Exercise Prescription in Rehab for Mobility Impairments

Causes for mobility impairments

Psychological-behavioural: cognitive changes

Neural: motor control, nociception

Tissue: changes in structure + fxn, vascular reorganization

Connective tissue physiological adaptations when immobile

Collagen fibres….

• Cross-link: fibres get sticky and won’t move as well w/o regular movement

  • Happens to both dense regular and irregular

• Adhesions: cross link btwn 2 diff types of tissues. sticky

• Disorganized orientation: Proliferation of Type 3. No instructions to lay fibres

  • Usually line up according to line of stress

TAKES A LONG TIME

Mechanotransduction

Body converts mechanical loading → cellular response

Promotes structural changes in MSK tissues

Activates tissue remodelling = tissue shortens in cast

Mm physiological adaptations when immobile

• Primer: length tension curve → optimal length for contraction

• Tone: passive state of mm contraction/resistance to passive tension @ rest

  • Occur quickly

• Less # of sarcomeres in series/row to move mm in optimal position

  • I.e. increase # sarcomeres to lengthen tricep tissue in cast

Connective tissue mobility components

Move joint thru ROM

Limited by connective tissue

Due to structural changes (i.e. collagen) requires time

C/o stiffness

Mm Flexibility components

Move mm thru full ROM

Limited by mm

Neural control impacts → occurs quickly

C/o: tightness

Connective tissue response to tension depends on…

• Rate

• Time: force over time

• Want to break to regain movement!

Bc its viscoelastic

Stress relaxation

Temporarily changes mobility

Elastic deformation phase

Stress relaxation: Some give when apply force to straighten fibres

• Tissue relaxes in response to stress

Creep: Increase tissue length over time

• Will eventually resume the previous position

TEMPORARILY CHANGE MOBILITY

Microscopic changes/failures. Breaks collagen cross-link adhesions. Discomfort.

Plastic deformation phase

Microscopic failure

Macroscopic failure

Permanent change in mobility!

Ways to improve connective tissue mobility

1. Low-load prolonged stretch

2. Total end range time (TERT)

Low-load prolonged stretch

F: > 3x/day [high intensity, low time]

I: into stiffness NOT pain

T: position of tension

V: 5 → 20 mins/session

P: ↑ volume (TERT > 60 mins/day)

• ↑ intensity w/ gravity/external load

Good for post-op

Connective tissue mobility

F: > 3x/day

I: into stiffness, not pain

T: slow PROM/AAROM/AROM into position of tension

V: 5 →10 reps. hold 10 → 30s , 1→3 sets

P: ↑ vol (TERT). Progress to AROM. [↑ AROM]

Mm response to tension/stretch

• Mm spindle activation: intrafusal. Sends 1a afferent sig to SC. Causes contraction thru alpha mn. Inhibitory sig to antagonist. Temporary contraction to mm in response to stretch

• Stimulates myotatic/stretch reflex

• Mm contraction

How to think of Myotatic/stretch reflex as….

NEUROLOGICAL RESET of mm tone via contraction to restore optimal position of myofilament overlap

Sensory theory

No lasting changes in mm length after static stretching

Temporary ↑ mm flexibility due to ↑ pain/tension tolerance

• Change in pain perception, environment around injury has changed.

Tendon response to tension (mm contraction) - GTO

• Activates GTO → GTO reflex

• MM relaxation

• In musculotendonous junction

• Stimulated by MM CONTRACTION (not stretch bc spindle does that).

• GTO relaxes mm

Consider GOT as…..

Neurological rest of mm tone via mm RELAXATION to restore optimal position of myofilament overlap.

Neuromuscular relaxation theory

Autogenic inhibition: hold-relax to get more mobility.

PNF

Contract relax

After contracting, it relaxes. Immediate response to tone.

Structure unchanged

Types of MM stretching

Dynamic, static, pre-contraction (Proprioceptive Neuromuscular Facilitation)

Benefits of Dynamic stretching

↑ ROM, performance (immediately be4 activity)

Dynamic stretching prescription

F: 3x/wk regularly

I: into tightness not pain

T: slow, controlled concentric of the antagonist to put the agonist in tension

V: 1-3 sets or 5-10 reps

Static stretching effects

↑ ROM

↓ performance be4 activity [strength, power]

• Bad for long-duration activity

Short static stretch

• DOESN’T affect neuromusclar activation & musculotendinous stiffness

  • Longer does

• Reduce injury risk in high intensity activities

Static stretching prescription

F: 2-3x/wk

I: into tightness not pain

T: slowly + passively assume position of tension in target mm

V: 10-30s (30-60s for older) 1-3 reps

What type of stretch is best?

Pre contraction stretching

Pre-contraction stretching prescription

Contract-relax (hold-relax)

F: 2-3x/wk

I: Gentle isometric contraction ~20% MVC of target mm

• Doesn’t take lots of effort to activate GTO

T: Slowly + passively assume position of tension in target mm until feel tightness

V: 3 ≥10s, repeat immediately x 1-3 reps (quickly)

Unilateral stretching improves…

Mobility in contra-lateral (non-stretched limb)

Centrally mediated neuromuscular mechanism

Stretch good leg to get benefits in immobilized leg

FOAM ROLLING

Improves mobility

Comparable to static stretching

• Best followed by static stretching

Due to neuromuscular + sensory mechanisms (not structural)

Neurophysiological changes

Temporarily changes tone to relax muscles

NO STRUCTURAL CHANGES!

Eccentirc training improves mobility

Comparable to static stretching

Sarcomerogenesis: increased fascicle length

Strength based

Less temporary, more permanent

Actual structural changes in length

Which type of stretch to use for mm?

Depends on client’s stage of healing, irritability & goal

Best practise to improve connective tissue mobility

Low load prolonged stretching w/ progressive total end range time