Chapter 6Chapter 6

Managing Impaired Muscle Managing Impaired Muscle PerformancePerformance

OverviewOverview

Muscle is the only biological tissue Muscle is the only biological tissue capable of actively generating capable of actively generating tensiontension

This characteristic enables human This characteristic enables human skeletal muscle to perform the skeletal muscle to perform the important functions of maintaining important functions of maintaining upright body posture, moving upright body posture, moving body parts, and absorbing shock body parts, and absorbing shock

Skeletal MuscleSkeletal Muscle

Skeletal muscle possesses four Skeletal muscle possesses four biomechanical properties:biomechanical properties:– Extensibility: the ability to be stretched or Extensibility: the ability to be stretched or

to increase in lengthto increase in length– Elasticity: the ability to return to normal Elasticity: the ability to return to normal

resting length following a stretchresting length following a stretch– Irritability: the ability to respond to a Irritability: the ability to respond to a

stimulusstimulus– The ability to develop tension. The ability The ability to develop tension. The ability

of skeletal muscle to develop tension is of skeletal muscle to develop tension is referred to as a contractionreferred to as a contraction

MusclesMuscles An agonist muscle contracts to produce An agonist muscle contracts to produce

the desired movementthe desired movement An antagonist muscle opposes the desired An antagonist muscle opposes the desired

movementmovement– Antagonists resist the agonist movement by Antagonists resist the agonist movement by

relaxing and lengthening in a gradual manner relaxing and lengthening in a gradual manner to ensure that the desired motion occurs, and to ensure that the desired motion occurs, and that it does so in a coordinated and controlled that it does so in a coordinated and controlled fashionfashion

Muscle groups that work together to Muscle groups that work together to produce a desired movement, are called produce a desired movement, are called synergistssynergists

MusclesMuscles

Most muscles span only one jointMost muscles span only one joint However, there are many muscles in However, there are many muscles in

the body that cross two or more joints:the body that cross two or more joints:– The erector spinaeThe erector spinae– The biceps brachiiThe biceps brachii– The long head of the triceps brachiiThe long head of the triceps brachii– The hamstringsThe hamstrings– The rectus femorisThe rectus femoris

Development of Development of Muscle TensionMuscle Tension

The magnitude of the tensile force generated The magnitude of the tensile force generated by a muscle is dependent on a number of by a muscle is dependent on a number of factors:factors:

Type of contractionType of contraction The force-velocity relationshipThe force-velocity relationship The ability to recruit motor unitsThe ability to recruit motor units Electromechanical delayElectromechanical delay Force-length relationshipForce-length relationship Angle of insertionAngle of insertion Angle of pennationAngle of pennation Stored elastic capabilitiesStored elastic capabilities GravityGravity FatigueFatigue Muscle temperatureMuscle temperature

Improving Muscle Improving Muscle PerformancePerformance Muscle performance can be measured Muscle performance can be measured

using a number of parameters:using a number of parameters:– Strength: the ability of a muscle to Strength: the ability of a muscle to

generate force against a specific generate force against a specific resistance, or to produce torque at a joint resistance, or to produce torque at a joint

– Endurance: the ability of a muscle to Endurance: the ability of a muscle to sustain or perform repetitive muscular sustain or perform repetitive muscular contractions for an extended period contractions for an extended period

– Power: the product of muscular force and Power: the product of muscular force and the velocity of muscle shortening the velocity of muscle shortening

Improving Muscle Improving Muscle StrengthStrength To increase strength, the load or To increase strength, the load or

resistance must be gradually resistance must be gradually increased during the muscle increased during the muscle contractioncontraction

Strengthening of a muscle occurs Strengthening of a muscle occurs when the muscle is forced to work when the muscle is forced to work at a higher level than that to at a higher level than that to which it is accustomedwhich it is accustomed

Improving Muscle Improving Muscle StrengthStrength If the metabolic capabilities of the If the metabolic capabilities of the

muscle are progressively overloaded, muscle are progressively overloaded, adaptive changes occur within the adaptive changes occur within the musclemuscle::– An increase in the size of the muscle An increase in the size of the muscle

(hypertrophy)(hypertrophy)– An increase in the efficiency of the An increase in the efficiency of the

neuromuscular system neuromuscular system – An enhancement of the muscle’s enduranceAn enhancement of the muscle’s endurance– An improvement in the power of the muscleAn improvement in the power of the muscle

Improving Muscle Improving Muscle StrengthStrength Four main types of strengthening Four main types of strengthening

exercise:exercise:– IsometricIsometric– ConcentricConcentric– EccentricEccentric– ““Functional”Functional”

Improving Muscle Improving Muscle StrengthStrength The parameters that must be The parameters that must be

considered when developing an considered when developing an exercise program include:exercise program include:– IntensityIntensity– DurationDuration– FrequencyFrequency

Improving Muscle Improving Muscle EnduranceEndurance To increase muscle endurance, To increase muscle endurance,

exercises are performed against exercises are performed against light resistance for many light resistance for many repetitions, so that the amount of repetitions, so that the amount of energy expanded is equal to the energy expanded is equal to the amount of energy supplied amount of energy supplied

Improving Muscle Improving Muscle PowerPower Muscle power is increased by Muscle power is increased by

having a muscle work having a muscle work dynamically against resistance dynamically against resistance within a specified periodwithin a specified period– Example: PlyometricsExample: Plyometrics

Specificity of TrainingSpecificity of Training

Specificity of training involves the Specificity of training involves the principle of the Specific Adaptation principle of the Specific Adaptation to Imposed Demand (SAID)to Imposed Demand (SAID)

Aim: To improve the strength and Aim: To improve the strength and coordination of functional or coordination of functional or sports-specific movements with sports-specific movements with exercises that approximate the exercises that approximate the desired activitydesired activity

Increasing FlexibilityIncreasing Flexibility

Flexibility training has long been Flexibility training has long been recognized as an essential recognized as an essential component of any conditioning component of any conditioning program as a means to prevent program as a means to prevent injury and improve performanceinjury and improve performance

Two broad types:Two broad types:– StaticStatic– DynamicDynamic

Static and Dynamic Static and Dynamic FlexibilityFlexibility Static flexibility is defined as the Static flexibility is defined as the

passive ROM available to a joint passive ROM available to a joint or series of jointsor series of joints

Dynamic flexibility refers to the Dynamic flexibility refers to the ease of movement within the ease of movement within the obtainable ROMobtainable ROM

Methods of StretchingMethods of Stretching

PassivePassive StaticStatic Ballistic StretchingBallistic Stretching Neuromuscular facilitationNeuromuscular facilitation

Delayed Onset Muscle Delayed Onset Muscle SorenessSoreness This type of soreness, which occurs This type of soreness, which occurs

between 48-72 hours after exercise, between 48-72 hours after exercise, may last for up to 10 daysmay last for up to 10 days

Prevention of this type of muscle Prevention of this type of muscle soreness involves careful design of soreness involves careful design of the eccentric program including the eccentric program including prepatory techniques, accurate prepatory techniques, accurate training variables and appropriate training variables and appropriate aftercareaftercare

SarcopeniaSarcopenia

Sarcopenia (Sarcopenia (sarcosarco = muscle, = muscle, peniapenia = = lack of), is not a disease but rather lack of), is not a disease but rather refers specifically to the universal, refers specifically to the universal, involuntary decline in lean body mass involuntary decline in lean body mass that occurs with age, primarily due to that occurs with age, primarily due to the loss of skeletal musclethe loss of skeletal muscle

When older people maintain muscular When older people maintain muscular activity, the losses in strength with age activity, the losses in strength with age are reduced substantiallyare reduced substantially

Neuromuscular Neuromuscular facilitationfacilitation The proprioceptive The proprioceptive

neuromuscular facilitation (PNF) neuromuscular facilitation (PNF) techniques of hold-relax, stretch-techniques of hold-relax, stretch-relax, and agonist contract-relax relax, and agonist contract-relax can be used to actively stretch can be used to actively stretch the soft tissues.the soft tissues.

Neuromuscular Neuromuscular facilitationfacilitation Hold-relax – autogenic inhibitionHold-relax – autogenic inhibition

– An isometric contraction of the An isometric contraction of the range limiting antagonist is range limiting antagonist is performed against slowly increasing performed against slowly increasing resistanceresistance

– This is followed by a voluntary This is followed by a voluntary relaxation by the patient and then relaxation by the patient and then passive movement of the extremity passive movement of the extremity by the clinicianby the clinician

Neuromuscular Neuromuscular facilitationfacilitation Hold-relax-active – reciprocal Hold-relax-active – reciprocal

inhibitioninhibition– Following application of the hold-Following application of the hold-

relax technique, the patient relax technique, the patient performs an active contraction into performs an active contraction into the newly gained range of the the newly gained range of the agonist patternagonist pattern

Neuromuscular Neuromuscular facilitationfacilitation Contract relaxContract relax

– And isotonic movement in rotation is And isotonic movement in rotation is performed followed by an isometric performed followed by an isometric hold of the range limiting muscles in hold of the range limiting muscles in the antagonist pattern against the antagonist pattern against slowly increasing resistance, slowly increasing resistance, voluntary relaxation, and active voluntary relaxation, and active movement into the new range of the movement into the new range of the agonist patternagonist pattern

Aquatic exerciseAquatic exercise

The indications for aquatic therapy The indications for aquatic therapy include instances when:include instances when:– Partial weight bearing ambulation is Partial weight bearing ambulation is

necessarynecessary– To increase range of motionTo increase range of motion– When standing balance needs to be When standing balance needs to be

improvedimproved– When endurance/aerobic capacity When endurance/aerobic capacity

needs to be improvedneeds to be improved

Aquatic exerciseAquatic exercise

Contraindications include Contraindications include incontinence, urinary tract incontinence, urinary tract infections, unprotected open infections, unprotected open wounds, heat intolerance, severe wounds, heat intolerance, severe epilepsy, uncontrolled diabetes, epilepsy, uncontrolled diabetes, unstable blood pressure or severe unstable blood pressure or severe cardiac, and/or pulmonary cardiac, and/or pulmonary dysfunctiondysfunction

Aquatic exerciseAquatic exercise

Pool temperatures should be:Pool temperatures should be:– 92 to 95°F for water exercise92 to 95°F for water exercise– 85 to 90°F for active swimming85 to 90°F for active swimming– 82.4 to 89.6°F for light activity82.4 to 89.6°F for light activity