Exam 3 Flashcards
what makes up a motor unit
nerve (motor neuron aka efferent)
muscle fibers
what are the filaments within the sarcomere
actin and myosin
small contractile units
sarcomeres
sliding filament theory
-action potential causes myosin heads to flex and create cross bridges with actin
-myosin pulls actin toward sarcomere center
-H-band becomes smaller
-Z discs move toward center
-changes in sarcomere length
I-bands
contains actin
A-band
contains myosin
action potential sequence
- action potential is released to trigger nerve response at motor end plate
- release of Ach at motor end plate initiates muscles response
- Ca+2 ions released from SR
- Ca+2 ions bind to troponin to slide tropomyosin away from actin binding sites
- extended myosin heads attach to actin’s binding sites, creating cross-bridges
- myosin contact with actin causes hydrolysis of ATP to ADP and phosphate, producing energy
- ADP releases from myosin heads creating “power stroke” as myosin heads move back to uncocked position while attached to actin
- new ATP attaches to myosin, detaching myosin from actin
- Ca+2 releases from troponin and re-enters SR
- tropomyosin covers actin binding sites
- sarcomeres returns to proactivity conditions
4 whole muscle functions
produce movement
maintain posture
stabilize joints
generate body heat
characteristics of type 1 muscle fiber
slow
small
red
greatest resistance to fatigue
lots of mitochondria
high oxidative capacity
oxidative system
endurance/aerobic activity
characteristics of type 2A muscle fibers
fast
larger
white
moderate to fatigue
high oxidative capacity
ATP-PC system
high-intensity activity less than 2min
characteristics of type 2B muscle fibers
fastest
largest
white
fatigue easily
minimal mitochondria
glycolytic system
max-intensity bursts, less than 30 sec
muscle strength
max force a muscle or muscle group can exert
determining factors: genetics, gender, exercise, neural recruitment, lifestyle, muscle fiber type
power
strength applied over a distance for a specific time (P = Fxd/T)
components of power
strength
speed
coordination
movement efficiency
timing
muscle endurance
ability to perform repeated contractions against less than max load
determining factors of muscle endurance
energy system used (type 1 recruited first then type 2 if enough stimulation)
quantity of force resisted
T/F endurance is inversely proportional to force intensity
true
strength is developed through
low reps with high resistance
endurance is developed through
high reps with low resistance
rest for strength
longer rests between sets and reps
rest for endurance
shorter rest periods
sources of muscle fatigue
neural system (out of Ach to use)
energy system (out of ATP)
sarcoplasmic reticulum (runs out of Ca+2)
T/F according to the sliding filament theory, action potential causes actin heads to flex and create cross-bridges with myosin filaments
false
what fiber type uses oxidative energy system
type 1 muscle fibers
T/F efferent input provides afferents response
false
force production determinants
joint angle
muscle length
muscle size
fiber arrangement
speed of contraction
numbers and type of fibers
muscle fiber recruitment
-recruits small (type 1 or 2a) for low intensity and before large (type 2b)
monoarticular muscles
recruited before biarticular muscles during low-level activities
-cross only 1 joint ex: vastus medialis
-provides the force
biarticular muscles
control direction of movement during joint motion
-cross over 2 joints ex: rectus femoris
-provides control over movement
static/isometric definition
tension is produced in the muscle without change in muscles length
advantages of isometrics/statics
-early in rehab
-low joint stress
-can be used with weak muscles
disadvantages of isometrics/statics
-strength gains isolated to minimal joint angles (not going thru full ROM)
-valsalva maneuver can occur more easily with other exercises
for optimal strength gains to occur the muscles effort must be at
66% to 100% of its max output
dynamic definition
implies that a change in muscles position occurs
isotonic
change in the muscles length occurs during activity
-concentric: muscle shortens
-eccentrics: muscle lengthens
isokinetic
velocity is controlled and maintained at a specific speed of movement, but amount of resistance provided to muscles varies (requires equipment)
open kinetic chain activities
-distal segments move freely and independently of proximal segments
-produce high velocity movements
-creates shear stress in joints
-have less joint stability
-occur in normal and sports activities
closed kinetic chain activities
-distal segment is weight bearing and moves with other segments
-produce forceful movements
-create less shear stress in joints
-have more joint stability
-occur in normal and sports activities
how to evaluate muscle strength
MMT
cable tensiometers
isokinetic machines
free weight or weight machines (1RM)
grip or pinch dynamometers
from least active to most active ROM
PROM
AAROM (assisted)
AROM
RROM
following major surgery which of the following gradients of muscle activity would you use
PROM
when should strength exercises start
soon after inflammatory phase of healing and when tissue is in the proliferation phase after flexibility and mobility have been restored
T/F straight plane exercises are used to isolate and strengthen weak muscles
true
ex: 4-way ankle
diagonal plane exercises
used after weak muscles is strong to perform activity correctly
progression of strengthening program
isometrics
single plane isotonics
multiple plane isotonics
functional
performance specific
SNAP principle
specific exercises
no pain
attainable goals
progressive overload
SAID principle
Specific Adaptations to Imposed Demands
-a muscles will adapt and perform according to the demands placed upon it
term used to identify a tendon that presents with pain, swelling, and impaired function
tendinopathy
mechanical stress of tendons
repeated stress applied to tendons cause fatigue resulting in tendon failure
vascular supply of tendons
tendons lack good blood supply making them more compromised perfusion, which results in tendon failure
neural basis of tendons
chronic tendon overuse leads to disproportionate substance P neurotransmitter facilitation, promoting mast cell production
intrinsic factors to tendinopathy
age
gender
pathomechanics
genetic or acquired systemic diseases
extrinsic factors to tendinopathy
overtraining
poor equipment or training surface
excessive duration or distance
excessive increases in speed
tendinopathy management
identify cause
correct the cause
identify level of tendinopathy
use eccentric exercises early
T/F according to sliding filament theory, the H-band becomes larger during muscle fiber contraction
false
which type of muscle fiber is white, has moderate fiber size, and high oxidative capacity
type 2a
example of lower extremity OKC activity
straight leg raise
definition of pylometrics
uses quick movement of eccentric activity followed by burst of concentric activity to optimize power output (explosive movements)
mechanical components of pylometrics
contractile (sarcomeres)
noncontractile (collage, elastic)
neurological components of pylometrics
muscle spindles and GTOs
contractile components
myofibrils
-increase speed of cross bridge detachment
-number of cross bridge formations increase
-control the noncontractile components
noncontractile
muscles tendons
connective tissues
series elastic components
tendons, sheaths, sarcolemma
parallel elastic components
muscles CT
concentric contraction
muscle force comes from contractile components and stretch is applied to series elastic components (stretch the muscle = stretch the tendon)
eccentric contraction
series and parallel components resist the muscle movement as muscle elongates
-contractile components controls speed and quality of movement
eccentric movements produce a stretch or
myotatic reflex (aka monosynaptic reflex)
what inhibits muscle activity
GTOs
-as muscle shortens the GTOs send signals to spinal cord to limit force production
3 phases of pylometrics exercises
- eccentric or lengthening phase where the muscle is prestretched
- amortization of transition phase amount of time it takes to change from eccentric to concentric
- concentric or shortening phase to produce the powerful output
pre-pylometric consideration
certain levels of strength, flexibility, and proprioception
intensity of pylometrics
-magnitude of effort applied during activity (stress)
-can change increased weight, height, distance, speed
volume of pylometrics
quantity of work (setsxreps)
depends on intensity and goals
recovery of pylometrics
-amount of rest determines if exercise will be more effective at improving power or endurance
-short = endurance
-longer = power
how often perform pylometrics
rest of 48hrs in between sessions
plyometric considerations
-age: 16+
-body weight: increase stress on joint in heavy PTs
-comp level: more appropriate level of fitness for plyos over recreational PTs
-surface: shock absorbing
-footwear: supportive and shock absorbing
-proper technique
-goals
precautions of plyomtrics
time: avoid long session
DOMS due to nature of plyos
contraindications of plyometrics
-acute inflammation
-postoperative conditions
-instability
if you are focusing on endurance, which of the following activity to rest ratios should you use
1:2
which of the following best describes the proper landing technique for plyometric activities
land on midfoot
functional exercises
-before performance-specific
-involve multiplanar activities, increased stressed and demands
-common across different sports
performance-specific exercises
-mimic tasks found within the sport
-move PT toward safe return to sport
-include exercises and skill drills
assessment of the PTs ability to perform an exercise or skill drills safely and accurately before being allowed to advance to next level
performance evaluation
early to middle program goals
-attain full functional levels of flexibility, strength, endurance, and coordination
-achieve full functional ability so normal speed, power, control, and agility are restored
late program goals
-restore PTs self confidence in their performance and confidence in injured part
-RTP safely and efficiently
considerations for basic to final phase therapeutic exercise
-normal motion
-multifaceted muscle activity
-multiplanar motion and multiple muscle group performance
-stabilization and acceleration changes
-proprioceptive stimulation
-agility and power development
-performance-specific skill development
-confidence development
what is the transition parameter for function or performance specific
proprioception
precautions to functional and performance specific
-explain the exercise to the PT
-avoid pain and swelling
-understand tissue integrity and healing process
-know their confidence level
-be aware of progression tolerance
step by step evaluation determines when the PT should advance to next stage in functional exercise program
final evaluation
-determine if PT is ready to RTP
final functional eval
-occurs before PT is allowed to RTP
-highly individualized
-based on specific demands to be placed on PT upon RTP
-should be as objective as possible
RTP participation steps
- acute S&S of injury are resolved, no pain or edema present
- PT has full ROM, normal strength, endurance, cardio endurance, proprioception, agility, coordination in relation to performance skills
- PT performs all activities as they could prior to injury
- PT has confidence in ability and ability of injured area without hesitation or doubt
performance specific progression would most likely occur in which phase of healing
maturation/remodeling
T/F performance specific exercises are multiplanar activities which are foundation for more specific skill activities
false
what determine progression of functional activities
proprioception
correct order of lower extremity functional progression
NWB -> stork standing -> dynamic -> running
massage characteristics
-collection of techniques
-muscle spasm relief may enhance lymph drainage
-mechanical energy may stretch CT
-little impact on blood flow
-may stimulate muscle repair
light massage
gate control theory explains analgesic benefits (rubbing area overrides nociceptor stimulation)
deep massage
activation of descending analgesic pathway explains relied (endogenous opiates)