Transcript Therapeutic Techniques to Increase Muscle Strength

Therapeutic Techniques
to Increase Muscle
Strength
PT 154: Therapeutic Exercises III
Ms. Mary Grace M. Jordan, PTRP
December 1, 2009
As physical therapists…
“…one of the major goal of physiotherapy in
neurological rehabilitation is the optimization
of functional motor performance..”
Major impairments limiting
motor performance




Muscle weakness or paralysis
Soft tissue contracture
Lack of endurance
Physical fitness
Muscle Strength

The ability of contractile tissue to produce tension
and a resultant force based on the demands
placed upon the muscle.
Functional Strength…
“The ability of the neuromuscular system to produce,
reduce, or control forces, contemplated or
imposed, during functional activities, in a smooth,
coordinated manner.”
Learning objectives…



Discuss muscular weakness, disuse
weakness, and paralysis
Review the principles of strength training
Discuss the following:





Strength training regimes
Isotonic vs. Isometric vs. Isokinetic exercises
Open chain vs. Close chain exercises
Complications of strength training
Considerations in force gradation
Learning objectives…


Discuss concepts of resistance training, PNF,
and Task-oriented approach to increase
strength of neurologic and developmental
conditions
Discuss evidence of technique effectiveness
Physiologic factors which
affect strength
STRUCTURAL
 Cross-sectional area
 Density of muscle
fibers per unit crosssectional area
 Efficiency of
mechanical leverage
across joints
FUNCTIONAL
 Number, type, and
frequency of motor
units recruited during
a contraction
 Initial length
 Efficient cooperation
between synergic
muscles
Strength is therefore…
A function of the properties of muscle and
depends on intact neurological function.
(Buchner and De Lateur, 1991)
Skilled motor performance
requires that…

Each muscle involved in the action has to
generate peak force at the length appropriate
to the action

Force has to be graded and timed so
synergic muscle activity is controlled for task
and context
Skilled motor performance
requires that…

Force has to be sustained over a sufficient
period of time

Peak forces must be generated fast enough
to meet environmental and task demands
Can strength impairments be
reliably measured in a patient
with a CNS lesion?
Assumptions…



Measuring strength was not appropriate
Primary impairment affecting functional
performance was not weakness but spasticity
Strength training in the CNS patient was
considered contraindicated, since it was
believed that strength training would increase
tone problems (Bobath, 1978; Davies, 1985)
Recent research says…


Paresis is an important factor in impaired
functional performance as spasticity.
Strength can be measured in 3 ways:
Isometrically
 Isotonically
 Isokinetically
***Alternative: dynamometers

Muscle weakness and
paralysis…


Results in loss of movement or stability of a
particular joint
Creates a state of muscular imbalance which
affects all the groups concerned in the
production of coordinated movements
“CONTRACTION is the only means by which
muscle power can be maintained or
increased…”
Muscle weakness and
paralysis…
“…any lesion or habit which prevents or limits
contraction will result in muscle wasting”

Paralysis


complete loss of ability to contract
Paresis

partial loss or a muscle may be merely weak or subnormal
Muscle weakness and
paralysis…

1.
2.
3.
4.
Causes
Lesions affecting the
Anterior Horn Cells
Lesions affecting the
Motor Pathways
Lesions affecting the
Muscle Tissue
Reduced endurance
due to decline in
physical activity.
Disuse Weakness…



A minimum level of strength
is necessary for the
performance of everyday
motor task.
Strength requirements of
people fluctuate over their
lifetimes, and even from day
to day.
The neuromuscular system is
capable of accommodating to
these fluctuations.
Disuse Weakness…
A patient may not use his
muscles because…
 He cannot
 He does not need to
 He will not
How will you know if its TRUE
weakness or APPARENT
weakness?
Hence…
Strength training
…is necessary after stroke to improve the force
generating capacity and efficiency of weak
muscles and to improve functional motor
performance.
Treatment of impaired strength





Focus on generating force to move a body
segment or alternatively, generating force to
resist a movement.
Use of PRE
Use of Isokinetic equipments
Eccentric vs. Concentric strength training
Task-specific circuit training
Principles of Strength Training




Overload (resisted
work)
Progression
Specificity
Reversibility
Strength training regimes





Static, Dynamic, and Isokinetic
Progressive resistance exercises
Use of manual resistance
Use of light weights
Use of isokinetic training systems
Strengthening regimes
What to use?

Isotonic vs. Isometric
vs. Isokinetic

Open chain vs. Close
chain exercises
Therapeutic techniques to
increase muscle strength



Resistance exercises
Proprioceptive Neuromuscular Facilitation
Motor Re-learning Program / Task-oriented
approach
Kinetic chain exercises…


Are given to strengthen lower limb extensor
muscles using body weight (i.e. step-ups,
modified squat to stand, heel raise, leg press)
Take advantage of the specificity principle as
muscles are exercised concentrically and
eccentrically in a movement pattern that
shares the dynamic characteristics of
commonly performed motor actions (i.e. sitto-stand, bending down to pick objects, stair
negotiation).
Eccentric vs. Concentric
exercise…

Voluntary eccentric contractions produce
greater muscle force than concentric muscle
contraction.

Eccentric exercise has greater mechanical
efficiency and has lesser metabolic energy
cost than concentric exercise.
Studies showed that…

Utilizing both concentric and eccentric muscle
contractions in strength training has been
shown to produce better gains in strength
than concentric contractions alone.
(Hakkinen and Komi, 1981)
Quick stretch…


Concentric activation of weak muscles may
be facilitated by the enhanced muscle spindle
activity occurring as a result of the rapid
switching from eccentric to concentric muscle
activity.
If an eccentric contraction immediately
precedes a concentric contraction, concentric
phase generates more force due to the effect
of the stretch-shortening cycle.
Elastic band resistance
exercise…




An inexpensive and simple means of exercising
which can be carried out by patients on their own.
Provides variable resistance throughout the range
of movement
There is some difficulty controlling the exact
amount of resistance
Recommended as a means of increasing ms.
Strength, preserving or inc. jt. range and ms.
extensibility, and encouraging unsupervised
exercise.
PNF

An approach to therapeutic exercise that
combines functionally based diagonal
patterns of movement with techniques of
neuromuscular facilitation to evoke motor
response and improve neuromuscular control
and function.
PNF techniques







Repeated contractions
Dynamic reversals of
antagonists
Stabilizing reversals
Rhythmic stabilization
Combination of isotonics
Repeated stretch from
beginning of range
Repeated stretch throughout
the range
Motor Re-learning Program


Task-oriented approach to
improve motor control focusing
on re-learning of daily
activities.
4 steps




Analysis of task
Practice of missing components
Practice of task
Transference of learning
What time / phase should you
start implementing
strengthening exercises?
What do you need to consider
in grading the force that you
will apply to your patient?
Resistance exercises

Any form of active exercise in which a
dynamic or static muscle contraction is
resisted by an outside force, applied
either manually or mechanically.

Take note:








Warm-up
Placement of resistance
Direction of resistance
Stabilization
Intensity/Amount of resistance
Number of repetitions and sets; rest
intervals
Monitor patient’s response
Cool-down
Eliciting activity in very weak
muscles






Grade 2-3
Partial body weight resistance
Resistance through a small range of
movement
Lifting small weights through a limited range
Elastic band exercises
Concentric and eccentric exercise on an
isokinetic dynamometer
Eliciting activity in very weak
muscles



Grade 0-1
More studies are needed to explore training
of severely weakened or paralyzed muscles
In theory, since lower levels of muscle
activation are required for the same force
effect in eccentric compared to concentric
exercise, attempts at eccentric contraction
may enable an individual with very weak
muscles to improve activation.
Resistance exercises

Precautions


Valsalva maneuver
High-risk patients






Coronary artery disease
Myocardial infarction
Cerebrovascular disorders
Hypertension
S ubstitute motions
Overwork weakness
Complications to strength
training





Spasticity
Incomplete innervation
Muscle substitution
Effect of drugs on exercise
Effects of length changes on
muscle
How to prescribe
strengthening
exercises?
Basic considerations…



Dosage can be increased by increasing the
number of repetitions, the number of sets,
and the resistance provided.
Muscles should be exercised to the point of
fatigue but not pain in order to obtain some
change.
Patients should be warned that they may
experience a small degree of delayed muscle
soreness.
Basic considerations…


Strength training utilizes resistance from body
weight, free weights, elastic bands, isokinetic
dynamometry, exercise machines, treadmill
walking.
Strength training can be carried out under
supervision, independently and in group
circuit training classes.
Basic considerations…



The exercise should be specific as possible to
the functional actions being trained to ensure
carryover.
In the case of patients with very weak
muscles, any type of exercise which results in
generation of some force can be practiced.
Strength training is carried out with submaximal loads (as a general rule 10 repetitions
at 50-80% of maximal possible 1RM load with
a goal of 3 sets)
Is there evidence on the
effectiveness of the
techniques?
Studies…



Research now is documenting the
contribution of impaired strength to functional
limitations in patients with CNS lesions.
Led to a growing awareness of the need to
examine and document weakness in the
patient with CNS pathology.
Training programs appear to be effective in
improving strength; the degree to which they
affect other primary impairments is not clear.
Studies reported…
The following changes after periods of strength
training and physical conditioning:
 Increases in muscle strength, improved
postural stability, and reduction of falls in the
elderly. (Aniansson et al 1980, Aniasson and Gustafsson 1981,
Sauvage et al 1992, Fiatarone et al 1990,1994, Judge et al. 1993, Tinetti et
al. 1994, Campbell et al. 1997, Gardner et al. 2000)

Increases in muscle strength after stroke
(Sunderland et al. 1992, Engardt et al. 1995, Sharp and Brouwer 1997,
Sherrington and Lord 1997, Brown and Kautz 1998, Duncan et al. 1998,
Teixeira-Salmela et al. 1999, 2000, Weiss et al. 2000)
Studies reported…

Improvement in gait performance

Improvements in the ability to balance (Hamrin et
(Nakamura et al,
1985, Bohannon and Andrews 1990, Nugent et al 1994, Lindmark and
Hamrin 1995, Sharp and Brouwer 1997, Krebs et al. 1998, Teixeira-Salmela
et al. 1999, 2000, Weiss et al. 2000)
al. 1982, Weiss et al. 2000)

Improvements in stair climbing (Bohannon and Walsh
1991)
Strengthening exercises for
the pediatric population…
Strengthening exercises for
the pediatric population…
In order to increase a child’s
strength…




Progress the movement from a gravity-eliminated
movement to one that is working against gravity.
Alter the amount of assistance given so that the
child has to use greater force control.
Increasing the number of repetitions or
lengthening the time of exercise will help improve
endurance.
Coordination should improve with an increase in
strength and endurance, depending on the lesion.
In order to increase a child’s
strength…




Progressive resistive exercises, isometric and
isokinetic training programs can be used for
children who demonstrate adequate
cooperation.
For the younger child, age appropriate play,
adaptive toys, and games can serve the
same purpose.
Practice of bimanual activities
Engagement into sports is recommended.
Learning objectives…



Discuss muscular weakness, disuse
weakness, and paralysis
Review the principles of strength training
Discuss the following:





Strength training regimes
Isotonic vs. Isometric vs. Isokinetic exercises
Open chain vs. Close chain exercises
Complications of strength training
Considerations in force gradation
Learning objectives…


Discuss concepts of resistance training, PNF,
and Task-oriented approach to increase
strength of neurologic and developmental
conditions
Discuss evidence of technique effectiveness
Laboratory session
Assignment: Identify muscle groups that are involve and formulate
exercises (using resistance, PNF, and MRP techniques) for the
following activities:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Rolling from supine to right side-lying
Long sitting from supine
Standing from short sitting
Walking:Initial contact, Midstance, and Swing phase
Ascending stairs
Descending stairs
Bathing
Dressing upper garments
Dressing lower garments
Carrying shopping bag weighing 2 kilos using the right hand
Use of bilateral arm crutches or walker
References:





Basmajian, J. & Wolf, S. (1990). Therapeutic exercise (5th
ed.).Baltimore:Williams & Wilkins.
Crosbie, J & McConnell, J. (1993). Physiotherapy: Foundations
for practice: Key issues in musculoskeletal physiotherapy.
Oxford:Butterworth-Heinemann Ltd.
Gardiner,M.(1981).The principles of exercise therapy (4th
ed).London: Bell & Hyman Ltd.
Kisner,C. & Colby, L. (2002). Therapeutic exercise:Foundations
and techniques (4th ed.). Philadelphia:F.A. Davis Company.
Shumway-Cook, A. & Woollacott, M. (2001). Motor control:
Theory and practical applications (2nd ed.).
Philadelphia:Lippincott Williams & Wilkins.
Thank you and see you in the
laboratory sessions…