Muscle strengthening

Why is adequate muscle strength important?

• Muscles provide support for joints.

  Rationale: Without adequate muscle support - greater rate of wear & tear in joints

• Optimum Function:

  Rationale: Adequate muscle strength allows the body to keep up with the demands of life.

  These demands depend on age, occupation and gender

Indications for muscle strengthening exercise

1. Extended periods of immobilisation causing muscle atrophy

2. After an injury, a patient needs to regain adequate muscle strength to prevent re-injury

3. In the presence of debilitating disease

4. Effects of postural dysfunction

Muscle strength definition

• Ability of contractile tissue to produce tension and a resultant force based on the demands placed on that muscle

Factors that affect muscle strength

1. Physiological strength: depends on factors such as muscle size, the cross-sectional area of the muscle and its responses to training.

2. Neurological strength of impulse: how weak or how strong the signal is that tells the muscle to contract

3. Mechanical strength: refers to a muscle’s pulling force and the way those forces can be changed using bones and joints as lever

Cardiovascular endurance

• The capacity to maintain strenuous activity of multiple muscle groups for prolonged periods of time.

• Is the aerobic activity of the cardiovascular system to supply oxygen to the muscles during prolonged physical activity.

EXAMPLES :

• running, cycling and swimming

Isokinetic contraction

• When muscle contracts and shortens at a constant rate of speed, despite possible changes in external resistance

EXAMPLE:

• leg work done while riding a stationery bike

Manual Muscle Test

• Application of increasing resistance to produce a concentric contraction of the muscle tested until a maximum contraction is reached

Isometric Test (manual testing)

• allows for structural differentiation because joint motion is prevented, and the test is isolated to the muscle’s isometric contraction

One-repetition maximum (1RM)

• the maximal load with which a task (movement) can be performed defined as “the greatest load (in kg) that can be fully moved (lifted, pushed or pulled) once, without failure or injury

One-repetition maximum (1RM) calculation

• 1RM = (0.033 x RTF x load in Kg) + load in Kg

Components of Muscle Performance

There are 3 components to improve muscle performance:

1. Muscle Strength

2. Muscle Power

3. Muscle Endurance

Muscle power

• The maximum force that a muscle or muscle group can generate in a minimum time. Its development depends on the right balance between speed and strength on a specific skill that requires explosiveness

To increase power you can:

1. Increase force (e.g., lift heavier weights),

2. Increase distance (e.g., move the weight through a greater range of motion),

3. Decrease time (e.g., perform the movement faster

Power training convention

• High-intensity, low-rep exercises.

• Fast execution of movements

• Adequate rest between sets to maintain explosivenes

Strength training convention

• high load/resistance and a low number of reps

• not dependant on time

Endurance

• The ability to perform low-intensity, repetitive or sustained activities over a prolonged period of time

Muscle endurance

• The ability of a muscle to sustain an isometric contraction or continued (concentric, eccentric) isotonic contractions

Principles of strengthening weak muscle

1. Overload

2. SAID

3. Reversibility

Overload

• An increased load or resistance should be applied to muscles to improve muscle performance

Sub principles of overload

1. To maintain muscle strength do not change load.

2. To increase muscle strength progressively increase: load & volume (reps, sets, frequency)

SAID (Specific Adaptation to Imposed Demand)

• the human body or in this case skeletal muscles will adapt

  specifically in response to the demands and stresses placed on it

Reversibility

• activity must continue at the same level to keep the

  same level of adaptation in muscle tissue. As activity declines, called detraining, muscle adaptations will regress

Types of exercise

1. Open kinetic chain exercise

2. Closed kinetic chain exercise

3. Resisted exercsie

Open kinetic chain exercise

• Movement when the distal segment moves freely in a non-weight bearing position

• Limb movement occurs distal to moving joint due to contraction of muscles that cross the joint

Open chain

• better for isolating movement to specific muscle group and improving control of a specific movement

Closed kinetic chain exerci

• The movement of the proximal body segment on a fixed distal segment. The extremity exercised remains in constant contact with the immobile surface, usually the ground

• promotes co-activation of muscle groups and dynamic

  stabilisation as well as improved proprioception, balance and neuromuscular con

Characteristics of closed kinetic chain exercise

1. Distal segment remains fixed in place

2. In weight-bearing position

3. Interdependent joint movement; predictable movement in adjacent joints

4. Movement of segment may occur distal/proximal to moving joint

5. Muscle activation in multiple muscle groups distal and proximal to moving joint

6. Internal stabilisation by means of muscle actio

Resisted exercise

• exercise whereby muscles contract against an external force

Benefits of resisted exercise

1. Improves mobility

2. Increased strength of connective tissues e.g. tendons

3. Increased bone mineral density (indicator of bone strength)

4. Decreased joint stress

5. Reduced risk of soft tissue injury

6. Improved capacity to repair (heal) damaged soft tissue

7. Possible improvements in balance in some population

Aesthetic and psychological benefits of resisted exercise

1. Positive changes in body composition: increased lean muscle mass and decreased body fat

2. Enhanced feelings of well-being

3. Improved perception of disability

Questions to answer before providing a strengthening intervention

• 1. What is the patients’ baseline muscle strength for the muscle or muscles affected?

• 2. What should the muscles strength be to assist the patient reach their previous functional ability?

• 3. What strengthening intervention should be done, to assist the patient to achieve their previous level of function optimally?

Precautions

• Severely impaired sensation (neurological fallout)

• Coordination difficulty

• Difficulty with balance

• Decreased cognition

• Choose appropriate resistance/weight modalities Example: no heavy resistance for children, elderly or patients with osteoporosis

• No breath-holding, especially with patients who have high blood pressure or cardiovascular disorders. Avoid the valsalva manoeuvre.

• Be aware of patient’s medication, e.g. use of corticosteroids – these drugs can weaken muscles and tendons, making them more prone to injury. This effect is especially concerning when corticosteroids are injected directly into a specific area, such as a joint.

• Stop if patient experiences dramatic increase in pain, dizziness or unusual shortness of breath (hyperventilation) during the session

Contraindications

• In post-surgical conditions (determine contraindications with the surgeon)

• Acute inflammation (gentle isometric exercises w/ little resistance can be used as tolerated, when you do isometric movement you don’t cause movement around the joint thus avoiding re-injuring the joint)

• Pain (stop and assess to why the pain is persisting )

NB: not everything applies to a single patient, apply what is necessary

Observations: Muscle Fatigue (during strengthening intervention)

• Discomfort

• Pain

• Muscle cramp (sudden, involuntary contraction of one or more muscles, often painful and temporarily disabling.)

• Visible tremor in contracting muscle

• Movement becomes visibly jerky (movement not visibly smooth).

• Inability to complete full movement (entire ROM)

• Compensation of the primary movement with other muscle groups

  NB: while muscles are under exertion for prolonged period it can fatigue and as physiotherapist you are concerned with the QUALITY of the movement not the quantity

Procedure in the consultation room

• Explain the purpose of the muscle strengthening exercise/programme to the patient and its ultimate intent help to improve their strength to ultimately improve joint mobility and functional ability

• Expose the limb to be strengthened, patient suitably undressed. Patient also suitably draped as necessary

• Choose a stable starting position

• Demonstrate and explain the movement that the patient needs perform

• Stabilise appropriately and correct trick movements –ensure that the patient engages the correct muscle group!

Principles of strengthening in the consultation room

• Stable starting position with focus on muscle(s) to be strengthened

• Smooth and rhythmical movement

• Isolate movement to correct muscle group: no trick movements/compensation

• Muscle must be strengthened for all types of muscle work: isometric, concentric and eccentric

• Very weak muscles: start strengthening in mid-range, then inner range, then progress to outer range and full range

• Strength training must be done progressively in sensible increments.

Muscle work training principles

• Isometric: Duration: hold for 1-5 seconds, allows peak tension to develop. Joint angle: Strength only gained at or close to the training angle therefore resistance into the range is recommended

• Concentric: Performing the physiological action that occurs in relation to the concentric contraction of the muscle e.g. flexion; extension etc.

• Eccentric: When strengthening a muscle eccentrically, the patient performs the concentric movement and then instruct the patient to return to the starting position “slowly” during the eccentric contraction.

Methods to alter resistance

• Change starting position and therefore effects of gravity (Gr 0-2 to Gr 3-5)

• Increasing training volume (number of repetitions and sets)

• Increase load (using heavier weights progressively)

• Increasing the lever arm length of the affected extremity or body part

• Alter the range of muscle work

• Speed

Muscle Strengthening Modalities (definition and examples)

• referred to as equipment or bodyweight used to either provide resistance (add load) to a physiological action to promote tensile strength or the ability for a muscle OR group of muscles to produce force

• EXAMPLES: Pendular exercises, Rehabilitation board, Manual resistance, Free weights, Body weight, Pulleys, Hydrotherapy,

Pendular exercises

• Also known as “Codmans Exercise”, used for patients who are very weak but can produce a palpable muscle contraction e.g. Grade 1.

Rehabilitation board

• Press-wood or plastic board that can be used to rest the limb on while doing exercises in a horizontal plane

Advantages:

• Change the resistance according to the patient’s needs with the tilt of a board.

• Good for patients who are bedridden and cannot sit up

• Independence: patient is doing the work on their own and PT is not helping by supporting the limb

Disadvantages:

• Not ideal for all limb movements.

• Must ensure that skin is protected: always powder the rehab board to reduce friction

• Patient requires an assistant to position and stabilise the board

Manual resistance

• may be used when no other weights are available for example a bed ridden patient

Advantages:

• You can adjust the resistance through range

Disadvantages:

• Patient cannot perform exercises which utilises manual resistance independently for home program unless a family member/caregiver can be trained to assis

Convention:

• To supply smaller amount of resistance (weaker patient): shorten the lever arm and apply resistance closer to patient’s joint

• To supply greater amount of resistance (stronger patient): lengthen the lever arm and apply resistance further away from patient’s joint

Free weight (dumb bells)

• Dumb bells are strengthening modalities that have a pre-defined mass indicated on the weight

• Resistance can be increased progressively by increasing the size of the load.

Advantages:

• To substitute use of conventional dumb bells, household items such as food cans or water bottles can be used

Disadvantages:

• Only feasible for upper limb strengthening (free weights are tricky to pick up with your feet!)

Body weight

• Good to use when patient has at least a Grade 3-4.

Advantages:

• No physical input from the physiotherapist is needed. For example, patient is able do wall squats or push-ups

Disadvantages:

• Requires the patient to weight-bear through the limbs. May not be possible in the initial phases of rehabilitation in cases of joint replacements or fractures. – these types of exercise are to be used based on assessment of capability

Cuff weights

• Rectangular sand/clay bags with a velcro strap that can be fastened around a limb. One can increase the resistance by increasing the size of the cuff weight. Cuff weights are available in varied mass.

Advantages:

• Good for use for upper and lower limb strengthening

• When a patient cannot hold the weight due to hand injuries

Disadvantages:

• May not be always available in all types of clinical settings

Exercise Ball

• versatile

• most exercises prescribed with an exercise ball require an ability for the patient to be able to weight bear through the upper or lower extremities

TheraBand

• colour grades resistance bands which the different colours represent the different densities of elastic

Advantages:

• can be used for upper and lower limb exercises

• can be folded double for double the amount of resistance

• affordable

• great for home exercise programs

• saves space

Disadvantages:

• provides variable resistance depending on stretch length making it harder to standardise or measure exact load for progressive training

Pulleys

• a wheel with a groove or channel along its edge through which a rope or cable can run

Hydrotherapy

• a form of therapy that uses water for pain relief, strengthening and promoting mobility

PRINCIPLES:

• Archimedes principle of buoyancy: When an object is immersed in fluid, the fluid exerts an upward force that opposes the weight of an immersed object. The force equals the weight of the water displaced by the object.

• Exercise must be chosen according to the patient's capability and progressed appropriately based on the patient’s ability.

• Use equipment e.g. pool noodles, paddle boards-for safety-to alter buoyancy

INDICATIONS:

• Pain

• PWB/NWB

• Polytrauma

• Movement restrictions

• Muscle weakness

PRECAUTIONS:

• controlled epilepsy

• hydrophobia

• resting blood pressure is low or high

• haemophilia

• pregnancy

CONTRAINDICATIONS

• acute vomiting

• recent heart attack

• skin

• pregooo

• recent DVT(deep vein thrombosis)

• incontinence

• shortness of breath