Muscle Weakness (ch5) Flashcards
What type of muscle is under voluntary control?
Skeletal muscle
What is a motor neuron and all the fibers it innervates?
Motor unit
Which type of muscle fibers are large in diameter and suited for quick, explosive actions?
Fast twitch fibers (type 2)
What is a muscle’s capacity to produce force depending on its length of muscle relative to its resting length.
Length tension relationship
At what length can muscle produce the most force?
Normal resting length
Which type of muscle fibers are smaller in diameter and most suitable for long duration low force contractions?
Slow twitch fibers (type 1)
Describe what takes place during a muscle contraction?
Action potential reaches the end of a motor nerve > Stimulates the release of Acetylcholine from nerve terminal > Acetylcholine binds to receptors on muscle fibers spreading the action potential > Results in myosin head binding to actin filaments > Myosin head pulls on actin filaments to cause muscle contraction
What causes a reduction in force production by a muscle that occurs after repeated contractions?
Fatigue
What are the different types of muscle fiber pennation (shapes)?
Longitudinal Radiate Fusiform Unipennate Bipennate Multipennate
How many muscle tear grading categories are there?
Grade 1 to 3
What are the characteristics of a grade 1 tear?
A few muscle fibers are torn
Minor swelling and discomfort, little pain w/ palpation
Little if any discoloration
Muscle can contract w/ normal strength
What are the characteristics of a grade 2 tear?
Partial tear, most common type
Causes moderate pain w/ contraction against resistance and contraction will be weak
Moderate pain w/ passive stretching
Moderate swelling and pain w/ palpation
What are the characteristics of a grade 3 tear?
Complete muscle rupture
Profound weakness
Severe swelling and discoloration, possible palpable gap in muscle belly
What percentage of muscle strains account for all athletic injuries?
50%
What can cause muscle weakness?
Muscle disuse
Myopathy
Neurological muscle conditions
What are neurological diseases that can affect performance?
Cerebral palsy
Myasthenia gravis
Peripheral nerve injury ie carpal tunnel
What causes cerebral palsy?
Non progressive lesion of the developing brain causes a persistent and changing disorder of movement and posture that appears early in life and is often associated w/ muscle weakness
Describe myasthenia gravis?
A disorder that prevent efficients transmission from the nerves to muscles, causes weakness primarily characterized by fatigue
Describe carpal tunnel?
its a peripheral nerve injury that causes weakness of the hand muscles innervated by the median nerve
What are typical musculoskeletal tests and measures?
Anthropometric measurements
ROM
Manual muscle testing
What is the contraction strength and movement of a Grade 3 manual muscle test?
Contraction strength: Fair 50%
Movement: Complete ROM against gravity
What is the contraction strength and movement of a Grade 5 manual muscle test?
Contraction strength: Normal 100%
Movement: Complete ROM against gravity w/ maximal resistance
What is the contraction strength and movement of a Grade 1 manual muscle test?
Contraction strength: trace amounts
Movement: Evidence of slight contractility but no joint motion
What is the contraction strength and movement of a Grade 4 manual muscle test?
Contraction strength: Good 75%
Movement: Complete ROM against gravity w/ some moderate resistance
What is the contraction strength and movement of a Grade 2 manual muscle test?
Contraction strength: Poor 25%
Movement: Complete ROM against gravity ELIMINATED
What is a hand held dynamometer?
A device used to measure force of muscle groups in the hand
What is the fastest and most efficient way to assess muscle strength?
Manual muscle testing
What is isokinetic testing ?
A strength test that measures force production during fixed velocity movement w/ an accommodating resistance
It is performed using an electrically powered device that maintains a chosen velocity of movement while maximizing the resistance throughout the ROM
What are the advantages of isokinetic testing?
The ability to measure concentric and eccentric contraction
What will you test for in the neuromuscular system?
Arousal, attention, and cognition
Pain, peripheral nerve integrity and sensory integrity
What will you test for in the cardiovascular system?
Circulation, ventilation, and respiratory/ gas exchange
Aerobic capacity and endurance
What test would you perform to examine a patient’s function?
Gait, locomotion, and balance
Assistive and adoptive devices
Orthotic, protective, and supportive devices
Describe the overload principle?
Exposure to load greater usual the body adapts by increasing strength, power, or endurance depending on the nature of the load.
To continually improve performance, the load must be progressively increased to promote progressive adaptation
Describe the SAID principle?
The body adapts according to the demands placed upon it
Therefor patients w/ muscle weakness should emphasize strength, power, and endurance according to the functional goals and needs of the individual patient
What are the factors to consider when designing a strengthening program?
Age, Sex, Med history, Previous training background, Injury history, functional goals, motivation, and any healing restraints related to their injury or surgery
What are anaerobic energy sources mostly used for?
Short, intense activities
What are aerobic energy sources use for?
Longer duration, less intense activities
What does the FITT formula stand for?
F= Frequency I= intensity T= Time (duration) T= Type (mode of exercise)
How can neuromuscular electrical stimulation (NMES) assist in the rehab program?
When the client is unable to voluntarily elicit strong muscle contractions
What has NMES been shown to improve?
Accelerated functional recovery after surgery
Prevent atrophy from disuse
Reduce ROM deficits
Improve motor control
Which type of muscle fibers does NMES recruit? Why
It strengthens type 2 fibers because it recruits motor units w/ type 2 fibers before type 1
This happens b/c the axons of type 2 fiber motor units are larger, more superficial, and offer lower resistance to e-stim
Believed to accelerate strengthening and shorten rehab time
When is NMES most effective?
When used in conjunction w/ voluntary muscle contractions
During the first 4 to 6 weeks of training, what is responsible for the initial strength increases?
Neural adaptation (learning and improved coordination)
What causes increases in strength following the initial 4 to 6 week introductory period?
Hypertrophy
Training that focuses more on strength and power uses more _______. Thus increasing __________.
Anaerobic metabolism
Anaerobic capacity
Also increases size of muscle fiber
What adaptations are expected from an endurance training protocol?
Improved aerobic capacity and efficiency
Selective hypertrophy of type 1 muscle fibers
What are overall benefits of a strength training routine?
Improved neuromuscular efficiency
Increase bone strength and density
Increased ligament and tendon strength and thickness
Improved balance and decreased the risk of falling
Increased gait stability and efficiency
Improved stair climbing and chair raising ability
Decreased resting BP, glucose tolerance, and insulin resistance
Decreased body fat and increased basal metabolic rate
What are the advantages of isometric strengthening?
Can be used early in rehab b/c there is no joint movement
Helps decrease swelling, and stops atrophy while increasing static muscular strength
Prevents neural dissociation
No special equipment needed and short periods of training time
Joint angle specific strengthening
20 degree strengthening overflow throughout ROM
What are the disadvantages of isometric strengthening?
Strengthening is limited to specific joint angles
Limited to no improvement in dynamic muscular performance
No eccentric work
Blood pressure concerns w/ valsalva maneuver
Patient motivation is likely to be less
Less proprioceptive & kinesthetc training
No contribution to muscular endurance
Can create an ischemic response in muscle
How can the valsalva maneuver affect an individual during muscle contractions?
Increases intraabdominal and intrathoracic pressure > decreased venous return to the heart > decrease cardiac output > temporary drop in arterial pressure & increased HR
This causes problems in high risk patients w/ hx of cardiovascular diseases, CVA and the elderly or recent abdominal surgery or abdominal wall injury
What is DOMS?
Delayed onset muscle soreness that occurs after vigorous or unaccustomed exercise
How does DOMS present?
Temporary stiffness and tenderness occurring approximately 12 to 24 hours after completion of exercise.
Clearly linked to exercise involving eccentric activity
At what increments does the ACSM recommend changes in total training volume?
2.5 to 5% per session
What types of movements should be avoided in patients w/ osteoporosis? What should be emphasized?
Avoid- High resistance, explosive, or twisting movements
Emphasize- endurance and low intensity strength training
What are two progression of exercise to optimize muscle performance?
The DeLorme technique and the Daily Adjustable Progressive Resistance Exercise (DAPRE)
Explain the DeLorme technique?
Based on your 10 rep max 3 sets of 10 1st set 50% of 10RM 2nd set 75% of 10RM 3rd set 100% 10RM
Explain the DAPRE technique?
Based on your 6 rep max
1st set 10 reps at 50% of 6RM
2nd set 6 reps at 75% of 6RM
3rd set as many reps as possible w/ working weight
4th set is determined by the # of reps completed in set 3.
What does the FITT formula mean?
A systemic method of prescribing exercise according to its frequency, intensity, time, and type to improve muscle performance.
What is the sheath that surrounds each muscle fiber?
endomysium
What is a system of progressively graded exercise?
Medical exercise training/ therapy (MET)
What is the dense connective tissue sheath covering the muscle fascicles?
perimysium
What is a sarcomere?
a segment of a myfibril that represents the functional unit of striated muscle
Name the complex of muscle proteins that binds to calcium to allow muscle contraction?
Troponin
What is tropomyosin?
a muscle protein that inhibits contraction unless its position is modified by troponin so that the myosin molecules can make contact w/ the actin molecules
What is the thin protein of a myofibril that acts w/ myosin to produce muscle contraction and relaxation?
Actin
What is a thick protein in the myofibril that acts w/ actin to produce muscle contraction and relaxation?
Myosin
What is the smallest complete contractile system?
Myofiber
Which type of muscle fiber fatigue rapidly?
Type 2 fibers
At what age is strength potential at its highest?
18 to 30 years
