Exam 2 Flashcards
Perimysium
Surrounds bundles of muscle fibers
Epimysium
Surrounds entire muscle
Endomysium
Surrounds individual muscle fibers
Sarcolemma
Muscle cell membrane
Myofibrils
-Threadlike strands within muscle fibers that contain the contractile proteins
-Actin (thin filament)
-Myosin (thick filament)
-Sarcomere
>Z-line, M-line, H-zone, A-band & I-band
Type I fibers
- Slow-twitch fibers
- Slow-oxidative fibers
- much more mitochondria
- most efficient bc you complete oxidation
- red in color
Type IIa fibers
- Intermediate fibers
- Fast-oxidative glycolytic fibers
- red in color
Type IIx fibers
- Fast-twitch fibers
- Fast-glycolytic fibers
- produces more force bc of less mitochondria
- white in color
In what order to muscle fiber types change?
Fast to slow
IIx to IIa to I
Satellite cells
-Undifferentiated cells
-Muscle growth and repair
>Can form new fibers
>Hypertrophy
contractile proteins
They fill Myofibrils
3 important factors of Force Regulation in Muscle
1) Types and number of motor units recruited
2) Initial muscle length
3) Nature of the motor units neural stimulation
Simple Twitch, Summation, and Tetanus
That order (least force to most force)
ST-Larger waves on graph
S-Smaller waves on graph but more of them raising in force
T-Long flat horizontal line on graph
Where is calcium stored?
Sarcoplasmic reticulum
How is calcium released and what does it bind with? And what does it do (what’s its function)?
1) Nerve impulse travels down T-tubules and causes release of Ca++ from SR
2) Ca++ binds to troponin and causes position change in tropomyosin, exposing active sites on actin
3) Permits strong binding state between actin and myosin and contraction occurs
Chronological events in muscle contraction
1) without ca++ found to trophin there in a weak binding state (natural stimulation begins, ca++ is released from sarcoplasmic reticulum
2) formation or strong binding state (release of Pi)
3) cross bridge movement begins (release of ADP)
4) cross bridge movement completed
5) ATP binds to cross bridge. Formation of weak binding state
6) neural stimulation either continues or stops
Motor Neuron
Nerve fiber branch from a nerve cell that is connected to each skeletal muscle cell
Motor Unit
Motor neuron and all the muscle fibers it innervates
The maximum velocity of shortening is greatest
at the lowest force OR The greatest speed of movement is generated at the lowest workloads. True or False
True
Atrophy
A decrease in the mass of the muscle.
Ex. Rigor Mortis
Ex. Sarcopenia
3 Types of dynamic contractions
1) Concentric
2) Eccentric
3) Isokinetic
Concentric Contraction
- Force exerted by muscle or muscle group exceeds external resistance or load
- Joint angle decreases
- Muscle shortens
Eccentric Contraction
- Joint angle increases
- Muscle lengthens while contracting
- Serves as a braking mechanism to decelerate body segment movement
Isokinetic Contraction
- Maximal contraction of muscle or muscle group at a constant velocity throughout entire range of motion (ROM)
- Specialized machines control velocity of contraction and adjust external resistance to match the force produced at degree in the ROM
- Resistance is variable, velocity is constant
Isometric
Static
-no visible change in joint angle
Isotonic
Dynamic
-visible change in joint angle
What are 2 devices used to assess static strength and endurance?
– Dynamometers
– Cable tensiometers
Isometric Training
• Older style of training requiring no special equipment
• Requires holding submaximal contraction at specific joint angle (no change in joint angle)
• Used in rehabilitative settings
• Benefit is limited to the specific joint angles
• Contraindications
– Coronary patients
– Patients with hypertension
Dynamic Training
• Appropriate for all ages, both sexes • Involves concentric and eccentric contractions using variable or constant resistance • Full range of motion • Basic concepts: – Intensity (percentage of 1RM) – Repetitions – Sets – Training volume – Sequence of exercises
Relationship between intensity, set, training volume
• Intensity: inversely related to number of
repetitions (reps)
• Set: specific number of reps for given exercise
• Training volume: total weight lifted in exercise
session
– Weight lifted x number of reps x sets
Guidelines to achieve goals – endurance and strength
-Endurance: low weight, high reps (15-25 repetitions maximum)
– Strength: high weight, low reps (8-12 repetitions maximum)
Intensity
• Mean optimal intensity for strength: 60% to
100% 1RM
• Can generally perform 1 to 12 repetitions at
these intensities
• Must vary to continue improvement
Sets
• Target client’s goals
• 1 or 2 sets: good for children, older adults
• 2 to 4 sets: good for novice and intermediate lifters
• Single sets: shorter programs, increased adherence, but not recommended by many
• Multiple sets: longer programs, increased training
stimulus
Frequency
• Consider client’s experience level
– Novice: 3 days a week
– Healthy population: 2 or 3 nonconsecutive days a
week
– Advanced lifters: 4 to 6 sessions a week; split
routines
• For maximum strength: at least 2 times a week
per muscle group
• Rest muscle group 48 hours between workouts
Volume
• Must manipulate sets, reps, weight, number of
exercises per muscle group throughout program to
continue improvement and adaptation
• Adjustments prevent plateaus
Linear periodization
Within and between cycles, training intensity increases as training volume decreases.
Macrocycle, mesocycle, microcycle
• Macrocycles: cover 9- to 12-month intervals
• Mesocycles: 3- to 4-month intervals that comprise macrocycles
• Microcycles: 1- to 4-week intervals that comprise
mesocycles
Reverse linear periodization
- Reverse sequence of LP
* Within and between cycles, training intensity decreases as training volume increases
Undulating periodization
- Considerably shorter intervals as compared to LP and RLP programs
- Frequent changes in training stimulus
- No chance for plateaus
- Nearly constant adaptations required by muscles
- Excellent for increasing exercise variety and adherence
Specificity
requires an exercise be specific to
– the muscle group that is exercised,
– the type of contraction, and
– training intensity.
Overload
Muscle group must be exercised at workloads that are greater than normal.
– For strength: ≥60% 1RM; faster gains at higher loads
– For endurance: 30% 1RM ≤ load < 60% 1RM, but with reps to fatigue
Progression
systematic, periodic, and gradual increase of the training volume, or total amount of work by manipulating – resistance or load, – reps (number or velocity), – sets, – number of exercises, and – rest periods.
Flexibility
is the ability of a joint, or series of joints, to
move through a full range of motion (ROM) without
injury.
Factors affecting flexibility
• Hypertrophied muscles and excess subcutaneous fat may impede flexibility.
• Static flexibility progressively decreases as muscle stiffness increases with aging.
• Females are generally more flexible than males,
regardless of age; may be joint-specific.
• Lack of physical activity is a major cause of inflexibility.
• Active warm-up combined with static stretching is more effective than static stretching alone.
Joint stability
resistance offered by various musculoskeletal tissues that surround a skeletal joint
Static flexibility
is a measure of total ROM at the joint, limited by the extensibility of the musculotendinous unit. (This is the one we normally find.)
Dynamic flexibility
is a measure of the rate of torque or resistance developed during stretching throughout the ROM.
Goniometer
protractor-like device with two steel or plastic arms that measure the joint angle at the extremes of the ROM
Alternate low back care
• Muscle endurance is more protective than muscle
strength for reducing low back injury.
• Lumbar mobility is directly related to low back injury.
Passive stretching
Client relaxes target muscle group as assistant moves the body part.
Duration of stretching
• ACSM recommends 15 to 60 seconds duration
for each stretch.
• ACSM recommends 4 reps per stretch initially.
• Stretching should be done daily
Traditional low back care
- Improve ROM by strengthening and stretching hip flexors, hamstrings, and low back extensors.
- Strengthen abdominal muscles.
- Some programs include exercises to increase the strength and endurance of both the abdominal and low back extensor muscles.
- Strengthening the low back (lumbar extensor) muscles requires pelvic stabilization.
Flexometer
consists of a weighted 360° dial and weighted pointer
Static stretching
slow, sustained, muscle lengthening
Most common
Inclinometer
measures the angle between the long axis of the moving segment and the line of gravity
Static balance
is the ability to maintain COG within the supporting base while standing or sitting.
Dynamic balance
is maintaining an upright position while COG and base of support are moving and the COG is moving outside of the supporting base.
Sit and reach test
• Client sits on the floor with knees extended and the soles of feet against the box edge.
• Client keeps knees fully extended, arms evenly
stretched, and hands parallel with the palms down
(fingertips may overlap).
Active stretching
Client moves body part without external assistance.
Ballistic stretching
fast, jerky, bouncing
Not recommended
Functional balance
is the ability to perform daily movement tasks requiring balance.
