Week 2: Heat, Ice, US

A smaller area _____ the risk of burn/frostbite

increases

Order of Thermal Conductivity (3 // High to Low)

1. Metal

2. Water

3. Air

Superficial vs Deep Heating

Superficial: mm; heat packs, paraffin

Deep: cm; ultrasound

Hemodynamic Effects of Thermotherapy

• Vasodilation (SUPERFICIAL)

• Increased venous and lymphatic drainage

• Increased capillary permeability

Neuromuscular Effects of Thermotherapy

• Increased nerve conduction velocity

• Decreased pain

• Decreased DOMs when applied within 1 hr

• detrimental to endurance athletes

To increase collagen extensibility, you must raise the temperature by ___ C / ___ F

4; 5.6

Increase of collagen extensibility due to thermotherapy is only _____, such as with scars

superficial

Superficial Heat Indications

• Pain control

• Increase ROM/decrease stiffness

• Muscle spasms

Superficial Heat Contraindications

• Recent hemorrhage

• Thrombophlebitis

• Impaired sensation or mentation

• Malignancies in the region

• Acute inflammation

Hot Pack Application: Tx time, layer count, skin check time

Tx time: 15-20 minutes

Layers: 6 to 8 layers (covers count as 2 layers)

Skin Check: 5 minutes or upon discomfort

Hemodynamic Effects of Cryotherapy

• Decreased blood flow

• Hunting response (cycles of dilation/constriction)

  • NOT desired

Neuromuscular Effects of Cryotherapy

• Decreased NCV (~5 minutes to effect)

• Decreased pain, increased pain threshold

• <5 min: mild isometric improvement

• >5 min: decreased muscle strength

• Decreased spasticity (10-30 minutes)

• Facilitation of muscle contraction (Brief application)

Cryotherapy Indications

• Acute inflammation control (~15 min to effect)

• Pain control

• Spasticity control

• Muscle facilitation

• Post-ex DOMs reduction

Cryotherapy Contraindications

• Cold intolerance (ex. rehumatic disease)

• Cryoglobulinemia (impaired blood flow)

• Paroxysmal cold hemoglobinuria

• Raynaud’s

• Regions of reduced circulation or sensation

Thermo/Cryotherapy Screening

• Sensation check

• Skin inspection

• Pulses

• Medical Hx

Urticaria

Localized OR systemic hives resulting from cryotherapy

Depth of cooling from ice packs

~1 cm into muscle (1cm subq)

Barrier Effect categories (3)

Low: Good for longer-duration icing or for sensitive patients

ex. padded ice

Moderate: Safer than direct contact but less efficient than wet wrap

ex. Dry wrap

High: Ideal for acute injury

ex. Wet wrap

Ice Massage Procedure

• Rub in local region until numb

• Area will turn red → white

• 5-6 minutes max

Therm vs Cryo for different stages of tissue healing

Acute: Cold only

Subacute: Cold or heat

Chronic: Cold or heat

Ultrasound Indications

• Shortened tissue

• Pain

• Dermal ulcers, sx scars

• Carpal tunnel

• Connective tissue injury

Ultrasound Contraindications

• Cancer (over region)

• Pregnancy (over trunk)

• CNS tissue

• total jt. near plastic or bone cement

• Pacemakers

• Thrombophlebitis

US Absorption by Tissue Type (Low to High)

• Blood

• Fat

• Muscle

• Tendon/Ligament

• Cartilage

• Bone

Also in order of density. Also the same as attenuation order.

Standing Wave

Adverse effect of US when a reflected wave combines with a source wave, resulting in periosteal burning.

Avoided by continuous movement over are 2x the size of the sound head.

Mechanical vs Thermal effects of US

Mechanical: Acoustic streaming and cavitation improve diffusion across cell membranes, increasing function/healing.

Thermal: Increased metabolic rate(+1C), reduced muscle spasm/pain(+2-3C), increased collagen extensibility(+4C).

US Frequency, Intensity, Duty Cycle, Tx Time

Frequency:

• 1 MHz: Deep (5 cm)

• 3 MHz: Superficial (up to 2.5 cm)

Intensity:

• 0.5 W/cm²: Superficial Thermal

• 0.5-1.0 W/cm²: Non-thermal

• 1.5-2.0 W/cm²: Deep Thermal

Duty Cycle:

• Pulsed 20%: Non-thermal

• Pulsed 50% or Continuous: Thermal

Tx Time:

• 4 min/area: Non-thermal

• 5-10 min/area: Thermal

Acute Healing US Settings

Non-thermal Indicated for Acute Healing

Frequency: 1 or 3 MHz for depth

Intensity: 0.5-1.0 W/cm²

Cycle: Pulsed 20%

Tx Time: 4 min/area

Chronic Healing US Settings

Thermal indicated for Chronic Healing

Frequency: 1 or 3 MHz for depth

Intensity: 0.5 W/cm² or 1.5-2.0 W/cm² for depth

Cycle: Pulsed 50% or continuous

Tx Time: 5-10 min/area