Managing Impaired Muscle Performance

1
Chapter 6

• Managing Impaired Muscle Performance

2
Overview

• Muscle is the only biological tissue capable of
  actively generating tension
• This characteristic enables human skeletal muscle
  to perform the important functions of maintaining
  upright body posture, moving body parts, and
  absorbing shock

3
Skeletal Muscle

• Skeletal muscle possesses four biomechanical
  properties
• Extensibility the ability to be stretched or to
  increase in length
• Elasticity the ability to return to normal
  resting length following a stretch
• Irritability the ability to respond to a
  stimulus
• The ability to develop tension. The ability of
  skeletal muscle to develop tension is referred to
  as a contraction

4
Muscles

• An agonist muscle contracts to produce the
  desired movement
• An antagonist muscle opposes the desired movement
• Antagonists resist the agonist movement by
  relaxing and lengthening in a gradual manner to
  ensure that the desired motion occurs, and that
  it does so in a coordinated and controlled
  fashion
• Muscle groups that work together to produce a
  desired movement, are called synergists

5
Muscles

• Most muscles span only one joint
• However, there are many muscles in the body that
  cross two or more joints
• The erector spinae
• The biceps brachii
• The long head of the triceps brachii
• The hamstrings
• The rectus femoris

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Development of Muscle Tension

• The magnitude of the tensile force generated by a
  muscle is dependent on a number of factors
• Type of contraction
• The force-velocity relationship
• The ability to recruit motor units
• Electromechanical delay
• Force-length relationship
• Angle of insertion
• Angle of pennation
• Stored elastic capabilities
• Gravity
• Fatigue
• Muscle temperature

7
Improving Muscle Performance

• Muscle performance can be measured using a number
  of parameters
• Strength the ability of a muscle to generate
  force against a specific resistance, or to
  produce torque at a joint
• Endurance the ability of a muscle to sustain or
  perform repetitive muscular contractions for an
  extended period
• Power the product of muscular force and the
  velocity of muscle shortening

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Improving Muscle Strength

• To increase strength, the load or resistance must
  be gradually increased during the muscle
  contraction
• Strengthening of a muscle occurs when the muscle
  is forced to work at a higher level than that to
  which it is accustomed

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Improving Muscle Strength

• If the metabolic capabilities of the muscle are
  progressively overloaded, adaptive changes occur
  within the muscle
• An increase in the size of the muscle
  (hypertrophy)
• An increase in the efficiency of the
  neuromuscular system
• An enhancement of the muscles endurance
• An improvement in the power of the muscle

10
Improving Muscle Strength

• Four main types of strengthening exercise
• Isometric
• Concentric
• Eccentric
• Functional

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Improving Muscle Strength

• The parameters that must be considered when
  developing an exercise program include
• Intensity
• Duration
• Frequency

12
Improving Muscle Endurance

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

13
Improving Muscle Power

• Muscle power is increased by having a muscle work
  dynamically against resistance within a specified
  period
• Example Plyometrics

14
Specificity of Training

• Specificity of training involves the principle of
  the Specific Adaptation to Imposed Demand (SAID)
• Aim To improve the strength and coordination of
  functional or sports-specific movements with
  exercises that approximate the desired activity

15
Increasing Flexibility

• Flexibility training has long been recognized as
  an essential component of any conditioning
  program as a means to prevent injury and improve
  performance
• Two broad types
• Static
• Dynamic

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Static and Dynamic Flexibility

• Static flexibility is defined as the passive ROM
  available to a joint or series of joints
• Dynamic flexibility refers to the ease of
  movement within the obtainable ROM

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Methods of Stretching

• Passive
• Static
• Ballistic Stretching
• Neuromuscular facilitation

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Delayed Onset Muscle Soreness

• This type of soreness, which occurs between 48-72
  hours after exercise, may last for up to 10 days
• Prevention of this type of muscle soreness
  involves careful design of the eccentric program
  including prepatory techniques, accurate training
  variables and appropriate aftercare

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Sarcopenia

• Sarcopenia (sarco muscle, penia lack of), is
  not a disease but rather refers specifically to
  the universal, involuntary decline in lean body
  mass that occurs with age, primarily due to the
  loss of skeletal muscle
• When older people maintain muscular activity, the
  losses in strength with age are reduced
  substantially

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Neuromuscular facilitation

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

21
Neuromuscular facilitation

• Hold-relax autogenic inhibition
• An isometric contraction of the range limiting
  antagonist is performed against slowly increasing
  resistance
• This is followed by a voluntary relaxation by the
  patient and then passive movement of the
  extremity by the clinician

22
Neuromuscular facilitation

• Hold-relax-active reciprocal inhibition
• Following application of the hold-relax
  technique, the patient performs an active
  contraction into the newly gained range of the
  agonist pattern

23
Neuromuscular facilitation

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

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Aquatic exercise

• The indications for aquatic therapy include
  instances when
• Partial weight bearing ambulation is necessary
• To increase range of motion
• When standing balance needs to be improved
• When endurance/aerobic capacity needs to be
  improved

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Aquatic exercise

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

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Aquatic exercise

• Pool temperatures should be
• 92 to 95F for water exercise
• 85 to 90F for active swimming
• 82.4 to 89.6F for light activity