Lecture 13 Flashcards
Muscle mass growth trends
grows from birth until young adulthood
peaks for women from 16-20
peaks for men from 18-25
Decreases beginning at age 25
decreases 1 per year, 8% each decade
rapidly decreases beginning age 50
How to decrease decline in muscle mass
happens at a later age or at a slower rate in active adults
Immobilization and muscle
type 1 (slow twitch) fibers atrophy at a faster rate than type 2 (fast twitch)
Elders and muscle injury
macrophage infiltration is lower/slower
fibrotic tissue interposed with muscle
fat infiltration
Resistance has an impact on
muscle hypertrophy, muscle strength, muscle fiber size, satellite cell count, glycolytic function, mitochondrial volume
Endurance exercise has an impact on
lactate tolerance, mitochondrial volume, protein synthesis, capillary density, oxidative function, endurance capacity, satellite cells count, glycolytic function
endurance has none or small impact on
muscle hypertrophy, muscle strength, muscle fiber size
Resistance has no or small impact on
lactate tolerance, protein synthesis, capillary density, oxidative function, endurance
Exam and Eval of muscle performance
MMT
handheld and isokinetic dynamometers
dynamic strength test
Benefits of submaximal loading
injury protection
after sedentary lifestyle
after prolonged immobilization
pt has bone demineralization
initially learning exercise
general goal is muscle endurance
confidence or self-efficacy are low
Finding submaximal load
estimate method
MMT method
Benefits of near-max or max loading
goal is muscle strength, power, hypertrophy
advanced phase of rehab
condition program
competitive weightlifting
Use 1 RM to determine load
Repetition maximum
greatest amount of weight a muscle can move through the full available ROM with control for a specific number of times before fatiguing
NEVER use with post op, joint instability, osteoporosis, cardiovascular pathology
Goal: increase muscle endurance
use dosages early in rehab process
load is approx 40% of 10 RM
Rest between sets, 45-60 sec
Goal: increase muscle strength
use after pt has made progress with endurance training
load is approx 60-80% of 1 RM or an amount that causes fatigue after 6-8 reps
Rest between sets, 2-3 minutes
DeLorme’s PRE
10 RM based program
3 Sets, changing weight throughout
1 = 50% of 10 RM
2 = 75% of 10 RM
3 = 100% of 10 RM
Rate of Perceived Exertion
use scale with patients who are easily fatigable, fearful, multiple co-morbidities. help assess the subjective intensity of load and intensity of effort.
5 main categories of how to alter dosage
duration
volume
intensity/load
rest interval
frequency
can also do lever arm
Muscle-Setting
tests muscle control
low-intensity muscle contractions performed against no resistance
Uses of muscle-setting
decrease muscle pain and spasm
promote relaxation and circulation during acute stage
slow muscle atrophy and maintain mobility of joint but protect healing
does not increase strength unless muscles are very weak
Indications for isometric exercise
minimize muscle atrophy when joint movement isn’t possible
re-establish neuromuscular control while protecting healing tissues
develop postural or joint stability
improve muscle strength but can’t do dynamic
develop strength in specific points of ROM
Multiple angle isometrics
system of isometric exercise in which resistance is applied at multiple joint positions within available ROM
examples: hamstring isometrics following hamstring strain that is still painful
Uses of multiple angle isometrics
improve strength when joint motion is permissible but dynamic resistance exercise is painful or inadvisable
Dosages of isometrics
6-10 seconds = 2s rise time, 6s hold, 2s fall time
Reps/sets = 1-2 sets of 6-10 reps, multiple times a day
10 degree shift between positions to use multiple angles
Precautions/contraindications of isometrics
precautions: no valsalva, hypertension
contraindications: history of cardiac or vascular disorders
Length-tension relationship
isometric tension generation is skeletal muscle is a function of the magnitude of overlap between actin and myosin filaments
Stretch-shortening cycle
when initiating movement, a brief eccentric contraction is followed by a concentric contraction
Concentric, dynamic exercise
accelerates body segments, shortens
external resistance is overcome by internal force
greater # of motor units must be recruited to control the same load vs eccentric contraction
Eccentric, dynamic exercise
decelerates body segment, lengthens
dynamic muscle activation and tension production that is below the level of external resistance
greater external loads can be controlled w/eccentric
eccentric has higher incidence of delayed muscle soreness
hardest to do
Manual Resistance
Indication: contact is necessary to ensure proper activation
Considerations: readily available, easily modified
Precautions: hypertension/CVD, labor intensive, not practical for home, precise measurement difficult
Pulley System
Indication: any time resistive exercise through a ROM is necessary
Considerations: applies constant load
Precautions: use after baseline is established, muscle max loaded in weakest portion of range
Variable Resistance Machine
Indication: stability and safety is of concern
Considerations: provides less resistance beginning/end of ROM
Precautions: balance or coordination is not learned
Elastics
Indications: any time strengthening by external resistance is required
Considerations: inexpensive, force increases w/stretch
Precautions: full ROM requires close attention to resistance angle and length. elastic decreases force fast
Free Weights
Indication: for discrete measurable overload
Considerations: can be used in many different ways
Precautions: little external stabilization
Isokinetic devices
Indication: muscle performance testing and training
Considerations: fully activate more muscle fibers for longer periods, can do a variety of speeds
Precautions: expensive, bulky, training is in a single plane, constant velocity
Types of resistance training
manual resistance
pulley system
variable resistance machine
elastics
free weights
isokinetic devices
Resistance Training Precautions
valsalva maneuver
possible stress on neighboring joints
possible pain, dizziness, shortness of breath
avoid children, sedentary adults, osteoporosis
Contraindications Resistance Exercise
Pain that is sharp, tearing, intense
unstable joint
force distal to a fracture that is not completely healed
inflammation, especially neuromuscular or around joint
severe cardiopulmonary disease
ACSM for Resistance Exercise
2-3 days per week
2 to 4 sets of each exercise
Reps: 8-12 strength/power, 10-15 middle age strength/starting exercise, 15-20 endurance
48 hours in-between
Open-chain
distal segment is free to move in space
closed-chain
body moves on a distal segment that is fixed or stabilized on support surface
