Biomechanical FOR and wound care

FORs are based on theoretical principles that

guide the evaluation and treatment of deficits.

For physical deficits we use

• Biomechanical →Musculoskeletal and Orthopedic conditions

• Sensorimotor → Neurological conditions

• Rehabilitation → anyone to return to highest level of

independence

Biomechanical FOR

Understanding biomechanics is essential for analyzing movement and function

Knowledge of anatomy and physiology supports accurate

assessment of body systems

Insight into the cardiopulmonary system helps evaluate endurance and activity tolerance

Enables clinicians to observe and assess functional movements

Identifies limitations in strength, range of motion, coordination, or endurance

Assists in linking physical deficits → occupational challenges

Assumption 1

The body is like a machine.

Dysfunction is viewed as a mechanical problem that can be corrected or adapted using biomechanical principles.

Assumption 2

Function is dependent on physical mobility and strength.

Movement quality, joint integrity, and muscular function are essential for occupational performance.

Assumption 3

Impairments in range of motion (ROM), strength, and endurance limit function.

Restoring or compensating for these deficits supports functional independence.

Assumption 4

Function can be restored through targeted intervention.

Strengthening, stretching, and endurance training can remediate impairments.

Assumption 5

Repetition and graded practice improve function.

Motor learning and performance improve with structured, meaningful repetition.

Assumption 6

Purposeful activity is an effective intervention.

Activities must be meaningful to the client to be effective and motivating.

Assumption 7

Activities can be modified to meet the client’s current

ability.

Tasks are modified in difficulty, duration, or resistance to challenge without overwhelming.

Assumption 8

Participation in activity helps maintain and improve

function.

“Use it or lose it” – movement must be practiced to be preserved.

Assumption 9

Improvement in physical function leads to better occupational performance.

Gains in ROM, strength, and endurance support participation in self-care, work, and leisure.

Assumption 10

The balance of rest and stress is essential.

Rest allows recovery; stress (challenge) promotes adaptation and growth.

Muscle Strength

Muscle strength may be limited due to

many different factors, including injury,

disease, disuse, immobilization, and

overwork.

• Lower motor neuron diseases → polio, amyotrophic

lateral sclerosis (ALS)

• spinal cord injuries (SCI) or disease,

• peripheral nerve injuries or damage,

• muscle diseases (e.g., muscular dystrophy), and

• stroke

All these above conditions can result in loss

of muscle strength.

Muscle Strength continued

Conditions like stroke – have muscle tone

problems

• First normalize the tone using sensorimotor/neurodevelopmental/motor control

approaches

• Then → strengthen the muscles – should have volitional

control

In rheumatoid arthritis (RA), strengthening

done in remission stage not in an acute,

inflammatory phase.

Multiple Sclerosis (MS), strengthening in AM vs

PM due to fatigue

Physiology of Muscle Strengthening

To increase strength, the muscle must be

overloaded to the point of fatigue, which

recruits more motor units and causes

hypertrophy and hyperplasia of glycolic type

II (fast-twitch) muscle fibers.

When a muscle is stressed, this message is sent

to the central nervous system, which then

stimulates ribosomes to replicate more actin

and myosin.

As a result, the myofibrils thicken and increase

in length. The number and size of the

sarcomeres increases so there is an increase of

strength in the muscle.

Determinants of Strengthening Activities or Excerises

More duration and fatigue means more recruitment of motor units, in addidtion, weak muscles activate more motor units than strong muscles

Velocity

The speed of the activity or exercise

Slower consistent speeds increase muscle strength

Low-speed, high load excerise improves muscular force mainly at slow speeds

Muscle Contraction Type: Concentric vs Eccentric

Contraction

eccentric contraction increases muscle strength than concentric contraction

Signs of muscle fatigue and stress

Slowed performance

• Distraction

• Perspiration

• Increased rate of respiration

• Decreased ROM

• Inability to complete prescribed number of

repetitions

• Inability to maintain a given force

• Decreased time of contraction

• Increased time for muscle lengthening

• Tremors with contraction

• Increased HR and respiration with no increase in load

General sense of tiredness

• Attention wanders

• Incoordination

• Loss of concentration

• Substitution movements

Active Excerises

Movements done entirely by the client through the available range of motion(ROM) without any external resistance(other than gravity)

To build muscle strength until the client can handle light resistance (like

small weights, putty, or even ADLs like dressing or cooking).

Progression is essential

Resistive Excerises

Resistive activities and exercise are done when an outside resistance is required to apply maximal stress to the muscle to promote adaptation.

Benefits of Resistance Exercise

enhanced muscle performance

increased strength of connective tissues

greater bone mineral density

decreased stress on joints during

activity

reduced risk of soft tissue injury

Progressive Resistance Excerises

1. PRE method first determines the RM, which is the greatest amount of weight that

can be lifted, pulled, or pushed 10 times through the full existing ROM.

2. The RM is based on the muscle grades as a guide and is determined through trial

and error.

3. The client then performs

A. 10 repetitions at 50% of the RM,

B. 10 repetitions at 75% of the RM, then

C. 10 repetitions at 100% of the RM,

D. with 2- to 4-minute rests in between exercise sets.

4. These exercises should be performed once per day, four to five times per week

for maximum strengthening benefit.

Edema

Edema, often referred to as swelling, is

the build-up of interstitial fluid between

the cells.

It most often affects the feet, ankles, and

legs, but can also occur in other areas of

the body, including the face and hands

Common causes for edema

Allergic reactions

Obstruction of flow.

Critical illness.

Congestive heart failure.

Liver disease.

Kidney disease.

Pregnancy.

Medications.

Acute Edema

Acute edema is still quite fluid and mobile the tissue pits (indents readily

when pressed) deeply and rebounds quickly.

The edema can be moved around with pressure or

massage.

subacute edema

Subacute edema has accumulated more

protein and is more viscous as a result.

the tissue pits but is slow to rebound

Chronic Edema

Chronic edema has accumulated even more protein, to the point that fibrotic adhesions start to

form.

the tissue pits minimally, and the tissues may feel hard or

leather-like.

Volumetric measurement

affected limb is placed in water tank as water spills out and is collected in a container, difference of swelling is then measured

Contraindications of Volumetric Measurement

open wounds or skin conditions,

• Immediately after postop,

• with percutaneous pinning and external fixation

devices, healing skin grafts, and suspicion of infection.

Circumferential Measurement

when the edema is very localized (such as to a single

digit, making measurement of the entire hand unnecessary).

It is essential to measure at the same place from test to test.

Using anatomical landmarks can assist in the placement,

such as over the third digit PIP joint or 5 cm proximal to the

ulnar styloid.

Management of acute edema

Elevation:

• Limb above heart = improves venous & lymphatic flow

• Slings ≠ elevation → Often worsen edema by holding

arm below heart & limiting motion

Compression:

• Use light compression (e.g., gloves, Tubigrip, Coban)

• Avoid >60 mmHg: Collapses lymphatic pathways

• Should be snug, but easily pulled from skin slightly

Special Tips:

• Web spaces: Use gauze or Kinesio Tape to improve

compression

• Prevent rolling of garments: Cut slit to splay edge (avoids

high-pressure zones)

• Coban: Wrap distal to proximal, no tension; leave digit tips

visible

Additional Interventions:

• Cryotherapy: Effective in first 3–5 days post-

injury/surgery

• AROM & PROM: Reduce edema—especially overhead

movements

• During inflammation stage: Prefer immobilization to

avoid worsening inflammation

Sub-acute and chronic edema management

Contains more protein → must be cleared by lymphatic

system, not veins

Lymphatic capillaries open via tension on anchoring

filaments (from movement)

Movement-Based Techniques

•AROM, PROM, Light Isometrics → stimulate

lymphatic flow

•Kinesio Tape:

• Apply to stretched skin with no tension on tape

• After return to neutral, tape wrinkles → creates light

skin tension to open lymphatics

•Use light compression (as for acute edema)

•Add a chip bag under garments to:

• Provide texture and varied pressure

• Soften thick/viscous edema

Thermal Support (Post-Inflammation Stage)

•Use mild heat (96–100°F) to soften tissue pre-exercise

•Neutral warmth (e.g., thin neoprene sleeve or pressure

garment) also helps soften edema

Scar tissue management

❑All wounds will heal with scar tissue,

but not all scar tissue will impact

motion.

❑Scar tissue, particularly scars that

cross joints or run along tendons, can

significantly impact motion.

❑The size, color, and pliability of any

wounds or scars should be described

about how they affect joint motion

during initial and subsequent

evaluations.

❑Typically, by manipulating the scar

tissue with the fingers and pinching the

skin around the scar, a therapist can

determine whether any significant scar

adhesions exist.

❑Skin puckering around the scar with

motion can also be a sign of

adhesions.

❑Adhesions will contribute to

decreased ROM around a joint.

Causes of immobility

Coma

Complete Bed Rest

Paralysis

Trauma or Surgical Repair

Connective Tissue

Elastic & contractile tissues may

shorten → contractures

• May also lose elasticity →

stiffness

Cartilage

Can thin, soften, and lose

shock-absorbing ability

Documenting ROM

❑0° to 150°: No limitation

❑20° to 150°: A limitation in extension

(problem with the start position)

❑0° to 120°: A limitation in flexion

(problem with the end position)

❑20° to 120°: Limitations in flexion and

extension (problems with start and end

positions)

For example, if 20° of elbow hyperextension (an unnatural

movement) is noted, it should be recorded as follows:

❑0° to 150° of flexion

❑0° of extension

❑0° to 20° of hyperextension

Viscoelasticity in Biological Tissues

❑Some biological tissues (e.g., muscle, tendon) are

viscoelastic = viscous + elastic

❑Strain (deformation) depends on both:

❑Stress (force)

❑Time

❑Elastic & plastic changes happen gradually, not

instantly

Creep

•Example: Hanging a weight from a tree

branch

• Immediate stretch = elastic response

• Gradual stretch over time = creep

•Creep = Constant stress → increasing

strain

•Used in rehab to lengthen tissues—but

overuse can cause microtrauma

Stress Relaxation

•Example: Bending branch and holding it in place

• At first, tension builds

• Over time, stress decreases while shape (strain)

stays the same

•Stress Relaxation = Constant strain →

decreasing stress

•Safer technique to gently elongate tissue

Passive ROM

❑ Therapist or external force moves joint

❑ Maintains joint mobility, prevents stiffness

❑ PROM ≠ Stretching

❑ PROM = gentle movement without overpressure

❑ Stretching = prolonged hold at end-range (EZ)

PROM Contraindications and Precautions

Priority: Structural Stability (Biomechanical FOR)

• Always ensure tissues can tolerate external forces

• Do not proceed unless safety is confirmed

When to Be Cautious or Avoid PROM

• Recent surgeries (e.g., tendon repair)

• Fractures not yet stabilized

• Severe inflammation or infection

• Fragile tissues at risk of rupture

Therapist's Responsibility:

• Confirm movement restrictions post-surgery

• If unsure → Contact the surgeon

Differential Diagnosis of AROM Loss

•Causes of Limited AROM

• Contracture vs. Lag vs. Passive Insufficiency vs.

Adhesions

•Flowchart Overview

• PROM normal? → Lag

• PROM restricted? → Joint issue (contracture, viscosity,

etc.)

Interventions based on diagnosis

Lag (muscle weakness)

• AAROM, place & hold, gravity-minimized resistance

•Tendon Adhesions

• AROM with resistance, heat, tissue mobilization

•Passive Insufficiency

• Stretching opposite action while repositioning joints

•Viscosity vs. Contracture

• Try heat + mild stretch → >20° gain = viscosity

Stretching Techniques

•Passive vs. Active Stretching

•Static Stretch Guidelines

• Use slow, gentle, and sustained stretching

• 15–60 sec holds, 3–5 reps, 3–6 days/week

• Avoid bounce/stretch reflex

•PNF Techniques

• Contract Relax (CR) & Hold Relax (HR)

understanding muscle endurance

❑Endurance → A muscle's ability to sustain effort over time

❑Essential for completing ADLs without fatigue

❑Factors That Affect Endurance

❑ Muscle capacity and conditioning

❑ Cardiovascular system

❑ Pulmonary (respiratory) system

Deconditioning is caused by

❑ Illness

❑ Disuse

❑ Immobilization

❑ Prolonged bed rest

❑ Too much sitting / not moving

How is endurance measured?

❑Time or duration

❑Number of repetitions

❑Ability to complete an activity

Use of occupation for endurance

•Everyday tasks = repeated motions with light

resistance

• folding laundry,

• stirring,

• walking errands,

• meal prep