Quantification of Human Mvmt: MMT & Functional Strength Training Flashcards
Factors affecting muscle performance
Muscle Fiber Type and Size
-Large cross-sectional area= greater force
Slow twitch (type I)
-fatigue resistant, recruited 1st
-small muscles across small lever arm (postural muscles)
Fast twitch (type IIa & type IIb)
-large force over short time, explosive mvmts
-fatigue more quickly, recruited last
Force-Velocity Relationships
-Increased speed generally decreases force (concentric)
-Opposite with eccentric contractions (more force to control)
Length-Tension Relationships
-Optimal force is at normal resting length
-Largest number of crossbridge dysfunction (passive-too lengthened and active insufficiency-too shortened)
Muscle architecture
-pennate (feathered shape muscles) more force
-Neural control-brain to neuromuscular junction
Age
-muscle mass peaks in mid 20’s (earlier in women)
-After 30’s there is a 10% decrease muscle mass per decade; more in 60’s
-Not symmetrical, LE’s> UE’s
-Exercise minimizes these changes
Fatigue
Cognitive Training
-Mental rehearsal/preparation
Corticosteriods
-Catabolic effects> muscle atrophy and weakness
Muscle Pathology
-Muscle strain: overstretch of a muscle esp, at musculotendinous junction (grade I, II, &III)
Disuse atrophy
-initially due to neural changes, then actual atrophy
Disease or condition
Muscle Performance
Ability of a muscle to do work
-Muscle strength: force exerted by a muscle or a group of muscles to overcome resistance in one maximal effort
-Muscle Power: work produced per unit of time (strength x speed)
-Muscle Endurance: ability of muscle to contract repeatedly overtime
WHO to muscle test and WHEN
Back to general observations
-Too weak to lift their head?
-Able to sit to stand from high seat with arms, with heavy effort and use arms, with lots of shaking…
Always access motion and strength, not always with goni or MMT
Assess Muscle Performance
- Gross Functional Check
ex. supine bridge or SLR, standing knee bend, how many pushups - Manual Resistive Assessment-MMT
-Static, dynamic…through the range - Manual Isometric resistive strength with hand held dynamometer
-objectively quantifies peak torque generated - Isokinetic Testing
Functional Strength Testing
- “Screening” of a muscular strength through observation of movement
-WFL/WNL, no focal weakness - A gross screen of key muscle groups
-LE: quads, hip flexors, dorsiflexors - An assumption of strength made through key functional mvmts
ex. sit to stand, sit up, pull up, squat, push up
Five Times Sit to Stand
-Amount of time it takes an individual to rise from a chair five times (without use of arms, 43 in)
-A FTSST time of <13 sec had the best Sn/Sp
-Reliability: intraclass correlation coefficient of 0.89 for in community-living individuals
-Performance associated with LE strength and with balance impairments
MMT
-Muscle testing is an attempt to determine a patient’s ability to voluntary contract a specific muscle
-In MMT, patients are asked to move against and hold a position against gravity and/or therapist’s manual resistance.
-Grades the relative magnitude of strength loss, to document the presence of impairments in strength
MMT indications
-Indicated in any patient with suspected impairment of muscle performance (strength, power, or endurance)
-Provides info for proper tx
-Provides an objective baseline to monitor
MMT precautions/considerations
-Important to determine patient’s ability to withstand the force to be applied
-Is there adequate stability of surrounding area for ability to sustain muscle test (fx, post-surgical, other tissue healing–postpone MMT)
-Proper breathing techniques (avoid valsalva)
Testing Considerations
Know anatomy, phys, function
-origin, insertion, line of pull
Proper positioning so the test muscle is the prime mover
-Test muscle is placed against gravity
Adequate stabilization of proximal/regional anatomy
-avoid substitutions by other muscles
Observation of how patient performs AROM
-Alter position based upon position
-muscle test <3 (less than full ROM against gravity) is then placed in a gravity minimized (eliminated) testing position
Consistent timing, pressure, and position enhances reliability
Comparison of one side to the other is a better indicator of loss
Avoidance of preconceived impressions regarding test outcome
Do no harm- caution with painful motions
Contraindications due to debilitative dz, acute pain, and local pathology or inflammation
MMT
-“Make” vs “Break Test
-Gravity vs. gravity minimized
Grading Muscle Strength
5: normal; subject completes ROM against gravity with maximal resistance
4+: Good Plus; completes ROM against gravity with moderate-maximal resistance
4: Good; completes ROM against gravity with moderate resistance
4-: Good Minus; completes ROM against gravity with minimal-moderate resistance
3+: Fair plus; completes ROM against gravity with only minimal resistance
3: Fair; completes ROM against gravity without manual resistance
3-: Fair Minus; doesn’t complete ROM against gravity, but does complete more than half the range
2+; Poor Plus; is able to initiate movement against gravity
2: Poor; completes ROM with gravity eliminated
2-: Poor Minus; doesn’t complete ROM in a gravity eliminated position
1: Trace; muscle contraction can be palpated, but there is no joint movement
0: Zero; patient demonstrates no palpable muscle contraction
Interpretation of MMT
-Reliability is dependent upon consistent test positions, accurate joint placement and avoiding use of compensatory muscle us
-Variability of +/- 1-2 full muscle grades under clinical conditions
-Be conservative when grading
-Grade 5 doesn’t necessarily mean a patient’s ability to return to his/her normal level of activity
3 key tx principles of cyriax
a. all pain arises from a lesion
b. all tx must reach the lesion
c. all tx must exert a beneficial effect on the lesion
Resistive Tests Outcomes
Performed at mid range isometric test
Outcomes: strong and painless, strong and painful, weak and painful, weak and painless