2. Muscle Performance and Resistance Exercise:
Definitions and Guiding Principles:
1. Strength.
2. Power.
3. Endurance.
4. Overload Principle.
5. SAID Principle.
6. Reversibility Principle.
3. ⢠Muscle performance refers to the capacity of a muscle
to do work (force Ă distance).
⢠The key elements of muscle performance are strength,
power, and endurance.
4. When there is a deficit of muscle
performance
Impairment of function
Resistance exercise is any form of active exercise in which dynamic
or static muscle contraction is resisted by an outside force applied manually
or mechanically.
5.
6. Muscle strength
It is a broad term that refers to the ability of contractile tissue to
produce tension and a resultant force based on the demands
placed on the muscle.
Functional strength relates to the ability of the neuromuscular
system to produce, reduce, or control forces, contemplated or
imposed, during functional activities, in a smooth, coordinated
manner
7. Strength training (strengthening exercise)
is defined as a systematic procedure of a
muscle or muscle group lifting, lowering,
or controlling heavy loads (resistance)
for a relatively low number of repetitions
or over a short period of time
8. Muscle power
It is related to the strength and speed of movement and is
defined as the work (force Ă distance) produced by a muscle
per unit of time (force Ă distance/time).
The greater the intensity of the
exercise and the shorter the
time period taken to generate
force, the greater is the muscle
power.
9. Muscle endurance (Aerobic Power)
It is the ability of a muscle to contract repeatedly against a
load (resistance), generate and sustain tension, and resist
fatigue over an extended period of time.
The key parameters of endurance
training are low-intensity muscle
contractions, a large number of
repetitions, and a prolonged time
period.
10. Overload Principle
If muscle performance is to improve, a load that exceeds the
metabolic capacity of the muscle must be appliedâthat is,
the muscle must be challenged to perform at a level greater
than that to which it is accustomed.
11. â In a strength training program, the
amount of resistance applied to the
muscle is incrementally and progressively
increased.
â For endurance training, more emphasis
is placed on increasing the time a muscle
contraction is sustained or the number of
repetitions performed than on increasing
resistance.
12. SAID Principle
The SAID principle (specific adaptation to imposed demands)
suggests that a framework of specificity is a necessary
foundation on which exercise programs should be built.
13. Reversibility Principle
Adaptive changes in the bodyâs systems, such as increased
strength or endurance, in response to a resistance exercise
program are transient unless training-induced improvements
are regularly used for functional activities or unless an
individual participates in a maintenance program of resistance
exercises.
15. Factors that Influence Tension Generation in
Normal Skeletal Muscle
1. Energy Stores and Blood Supply
2. Fatigue
3. Age
4. Psychological and Cognitive Factors
17. Muscle (local) fatigue: The diminished response of muscle to
a repeated stimulus is reflected in a progressive decrement in
the amplitude of motor unit potentials
18.
19. Factors that influence fatigue.
1. A patientâs health status,
2. diet,
3. Lifestyle
4. In patients with neuromuscular, cardiopulmonary, inflammatory,
cancer-related, or psychological disorders, the onset of fatigue is
often abnormal.
20. Cardiopulmonary (general) fatigue. This type of fatigue is the diminished
response of an individual (the entire body) as the result of prolonged physical
activity, such as walking, jogging, cycling, or repetitive lifting or digging. It is
related to the bodyâs ability to use oxygen efficiently. Cardiopulmonary fatigue
associated with endurance training is probably caused by a combination of the
following factors.
â Decrease in blood sugar (glucose) levels.
â Decrease in glycogen stores in muscle and liver.
â Depletion of potassium, especially in the elderly patient.
21. Threshold for fatigue:
It is the level of exercise that cannot be sustained indefinitely.
A patientâs threshold for fatigue could be noted as the length
of time a contraction is maintained or the number of
repetitions of an exercise that initially can be performed.
This sets a baseline from which adaptive changes in physical
performance can be measured.
22.
23.
24.
25.
26.
27.
28. Determinants of a Resistance Exercise Program
â Alignment of segments of the body during exercise
â Stabilization of proximal or distal joints to prevent substitution
â Intensity: the exercise load (level of resistance)
â Volume: the total number of repetitions and sets in an exercise session
â Exercise order: the sequence in which muscle groups are exercised during an exercise session
â Frequency: the number of exercise sessions per day or per week
â Rest interval: time allotted for recuperation between sets and sessions of exercise
â Duration: total time frame of a resistance training program
â Mode of exercise: type of muscle contraction, position of the patient, form (source) of resistance, arc of
movement, or the primary energy system utilized
â Velocity of exercise
â Periodization: variation of intensity and volume during specific periods of resistance training
â Integration of exercises into functional activities: use of resistance exercises that approximate or
replicate functional demands
29.
30. Initial Exercise Load (Amount of Resistance)
⢠Repetition Maximum
⢠A percentage of body weight
31. Training Zone
After establishing the baseline RM, the amount of resistance
(exercise load) to be used at the initiation of resistance training
often is calculated as a percentage of a 1-RM for a particular
muscle group. At the beginning of an exercise program the
percentage necessary to achieve training-induced adaptations in
strength is low (30% to 40%) for sedentary, untrained individuals
or very high (>80%) for those already highly trained. For healthy
but untrained adults, a typical training zone usually falls between
40% and 70% of the baseline RM. The lower percentage of this
range is safer at the beginning of a program to enable an
individual to focus on learning correct exercise form and
technique before progressing the exercise load to 60% to 70%.
32. Percentage of Body Weight as an Initial Exercise
Load for Selected Exercises
ďą Universal bench press: 30% body weight
ďą Universal leg extension: 20% body weight
ďą Universal leg press: 50% body weight
33.
34.
35.
36. Types of Resistance Exercise
ďś Type of resistance
Manual and Mechanical Resistance Exercise
ďś Type of muscle contraction
⢠Isometric Exercise (Static Exercise)
⢠Dynamic Exercise: (Concentric and Eccentric)
(Constant and Variable Resistance)
37. Eccentric Versus Concentric Exercise:
â Greater loads can be controlled with eccentric than concentric exercise.
â Training-induced gains in muscle strength and mass are greater with
maximum effort eccentric training than maximum effort concentric
training.
â Adaptations associated with eccentric training are more mode- and
velocity-specific than adaptations as the result of concentric training.
â Eccentric muscle contractions are more efficient metabolically and
generate less fatigue than concentric contractions.
â Following unaccustomed, high-intensity eccentric exercise, there is
greater incidence and severity delayed-onset muscle soreness than after
concentric exercise.
38.
39. Characteristics of Open-Chain and Closed-Chain Exercises
Open-Chain Exercises Closed-Chain Exercises
Distal segment moves in space.
Distal segment remains in contact with or stationary
(fixed in place) on support surface.
Independent joint movement; no predictable joint
motion in adjacent joints.
Interdependent joint movements; relatively
predictable movement patterns in adjacent joints.
Movement of body segments only distal to the moving
joint.
Movement of body segments may occur distal and/or
proximal to the moving joint.
Muscle activation occurs predominantly in the prime
mover and is isolated to muscles of the moving joint.
Muscle activation occurs in multiple muscle groups,
both distal and proximal to the moving joint.
Typically performed in non-weight-bearing positions.
Typically but not always performed in weightbearing
positions.
Resistance is applied to the moving distal segment.
Resistance is applied simultaneously to multiple
moving segments.
Use of external rotary loading. Use of axial loading.
External stabilization (manually or with equipment)
usually required.
Internal stabilization by means of muscle action, joint
compression and congruency, and postural control.
40. Isokinetic Exercise
Isokinetic exercise is a form of dynamic exercise in
which the velocity of muscle shortening or lengthening
and the angular limb velocity is predetermined and
held constant by a rate-limiting device known as an
isokinetic dynamometer.
41.
42.
43. Manual Resistance Exercise: Advantages and
Disadvantages
Advantages
â Most effective during the early stages of rehabilitation when muscles are weak
(4/5 or less).
â Effective form of exercise for transition from assisted to mechanically resisted
movements.
â More finely graded resistance than mechanical resistance.
â Resistance is adjusted throughout the ROM as the therapist responds to the
patientâs efforts or a painful arc.
â Gives the therapist an opportunity for direct interaction with the patient to
monitor the patientâs performance continually.
44. â Muscle works maximally at all portions of the ROM.
â The range of joint movement can be carefully controlled by the therapist to
protect healing tissues or to prevent movement into an unstable portion of the
range.
â Useful for dynamic or static strengthening.
â Direct manual stabilization prevents substitute motions.
â Can be performed in a variety of patient positions.
â Placement of resistance is easily adjusted.
45. Disadvantages
â Exercise load (amount of resistance) is subjective; it cannot be measured or
quantitatively documented for purposes of establishing a baseline and exercise-
induced improvements in muscle performance.
â Amount of resistance is limited to the strength of the therapist; therefore,
resistance imposed is not adequate to strengthen already strong muscle groups.
â Speed of movement is slow to moderate, which may not carry over to most
functional activities.
â Cannot be performed independently by the patient to strengthen most muscle
groups.
â Not useful in home program unless caregiver assistance is available.
â Labor- and time-intensive for the therapist.
â Impractical for improving muscular endurance; too time-consuming.
46. General principle for application
1. Examination and evaluation.
2. Preparation for resistance exercise.
3. Implementation of resistance exercise.
47. Implementation of resistance exercise
1. Warm up
2. Resistance placement
3. Direction of resistance
4. Stabilization
5. Intensity of exercise
6. Number of Repetitions(8-12),
Sets(3), and Rest Intervals.
7. Verbal or Written Instructions
8. Monitoring the Patient
9. Cool-Down
48. General Precautions During Resistance Training
1. Keep the ambient temperature of the exercise setting comfortable for
vigorous exercise. Select clothing for exercise that facilitates heat dissipation
and does not impede sweat evaporation.
2. Caution the patient that pain should not occur during exercise.
3. Do not initiate resistance training at a maximal level of resistance,
particularly with eccentric exercise to minimize delayed-onset muscle soreness
(DOMS). Use light to moderate exercise during the recovery period.
49. 4. Avoid use of heavy resistance during exercise for children, older adults, and
patients with osteoporosis.
5. Do not apply resistance across an unstable joint or distal to a fracture site that is
not completely healed.
6. Have the patient avoid breath-holding during resisted exercises to prevent the
Valsalva maneuver; emphasize exhalation during exertion.
7. Avoid uncontrolled, ballistic movements as they compromise safety and
effectiveness.
8. Prevent incorrect or substitute motions by adequate stabilization and an
appropriate level of resistance.
50. 9. Avoid exercises that place excessive, unintended secondary stress on the
back.
10. Be aware of medications a patient is using that can alter acute and chronic
responses to exercise.
11. Avoid cumulative fatigue due to excessive frequency of exercise and the
effects of overtraining or overwork by incorporating adequate rest intervals
between exercise sessions to allow adequate time for recovery after exercise.
12. Discontinue exercises if the patient experiences pain, dizziness, or unusual
or precipitous shortness of breath.
52. Proprioceptive Neuromuscular Facilitation
⢠PNF is an approach to therapeutic exercise that
combines functionally based diagonal patterns of
movement with techniques of neuromuscular
facilitation to evoke motor responses and improve
neuromuscular control and function.
53. ⢠PNF techniques can be used to develop muscular
strength and endurance; to facilitate stability,
mobility, neuromuscular control, and coordinated
movements; and to lay a foundation for the
restoration of function.
54. Diagonal Patterns
⢠The patterns of movement associated with PNF are composed of
multi-joint, multiplanar, diagonal, and rotational movements of the
extremities, trunk, and neck. Multiple muscle groups contract
simultaneously. There are two pairs of diagonal patterns for the
upper and lower extremities: diagonal 1 (D1) and diagonal 2 (D2).
Each of these patterns can be performed in either flexion or
extension. The diagonal patterns can be carried out unilaterally or
bilaterally.
56. Basic Procedures with PNF Patterns
⢠Manual Contacts
⢠Maximal Resistance
⢠Position and Movement of the
Therapist
⢠Stretch
⢠Normal Timing
⢠Traction
⢠Approximation
⢠Verbal Commands
⢠Visual Cues