This document discusses different types of active resisted exercise for rehabilitation programs. It defines resistance exercise as any exercise where a muscle contraction is overloaded by an external force. The types of resisted exercise discussed include isometric, dynamic/isotonic, and isokinetic exercise. Factors that determine appropriate resistance training are also outlined.

1. Active Resisted Exercise

2. Introduction
•Resistance exercise is an essential element of Rehab
programs for person with impaired function and for those
who wish to promote and maintain health and physical
well-being.
•It can be defined as any form of active exercise in which a
dynamic or static muscle contraction is overloaded
(resisted) by an external force (manually or mechanically).
•The resistance must be sufficient to increase the intra-
muscular tension to the maximum without interfering with
the ability of the muscle to do coordinated movements.

3. *A comprehensive examination and evaluation is the basis
upon which a program of resisted exercise is warranted
and will improve a person's current level of function.
Factors affecting the appropriate resistance training:
1- Underlying pathology.
2- Extent and severity of impairment.
3- The presence of other deficits.
4- The stage of tissue healing after injury of surgery.
5- Patient's age
6- Overall level of fitness.
7- Cooperation of the patient with the program.

4. Forms of resistance:
•Free weights (dumbbells, weight machines).
• Pulley circuit
•Springs
•Water
•The patient
•The physiotherapist
•Strong elastic bands,
and even the body itself.

5. *In resistance training, intensity is determined by the
amount of weight against which subjects are working.
It is very important to start at a low level to avoid
injury

6. Types of Resistance Exercise
•Isometric resistance exercise:
Muscle contracts without change in length or visible
motion.
•Dynamic (Isotonic) exercise:
Muscle contracts against load which may be
- Manual: in which the resistance force is applied by the
therapist
- Mechanical: in which the resistance force is applied by
mechanical equipment.
•Isokinetic exercise:
Muscle contraction is controlled by a rate-limiting device
that controls the speed of movement of a body part.

7. Isometric (Static) Exercise
- Is static form of exercise during which muscle
contracts and produces tension without change in
the length of the muscle or visible joint motion.
- During isometric contraction a great amount of
tension and force output produced from the
muscle, which will increase strength if it is
sustained against resistance for at least 6 seconds.
- Capable of increasing muscle strength at specific joint
angles

8. *May produce problems in systolic blood pressure
•Could cause life-threatening cardiovascular accident
•To reduce this event to occur - ASK the person to
breath.
•Widely used in rehabilitation
•Attempt to use positional or functional exercise –
work at multiple angles throughout the range if
possible
•Contractions should be held for 10 seconds at
frequency of 10 or more per hour
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9. Types of Isometric (Static) Exercise
Muscle-setting exercises: low –intensity, isometric
exercises performed against little to no resistance. It
will not improve strength but retard muscle atrophy in
early stage of rehabilitation. Quadriceps and Gluteal
muscles are common examples for Muscle-setting
exercises.
Resisted isometric exercise: isometric exercises
performed against manual or mechanical resistance to
increase strength when active movement is painful.
- The amount of tension produced during isometric
exercise, is directly affected by the length of muscle at
the time of contraction. Therefore, the amount of
resistance also must be vary at different angles in the
range.

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3- Stabilization exercise: joint or postural stability can
be developed by isometric exercise through activating
co-contraction, that is, the contraction of antagonist
muscles that surround proximal joints. Co-contraction
is achieved by mid-range isometric holding against
manual resistance or against gravity, in which
emphasis is placed on isometrically controlling trunk
musculature and proximal muscle of the extremities.
4- Multiple-angle isometric exercise: in which the
resistance ( manual, mechanical), is applied at
multiple joint positions within the available ROM

11. Dynamic Exercise
• When a muscle contracts dynamically against a fixed
resistance, the tension produced from the muscle varies as
the muscle contracts and shortens
• Types of Dynamic Exercise
1- Manual or mechanical resistance: the Dynamic Exercises
are performed against manual or mechanical resistance.
2- Concentric and Eccentric exercise: in which the resistance is
applied to a muscle as it shortens or lengthens.
• Concentric exercise involves dynamic resistance of a muscle
while muscle shortening occurs as in lifting a weight.

12. Eccentric exercise involves dynamic resistance of a muscle
while muscle lengthening occurs in an attempts to control the
resistance. It involves negative work as in lowering a weight,
descending stairs and provide a source of shock absorption
during closed-chain functional activities.
Eccentric contraction produces more tension than an
isometric or concentric contraction.
Eccentric contraction consumes less oxygen, fewer energy
stores, fewer motor units fire to control the same load than
concentrically.
■ Concentric muscle contractions accelerate body segment,
while eccentric muscle contraction decelerate body segment.
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13. Open and Closed Kinematic chains exercises: are
used to describe how forces occur during human
motion and how segments of the body are linked
together.
Open Kinematic chain exercise refers to
movement in which the distal segment (the foot or
hand) moves freely in space.
- Most manual and mechanical resistance
exercise have been applied using Open Kinematic
chain exercise.
- Open Kinematic chain exercise can be used if
weight bearing is contraindicated.
- Also Open Kinematic chain exercise can be
performed in a dynamic or static manner.

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Closed Kinematic chain exercise refers to
movement where the body moves over a fixed distal
segment.
- Closed-chain exercise are performed in a weight-
bearing position when the foot is planted on the
ground and the muscle action lifts or lowers the
body as in stair climbing or squatting activities.
- Closed-chain exercise occurs in upper limb when
a person performs a push-up.
- Closed-chain exercise are used to stimulate
mechanoreceptors in and around joints more
effectively than open-chain exercise.
- Closed-chain activities improve stability, balance,
coordination and agility in functional weight-bearing
posture.

15. Isokinetic Exercise
- Is a form of dynamic exercise in which the velocity
of muscle shortening or lengthening is controlled by
a rate-limiting device that control the speed of
movement.
- The resistance met during Isokinetic Exercise
accommodate to the tension-producing capabilities
of the muscle and loads the muscle to capacity
throughout the ROM, and that is why is called
“accommodation resistance exercise”.
- Isokinetic training can occur in either concentric or
eccentric mode.
- Speeds of exercise may range from a slow velocity
(15-30o/ sec) to a very fast velocity (300-400o/ sec).
- Isokinetic training can be used safely to increase
muscle strength, endurance and power.

16. Uses and indications
The main purposes of resistance exercise is to improve
muscle performance which refers to, the capacity of a
muscle to do work (force x distance), this muscle
performance can be enhanced by some form of resisted
exercise.
Elements of muscle performance:
1- Strength: the greatest measurable muscle tension exerted
by a muscle or muscle group to overcome resistance during
a single, maximum effort.
In order to increase the strength of a muscle, muscle
contraction should be loaded for a relatively low number of
repetition or over a short period of time.

17. 2.Endurance: the ability to perform low-intensity,
repetitive, or sustained activities over an extended
period of time without fatigue.
Unlike strength, endurance develops by increase the
oxidative and metabolic capacities due to low-intensity
muscle contractions, high repetitions, and a prolonged
time period.
Endurance can be classified into:
i) Muscular endurance (local endurance).
Ii) Cardiorespiratory endurance (total body endurance),
is characterized by having a muscle contract and resist
a light load for many repetitions or sustain a muscle
contraction for an extended period of time.

18. 3. Power: is the work produced by a muscle per unit
of time (force x distance).
Power can be improved by either increasing the work
that a muscle must perform in a specified period of
time or by reducing the amount of time required to
produce a given force.
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19. Factors That Determine Levels of Strength, Endurance &
Power
• Size of Muscle
–Proportional to cross-sectional diameter of muscle fibers
–Increased cross-sectional area = increased strength and
force production
–Hypertrophy
• Increase in muscle size
–Atrophy
• Decrease in muscle size
• Number of Muscle Fibers
• Neuromuscular Efficiency
• Strength is directly related to efficiency of the
neuromuscular system
• Initial increases in strength during first 8-10 weeks are
attributed to neuromuscular efficiency

20. • Age
• Men & women increase strength throughout puberty
& adolescence
• Peaks at age 20-25
• After age 25, max strength declines 1% annually
• Decline is related to physical activity
• Able to retard decline in performance through
activity
• Overtraining
• Imbalance between exercise and recovery
• Training exceeds physiological and psychological
capacity of individual
• Can have negative effect on strength training
• May result in psychological or physiological
breakdown
• Injury, illness, and fatigue can be indicators

21. Fast-Twitch vs. Slow Twitch
•Slow Twitch Fibers
• Type I or slow oxidative (SO)
• More resistant to fatigue
• Time required to generate force is greater in slow twitch
fibers
• Primarily associated with long duration, AEROBIC activities
•Fast Twitch Fibers
•Type IIa (fast oxidative glycolytic- FOG)
•Moderately resistant to fatigue
•Type IIb (fast glycolytic - FG)
•Fatigues rapidly – true fast twitch
•Type IIx – fatigue resistant with force capacity (a<x<b)
•Produce quick, forceful contractions
•Short-term, high intensity activities, ANAEROBIC

22. • Ratio in Muscle
▫ Both fiber types exist in individual muscles
▫ Ratio varies by muscle and by individual
▫ Postural muscles =  % primarily type I fibers
▫ Power, explosive strength muscles =  % type II fibers

23. Physiology of Strength Development
• Muscle Hypertrophy – 3 theories
• Hyperplasia –  in number of muscle fibers
• Genetically determined & does not seem to increase
with training
• Evidence exists of fibers splitting – conducted in
animals
• Hypothesized increased number of capillaries – partially
correct
• No new capillaries
• Increase in dormant capillary activity to meet needs of
muscle
• Reversibility – adaptations of muscle due to training
can begin to reverse within 48 hours of removing
training

24. Other Physiological Adaptations to Resistance Exercise
• Strength of non-contractile structures
–Tendons and ligament increase
–Increased bone-mineral content
• Improved oxygen uptake
–If resistance training is high enough to elicit a cardiovascular
response/adaptation
• Increased metabolic enzymes

25. Overload Principle
• To improve strength, muscle must be worked at a level higher
than it is accustomed to
• Muscle will maintain strength if it is trained against a
consistent resistance that it is accustomed to
• Existence of current strength & will result in increased
muscle endurance
• Effective training requires a consistently increasing effort
against progressively more resistant loads
• In rehabilitation, rate of progression is determined by athlete’s
response to specific exercise
• Be mindful of pain when dealing with progression

26. Purpose of Resisted exercises
1- Improvement and maintenance of muscle strength, power and
endurance.
2- Increase strength of connective tissues, ligament and tendons.
3- Increase bone mineral density
4- improve coordination and balance.
4- Increase muscle mass (hypertrophy) and decrease body fat.
5- Increase blood flow of the working muscle.
6- Enhance physical performance during ADL .
7- Increase heat production and improve repair and healing process.
8- Decrease stress on joint and reduce risk of soft tissue injury during
physical activities.

27. Precautions for Resistance exercise
Cardiovascular precautions which include
* The Valsalva maneuver:which is an expiratory effort against
a closed glottis, should be avoided during resistance
exercise, especially during isometric and heavy resistance
exercise.
Sequences:
Deep inspiration, closure of the glottis, contraction of
abdominal muscles, increased in the intra-abdominal
pressures, decreased in venous return leads to a
decreased in in cardiac output, a temporary drop in ABP
leads to an increase in the H.R.
When the expiration occurs, there is a pronounced increase in
blood pressure due to rapid venous blood flow into the
heart that leads to a forceful contraction of the heart.

28. Prevention:
- Patient should not hold his breath
- Have the patient exhale during the exercise
- Ask the patient to count or talk during exercise
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29. Fatigue: is the diminished response of a muscle or muscle groups
to repeated stimulus. The therapist should be aware of the
pattern of fatigue that occur either during the static or dynamic
exercise and gear the exercise program accordingly to avoid its
occurrence.
Recovery from exercise: the body must be given time to restore
itself to the existed state before the exhaustive exercise.
Overwork and Overtraining: in heavy resisted training, exercise
program must be progressed cautiously to avoid acute muscle
fatigue induced individual to stop exercising.
Overtraining: a decline in physical performance in healthy
subjects due to high-intensity, inadequate rest intervals between
training sessions or too rapid progression of exercise.
Overwork: progressive deterioration of strength in already
weakened muscles by non-progressive neuromuscular disease.

30. Muscle soreness:
- Acute Muscle soreness: - Muscle pain develops during or directly
after strenuous exercise due to lack of adequate blood flow &
oxygen and accumulation of lactic acid and potassium in the
exercised muscle.
- it is transient and subside quickly when adequate blood flow &
oxygen are restored to the muscle.
- Delayed-onset Muscle soreness: Muscle tenderness and temporary
stiffness develop 12-24 hours after exercise. This may be due to
microtrauma to muscle fibers and/or connective tissues that result
in tissues degeneration.

31. Substitute motions: it occur if too much resistance is applied
during exercise. An appropriate amount of resistance and correct
stabilization should be applied to avoid substitute motions.
Osteoporosis: A reduction of mineralized bone mass associated
with an imbalance between bone resorption and bone formation.
Resistance exercise must be applied and progressed vary
cautiously to avoid pathological fracture.
Contraindications
1- Inflammation: the use of dynamic resisted exercise can lead to
increase swelling and more damage to muscle. In this case it can
be replaced by low-intensity isometric exercise.
2- Pain: severe joint or muscle pain during exercise or 24 hours
after it, should be carefully evaluated.