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PT 670 App. Ms. Phys

What are the purposes of muscle contractions? 1. Maintain and sustain low-level stability 2. develop force through the range for controlled movement 3. provide dexterous skilled movement
Name the three types of contractions of muscles. 1. isometric 2. concentric 3. eccentric
Name the ultrastructure of muscles? 1. Muscle 2. Fascicle 3. Fibers 4. Myofibril 5. Sarcomere 6. Myoneural junction
Three types of muscle fibers. Type I-large muscles, contr. posture, endurance, and large # of mitoch. Type IIa- large amnts of myoglobin and mitochond., resistant fatigue (not as much as II), (eg. middle distantce running or swimming) Type IIb- fatigue easily, low # mitoch., anaerobic
Importance of the length-tension curve too long or too short decreases the ability of a muscle contraction
What is a motor unit? alpha motor neuron and all the fibers it innervates
What in the CNS controls motor function? 1. motor cortex 2. basal ganglia 3. cerebellum 4. spinal cord (interneurons)
What in the PNS is responsible for motor function? 1. peripheral nerves 2. Muscle spindle (in the muscle) sensitive to stretch 3. GTO (loc. in tendon) sensitive to load; reflex inhibition against agonist
Describe the physiological properties of muscle. 1,Twitch or contrxn in response to a single electrical impulse (action potential) travels down the motor neuron 2. In a twitch response, the muscle generates peak force that drops off rapidly and returns to resting 2. twitch resp. depends on fiber type
Define All or none 1. Either the muscle stimulus is strong enough to generate a contraction or not 2. All muscle fibers are stimulated to contract
Define tetany. If AP are sequenced close enough, the tension generated by one muscle twitch will be summed with others to form a constant tension in the muscle fiber
What is fatigue depenedent on? what fibers fatigue easy? not so easy? depends on energy sources, Type IIB easy fatigue, Type I or IIa slow fatigue
Characteristic of motor units 1, each muscle is heterogenous 2. percent of fiber type is strongly genetic
Vastus lateralis, rectus femoris, deltoid and the gastrocnemius exhibit similarities among individuals (what percentage of FG or SO?) 50% of both
Percentage of SO and FG in the soleus? 80%
What determines force/tension? determined by the recruitment of motor units and the freq. of their discharge
What is the prime determinant for force production? fiber recruitment
Recruitment is based on what order? small to large, slow to fast, fatigue resistant to fatiguable
Low intensity recruits what fibers? less than 40A%, recruits SO
Fiber recruitment for graded exercise SO, FOG, FG
fiber recruitment for ballistic activity/high intensity FG
what is the order of derecruitment? reverse order
What are some causes of decreased muscle performance? Immobilization, myofascial trigger point, muscle imbalance, joint dysfunction, lesions of specific structures, motor unit recruitment problems, and age related changes
What changes occur due to immobilization? CT changes, decreased activity of muscles
What kinds of muscle imbalance can occur? strength, antagonist or agonist, atrophy leads to disuse
What are types of joint dysfunction? joint play, defect in articular cartilage, change in biomechanics of the joint, scapulohumeral rhythm
What are some areas of injury in the brain CVA, TBI, Degenerative diseases, infections, chemical exposure
What are some injuries of the spinal cord? SCI, Polio
What results in muscles that are weak or hypotonic? Trauma, compression, motor end-plate disorders (myasthenia gravis), and Inflammation (Guillain Barre)
What are some metabolic abnormalities? McArdles Disease )energy source problem, prob. with glycogen stores) Malnutrition Disuse (muscle fiber atrophy)
Describe the process of muscle fiber atrophy? fast with immobilization, decreased ability to produce tension due to changes in the cross bridges of actin and myosin, and decreased ability to synthesize protein
What are some vascular problems that could cause a decrease in muscle performance? Diabetes, PVD, and Global CV issues
What may cause fatigue? problems with decreased in energy stores, acidosis (electrolyte imbalance, and CNS
What happens with aging 1, fiber atrophy most pronounced in type II 2. loss of sarcomeres from fibers therfore decrease in length 3. change s in CT 4. decrease in motor end plate area 5. decrease energy sources 6. loss of neurons
What happens to the motor unti inervation ratio with age after 60, as well as motor unit numbers greater loss in neurons as opposed to fibers, and increasing need to recruit more
How can injury cause decreased muscle performance? inflammation, structural changes to the muscular component, and CT
What muscle performance impairments can be seen? strength and stability
What impairments of the myofascia can be noted? CT and muscle structure
What is evidence of muscle length impairment decreased PROM caused by decrease in muscle length
What neuromuscular changes can be seen? change in tone
If muscle performance is impaired, and particularly strength what would the intervention focus on? History, results of the exam, and required function of the muscle
What are considerations for increased force development, especially resistance technique and goals? Healing status, present status of muscle, pain, goal (stability vs. strength)
What is the difference in training strength vs. stability strength- all contractions, including isokinetics stability- isometrics and use of neurophysiological facilitation techniques
What is SAID principle for resistive training? consider individual muscles and what they will be used for, specific adaptation to imposed demands, a muscle needs to train in the fashion that it will be used, open or closed chain
What is the specificity principle of resistive training? training must be specific to activities
What is the overload principle? A muscle must be overloaded to a particular threshold before it will respond and adapt to training It needs to exert more force that it does during usual activities
What is the intensity needed for an overload? 60-80% of a muscle's force; the more deconditioned a muscle, the lower the need for starting intensity
Ways of measuring strength cable tensiometer- duting static or isometric cotnraction dynamometer- hand held and isokintetic repetition max- 1RM, 5RM, 10 RM manual muscle testing
What interventions are used for Muscle stability? Sustained isometric contractions of low force in a shortened range for increasing periods of time Recruit primarily slow twitch
What type of intervention used for postural stability? Coordinated isometric contractions Technique performed at the joint position that best mimics functional use of the joint Alternating isometrics (AI) Rhythmic stabilization (RS)
What do neurophysiologic techniques facilitate? muscle contraction response
Types of neurophysiological techniques Quick stretch Tapping over muscle belly Jiont approximation synergistic movement patterns exteroceptive stimulation
What does joint approximation do? 1. activates joint and muscle mechanoreceptors 2. facilitates postural extensors 3. force can be applied manually or with a weight belt 4. Patient is usually WB ( eg. pt bounce on swiss ball)
Why does synergistic movement patterns work? principle of overflow from stroneger segment to weaker segment
example of synergistic movement patterns D1 flexion; D1 extension ADD and stretch overhead and return D2 flexion; D2 extension; arms crossed in front reach up touchdown and return
describe exteroceptive stimulation Light touch: provokes phasic withdrawal, incr arousal, and withdrawal from stimulat. (light stoking, light pinching or squeezing, swipe w/ ice cube) Man. contact: activat tactile receptors and proprioceptors
 (response contraction of mscle under the hand
what are the components of a strengthening program? Goal Warm-up Mode of Resistance (patient pos; open or closed) Intensity Duration: #reps/sets Frequency Cool down
What are different modes of resistance? Gravity Bodyweight Mechanical Water
What are the types of mechanical resistance? elastic bands/theraband free weights resistance machines
What are different types of intensity? Manual- graded by therapist Weights-
What are the concept behind weights when used for intensity? Concept of RM: 1 RM, 5RM, 10 RM and use of various %; in rehab commonly use % of 10RM; Rate of perceived exertion (RPE): patient exercises to a certain % of max based upon subjective feeling
How is trial and error used when choosing intensity? In rehab, often use “trial and error” in choosing an initial weight, and then adjust according to the patient’s RPE and success of movement Trial and error should still be based on some objective data
What is the duration for endurance vs. strength/hypertrophy? Endurance (15+ reps to fatigue) Strength/hypertrophy (6-12 reps)
What rest periods are considered for endurance, heavy strength, or rehab? Endurance: 30 seconds-2 minutes Heavy strength: 3-5 minutes Rehab: 30 seconds-2 minutes
What is the frequency considered for an exercise prescription? Weekly Depending on intensity: generally 3-4x per week In early rehabilitation, isometrics may be done 2-3x/day
What are some types of resistance programs? Static- one position Dynamic - move in different position Variable resistance through the range where max resistance is at its strongest point Calisthenics
How is a static program used for stability vs. strength? Low intensity for stability (e.g. 40% for > 10 seconds) Higher intensity for strength
Wha is the primary goal of static program? Primarily enhances strength at the angle in which the muscle is stressed, physiologic overflow can occur 10 deg. in either direction (total of 20 deg) Maintain contractn for 3-10 seconds when used for strengthening; longer for stability Daily training OK
What is a dyanmic program used for? weight training
Define progressive resistive exercise? DeLorme (mid 1940s) First set: 50% of 10 RM x 10 repeats Second set: 75% of 10 RM x 10 repeats Third set: 100% of 10 RM x 10 repeats
Describe other exercise programs: single set, multiple set Singlet: one set per exercise with 8-12 rep to max Multiple: 2-3 warm up sets with increasing resistance followed by 2-5 sets of 5-6 RM; this syst may yield optimal results for strength increases
Describe a pyramid system Pyramid system: continuous sets of exercises progressing from light to heavy while decreasing the number of reps
Describe variable resistance program Dynamic accommodating exercise goal is to load the muscle near maximum at each point in the range. e.g. Nautilus, however this has not been shown to be any more effective than PRE
Describe calisthenics Body weight used for resistance initially; supplemental weights may be used Upper body: push ups, pull ups Abdominals: abdominal curls, leg lifts Lower body: calf raises, squats, lunges, leg lifts
How does one train for power Speed training (bikes, treadmill, swimming) Explosive/power weight lifting techn Isokinetics: the velocity of the movement is set and any force applied vs. the equip results in an equal rxn force (machine controlled velocity, pt give variable resistance
What are plyometrics? Described by Wilt in 1975 Had been an Eastern European training technique known as “jump training” Develops explosive strength and power: quick eccentric stretch followed by a powerful concentric contraction (trampoline, rebounder, jumping medicine ball)
Precautions for exercise Valsalva Unsafe exercise posture,(fatigue) Substitute motions, particularly with fatigue Inadequate rest during exercise session Inadequate rest between session Equipment safety Patient: signs of overexertion, symptoms of intolerance Pain Swelling
What is Delayed onset muscle soreness? Generally dev. 12-24 hours after the completion of the exercise most pronounced symptoms on day 2 usually symptom free at 4-6 days common after eccentric exercise Tenderness to palpation throughout the involved muscle belly or at the myotendonous junction
Metabolic waste theory Multiple studies have shown that about 1 hour of recovery after exercise to exhaustion is needed to remove all lactic acid (Francis, 1983)
Muscle spasm theory Suggests that a feedback cycle of pain caused by ischemia and a buildup of metabolic waste products during exercise leads to spasm. It was hypothesized that in turn this caused the DOMS sensation and an ongoing pain spasm cycle (Devries, 1966).
Etiology of DOMS Current research suggests that DOMS is linked to some form of contraction induced microtrauma to muscle fibers and/or connective tissues resulting in some degeneration of tissue
Describe the damage tomuscles that last for several days The damage which is evident for several days after exercise is accompanied by inflammation (Abraham, 1977) Myofibular damage at the Z bands This effects the structural integrity of the contractile units
Immobilization can cause _____________. atrophy
What factors influence the rate of atrohpy Position of limb and length of muscle during immobilization (lengthened muscle will atrophy less than shortened) Muscles with high % of ST atrophy to a greater extent than those with high % of FT Antigravity muscles greater than their antagonists
What muscle are the most vulnerable to atrophy? Antigravity muscles that cross a single joint and contain large % of ST (e.g. soleus, multifidus, vastus medialis) Antigravity; multi joint; primarily ST (e.g. erector spinae, gastrocnemius, rectus femoris)
What is known about remobilization? Not good data that supports how long it takes to recover following immobilization Muscle detraining may be twice as fast as training
What components must be considered for adaptations to resistance training? Connective tissue Muscle Biochemical Neural Endocrine
What adaptations are made with CT during resistance training? Tension overload may stimulate a prolif of CT that surround the indiv muscle fibers, fascicles This thickens and strengthens the muscles’ connective tissue harness; and results in improved structural and functional integrity of both tendons and ligaments
What happens to muscle during resistance training? Hypertrophy (esp. Type II) Cross sectional area of the muscle increases Increase in myofibril volume of individual fibers Fiber splitting Potentially, an increase in number of fibers Changes in muscle depend on fiber type and the type of stimulus
What are the biochemical changes with resistance training? Increase in glycolytic enzymes (myokinase, creatine, creatine phosphokinase)
What are the neural changes with resistance training? Neural changes most obvious in the first 2-8 weeks of resistance training A more efficient activation of motor units Increased inhibition of antagonistic muscle and improved cocontraction of synergistic
What endocrine changes occur during resistance training? Heavy resistance training has been shown to increase the ability of an athlete to secrete greater amounts of epi during max exercise physiologic
What are the functions of epi and norepi in muscle? Increased force production Increased muscle contraction rate Increases energy availability Augments secretion of other hormones such as testosterone
Tyoes of equipment Biomechanical ankle platform system (BAPS) Fitter Kinetron/Biodex (isokinetic) Lateral slide board stair climber stationary bike theraband treadmills UE ergometer Univ. weight training X-c ski stimulator
Created by: 696592119