PTH 226: Ch 6 Resistance Ex for Impaired Muscle Performance
Fast-twitch (FT) fibers Type IIa
•Fast contraction speed •Fatigue resistance •Characteristics can be influenced by type of training •Type IIa muscles: strength and movement (gastrocnemius)
Fast twitch (FT) fibers Type IIb
•Fast contraction speed •High force production •Susceptible to quick fatigue •Type IIb muscles: quick movement (eye muscles)
Slow-twitch (ST) fibers Type I
•Slow contraction speed •Low force (tension) production •Type I muscles: postural muscles (multifidi)
strength
"The greatest amount of force that can be produced within a muscle during a single contraction".
power
"The rate at which work is performed (work/time)."
plyometric training
(stretch-shortening drills), the speed of movement is the variable.
clinical information on fatigue
-A patient's health status, diet, or lifestyle (sedentary or active) all influence fatigue. -In patients with neuromuscular, cardiopulmonary, inflammatory, cancer-related, or psycho-logical disorders, the onset of fatigue is often abnormal. -It is advisable for a therapist to become familiar with the patterns of fatigue associated with different diseases and medications.
length-tension relationship
-A principle that states that the ability of a muscle to produce force depends on the length of the muscle.
High intensity resistance exercises leads to increases in:
-ATP -Creatine kinase -Creatine phosphate
High velocity ISOK exercise can allow for:
-Accommodation of the patient's pain -Reduce compression forces -Improve functional speeds of contraction
resistance exercise
-Any form of active exercise in which dynamic or static muscle contraction is resisted by an outside force. -Can be applied mechanically or manually. -Essential element of rehabilitation programs for persons with impaired function (pathology).
white fibers
-Are larger in diameter than red fibers -Have low myoglobin
Eccentric training is an essential component of rehabilitation programs following musculoskeletal injury or surgery and in conditioning programs to reduce the risk of injury or re-injury.
-Associated with activities that involve high-intensity deceleration, quick changes of direction. -Progressive eccentric training early in the rehabilitation process has been advocated to more effectively reduce deficits in strength and physical performance.
muscle setting contraindications:
-Cardiac or vascular disorders -Holding your breath produces a Valsalva maneuver, which increases the risk for stroke, aneurysm or a cardiac episode.
isokinetic exercise characteristics
-Constant velocity which allows the muscle to exert maximum tension throughout the ROM. -The amount of resistance encountered is directly proportional to the force exerted by the muscle being exercised (what you put in is what it resists). -If your patient fatigues: -The patient is still able to perform additional reps and move through the entire ROM (because of the decreased resistance). -Also allows your patient to push less through a painful arc.
cardiopulmonary fatigue factors:
-Decrease in blood sugar (glucose) levels. -Decrease in glycogen stores in muscle and liver. -Depletion of potassium, especially in the elderly patient.
multi-angle iso intensity:
-Depends on joint position and muscle length (at time of contraction). -60% of muscle maximum contraction to increase strength.
exercise intensity
-Determined by the amount of weight that is being used which will determine how many repetitions of the exercise can be performed. The amount of weight used is expressed as a percentage of the patient's 1RM
SAID factors to consider:
-Endurance VS strength -Type and velocity of exercise. -Isometric, concentric or eccentric -Position of the body or body parts.
frequency is dependent on intensity and volume of exercise and the fitness level of the individual.
-For intense exercise - 2-3 time per week. -Rehabilitation programs - several times per day (if intensity and volume is kept low). -Exercises performed too frequently may lead to overtraining and a decline in patient's condition or performance.
eccentric characteristics
-Greater loads can be controlled with eccentric. -Training-induced gains in muscle strength and mass are greater with maximum-effort eccentric training. -Eccentric muscle contractions are more efficient metabolically and generate less fatigue. -Following unaccustomed, high-intensity eccentric exercise, there is greater incidence and severity delayed-onset muscle soreness (DOMS) than after concentric exercise.
The total number of repetitions is inversely related to intensity.
-Heavy weight = fewer reps (as in training to increase power or strength). -2-4 sets of repetitions is common exercise prescription.
strength training parameters:
-High resistance, low repetition exercises -Occurs through neural adaptations and increase muscle fiber size.
sources of resistance for isometric ex:
-Holding against a force applied manually. -Holding a weight in a particular position. -Maintaining a position against the resistance of body weight. -Pushing or pulling an immovable object.
multi-angle isometrics
-Isometric exercise which resistance is applied at multiple joint positions within the available ROM. -This approach is used when the goal of exercise is to improve strength throughout the ROM when joint motion is permissible but dynamic resistance exercise is painful or inadvisable.
When several muscle groups are exercised in a single session:
-Large muscle groups should be exercised before small muscle groups. -Multi-joint exercises should be performed before single-joint exercises. -After an appropriate warm-up, higher intensity exercises should be performed before lower intensity exercises.
stimulate type 1 fibers:
-Low intensity, long duration exercises are appropriate. -Stationary bicycle -Upper body ergometer (UBE)
muscle setting:
-Low-intensity isometric contractions performed against little to no resistance. -Quad Sets, Glut Sets -Used to decrease muscle pain and spasm and promote relaxation and circulation after injury to soft tissues during the acute stage of healing.
muscle fatigue
-Most relevant to resistance exercise. -This occurs when a muscle repeatedly contracts statically or dynamically against an imposed load.
An individual muscle's potential to gain strength and power is determined by:
-Muscle fiber length -Mass of the muscle -Angle of attachment of the muscle to the tendon
isokinetic exercise
-Muscular contraction is generated with a constant maximal speed and variable load. -The reaction force is identical to the force applied to the machine.
isotonic ex
-Muscular contraction is generated with the muscle exerting a constant tension. -Muscle movement with a constant load. -Performed against resistance, using equipment (hand-held weights).
The foundations of all clinically applied strength programs involve the following principles:
-Overload -Specificity -Reversibility
Precautions for endurance/progression of overload must always be applied in the context of the underlying:
-Pathology -Age -Stage of tissue healing -Fatigue -Abilities and goals of the pt
recovery and age:
-Recovery times generally take 3-4 minutes after acute exercise. -Light exercise during recovery period, as opposed to total rest, actually results in faster recovery. -Age is a factor in a muscle's ability to produce tension. -Elderly patients who maintain a fairly active life-style experience fewer declines in muscle performance.
red fibers
-Slow twitch -Type I fibers -Oxidative
positive change in response to strength:
-Strength -Bone mass -Body composition (fat to lean) -Weight control (decreased risk of Diabetes) -Reaction time -Metabolism -Cardiovascular (BP) -Immune system function -Balance and coordination -Gait and functional mobility -ADLs -Job/recreational/athletic performance -Sense of well-being, posture, and self-image
isometric exercise
-Submaximal exercises are traditionally used in rehabilitation programs. -No visible joint motion. -A measurable amount of tension (force) output are produced by the muscle.
isokinetic velocity
-The angular velocity of the human knee during normal walking is approximately 240º per second. -high V = less R
threshold fatigue
-The level of exercise that cannot be sustained indefinitely. -This sets a baseline from which adaptive changes in physical performance can be measured.
rational for use of iso ex:
-The need for static strength and endurance in all aspects of control of the body during functional activities. -Loss of static muscle strength occurs rapidly with immobilization and disuse, with estimates from 8% per week to as much as 5% per day. -Functional demands often involve the need to hold a position against either a high level of resistance for a short period of time or a low level of resistance over a prolonged period of time.
typical velocity spectrum rehab (VSR) protocol:
-The patient performs one or two sets of 8 to 10 or as many as 20 repetitions of agonist/antagonist muscle groups (reciprocal training) at multiple velocities. -For example, at medium velocities (between 90˚ and 180˚/sec) training could occur at 90˚, 120˚, 150˚, and 180˚ per second. -A second series would then be performed at decreasing velocities—180˚, 150˚, 120˚, and 90˚ per second.
rest interval
-The recovery period between sets will vary depending on intensity. *Higher intensity - longer rest intervals (3 or more minutes). *Low intensity - shorter rest interval (1-2 minutes). **All depends of patient's condition level*
Transfer of Training Principle
-There can be a carry-over effect from one exercise or task to another. -Ex: a patient who performs exercises to improve muscular strength may also see improvements in muscular endurance.
cardiopulmonary (general) fatigue:
-This type of fatigue is the diminished response of an individual (the entire body) as the result of prolonged physical activity. -It is related to the body's ability to use oxygen efficiently.
isokinetic velocity spectrum rehab (VSR)
-To deal with the problem of limited physiological overflow of training effects (by-pass pain arc) from one training velocity to another, a regimen called velocity spectrum rehabilitation (VSR) has been advocated. uWith this system of training, exercises are performed across a range of velocities. -Selection of training velocities -Typically, medium (60˚ or 90˚ to 180˚/sec) and fast (180˚ to 360˚/sec) angular velocities are selected.
stabilization ex:
-To develop a submaximal but sustained level of co-contraction to improve postural stability or dynamic stability. -Include rhythmic stabilization (alternating contractions of PNF). -Stabilization exercises that focus on trunk/postural control are referred to as dynamic, core, and segmental stabilization exercises. -Equipment, such as the BodyBlade and stability balls are designed for dynamic stabilization exercises.
near max or max loading at high intensities is indicated:
-To increase muscle strength, power and/or size -In later stages of rehab for otherwise healthy patients, to prepare for return to normal, high-demand activities -In conditioning programs, if no other pathology is present -For competitive weight training or body building training
s/s of muscle fatigue
-Uncomfortable sensation in the muscle (pain and cramping). -Tremulousness in the contracting muscle. -Unintentional slowing of movement. -Jerky, not smooth movements. -Inability to complete the movement pattern through the full ROM. -Substitute motions
1 RM precautions
-Use of a 1-RM as a baseline measurement is inappropriate for some patient populations because it requires one maximum effort. -It is not safe for patients with joint impairments, patients who are recovering from or who are at risk for soft tissue injury, or patients with known or at risk for osteoporosis or cardiovascular pathology.
Specific Adaptation to Imposed Demands:
-Whenever possible, exercises in a training program should mimic the functional goal. -The body will adapt according to the specific type of training that is utilized. -Wolf's law
concentric contractions
-accelerate body segments. -A decrease in peripheral resistance and stroke volume of the atria often occurs with repeated active muscle contractions.
eccentric contractions
-decelerate body segments (sudden changes of direction or momentum). -Eccentric contractions also act as a source of shock absorption during high-impact activities.
submax (mod to low intensity) loading is indicated:
-in early stages of healing -after immobilization, to avoid injury to cartilage -to improve endurance -to warm up or cool down before and after exercise -during slow-velocity isokinetic training to minimize compressive forces on joints
Manual Resistance: Active-Resistive Exercise
-resistance by a therapist. -A patient can be taught how to apply self-resistance. -The amount of resistance cannot be measured quantitatively. -Useful in the early stages of an exercise program when the muscle to be strengthened is weak (only minimal to moderate resistance). -Useful when the ROM needs to be carefully controlled.
muscle performance
-the ability of a muscle to perform work. -A complex component of functional movement which is influenced by all the body systems.
isometric isokinetic velocity
0 deg/sec
strength assessment
1 RM (Maximum amount of weight that can be lifted once)
Two types of isotonic contractions:
1.Concentric (muscle shortens) Concentric contractions → ↑ speed, ↓ tension 2.Eccentric (muscle lengthens) Eccentric contractions → ↑ speed, ↑ tension
2 reasons for determining 1 RM:
1.To document a baseline measurement of the dynamic strength of a muscle (which exercise-induced improvements in strength can be compared). 2.To identify an initial exercise load (amount of weight) to be used during exercise for a specified number of repetitions.
fast isokinetic velocity
180-240 deg/sec
slow isokinetic velocity
30-60 deg/sec
medium isokinetic velocity
60-180 deg/sec
internal stabilization
Achieved by an isometric contraction of an adjacent muscle group that does not enter into the movement pattern but holds the body segment of the proximal attachment of the muscle being strengthened firmly in place.
PTA should remember:
Avoid substitute motions during resistance exercises by applying alignment and stabilizing principles like "MMT", "stretching".
external stabilization
Can be applied manually by the therapist or sometimes by the patient with equipment, such as belts and straps, or by a firm support surface, such as the back of a chair or the surface of a treatment table.
To recover functional use of the knee following injury, the most appropriate selection of muscle contraction types to regain strength is:
ISOM f/b isotonic (concentric and eccentric)
The alignment or position of the patient or the limb with respect to gravity also important during resistance exercises:
If body weight or free weights (dumbbells, barbells, cuff weights) are the source of resistance, the patient or limb should be positioned so the muscle being strengthened acts against the resistance of gravity and the weight.
power training
Many motor skills in our lives are composed of movements that are explosive and involve both strength and speed.
Rule of 6's:
Recommended Duration of Isometrics: -Should be held 6-10 seconds to develop peak tension and prevent cramping . -Resistance at 4-6 points in the ROM is recommended. -Resistance should be applied and released gradually. -Be sure patient does not hold breath during isometrics.
SAID principle
Specific Adaptation to Imposed Demands
Wolf's law
The body systems adapt over time to the stresses placed on them.
frequency
The number of times per week resistance exercises are performed.
force-velocity relationship
The speed of a muscle contraction affects the force that the muscle can produce.
volume
The total amount of worked performed and is calculated as the total number of repetitions multiplied by the intensity of the exercise.
The combination of concentric and eccentric muscle action is evident in countless tasks of daily life:
Walking up/down inclines, ascending/descending stairs, rising from a chair and sitting back down, or picking up or setting down an object.
Muscle fatigue characterized by a gradual decline in the force-producing capacity of the neuromuscular system (exhaustion), leading to a:
decrease in muscle strength
proper alignment is determined by the:
direction of muscle fibers and the line of pull of the muscle to be strengthened.
The average person has a ratio of 50%:
fast to slow twitch motor units
Insufficient strength contributes to:
functional losses
Many older persons experience:
general muscle fatigue or total body fatigue due to depletion of potassium
goal: endurance
higher reps (20+) of a lower intensity load.
remodeling
individual muscle fibers are enlarged to contain more actin and myosin. -Increase in motor unit recruitment and synchronization of firing to facilitate contraction (force production)
A patient's threshold for fatigue could be noted as the:
length of time a contraction is maintained or the number of repetitions of an exercise that initially can be performed
These carryover effects are far _______ beneficial than the adaptations that result from more specific training.
less
If a muscle is lengthened or shortened, it will likely produce:
less force
strength training may be increased by:
lifting, lowering, or controlling heavy loads for a low number of repetitions or over a short period of time.
goal: power
low reps (1-3) of a very high intensity load.
goal: strength
lower reps (6-12) of a higher intensity load.
endurance training
more emphasis is placed on increasing the time or number of repetitions.
It has been suggested that the basis of specificity of training is related to:
morphological and metabolic changes in muscle as well as neural adaptations to the training stimulus associated with motor learning.
strength occurs through neural adaptations and increase in:
muscle fiber size
functional strength relates to the ability of:
neuromuscular system to produce, reduce, or control forces, during functional activities, in a smooth, coordinated manner.
A muscle can usually produce a maximal force near its:
normal resting length
hypertrophy
observed over 6-8 weeks of training
disuse atrophy
occurs when a muscle loses both size and strength.
Physical demands of everyday life (safe and efficient) the body's muscles must be able to:
produce, sustain and regulate muscle tension to meet the demands.
aerobic power
repeated bursts
The patient or a body segment must be positioned so the direction of movement of a limb or segment of the body:
replicates the action of the muscle or muscle groups to be strengthened
anaerobic power
single burst
muscle power is related to the:
strength and speed of movement.
components of muscle performance
strength, endurance, power
During an eccentric contraction, as the speed of contraction increases....
the force of contraction also increases.
During a concentric contraction, as the speed of contraction increases...
the force of contraction decreases.
Repeated bursts with less intensity
the terms anaerobic power and aerobic power, respectively, are sometimes used to differentiate these two aspects of power.