Chapter 6 Flashcards
Muscle performance
capacity of a muscle to do work (force x distance)
Key elements of muscle performance
strength, power, endurance
Resistance training
any form of active exercise in which dynamic or static muscle contraction is resisted by an external force applied manually or mechanically
Examination and Evaluation
- consider underlying pathology, stage of tissue healing, age, overall level of fitness, ability to cooperate and learn
- foundation to determine whether a program of resistance exercise is warranted and can improve current level of function/prevent dysfunction
Muscle strength
broad term that refers to the ability of contractile tissue to produce tension and a resultant force based on the demands placed on the muscle
Muscle power
strength and speed of a movement and is defined as muscle work (force x distance) produced by a muscle per unit of time (force x distance/time); AKA rate
Muscle endurance
ability of a muscle to contract repeatedly against a load, generate and sustain tension, and resist fatigue over an extended period of time
How can the overload principle be applied?
increasing resistance, time under tension, or repetitions
SAID principle is an extension of which law?
Wolff’s law - body systems adapt over time to the stresses placed on them (SAID = specific adaptation to imposed demands)
How quickly does detraining occur?
within 1-2 weeks after the cessation of resistance exercises
Factors that affect tension generated by a muscle:
- cross-section and size of muscle
- muscle architecture - fiber arrangement and length
- fiber-type distribution
- length-tension relationship
- recruitment of motor units
- frequency of firing units
- type of muscle contraction
- speed of muscle contraction (force-velocity relationship)
Factors contributing to muscle (local) fatigue:
- decrease in energy stores
- insufficient oxygen
- reduced sensitivity and availability of intracellular calcium
- build-up of H+
- reduced excitability at the NMJ or inhibitory effects of the CNS
Factors contributing to cardiopulmonary (general) fatigue:
- decrease in blood sugar level
- decrease in glycogen stores in muscle and liver
- depletion of potassium, especially in elderly
Neural adaptations to resistance training include:
- increased recruitment
- increased rate and synchronization of firing
- speculated to be caused by decreased inhibition and decreased sensitivity of the GTO
Determinants of resistance exercise:
- alignment of segments of body during exercise
- stabilization of proximal/distal to prevent substitution
- intensity (level of resistance)
- volume (reps/sets)
- exercise order
- frequency (per day/per week)
- rest interval (between sets/sessions)
- duration
- mode of exercise (type, position, arc of movement, energy system)
- velocity
- periodization or variation of intensity/volume
- integration of exercises into functional activities
When injured muscles are immobilized, type __ muscle fibers atrophy the fastest.
I (slow twitch)
_____ recovery is more effective than _______ recovery for neutralizing the effects of muscle fatigue.
Active; passive
During a maximum effort concentric muscle contraction, as the velocity of the muscle shortening increases, the force the muscle can generate _________.
decreases
This type of exercise stimulates co-contraction of agonists and antagonist.
closed-chain exercises
DeLorme Regimen
Determination of 10 RM:
10 reps @ 50% of the 10 RM
10 reps @ 75% of the 10 RM
10 reps @ 100% of the 10 RM
Oxford Regimen
Determination of 10 RM:
10 reps @ 100% of the 10 RM
10 reps @ 75% of the 10 RM
10 reps @ 50% of the 10 RM
DAPRE (Daily Adjustable Progressive Resistive Exercise)
Sets/Reps/Amount of Resistance: 1/10/50% of 6 RM 2/6/75% 6 RM 3/Max possible/100% of 6 RM 4/Max possible/100% adjusted working weight*
Functional Strength
ability of the neuromuscular system to produce, reduce, or control forces, contemplated or imposed, during functional activities in a smooth, coordinated manner
The most common adaptation to heavy resistance exercise?
increase in the maximum force-producing capacity of muscle (increase in muscle strength)
What two factors are primarily responsible for increase in muscle strength?
neural adaptations and increase in muscle fiber size
Specificity of training should be considered with respect to:
- mode (type)
- velocity
- patient or limb position (joint angle)
Cross-training effect can occur from an exercised limb to a non-exercised, contralateral limb in a resistance training program. (T/F)
True
Characteristics of Type I muscle fiber:
- high resistance to fatigue
- high capillary density
- aerobic energy system
- small diameter
- slow twitch
- slow max muscle-shortening velocity
Characteristics of Type IIA muscle fiber:
- intermediate resistance to fatigue
- high capillary density
- aerobic energy system
- intermediate diameter
- fast twitch
- fast max muscle-shortening velocity
Characteristics of Type IIB muscle fiber:
- low resistance to fatigue
- low capillary density
- anaerobic energy system
- large diameter
- fast twitch
- fast max muscle-shortening velocity
Change in fiber type distribution is relatively complete by the age of __, shifting from a predominance of type II fibers to a more balanced distribution of type I and type II fibers.
1
Rapid increase in muscle strength in both sexes occurs during this phase of life:
puberty
Muscle mass peaks occur during this phase of life:
young and middle adulthood
The decline in the number of motor units appears to begin after the age of __.
60
Deterioration of muscle _____ with age has a stronger relationship to functional limitations and disability than does muscle strength.
power
Chronic strength training adaptations:
- muscle fiber hypertrophy (type IIB greatest)
- change from type IIA to IIB
- decrease capillary bed, mitochondrial density
- increase motor unit recruitment, rate of firing, synchronization
- increase ATP, PC, myoglobin, creatine phosphokinase, and myokinase storage
- increase lean body mass
- decrease % body fat
- increase tensile strength of tendons, ligaments, connective tissue
- increase bone mineral density
Chronic endurance training adaptations:
- increase in capillary bed density, mitochondrial density and volume
- increase ATP, PC, myoglobin, triglycerides, creatine phosphokinase, and myokinase storage
- no change in LBM, decrease % body fat
- increase tensile strength of tendons, ligaments, connective tissue
- increase bone mineral density with land-based, weight-bearing activities
Proposed mechanism for neural adaptations of resistance training?
decrease in the inhibitory function of the CNS, decreased sensitivity of the GTO, or changes of the myoneural junction of the motor unit
Substitute motions
compensatory movement patterns caused by muscle action of a stronger adjacent agonist or a muscle group that normally serves as a stabilizer
External stabilization
applied manually by the therapist or by the patient with belts, straps, or a firm surface such as chair or table
Internal stabilization
achieved by 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; i.e. abdominals stabilize the pelvis and lumbar spine as the hip flexors raise the legs
Methods to determine initial exercise load (amount of resistance):
- 1-RM or estimate of RM
- cable tensiometry
- isokinetic dynamometer
- percentage of body weight
For healthy but untrained adults, a typical training zone usually falls between ___-___% of the baseline 1-RM.
40-70%
For patients with significant deficits in muscle strength or to train for muscular endurance, training zones of ___-___% of the 1-RM is safe, yet challenging.
30-50%
Why would endurance training be indicated initially after injury or surgery?
type I fibers atrophy at a faster rate than type II fibers following immobilization
It is sufficient to use an exercise intensity of at least __% of a muscle’s maximum voluntary contraction to improve strength during isometric muscle contraction.
60%
At slow velocities with a maximum load, an ________ contraction generates greater tension than a ________ contraction.
eccentric, concentric
Eccentric vs. concentric (in a nutshell)
eccentric - greater loads controlled, greater gains, more specific adaptations, more efficient contractions, more DOMS
Variable resistance exercise vs. constant external resistance
variable loads the muscle more effectively throughout the ROM
Characteristics of isokinetic training:
- constant velocity
- range and selection of training velocities (30-360 degrees per second)
- reciprocal vs. isolated muscle training
- velocity-specific training
- compressive forces at the joint decrease as velocity increases
- accommodation to fatigue
- accommodation to painful arc
Slow to medium isokinetic training velocities
60-180 degrees/second
Identifies strength deficits and improves muscle performance of individual muscles or muscle groups more effectively…closed-chain or open-chain?
open-chain
Precautions for resistance exercise:
- Valsalva
- substitute motions
- overtraining and overwork
- exercise-induced muscle soreness
- pathological fracture
Contraindications to resistance exercise:
- pain during AROM or isometric
- inflammation
- severe cardiopulmonary disease
D1 Flexion UE
flexion-adduction-external rotation-supination
D1 Extension UE
extension-abduction-internal rotation-pronation
D2 Flexion UE
flexion-abduction-external rotation-supination
D2 Extension UE
extension-adduction-internal rotation-pronation
D1 Flexion LE
flexion-adduction-external rotation-dorsiflexion-inversion
D1 Extension LE
extension-abduction-internal rotation-plantarflexion-eversion
D2 Flexion LE
flexion-abduction-internal rotation-dorsiflexion-eversion
D2 Extension LE
extension-adduction-external rotation-plantarflexion-inversion
Specific techniques with PNF:
- rhythmic initiation
- repeated contractions
- reversal of antagonists
- alternating isometrics
- rhythmic stabilization
Primary difference between alternating isometrics and rhythmic stabilization?
alternating isometrics - manual resistance is applied in a single plane on one side of the body and then the other
rhythmic stabilization - simultaneously applying resistance in opposite directions
