THER EX: Exam II Flashcards
Types of muscular strength
- Absolute
- Relative
- Dynamic
- Static
Absolute = force produced by a muscle
Relative = strength normalized by body weight (usually kg)
– Ideally would use lean muscle mass
– Used to compare among people of different sizes
Dynamic = muscle shortens/lengthens with contraction (joint moves)
– Concentric or eccentric
– Ability to move an object
– Work performed (force x distance)
Static = muscle contracts with no change in muscle length
– Isometric
– No work performed but tension generated in muscle
Components of muscle performance
- Strength
- Power
- Endurance
Strength
= Ability to generate force against a resistance
– Ability of contractile tissue to produce tension
– Greatest measurable force generated by muscle during single max effort
KEY: High intensity
Examples: gripping a handrail, pushing open a door
Power
= Ability to produce force quickly
– Work produced by a muscle over a period of time
– (Force x Distance)/Time = Force x Velocity
KEY: Low intensity, high velocity
Examples: throwing shotput, sprinting
Endurance
= Ability to maintain force during repeated muscle contractions
– Ability to resist fatigue and generate/sustain tension over extended period
KEY: Low intensity, high repetitions (e.g., >15)
Examples: yoga, standing, putting 100 cans on a shelf
Characteristics of muscle power
- Short burst
- Multiple burst
– Methods for improving power
NOTE: Power = Work/Time
= Force x Distance/Time = Force x Velocity
Single burst activity = Single, rapid, explosive action
- Examples:
- Throwing shotput
- Lifting heavy piece of luggage
Multiple burst activity = Repeated burst of power
- Examples:
- Biking very fast
- Sprinting
Increase power:
(1) Increase FORCE produced during fixed amount of time
(2) Decrease TIME it takes to move a given force (increase VELOCITY)
- - Key characteristic = LOW intensity at HIGH velocity
- - Increased force = Decreased velocity
- - High training velocities promote power development
- - Keep intensities lower to allow higher velocities
Health benefits of resistance training
Demonstrated effects:
- Enhanced muscle performance
- Increased strength of CTs (e.g., ligaments, tendons)
- Greater bone mineral density or less bone demineralization
- Decreased stress on joints during physical activity
- Reduced risk of soft tissue injury during physical activity
- Enhanced physical performance during ADLs, work, recreation
- Improved body composition (decrease fat, increase LBM)
- Enhanced feeling of physical well-being
Possible effects:
- Improved perception of disability and quality of life
- Improved capacity to repair soft tissue (tissue remodeling)
- Improved balance
Adaptations to resistance training
– Neural
Time: First 2-4 weeks
– account for most initial strength gains
Effects:
(1) Increased motor unit recruitment
- - More fibers recruited = more force production
(2) Increased motor unit synchronization
(3) GTO inhibition
- - Some Inhibition of protective reflex mechanism (relaxation)
- - Increases ability to generate force
Adaptations to resistance training:
- Muscular adaptations
- Increases
- Decreases
Time: 4-8 weeks
Increases:
- Muscle fiber size (XSA) (= muscle hypertrophy)
- Transition from Type IIb to IIa fibers (= fatigue resistance)
- Glycolytic and high energy phosphate enzymes (= ATP production)
- Resting ATP and PCr (= capacity)
- Fiber pennation angle (= better line of pull)
Decreases:
– Body fat (limited evidence)
– Mitochondria volume and density
– Capillary density
NOTE: Muscle mass increases in greater proportion to mitochondria and capillary density
– RELATIVE decrease (ratio of mitochondria/capillary # to mass)
– Minimal effect (positive or negative) on aerobic capacity
– ACSM recommends training aerobic before resistance (do both)
NOTE: No evidence for new fibers made (hyperplasia) in humans
- Likely a very low contribution to overall strength gains
- Likely varies with type of exercise
Overload principle
- Definition
- Progressive resistance exercise
- FITT
- Strength overload
- Endurance overload
- General recommendation
- Recovery and maintenance
= Physiological adaptations occur only when muscle is challenged
Progressive resistance exercise (PRE)
= Incrementally increasing muscle load over time by varying resistance parameters
– Intensity (resistance) or volume (reps, sets, or frequency)
– Overall increased strength occurs as muscle is challenged
– Interspersed with periods of rest/recovery (decreased intensity)
Examples:
– FITT principle: Variables to manipulate
– Frequency (# sessions)
– Intensity (resistance or muscular tension)
– Type or mode (# exercises)
– Time or duration (reps, sets, rest)
– Strength overload = Incrementally increase resistance (intensity)
– Endurance overload = Incrementally increase reps
General recommendation:
= Increase resistance by 2-10% when all reps/sets completed w/o significant fatigue
Recovery and maintenance:
- Muscle must be given time to adapt and recover before load or reps are increased
- Performance maintained if demands remain constant after muscle has adapted
Specificity principle
- Definition
- Variables
- Transfer of training
= Adaptive effects of training highly specific to training method
- Critical that rehab mimics desired functional goals (task specific)
- Due to morphological, metabolic, and neural adaptations to training stimulus
Variables:
- Endurance, strength, or power
- Type of contraction
- Mode of exercise
- Velocity of exercise
- Joint angle and movement patterns
- Single vs. multi-plane movements
Transfer of training (= “Crossover” or “Overflow”)
- Minimal carryover between
- Exercises (for same muscle)
- Contraction types
- Body parts (cross-training)
- Muscular performance parameter (e.g., strength vs. endurance)
- Some overflow from
- Exercised to non-exercised contralateral limb
- Strength to endurance (not vice versa)
Individuality principle
- Definition
- Reason
- Significance
= Identical training regimen may not benefit everyone equally
- Numerous variables confound response
- Baseline fitness
- Fatigue status
- Muscle properties of individual
- Age
- Disease
- Genetic potential
- Responders vs. nonresponders
- Polymorphism = greater increase in lean muscle mass with resistance training
- Must focus training on individuals’ needs and capacities
Reversibility principle
- Definition
- Timeframe
- Factors
= Adaptations are transient unless regularly used
– Functional ADLs or maintenance program
– Detraining or deconditioning of strength, power, size, and BMD
= Reduced muscle performance after stopping resistance ex (e.g., injury)
Timeframe:
– Begins in 1-2 weeks (very quick)
– Continues until training effects are lost
Factors:
- Larger drops in inactive and older individuals
- Less drop in recreationally active individuals
- Minimal activity level required to maintain adaptations (neural and muscular)
- 1 time per week at high intensity may be adequate
NOTE: Important to emphasize program that individual can do on their own
– Incorporate muscle performance activities into daily life
Types of muscle contractions
- Dynamic
- Concentric
- Eccentric
- Static
- Isometric
– Dynamic = Muscle changes length (joint moves)
– Concentric = muscle shortened
– Force of contraction > external force
– Accelerate body parts
Example: Bicep curl
– Eccentric = muscle lengthened
– External force > force of contraction
– Decelerate body parts
Example: Walking downhill (quads); decelerating baseball throw (triceps)
– Static
– Isometric = no change in muscle length
– Force of contraction = external force
Example: Holding heavy book
Components of resistance exercise program
- Warm-up/Cool down
- Task-specific exercises
- Alignment
- Stabilization
- External
- Internal
Warm up:
– Increase blood flow and activate enzymes
– Muscle more responsive
Cool down:
– Blood pools in limbs when exercise stops
– Light intensity redistributes blood flow to vital organs
Task-specific:
– Design exercises to closely mimic functional or recreational needs
Alignment:
– Target muscle groups by aligning with pull of fibers
– Increasing intensity by aligning action against gravity
Stabilization:
– External = Outside supporting structure (e.g., PT, chair, wall, machine)
– Allows for pure muscle action (minimizes substitute motions)
– Internal = Adjacent muscle groups stabilize muscle being targeted (e.g., abs for SLR)
– Weak surrounding muscles may prevent ability to perform exercise
Recommendations for resistance exercise
- Exercise order
- Velocity
Exercise order:
– Large muscle groups > small muscle groups
– Multijoint > single joint exercises
– High intensity > low intensity
NOTE: More challenging first to minimize injury risk due to fatigue
Velocity:
- Early to advanced rehab = slow then fast
- Allows less trained individuals to learn movement
- Training velocities should match functional needs (little transfer)
- BUT many functional activities performed at much higher velocities
- Control velocities with isokinetic dynamometer
Recommendations for resistance exercise program
– Frequency
Frequency:
- Early rehab = 2-3 times per week
- Advanced rehab = 3-4 times per week
- Split upper/lower body or muscle groups (e.g., 2 days UE, 2 days LE)
- Factors:
- Intensity and volume (higher = less frequent/longer recovery)
- Health status (weaker = less frequent/more rest)
NOTE: Too frequent exercise is one main cause of overtraining
Recommendations for resistance exercise program
- Intensity
- Submaximal loading
- Maximal loading
= Amount of external resistance
Submaximal loading (50% of 10 RM or 30-40% 1 RM)
- Early stages of soft tissue healing
- Following prolonged immobilization
- Children and older adults
- Unfamiliar with correct form and technique
- Muscle endurance goals (30% 1 RM)
Maximal loading (100% 10 RM of 70-75% 1 RM) -- Advanced stages of rehab
Recommendations for resistance exercise program
- Time or duration
- Volume
- Reps
- Sets
- Rest intervals
- Active recovery
Duration:
– Depends on patient response and goals (usually 1-2 months)
Volume (per exercise) = sets x reps
– Repetitions = # of muscle contractions
– Sets = consecutive contractions interspersed with rests
– Start with 1-2 sets of 8-10 reps and progress to higher
NOTE: Ensure correct technique before progressing
Rest interval:
- Between sessions >48 h
- Between sets:
- 2-3 min for light intensity; 3-5 min for high intensity
- Higher intensity needs longer recovery to replenish energy stores
- Active recovery = another exercise between sets
- Alternating high-low intensity, UE-LE (e.g., low intensity spin or walk)
- Allows metabolic byproducts to be flushed
- May enhance recovery over passive rest
Recommendations for resistance exercise program
- Type or mode
- Type of muscle contraction
- Positioning of exercise
- Energy system
- Type of resistance
- Range of motion
- Types of muscle action/contractions
- Isometric (static) or dynamic (concentric or eccentric)
- Isokinetic = velocity of limb movement held constant
- Position
- NWB or WB
- Open chain = NWB position and distal segment free to move
- Closed chain = WB (usually) and body moves over fixed distal segment
- Forms of resistance
- Manual or mechanical
- Constant or variable
- Accommodating (isokinetic)
- BW or PWB if performed in antigravity position
- Energy systems
- Anaerobic = high intensity for short duration (strengthening)
- Aerobic = low intensity, repetitive, prolonged, large muscle groups (endurance)
- Range of movement
- Full arc = resistance through full available ROM
- Short arc = resistance only through portion of available range
NOTE: Mode used for training must be specific to desired functional activity
Training healthy adults: Strength
- Mode (order)
- Load and volume
- Rest
- Velocity
- Frequency
NOTE: Novice/intermediate to advanced
KEY: High intensity
Mode: CONC, ECC, ISO contractions
- U and B, multiple & single joint (emphasis on multiple)
- Free weights & machines (emphasis on free weights for advanced)
- Large muscle > small
- Multi-joint > single
- High intensity > low
Load and volume:
- 60-70% 1 RM for 8-12 reps (novice to intermediate) or 80-100% 1 RM (advanced)
- Increase load 2-10% when person can perform 1-2 reps more than target
- 1-3 sets per exercise (novice)
- Multiple set programs (vary volume and intensity) for intermediate/advanced
Rest: 2-3 min for core exercises, 1-2 min for assistance exercises
Velocity:
- Slow and moderate (novice), moderate (intermediate)
- Continuum from unintentionally slow to fast (advanced) (correspond to intensity)
Frequency:
- 2-3 days/wk total body (novice)
- 3-4 days/week (intermediate, depending on # muscle groups per workout)
- 4-6 d/wk (advanced, especially for split routines, 2 days per group)
Training healthy adults: Hypertrophy
- Mode
- Load
- Volume
- Rest
- Frequency
Mode: CON, ECC, ISOM muscle actions
– Free weight and machines
Load:
- Moderate loading (70-85% 1 RM) for novice to intermediate
- 70-100% 1 RM advance
Volume:
- 8-12 reps per set for 1-3 sets per exercise (novice - intermediate)
- 1-12 reps per set for 3-6 sets per exercise (advanced)
Rest:
- 1-2 min rest (novice to intermediate)
- 2-3 min rest (advanced)
Frequency:
- 2-3 days/week for novice or intermediate
- 4-6 days/week advanced
Training healthy adults: Power
- Mode
- Load and velocity
- Volume
- Rest
- Frequency
KEY: Light-moderate loads with high velocity
Mode: Multi-joint exercises
Load: Light to moderate loading (novice to intermediate)
- Various loading strategies for advanced
- Heavy to increase force, light at high (explosive) velocity to increase fast force
Volume:
– 3-6 reps (not to failure) for 1-3 sets per exercise
– Integrated into strength program
Rest:
– 2-3 min between sets for high intensity
– 1-2 min for lower intensity
Frequency:
- 2-3 days/week novice
- 3-4 days/week intermediate
- 4-5 days/week advanced
Training healthy adults: Endurance
- Mode
- Load and volume
- Rest
- Frequency
- Velocity
KEY: Light loads, high reps, short rest
Mode:
– Multi & single joint (U and B) (various sequencing combos)
Load and volume
- Relatively light loads with moderate to high volume (10-15 reps) (novice)
- Various loads with higher overall volume (multiple sets for >10-25 reps) (advanced)
Rest:
– Short rest periods (<1 minute to 1-2 min depending on number of reps)
Frequency:
- 2-3 days/week in novice
- 3-4 days/week for intermediate
- 4-6 days/week for advanced with split routine
Velocity:
- Intentionally slow velocities for moderate reps
- Higher velocities for higher reps
Resistance training contraindications
(1) Periods of acute inflammation
- - Dynamic resistance contraindicated
- - Static exercises with low resistance OK
(2) Inflammatory neuromuscular diseases (e.g., Guillan-Barre, poliomyositis)
- - May actually cause irreversible deterioration of strength due to muscle damage
- - Dynamic and static resistance contraindicated
(3) Pain
- - Dynamic: Severe joint or muscle pain during unresisted movements
- - Static: Muscle pain during resisted isometric contraction
(4) Severe cardiopulmonary disorder
- - Severe coronary artery disease, carditis, or cardiac myopathy
- - Any vigorous activity contraindicated
- - No resistance training within 12 weeks of MI or coronary artery bypass
Resistance exercise precautions
(1) Overtraining = decline in performance due to inadequate recovery
(2) Substitute or uncontrolled motions
- - Avoid ballistic motions
- - Use appropriate stabilization and resistance level
- - Avoid excess stress on back
(3) Fatigue
(4) Muscle soreness
- - Acute = temporary burning due to pH change
- - DOMS = delayed onset muscle soreness
(5) Valsalva
- - Avoid breath holding
- - Emphasize exhalation on exertion
(6) Fracture or unstable joint
(7) Medications that may alter response to exercise
(8) Patient discomfort
- - Discontinue exercise in case of pain, dizziness, or unusual SOB
- - Keep ambient temperature comfortable
- - Wear clothing appropriate for vigorous exercise
- - Educate patient that pain should not occur
(9) Elderly, children, and osteoporotic patients
- - Avoid heavy resistance
Factors affecting force production capacity
- Muscle structure
- Neurological
- Muscle contraction
- Physiological
- Psychological and cognitive
- Muscle structure or architecture
- Muscle size (XSA) = fiber number and size (large > small)
- Fiber arrangement (pennate > parallel, but slower velocity)
- Fiber type (Type IIa and IIb > I, but fatigue more easily)
- Length-tension relationship = highest force when at physiological resting position
- Neurological
- Motor unit recruitment (greater # and coordination = greater force)
- Frequency of motor unit firing (higher = greater force)
- Muscle contraction
- Type: eccentric > isometric > concentric force
- Speed:
- Concentric: increase speed = decreases force
- Eccentric: increase speed = increase force
- Physiological
- Energy stores and blood supply
- Fatigue (local or general)
- Age of patient (diminished mass/strength in elderly)
- Psychological and cognitive
- Fear, depression, anxiety, inability to focus, motivation
Training pediatrics recommendations
- Toddlers (<6-7 years)
- Preadolescents and adolescents
Toddlers:
- Emphasize play rather than structure program
- Motor learning (development of motor control)
Preadolescents and adolescents:
– Increased focus on strength and endurance training
– Emphasize safety and technique:
– Warm up, supervise, spot
– Simple and sport-specific activity
– Target antagonist and agonist muscles
– Avoid maximal lifts and eccentric exercise (may damage growth plates)
NOTE: Most strength gains due to neural adaptations rather than hypertrophy
– Parameters
– 10-15 reps w/ BW; increase #reps/sets before resistance
– 1-2 sets per exercise
– 3 min rest
– 2x per week
NOTE: Machines not designed for children (starting weight and fit)
Training geriatrics recommendations
- Benefits
- Recommendations
Benefits:
- Increase muscle strength and size
- Improve balance, speed, walking, chair rise
- Decreased falls
Recommendations:
- Close supervision
- Monitor vital signs
- Warm up 5-10 min
- Start low intensity (40-60% 1 RM), progress to moderate (60-80% 1 RM)
- 8-12 reps, 2-3 sets, 2-3 days/week, 48 hr between sessions
- Target major muscle groups
- Weight machines may be safer
- Eccentric exercise may be beneficial but beware high intensity
Muscle architecture effects on force production
- Muscle size
- Fiber arrangement and length
- Sarcomere arrangement
- Fiber type
- Muscle size = number and size of fibers
- Large diameter = high force production
- Fiber arrangement (pennation angle)
- Short pennate fibers = high force production (e.g., quads, gastroc)
- Long pennate fibers = high rate of shortening (velocity) but low force (e.g., sartorius)
- Sarcomere arrangement
- Sarcomeres in parallel = High force (e.g., obliques)
- Sarcomeres in series = High velocity
- Fiber type
- High proportion of type I = slow, low force; fatigue resistant (e.g., soleus)
- High proportion of type IIb or IIa = rapid, high force; rapid fatigue
- Type IIa = fast, intermediate resistance
- Most muscles have mix of types; some designed for force vs. endurance
Muscle mechanical properties
- Length-tension relationship
- Force-velocity relationship
Length-tension:
- Optimal force production when at or near physiological resting length
- Peak force production at given muscle length at point of ROM
- Contact between actin and myosin greatest at given length
- Too long, lose contact
- Too short, filaments butt against each other
Force-velocity:
- Concentric: Increase velocity = Decrease force
- Max velocity when zero load
- Eccentric: Increase velocity = Increase force, plateau, and decline
- Initially addition of passive tension from noncontractile tissues
- Elastic properties of titin aligned in series with contractile fibers
- Eccentric: Increase velocity = Increase force, plateau, and decline
- Isometric: Zero velocity (load = muscle tension)
