RESISTANCE EXERCISE

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RESISTANCE EXERCISE
RESISTANCE EXERCISE
RESISTANCE EXERCISE
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RESISTANCE EXERCISE

• Definition
• Resistance exercise is active exercise
• (a dynamic or static muscular contraction) in
  which muscle contraction is resisted by an
  outside force. This outside force may be manual
  or mechanical.

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Goals and indications of resistive exercises

• Increase muscle strength
• Strength refers to the force out put of a
  contracting muscle and is directly related to the
  amount of tension of contracting muscle.
• In order to increase the strength of a
  muscle, the muscle must be loaded or resisted so
  that the increasing level of tension will
  develop due to hypertrophy and recruitment of
  muscle fibers.
• B. Increase muscular endurance
• Endurance is the ability of the muscle to
  perform low intensity repepitative exercises over
  a prolonged period of time
• Muscular endurance is improved by
  performing exercises against mild resistance for
  many repetitions.

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• Increase power
• Power is defined as work per unit of time (Force
  x distance/time)
• The rate at which a muscle contracts and develop
  force throughout the range of motion and
  relationship of speed and force are factors that
  affect power.
• There is no question that strength, endurance and
  power are all related and can be improved with
  resistance exercises.

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Physiological Adaptations to Resistive Exercise

• Regular resistive exercise is associated with
  several positive adaptations which is dosage
  dependant. These changes include

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• Muscle
• Increase of the cross sectional area of the
  muscle due to
• increase myofibril per muscle fiber
• fibers splitting
• increase number of muscle fiber
• Increase protein content of the muscle fiber.
• Increase energy source necessary to fuel muscle
  contraction and increase levels of ATP, and
  creatine phosphate.
• Increase neural activation, motor unit
  recruitment, and firing rate of each unit.

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• Connective tissue
• Resistive exercise may alter tendon and ligament
  structure make them larger stronger and more
  resistance to injury.
• Increase tensile strength of tendon and ligament

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• Bone
• Improve and maintain bone density.
• Cardiovascular system
• Increase cardiac output
• Increase stroke volume
• Increase maximal oxygen consumption
• Decrease heart rate
• Decreased or unchanged systolic and diastolic
  blood pressure.

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Overload Principle

• the foundation of training to increase muscular
  strength and endurance is the overload principle
  which states that In order to increase strength
  or endurance a load that exceeds the metabolic
  capacity of the muscle must be used to induce
  adaptive changes in muscle that lead to
  increasing strength and endurance

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Isometric
Isotonic
Isokinetic
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Isometric Resisted Exercise

• Isometric resisted exercise is a static
  contraction of muscle against external resistance
  without appreciable change in its length or joint
  motion.
• Advantage
• Isometric exercise is valuable when joint motion
  is uncomfortable or contraindicated, during
  immobilization.
• Isometric exercise is effective when weakness
  exist at a specific point in the ROM.
• Easy to understand.
• Disadvantage
• Isometric strength is specific to the joint angle
  (joint angle dependent).

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Isotonic Resisted Exercise

• Isotonic resisted exercise is dynamic exercise
  that is carried out against resistance as a
  muscle lengthens or shortens through the
  available range of motion.
• CONCENTRIC CONTRACTION occurs when active muscle
  undergoes shortening while overcoming external
  resistance.
• ECCENTRIC CONTRACTION occurs when active muscle
  undergoes lengthening while being overcome by an
  external resistance.
• Eccentric contraction performed against
  supramaximal resistance generates greater force
  production than concentric contraction.

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Mode of Resistance Application

• Manual Resisted Exercise
• Manual resistance exercise is active resisted
  exercise in which the resistance force is applied
  by the therapist to either a dynamic or isometric
  contraction.
• Advantage
• The resistance can be varied with changes in
  strength production throughout the range.
• When joint motion is allowed, manual resisted
  exercise offer an easy inexpensive method of
  strengthening muscle.
• Specific or individual muscle could be
  strengthened.
• Disadvantage
• The amount of resistance depend on the therapist
  condition.
• The resistance can not be measures so the
  treatment results can not be documented.
• Effort and time consuming as the therapist can
  treat only one patient at a time.

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Mechanical Resistance Exercise

• Mechanical Resistance Exercise
• Mechanical resisted exercise is active resisted
  exercise in which the resistance provided by
  equipments to either a isotonic or isometric
  muscle contraction.
• A variety of mechanical equipment are available
  ranging from simple to complex, small to large,
  and expensive to inexpensive. The choice between
  them depend on the patients need and ability,
  goal of the exercise and availability of the
  apparatus.
• Free weights
• Weight machine
• Exercise bicycle
• Pulley system

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• Advantage
• Objective quantitative documentation of the
  patient progress.
• The level of resistance not limited by the
  therapist strength.
• Add a variety to the exercise.
• Safe time and effort of the therapist.
• Disadvantage
• The resistance can not be varied throughout the
  range of motion. Amount of resistance is fixed
  all over the range.
• Need space and may be expensive.

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The exercise dosage can be increases by

• 1- Changing the relationship to gravity
• 2- Increase lever arm (hand placement)
• 3- Increase repetition of exercise
• 4- Increase duration of exercise
• 5- Increase amount of resistance (mild-
  moderate- maximum)
• 6- Speed
• Be sure not to proceed to a more difficult
  exercise before the patient perform the lower
  graduation first, otherwise overwork and fatigue
  occur

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Isokinetic Resistive Exercise

• Isokinetic exercise is a form of active exercise
  in which a muscle or group of muscles contracts
  against a controlled accommodating resistance
  which is moving at a constant angular velocity.
• The isokinetic exercise are performed with a
  specialized apparatus that provides variable
  resistance to a movement, so that no matter how
  much effort is exerted, the movement takes place
  at a constant speed.
• The isokinetic device are computerized training
  and testing device that provide maximum
  resistance through the entire ROM.
• The device provide multi-angle isometric
  resistance, resisted concentric and eccentric
  exercise.

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Advantage

• Ability to fully activate more muscle fiber for
  longer period because the machine accommodate the
  resistance according to the changing ability
  throughout the ROM.
• Allow training at a variety of speeds
• Provide objective documentation
• The isokinetic device provides many strengthening
  protocols to chose from according to the patient
  condition and the goal of exercise. For example
  (isometric conditioning, isokinetic conditioning,
  eccentric eccentric conditioning and open
  closed chain conditioning)

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Disadvantage

• The device is expensive
• Require trained personnel for setting up the
  patient training program.

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Precaution with Resisted Exercise

• The use of valvasia maneuver should be avoided
  during resistive training especially by a patient
  with cardiopulmonary disease, recent abdominal,
  intervertebral disc, or eye surgery.
• During resistive training especially with
  eccentric contraction and increase exercise dose
  minor lesions of the muscle and inflammation
  occur resulting in delayed onset muscle soreness.
  If this occur, start with warming up period and
  decrease exercise dose.

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Contraindication of Resisted Exercise

• Acute inflammation of the musculoskeletal system
• Pain
• Infection.
• Recent fracture or non-united fracture