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Thermal Modalities. ESAT 3640 Therapeutic Modalities. Infrared Modalities. Ice packs, hot packs, paraffin bath, H/C whirlpools are all infrared modalities Wavelength and frequency that falls within the infrared region. Mechanisms of Heat Transfer. Conduction Convection Radiation
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Thermal Modalities ESAT 3640 Therapeutic Modalities
Infrared Modalities • Ice packs, hot packs, paraffin bath, H/C whirlpools are all infrared modalities • Wavelength and frequency that falls within the infrared region
Mechanisms of Heat Transfer • Conduction • Convection • Radiation • Conversion
Appropriate Use of Infrared Modalities • Sometimes abused by athletic trainers • Don’t use just because you have it available • Know benefits of use
Terminology Related to Infrared Modalities • Thermotherapy • Cryotherapy • Hydrotherapy
Clinical Applications • Effect is primarily superficial and directly affects cutaneous blood vessels and cutaneous nerve receptors • Depth of penetration is 1 cm or less • Used primarily to provide analgesia and pain reduction
Clinical Applications continued • Cutaneous heat can cause a reflexive increase in blood flow to underlying tissue • Cutaneous cold can decrease blood flow in injured area • If primary goal is to decrease temperature and decrease blood flow to injured area you must use ice or cold application
Effects of Tissue Temperature Change on Circulation • Main physiological effect is on superficial circulation • Circulation through skin serves 2 major functions • Nutrition of skin • Conduction of heat from internal structures
Circulatory Apparatus • Arteries, capillaries, and veins • Vascular structures for heating the skin • Subcutaneous venous plexus • Arteriovenous anastomosis
Response of Circulatory Apparatus to Cold • Cold application to the skin causes constriction of the skin vessels to a temperature of 57° F • At temperatures below 57° F vessel begin to dilate
Thermoreceptor Response • Both cold and warm receptors adapt rapidly to temperature change • The faster the temperature change; the more rapid the receptor adaptation • Small vs. Large surface areas
Hypothalamic Centers • Stimulation of anterior hypothalamus causes cutaneous vasodilation • Stimulation of the posterior hypothalamus causes cutaneous vasoconstriction
Effects of Tissue Temperature Change on Muscle Spasm • Physiological mechanism related to heat or cold treatment in the reduction of muscle spasm lie at the level of the muscle spindle, GTO, and the gamma efferent system • Heat has relaxing effect • Lessens stimulus threshold of muscle spindle • Decrease in gamma efferent firing rate
Effects of Tissue Temperature Change on Muscle Spasm Continued • Cold decreases local neural activity • GTO firing rate decreases • Decreased rate of afferent activity with increased amount of tension on the muscle • Miglietta study
Physiologic Effects of Tissue Cooling • Local decrease in temperature • “primary reason for using cold in acute injury is to lower the temperature in the injured area, thus reducing the metabolic rate with a corresponding decrease in production of metabolites and metabolic heat” • Ho, et al Am J Sports Med 23(1): 74-76, 1995 • Cold + Compression is most effective
Progression of Sensations Related to Cold • Cold • Burning • Aching • Analgesia • numbness
Cold Reduction in release of inflammatory mediators Decreased prostaglandin synthesis Decreased capillary permeability Heat Accelerate inflammation Effects of Cold and Heat on Inflammation
Cold Gate Theory Heat Gate theory Increased blood flow = removal of waste product Removal of swelling Pain Control
Cryotherapy Techniques • Ice packs • Ice massage • Cold whirlpool • Cold spray • Ice immersion • Cryo-cuff • Contrast bath
Thermotherapy Techniques • Hydrocollator packs • Warm whirlpool • Paraffin bath • Fluidotherapy