU
*slide 25
18
Q
order of MU recruitment
A
- slow oxidative
- fast fatigue resistant
- fast fatigable
- low ratio of fibers to nerves (fine movements) –> high ratio of fibers to nerves (gross movements)
19
Q
history and strength
A
- fatigue
- PAP
20
Q
post-activation potentiation
A
- short term increased in maximal force following maximal or near maximal contractions
- may be do to greater CNS drive (increased MU recruitment)
- optimizes cross-bridging + primes the system
21
Q
facilitation effect (stretch shortening potentiation)
A
- “preloading” a muscle (group) with an eccentric contraction enhances the force of a subsequent concentric contraction
22
Q
fatigue
A
- decreased ability due to reduced substrate ability
- activating fast glycolytic fibers that fatigue quickly
23
Q
strength testing considerations
A
- standardize instructions prior to test
- ensure uniformity in duration/intensity of warm up (not tiring systems)
- provide practice before testing to minimize “learning effect”
- ensure consistency among subject in angle of limb measurement and body position on device (rom, angle of joint)
- predetermine a min number of trials
- select measures with high reproducibility
- recognize individual differences in body size and comp.
24
Q
isometric strength
A
- amount of muscle force with “no” movement (zero velocity)
- tensiometers, isokinetic dynamometers , handgrip dynamometer
- gold standard technique for generating maximal absolute strength
25
Q
dynamometry
A
- external force applied to a dynamometer compresses a steel spring and moves a pointer
- the force required to move the pointer a given distance determined the applied external force
26
Q
isometric strength protocol considerations
A
- body position and isolation of movement pattern that is being tested
- joint angle is CRITICAL: could lead to isometric strength curve
- standardize warm-up: general to specific
- avoid jerking motions by gradually increasing tension development
- hold max contraction for 3 seconds
- repeat 3 times , take best score
27
Q
handgrip dynamometer
A
- has a moderate correlation with total upper body strength in large pops.
- early screening to identify those with risk for physical disability related to low muscle strength
- cut off of 21.0 kg - minimum level of old-age grip strength
- scores close to this are 8x higher of developing muscular strength disabilities
- test retest = 0.96 and 0.94 for left and right hands for males and 0.93 -0.92 for females
28
Q
cable tensiometry
A
- isolates limbs, muscle groups, + joint angles
- increasing force on a cable depresses riser over which the cable passes
- deflects pointer and indicates subject’s score
- measures muscle force in a static or isometric muscle action that elicits little or no change in the muscles external length
29
Q
1 rep max
A
- the max amount of weight that can be voluntarily lifted once while muscle shorted (concentric)
- free weights or machine loading system
- gold standard for strength
- real world measurement of strength
30
Q
N.S.C.A 1 Rm protocol
A
- set 1: 8-10 reps of light load ~ 40-60 of 1RM
- set 2: 3-5 reps of higher load ~ 70% of 1 RM
- set 3: 2-3 reps of higher load ~ 80-90% 1RM
- set 4: increase load for a 1 rep max
- 2nd rep can be attempted after rest
31
Q
protocol considerations for 1RM test
A
- accuracy of weight / bars etc.
- avoid bouncing or rebound effect
- a pause is included (if lowering the weight is allowed) and starting position standardized to ensure a concentric only contraction occurs
- number of lead-up sets and reps controlled
- avoid fatigue and assess readiness to lift
- adequate rest (~3min)
- ROM, joint angle, posture, grip, timing, time of day controlled `
32
Q
stats of the 1 rm test
A
- test retest : 0.94 - 97
- ICC 0.87
- validity is good if weight lifted once is relevant to the population
33
Q
cautions of the 1RM test
A
- not recommended for certain groups like people who are untrained , would want to use other submaximal tests
- difficult to receive true 1Rm in untrained populations
- variety of protocols depending on movement, type of weight , population
34
Q
how to express 1Rm data
A
- max amount of weight or relative to body mass
- larger individual = more fibers = lifting bigger weight
35
Q
multiple repetitions
A
- alternative to 1 Rm testing
- based on a reasonably linear relationship btw. multiple regression scores and 1 RM
- best predictive power is btw 3-10 max repeated reps
36
Q
protocol of multiple regressions
A
- set 1: 10 reps at 50% of estimated 1 RM
- set 2: 8 reps at 60-70% 1RM
- set 3: 6-10 reps to failure at 80% 1RM
- if set 3 is too light, stop before completion and add more weight
37
Q
quantifying strength as a total lift score
A
- multiply the reps to failure by the weight to get a total load lifted score
- kg x reps = kgs
38
Q
isokinetic strength
A
- isokinetic biodex
- can contract velocity of motion
- set it to particular angles + contract to the angle
- fixed force / weight
- see how quickly someone can push through the fixed weight
39
Q
isokinetic dynamometer
A
- very expensive
- keeps velocity static to isolate changes in strength across a ROM
- identifies impaired motion due to muscle weakness
- controls velocity of movement up to 400 degrees but can be set to 0 for isometric contractions
40
Q
problems with isokinetic machines
A
- expensive
- device control settings and calibration have to be followed according to manufacturer
- have to be trained to use them
- “learning” is a factor so familiarization is important
- clunky to use
- awkward to go through velocity at rom
41
Q
aging and strength
A
- decline begins at 45-50 and progresses at a rate of 12-15% per decade
- 25-40% of muscular strength lost by 6th or 7th decade
- disuse over time
- large portions of the decreased strength in old age is due to muscle atrophy
- women have a higher % of loss strength than men
42
Q
0030 sec arm curl test
A
- upper body strength related to daily living tasks
- number of arm curls in 30 sec
- 8lbs for men
- 5lbs for women
- light loads to ensure full ROM
- criterion validity with combined 1RM for chest, upper back , and biceps (0.84, 0.79)
- test-retest reliability is 0.81
43
Q
30 sec chair stand test
A
- lower body strength related to daily living tasks
- number of sit-stand reps in 30s
- criterion validity with respect to 1RM leg press (0.78,0.71) for men and women
- test-retest : 0.86 and 0.92
44
Q
muscle balance
A
- balance or ratio of strength between agonist and antagonist muscle groups
- set ratios to look for
- usually assessed with isokinetic dynamometers in rehab settings but can be done with other strength tests
- important for joint stability and to avoid injury
45
Q
muscle balance between limbs
A
- dominant to non dominant limbs should be <10-15% different
- ex. tennis players, one arm bigger than the other
