Strength- PT 714
effects of concentric and eccentric exercise and the rationale for choosing which to incorporate into an exercise routine
-Greater external loads can be controlled with eccentric exercise. -gains in muscle strength and mass are greater with maximum-effort eccentric training -Adaptations associated with eccentric training are more mode and velocity specific -Eccentric muscle contractions are more efficient metabolically and generate less fatigue -Following unaccustomed, high-intensity eccentric exercise, there is greater incidence and severity of delayed-onset muscle soreness
isokinetic machines advantages
-If the patient puts forth a maximum effort, isokinetic equipment provides maximum resistance through the entire ROM. -Both high- and low-velocity training can be done -accommodates for a painful arc of motion. -As a patient fatigues, exercise can still continue. -Isolated strengthening of muscle groups is possible -External stabilization keeps alignment of patient -Concentric and eccentric contractions of the same muscle group can be performed repeatedly -reciprocal exercise of opposite muscle groups can be performed, minimizes muscle ischemia. -Computer-based visual or auditory cues provide feedback
precautions for resistance training
-Keep the temperature of the exercise setting comfortable -clothing for that facilitates heat dissipation and sweat evaporation. -Do not initiate resistance training at a maximal level -Avoid use of heavy resistance during exercise for children, older adults, and patients with osteoporosis. -Do not apply resistance across an unstable joint or distal to a fracture site -Have the patient avoid breath-holding; emphasize exhalation during exertion. -Avoid uncontrolled, ballistic movements. -Prevent incorrect or substitute motions by adequate stabilization -Avoid exercises that place excessive, unintended secondary stress on the back. -Be aware of medications -Avoid cumulative fatigue due to excessive frequency of exercise -Incorporate adequate rest intervals -pain, dizziness, or unusual or precipitous shortness of breath with exercise
mode: periodization: integration of exercise into functional activities:
-Mode: the type of muscle contraction, type of resistance, arc of movement used, and primary energy system utilized during exercise -Periodization: the variation of intensity and volume during specific periods of resistance training -Integration of exercises into functional activities: exercises that approximate or replicate functional demands
Young and Middle Adulthood muscle changes
-Muscle mass peaks in women between 16 and 20 years of age; muscle mass in men peaks between 18 and 25 years of age. -Muscle mass= 40% of total body weight during early adulthood, (men have slightly more) -Muscle continues to develop into the second decade, especially in men. -Muscle strength and endurance reach a peak during the second decade, earlier for women than men. -Decreases in muscle mass begin to occur as early as 25 years of age. -Starting in the third decade, strength declines between 8% and 10% per decade through the fifth or sixth decade.
signs and symptoms of overtraining, overwork, and exercise‐induced muscle soreness
-Muscle soreness and aching beginning 12 to 24 hours after exercise, peaking at 48 to 72 hours, and subsiding 2 to 3 days later -Tenderness with palpation -Increased soreness with passive lengthening or active contraction -Local edema and warmth -Muscle stiffness -Decreased ROM -Decreased muscle strength prior to onset of muscle soreness that persists for up to 1 to 2 weeks after soreness has remitted
open chain: closed chain:
-Open-chain: involve motions in which the distal segment (hand or foot) is free to move in space, without necessarily causing simultaneous motions at adjacent joints; Limb movement only occurs distal to the moving joint -Closed-chain: involves motions in which the body or proximal segments move on a distal segment that is fixed or stabilized on a support surface; weight bearing
isokinetic exercise
form of dynamic exercise in which the velocity of the joint angular velocity is predetermined and held constant by a rate-limiting device known as an isokinetic dynamometer
isometric exercise
static form of exercise in which a muscle contracts and produces force without an appreciable change in the length of the muscle and without visible joint motion
muscle fatigue
the diminished response of a muscle to a repeated stimulus, gradual decline in the force-producing capacity of the neuromuscular system, a temporary decline in muscle strength
Infancy, Early Childhood, and Preadolescence changes in muscle structure
-At birth, muscle accounts for about 25% of body weight. -Total number of muscle fibers is established prior to birth or early in infancy. -changes in distribution of type I and type II fibers are relatively complete by the end of the first year -Muscle fiber size, muscle mass, muscle strength, and muscle endurance increase linearly from infancy to puberty. -Muscle mass and strength are approximately 10% greater in boys than girls -Training-induced strength gains occur equally in both sexes during childhood without evidence of hypertrophy until puberty.
Free weight and pulley disadvantages
-Dumbbells and barbells that allow adjustable resistance through interchangeable plates require patient or personnel time for proper assembly. -Bilateral lifting exercises with barbell weights often require the assistance of a spotter
exercise order: frequency: rest interval: duration: velocity:
-Exercise order: the sequence in which muscle groups are exercised during a session -Frequency: the number of exercise sessions per day or per week -Rest interval: the time allotted for recuperation between exercise sets and sessions -Duration: total time committed to a resistance training program -Velocity: the rate at which each exercise is performed
physiological adaptation of muscle to endurance exercise
-Minimal or no muscle fiber hypertrophy -↑ in capillary bed density -↑ in mitochondrial density and volume (↑ number and size)
physiological adaptation of muscle to strength exercise
-Muscle fibers hypertrophy: greatest in type IIB fibers -Possible hyperplasia of muscle fibers -Fiber type composition: remodeling of type IIB to type IIA; no change in type I to type II distribution (i.e., no conversion) -↓ or no change in capillary bed density: -↓ in mitochondrial density and volume
late adulthood muscle changes
-Muscle strength declines at a rate of 15% to 20% per decade during the sixth and seventh decades and declines at a rate of 30% per decade thereafter. -By the eighth decade, skeletal muscle mass will have decreased by 50% -Muscle fiber size, type I and type II fiber quantity, and the number of alpha motoneurons all decrease. -atrophy of type II muscle fibers occurs. -Muscle contraction speed, force production, and peak power production both decrease. -Endurance and maximum oxygen uptake gradually but progressively decrease. -Performance of functional skills begins to decline during the sixth decade. -Significant deterioration in functional abilities by the eighth decade is associated with a decline in muscular endurance.
adolescence muscle changes
-Rapid acceleration in muscle fiber size, and muscle mass, especially in boys. -During puberty, muscle mass increases more than 30% per year. -Rapid increase in muscle strength in both sexes. -strength levels develops between boys and girls. -In boys, muscle mass and body height and weight peak before muscle strength peaks -in girls, strength peaks before body weight peaks. -significantly greater muscle hypertrophy in boys
dynamic exercise against constant external resistance and variable resistance
-a limb moves through a ROM against a constant external load, provided by free weights such as a handheld or cuff weight, weight machines, or weight-pulley systems -addresses the primary limitation of dynamic exercise against a constant external load
alignment: stabilization: intensity: volume:
-alignment of body segments during each unique exercise -Stabilization of proximal or distal joints to prevent substitute motions -Intensity: the exercise load or level of resistance -Volume: the total number of repetitions and sets in an exercise session
indications for the use of proprioceptive neuromuscular facilitation (PNF) as an exercise technique for the extremities
-combines functionally based diagonal patterns of movement with techniques of neuromuscular facilitation to improve neuromuscular control and function -used to develop strength and endurance, to facilitate stability, mobility, neuromuscular control and coordinated movements, and lay a foundation for the restoration of function
overtraining
-decline in performance by healthy individuals participating in high intensity, strength and endurance training -individual progressively fatigues more quickly and requires more time to recover from strenuous exercise -due to inadequate fluid intake, rest periods, and rapid progression of exercises
Variable resistance machines disadvantages
-disadvantage of weight machines is the initial expense and ongoing maintenance costs. -Multiple machines required to target many muscles and takes up a lot of space in facility
free weights and pulley advantages
-good for home exercise programs -Exercises can be performed in many positions -typically used for dynamic, nonweight-bearing exercises but also can be set up for isometric exercise and resisted weight-bearing activities. -Stabilizing muscle groups are recruited; however, because there is no external source of stabilization and movements must be controlled entirely by the patient -Many movement patterns are possible -resistance can be increased by very small increments -performed slowly to minimize acceleration and momentum and prevent uncontrolled, end-range movements that could compromise patient safety (slow movements during strengthening activities has less carryover to ADLs)
possible causes and impact of overtraining, overwork, and exercise‐induced muscle soreness on muscle performance
-heavy resistance and exhaustive training is performed repeatedly, and strenuous exercise -inadequate rest periods, inadequate fluid intake, or too rapid progression of exercise -can be due to inadequate blood flow and oxygen and can cause a build-up of lactic acid -decreases in muscle strength and performance are the results
DOMS (delayed onset muscle soreness)
-high-intensity eccentric muscle contractions consistently cause the most severe DOMS symptoms -current research seems to suggest that DOMS is linked to some form of contraction-induced, mechanical disruption or microtrauma of muscle fibers and/or connective tissue in and around muscle that results in tissue degeneration. - Evidence of tissue damage such as elevated blood serum levels of creatine kinase is present for several days after exercise and is accompanied by inflammation and edema.
contraindications for resistance training
-joint or muscle pain -inflammatory neuromuscular disease -dynamic resistance is contraindicated in the presence of acute inflammation of a joint -severe cardiac or respiratory diseases
isokinetic machine disadvantages
-large and expensive to purchase and maintain. -Setup time and assistance from personnel are necessary -Most units allow only open-chain movement patterns -most exercises are performed in a single plane and at a constant velocity. -range of concentric training velocities is comparable to some lower extremity limb speeds during functional activities, even the upper limits of this range of velocities cannot begin to approximate the rapid limb speeds that are necessary during many sports-related motions -the eccentric velocities available only begin to approach medium-range speeds
recover from exercise
-muscle returns to 90-95% of pre-exercise capacity in 3-4 min -lactic acid and blood removed from muscle in an hour -oxygen and energy restored fast -glycogen stores repleted over several days
elastic resistance disadvantages
-need to refer to a table of figures for quantitative information about the level of resistance for each color-coded grade of material. -no source of stabilization or control of extraneous movements -should be replaced on a routine basis to ensure patient safety -Some elastic products contain latex. However, there are latex-free products on the market at a relatively comparable cost.
elastic resistance advantages
-portable and relatively inexpensive -extremely versatile, allowing many combinations of limb and trunk movement patterns and patient positions. -safe to exercise at moderate to fast velocities with elastic resistance because the patient does not have to overcome the inertia of a rapidly moving weight. -good substitute for weight machines and free weights
power: endurance:
-power: related to the strength and speed of movement and is defined as work (force x distance) produced by muscle unit per time (force x distance/time); rate of performing work -endurance: refers to the ability to perform repetitive or sustained activities over a prolonged period of time
variable resistance machines advantages
-resistance is adjusted in an attempt to match a muscle's torque-generating capabilities throughout the ROM. -designed to isolate and exercise specific muscle groups. -most machines allow only single-plane movements, some newer units now allowing multiplanar motions -adjustable to allow individuals of varying heights to perform each exercise -provides substantial external stabilization to guide or limit movements.
strength: functional strength:
-strength: the extent that the contractile elements of muscle produce force -functional strength: the ability of the neuromuscular system to produce the appropriate amount of force during functional activities in a smooth and coordinated manner
Reciprocal Exercise Equipment
-strengthen multiple muscle groups across multiple joints -appropriate for low-intensity, high-repetition resistance training to improve muscular endurance, reciprocal coordination of the upper or lower extremities, and cardiopulmonary fitness -often used for warm-up or cool-down exercises
specificity
-the adaptive effects of training are highly specific to the training method employed -they should mimic the anticipated function along with the type and velocity of exercise, the joint position, and movement patterns used (part of the SAID principle)
transfer of training: reversibility: overload:
-transfer of training: carryover of training effects from one variation of exercise task to another; can transfer to a non-exercised contralateral limb (part of SAID principle) -reversibility: reductions in muscle performance can begin 1-2 weeks after detraining -overload: for muscle performance to improve a resistance load that exceeds the metabolic capacity of the muscle must be performed
physiological adaptation of connective tissue to strength exercise
-↑ tensile strength of tendons, ligaments, and connective tissue in muscle -↑ bone mineral density; no change or possible ↑ in bone mass
physiological adaptation of connective tissue to endurance exercise
-↑ tensile strength of tendons, ligaments, and connective tissue in muscle -↑ in bone mineralization with land-based, weight-bearing activities
