Improving Muscle Performance Flashcards
What is the only biologic tissue capable of actively generating tension?
muscle
What is a prime agonist?
The muscle that is directly responsible for producing movement
What is a synergist?
The muscle that provides cooperative muscle function in relation to the agonist
Synergists function as either _____ or _____.
stabilizers or neutralizers
What is a stabilizer?
The muscle that contracts statically to steady or support some part of the body against the pull of the contracting muscle
What is a neutralizer?
The muscle that acts to prevent an undesired action of one of the movers
What is an agonist?
The muscle that has an effect opposite to that of the agonist
When does a concentric contraction occur?
When the tension generated by the agonist muscle is sufficient to overcome an external force and to move the body segment of one attachment toward the segment of its other attachment
Does a muscle that eccentrically contracts lengthen?
No, it merely returns from its shortened position to its normal resting length
What type of activities are eccentric contractions involved in?
activities that require deceleration to occur
Eccentric contractions generate forces ____ than isometric or concentric
greater
During an eccentric contraction the load exceeds the contractile force, how does this effect the cross bridges between actin and myosin
Some of the myosin filaments are torn from the binding sites on the actin filament while the remainder complete the contraction cycle
What are the 2 reasons tension is greater in a lengthening muscle than the tension that could be created during a shortening muscle action
- The combined increase in force per cross-bridge
- The number of active cross-bridges
What is an isokinetic contraction?
A contraction in which the muscle is maximally contracted at the same speed throughout the whole range of it related lever
What is required in order to perform an isokinetic contraction?
Special equipment that produces an accommodating resistance
What are the advantages of isokinetic contractions?
Both high-speed/low-resistance and low-speed/high-resistance regimens result in excellent strength gains
What are the disadvantages of isokinetic contractions?
- it is very expensive
- there is the potential for impact loading and incorrect joint axis alignment
- also has questionable functional carryover
What is an econcentric contraction?
A contraction that combines both a controlled concentric and a simultaneous eccentric contraction of the same muscle over two separate joints
What is an example of an econcentric contraction?
A standing hamstring curl in which the hamstrings work concentrically while the hip flexes eccentrically to lengthen the hamstrings
What is an isolytic contraction?
a type of eccentric contraction that makes use of a greater force than the patient can overcome
What is the difference between an isolytic and an eccentric contraction?
An eccentric contraction is voluntary whereas an isolytic contraction is involuntary
When can you utilize an isolytic contraction as a PT?
In certain manual techniques to stretch fibrotic tissue
The ability of a muscle to carry out its various roles is a measure of what?
muscle performance
Muscle performance is measured using what 3 things?
- strength
- endurance
- power
What is strength?
The amount of force that may be exerted by an individual in a single maximum muscular contraction against a specific resistance, or the ability to produce torque at a joint
What are the 4 ways strength can be measured?
- MMT
- Dynamometer
- Isometric
- Isokinetic
What is endurance?
The ability of a muscle, or group of muscles, to continue to perform without fatigue
Describe the phenomenon of “steady state”
The body is encouraged to work aerobically by the nature of muscular endurance which typically occurs after 5-6 minutes of constant intensity exercise
Compare the rate of ATP production and ATP hydrolysis during steady state. What does this demonstrate?
They are virtually the same
This demonstrates the existence of efficient cellular mechanisms to control mitochondrial ATP synthesis in a wide dynamic range
Endurance exercise training produces an increase in what?
Mitochondrial volume density in all three muscle fiber types and thus muscle aerobic power
What is power?
The product of force and velocity
What is muscular power?
The maximum amount of work an individual can perform in a given unit of time.
The product of muscular force and the velocity of muscle shortening
Maximum power occurs at approximately ____ of maximum velocity
one-third
Muscles with a predominance of ___-twitch fibers generate more power at a given load than those with a high composition of ___-twitch fibers
fast
slow
What does training volume refer to?
The total amount of resistance lifted during a strength training session
What does training volume equal?
Training volume = (number of sets) X (number of repetitions) X (weight lifted per repetition)
When are a patient’s symptoms considered irritable and when are they not?
If pain is present before resistance or the end-feel of a joint, the patient’s symptoms are considered irritable.
If pain occurs after resistance, then the patient’s symptoms are not considered irritable
Can strength training interfere with aerobic training?
Yes
What are the 2 contraindications to exercise?
Inflammation and Pain
What should each exercise session begin and end with?
5-15 minute warm-up and 5-15 minute cool-down
What are the 4 early goals of exercise (warm-up)?
- Increasing circulation
- Preventing atrophy
- Increasing protein synthesis
- Reducing the level of metabolites
What does training frequency refer to?
The number of times strength-training sessions are completed in a given period
In order to enhance strength, a program should feature ___ resistance and ___ reps
high
low
How often should strength regimens be performed at first and then later on after healing has progressed?
Every day at first and then every other day later on
Weight selected should allow _-__ reps; _ sets; with __-__ seconds recovery between sets
8-12 reps
3 sets
60-90 seconds recovery
Average conditioning time is __-__minutes for moderate intensity exercise
20-30
The heavier the load lifted, the ____ the rest period between sets
longer
How long should rest breaks be when training for muscular endurance?
less than 30 seconds
How long should rest breaks be when training for muscular hypertrophy?
60-90 seconds
How long should rest breaks be when training for muscular strength?
2-5 minutes
How long should rest breaks be when training for muscular power?
2-5 minutes
What does intensity refer to?
The power output, how much effort is required to perform the exercise, the weight or resistance lifted by the patient
What is the RPE scale?
1 - very light activity
5 - strong (heavy)
10 - Very, very strong (almost maximum)
What is the most commonly examined resistance-training theory?
Periodization
What is periodization?
the process of planned variations in a training program over a specified training cycle to prevent over-training and to perform at peak levels at the right time
What are the 2 models or periodization?
- classic
- undulating
Describe the classic/linear model of periodization
This model is characterized by high initial training volume and low intensity. As training progresses, intensity increases and volume decreases
Describe the undulating/nonlinear model of periodization
This program enables variation in intensity and volume within each 7-10 day cycle by rotating different protocols over the course of the training program. During each workout, only one characteristic is trained in a given day
A macrocycle is divided into several mesocycles that can be classified as what 3 things?
- conditioning
- precompetition
- competition
Exercise progression in the orthopedic population is determined by what 4 things?
- The stage of healing
- Degree of irritability of the structure
- Patient response
- Co-morbidities
- Patient’s age
What does SAID stand for?
specific adaptation to imposed demand
What are the 3 important concepts related to the SAID principle?
- Overload
- Underload
- Overtraining
Describe the concept of overload
When tissues are loaded beyond what they are required to do, they will adapt to permit them to deal with these new loads more effectively
Describe the concept of underload
When tissues are loaded at a level under what is normally performed, the body will adapt by decreasing its ability in the underloaded component (detraining)
A reduction in VO2 max can be detected within how many weeks of detraining?
4
Describe the concept of overtraining
This phenomenon occurs because of an inappropriate amount of rest, recovery, and unloading that manifests as loss of appetite, inability to sleep, lethargy, muscle soreness, declining performance, and an altered metabolism
Tonic muscles function as _____ muscles, whereas phasic muscles function as _____ muscles.
endurance (Type I)
power (Type II)
In what 5 ways does the body return to pre-exercise levels during the recovery phase
- Promotion of venous return and removal of metabolites from muscle
- Reestablishment of fluid balance
- Replacement of depleted fuel energy reserves
- Relaxation in muscles that were active
- Replenish muscle glycogen following prolonged exercise
If the recovery period is insufficient what can result?
acute or delayed onset muscle soreness
When is acute soreness apparent?
during the later stages of an exercise bout and during the immediate recovery process
When is DOMS apparent?
24-56 hours after the exercise bout
What does DOMS most commonly cause?
a reduction in joint ROM, shock attenuation, and peak torque
What type of contraction is linked to the development of DOMS?
Eccentric, more so than concentric
If the prevention of DOMS in unsuccessful what 4 things should you do next?
- rest
- reduce edema by way of cryotherapy and elevating the limb
- continue with aerobic submaximal exercise with no eccentric involvement
What are the 6 ways resistance can be applied to a muscle
- Gravity
- Body Weight
- Small Weights
- Medicine Balls
- Exercise Machines
- Manual Resistance
Are AROM exercises are designed to work with or against gravity?
against
Active assist exercises are typically performed _____ to gravity
perpendicular
What is the disadvantage of using small weights?
There is no variable resistance throughout the ROM
What are the advantages of exercise machines compared to small weights?
They provide more adequate resistance, they are safer than free weights, and the clinician is able to quantify the amount of resistance
What are the 2 disadvantages of using exercise machines?
The inability to modify the exercise to be more functional and the inability to modify the amount of resistance
What is an example of manual resistance?
Proprioceptive neuromuscular facilitation (PNF)
What are the advantages of manual resistance?
- Control of the extremity position and force applied
- More effective re-education of the muscle
- Tactile stimulation and appropriate facilitation techniques
- Accurate accommodation and alterations in the resistance applied throughout the range
- Ability to limit the range
What are the disadvantages of manual resistance?
- Cannot be measured quantitatively
- Amount of resistance is limited by the strength of the clinician
- Difficulty with consistency of the applied force
What 4 things should an exercise program include in order to condition the patient for a return to activity and to prevent overload injuries?
- Flexibility
- Strengthening
- Power
- Endurance
What are the _ adaptive changes that occur within a muscle as it gets stronger?
- Hypertrophy (an increase in size of the muscle_
- Increase in the force per unit area
- Reduction in the time to peak force
- Increase in the efficiency of the neuromuscular system
- Stimulation of slow-twitch fibers fast-twitch IIa fibers
- Rhythmic activities increase blood flow to the exercising muscles via contraction and relaxation
- Power of the muscle improves
- Improved bone mass (Wolff’s Law)
- Increase in metabolism/calorie burning/weight control
- Increased intramuscular pressure results from a muscle contraction of ~60% of its force generating capacity
- Cardiovascular benefits when using large muscle groups
- Increase in the rate of force development
A _ second isometric contraction at __% of max resistance is sufficient to increase strength when performed repetitively
6
75%
What are the goals of isometric exercise?
To prevent atrophy and subsequent decreased ligament, bone and muscle strength
What are the 6 disadvantages of isometric exercise?
- Strength gains are not increased throughout the ROM
- Do not activate all of the muscle fibers
- There are no flexibility or cardiovascular fitness benefits
- Peak effort can be injurious to the tissues because of vasoconstriction and joint compression forces
- There is limited functional carryover
- Considerable internal pressure can be generated
Describe how concentric exercise is dynamic
The clinician can vary the load and the speed of contraction can also be manipulated
How often should you perform concentric exercise?
Initially strengthening exercises are performed on a daily basis
Progressed to every other day
Then to at least three times per week
What are the 7 clinical indications for eccentric exercise?
- mechanical joint pain
- Joint pain resistant to modality intervention
- Unidirectional joint crepitus or painful arc
- Deconditioned or low endurance patients
- Plateaus in strength gains
- Tendonitis presentations
- Late-stage rehab
In order to increase muscle endurance what kind of exercise should a patient perform?
light resistance exercises for many reps (20-30+ per set)
What is the major drawback to endurance training?
the potential for overuse injuries, especially if the exercise is not performed correctly
How is power increases?
by having a muscle work dynamically against resistance within a specific period
What type of training has been viewed as a bridge between pure strength and sports-related exercises?
plyometric training
Describe how plyometric training works
Involves a concentric contraction that is preceded by a phase of active or passive stretching, in which elastic energy is stored in the muscle. This stored energy is then used in the subsequent contractile phase.
What is the goal of plyometric training?
To decrease the amount of time required between the yielding eccentric muscle contraction and the initiation of the overcoming concentric contraction
Plyometrics is associated with an enhancement of what?
The ability of the muscle-tendon unit to produce maximal force in the shortest amount of time through activation of the myotatic reflex
What are the 3 nerve receptors involved in plyometrics?
- muscle spindle
- the GTO
- the joint capsule/ligamentous receptors
Other than the myotatic reflex, what are 2 other reflex mechanisms that can be initiated during plyometric exercise and may assist with motor coordination and joint stability?
- Length feedback
- Force feedback
What generates the length feedback?
muscle stretch
Length feedback links what 2 things?
1) Muscles that are synergists through excitatory feedback and those with opposite actions by reciprocal inhibition
2) Monoarticular muscles with excitatory feedback and contributes to joint stiffness
What generates the force feedback?
muscle force
Force feedback is provided by the stimulation of what?
the GTO which connects muscles that cross different joints and exert torque in different directions through inhibitory feedback.
Which type of feedback regulates coupling between joints?
force feedback
What are the 3 phases of plyometrics?
1) loading phase
2) coupling phase
3) unloading phase
What are the two mechanisms associated with the stretch of active muscle during the loading phase of plyometrics?
- Muscle potential: increase in the poportion of cross-bridges
- Activation of the muscle spindle: provides excitatory feedback
The coupling phase is generally a period of what?
quasi-isometric muscle action
What does the unloading phase involve?
shortening of the muscle-tendon unit
During plyometric training decreased contact duration is associated with ____ force
increased
When is plyometric training indicated?
When patients desire to return to activities that include explosive movements
What are the contraindications of plyometrics?
- Acute inflammation
- Acute pain
- Immediate post-op status
- Joint instability
What are the precautions to plyometrics?
- Joint pathologies
- Bone contusion
- Chondral injury
- Musculotendinous injury
Generally how long should rest periods be between plyometric training sessions?
48-72 hours
What type of plyometrics are preferable for most initial rehab plans and why?
Horizontal plyometrics (performed perpendicular to the line of gravity) because the contraction force is reduced and the eccentric phase is not facilitated
What form of plyometrics is more advanced?
vertical
What are the absolute contraindications to exercise?
- Unstable angina
- Uncontrolled hypertension
- Uncontrolled dysrhythmias
- Hypertrophic cardiomyopathy
- Certain stages of retinopathy
What are the relative contraindications to exercise?
- Congestive heart failure
- Myocardial ischemia
- Poor left ventricular function
- Autonomic neuropathies
What are the 3 stabilization exercises?
- Static
- Transitional
- Dynamic
What type of receptor contributes to joint stability?
Articular mechanoreceptors
Initially should you start with open or close chain exercises?
Start with closed kinetic chain exercises and then open kinetic chain exercise can be built upon the base of CKCE
What is the benefit of CKCE over OKCE?
CKCEs appear to replicate functional tasks better than OCKEs (esp. in the LEs). They also allow the entire linkage system of the kinematic chain to be exercised together
What are the 3 things CKCE have been shown to do?
- Enhance joint congruency
- Decrease the shearing forces
- Stimulate the articular mechanoreceptors using axial loading and increased compressive forces
What is the benefit of OKCEs?
They have a beneficial effect on function, especially when combined with specific CKCEs or when used to strengthen individual muscles
What are the 3 objectives that must be met if the rehab of the functional kinematic chain is to be comprehensive?
1) Restoration of functional stability, which is the ability to control the translation of the joint during dynamic functional activities, through the integration of both the primary and the secondary stabilizers
2) Restore sports-specific or functional-specific movement patterns
3) Assessing the readiness of the patient to return to his or her prior level of function or level of athletic performance
