Physical Modalities in Sports Medicine

General Principles

A modality is the application of a therapeutic treatment in order to elicit an adaptive response within the body. The aim of modalities is to create an optimal healing environment. They are external treatments best thought of as an adjunct to the body’s own recovery process. Although they should not be the only treatment, they show value in the sports medicine realm by speeding up the return-to-play process. Some experts may claim that certain modalities are an integral part of healing and recovery from injury, although minimal evidence exists to support many claims.


Thermotherapy uses devices to conduct thermal energy via direct contact with skin to increase tissue temperature. The depth of thermal energy conduction is dependent on the method and duration of treatment application.

An increase in tissue temperature has the following therapeutic effects:

    • Vasodilation

    • Increased blood flow

    • Increased cell metabolism

    • Increased elasticity of collagen tissues

    • Decreased pain

    • Decreased muscle spasm

    • Decreased joint stiffness

Methods of Thermotherapy

  • Moist heat pack

    • Canvas covers filled with silica gel that come in varying sizes

    • Heated in hot water tanks (approximately 160°F [71°C])

    • Placed in insulating layers of clean towels or cloth covers

    • Heat dissipates quickly

    • Easier to get the patient in a comfortable position

    • Treatment duration: 10–20 minutes

  • Dry heat pad

    • Plug-in electrical or microwaveable varieties

    • Do not heat tissue as rapidly and comfortably as moist heat packs

    • Skin can be burned by prolonged or overly intense heat exposure

    • Treatment duration: 10–20 minutes

  • Whirlpool

    • The body part is immersed in a tub of water that has a motor for circulation

    • Water temperature usually ranges between 92°F and 110°F [33°C and 43°C], lower temperatures used with larger treatment areas

    • Water circulation keeps the temperature next to the skin constant and has a massaging effect

    • Care must be taken to keep open wounds and tank clean to prevent transmission of bacteria and infection

    • Treatment duration: 10–20 minutes

  • Paraffin bath

    • Mixture of wax and mineral oil melted to a liquid state (126°F–130°F [52°C–54°C])

    • Low specific heat of wax allows for comfort at higher temperatures

    • Apply multiple coats to a body part by dipping or brushing on, then allow to cool, which transfers heat into body tissues

    • Effective with irregularly shaped body parts such as hands and feet

    • Treatment duration: 10–15 minutes

Active Warm-Up

Exercise is the most effective at deep heating, as heat is a by-product of muscular work. Heat is transmitted from muscle into other body tissues and is carried away by the bloodstream. The more intense the exercise, the greater and quicker the heating. The benefits of using active exercise for tissue heating go beyond the thermal effects. Active warm-up increases vasodilation for increased speed of oxygen flow, heart rate elevation, achievement of metabolic steady state faster than with passive heating, and possibly lower lactate accumulation.

Thermotherapy Indications

  • Subacute conditions

  • Chronic inflammatory conditions

  • Pain modulation

  • General relaxation

  • Decreased range of motion

  • Hematoma

  • In preparation for therapeutic exercise

  • Injuries wherein the goal of treatment is to increase circulation

Thermotherapy Contraindications

  • Acute injuries (risk of increased swelling)

  • Circulatory insufficiency

  • Poor thermal regulation

  • Anesthetic areas

  • Fever

  • Skin conditions

  • Uncovered open wounds

  • Tumors

  • Thrombophlebitis

  • Nerve sensitivities

Thermotherapy Precautions

  • Fair skin that burns easily

  • Areas of decreased sensation

  • Dermatologic problems and disease transmittal

  • Vasovagal response


Cryotherapy involves the loss of thermal energy via skin with the application of a cold modality. As with thermotherapy, the depth of thermal energy conduction is dependent on the method and duration of treatment application. A decrease in tissue temperature has the following therapeutic effects:

  • Vasoconstriction

  • Decreased blood flow

  • Decreased swelling

  • Reduction in inflammatory mediators

  • Reduction in pain-producing substances

  • Decreased cell metabolism

  • Reduced elasticity in collagen tissues

  • Analgesia

  • Decreased muscle spasm

  • Increased joint stiffness

Methods of Cryotherapy

  • Ice bag

    • More conforming to the body part, which also results in greater cold effects

    • Treatment duration: 15–20 minutes

  • Reusable ice pack

    • Silica gel pack kept in a freezer that allows for multiple uses

    • To avoid potential skin irritation because of lower temperatures specific to reusable ice packs, apply insulating layer between the pack and skin

    • Treatment duration: 15–20 minutes

  • Chemical cold pack

    • Water and ammonium nitrate separated within a pack until ready to use

    • Chemicals mix when barrier is broken by squeezing

    • More expensive than ice bag or reusable ice pack

    • Chemicals can irritate skin if bag leaks

    • Treatment duration: 10–15 minutes

  • Ice cup massage

    • Water frozen in paper or plastic cups applied directly to skin in circular massaging motions

    • Limited to small treatment areas and requires active participation

    • Treatment duration: 5–10 minutes (or until analgesia is achieved)

  • Cold-water immersion

    • The body part is immersed in a tub of water and ice

    • Whirlpool uses a motor for circulation that keeps the temperature next to the skin constant and has a massaging effect

    • Water temperature usually ranges between 50°F and 65°F (10°C and 18°C), higher temperatures used with larger treatment areas

    • Care must be taken to keep open wounds and tank clean to prevent transmission of bacteria and infection

    • Treatment duration: 10–20 minutes

  • Whole-body cryotherapy (cryosauna)

    • A device (chamber- or barrel-like) that exposes the minimally dressed patient to extreme cold (<−212°F [−100°C]) via liquid nitrogen and refrigerated air

    • Currently, research on the effectiveness of whole-body cryotherapy is inconclusive, with the majority supporting effectiveness for relieving inflammatory conditions and symptoms and improving postexercise recovery

    • Treatment duration: no longer than 3 minutes

  • Vapocooling sprays

    • Chemical spray (ethyl chloride) topically applied on skin that cools immediately and evaporates quickly

    • Used whenever quick numbing is desired; trigger point treatment

  • Cryokinetics

    • Combination of cryotherapy with exercise in order to achieve normal range of motion using analgesia of the injured area

    • Exercise is done progressively and in pain-free ranges and can have multiple applications of cryotherapy

Cryotherapy Indications

  • Pain modulation

  • Swelling control

  • Desired analgesia effect

  • Muscle recovery

  • Muscle spasm

  • Heat-related illness

  • Inconclusive evidence for improvement of delayed-onset muscle soreness

Cryotherapy Contraindications

  • Uncovered open wounds

  • Circulatory insufficiency

  • Cold allergy/urticaria

  • Anesthetic area

  • Advanced diabetes

  • Peripheral vascular disease

  • Raynaud phenomenon

  • Rheumatoid arthritis

  • Lupus

  • Hypertension

  • History of vascular impairment (i.e., frostbite or arteriosclerosis)

  • Paroxysmal cold hemoglobinuria

  • Hypothyroidism (cryosauna)

  • Acute respiratory disorders (cryosauna)

Cryotherapy Precautions

  • Hypertension requires careful monitoring, and treatment should be discontinued if increases are shown

  • Elderly patients

  • Extended treatment could cause injury to superficial peripheral nerves

  • Claustrophobia (cryosauna)

Thermotherapy Versus Cryotherapy

  • In general, thermotherapy is used for stiffness and cryotherapy is used for pain

  • Only cryotherapy should be used with injuries in the acute inflammatory phase (∼24–72 hours postinjury)

  • Thermotherapy can be safely applied when out of the acute inflammatory phase

  • Only thermotherapy should be used before activity, exercise is the most optimal modality to achieve deep heating effects

Contrast Therapy

  • Alternating thermotherapy and cryotherapy applications to achieve neurogenic and cardiovascular effects for pain control, reducing fatigue, reducing delayed-onset muscle soreness, and swelling control

  • Most common method involves whirlpool; however, other methods may be used

  • Evidence suggests contrast therapy is superior to passive recovery but shows little difference compared with other recovery interventions

  • Treatment duration: warm:cold 1–3:1 for 10–20 minutes; no data for optimal dosage

Therapeutic Ultrasound

Therapeutic ultrasound (US) uses acoustic energy inaudible to the human ear to create metabolic changes at the cellular level via a coupling agent. Continuous US delivers a constant stream of energy, whereas pulsed US delivers energy in time-specific bursts. Treatment frequency is generally between 0.7 and 3.3 megahertz (MHz). Frequency and depth of penetration have an inverse relationship; 1 MHz penetrates 2–5 cm into the skin and 3MHz penetrates 1–2 cm into the skin. US can have the following therapeutic effects depending on the parameters chosen:

  • Thermal effects (continuous US):

    • Increased tissue temperature 1–5 cm below skin surface

    • Increased circulation, which may increase metabolic rate

    • Increased soft tissue extensibility

    • Reduced muscle spasm

    • Pain modulation

  • Nonthermal effects (pulsed and continuous US):

    • Acoustic streaming movement of fluids along cell membranes

    • Cavitation formation of gas-filled bubbles that can change cellular diffusion gradients

    • Micromassage-microscopic movement of fluids that is theorized to stimulate mechanoreceptors

  • The treatment area is two to three times the size of the device’s sound head, called the effective radiating area (ERA). If a larger area is desired, multiple treatments will be needed or another modality should be considered.

  • Sound head must be kept moving (∼2 inches/second) during the treatment to mitigate adverse effects and discomfort

  • Treatment duration: 1–10 minutes dependent on desired treatment effects

US Indications

  • Pain modulation

  • Muscle spasm reduction

  • Increase soft tissue extensibility

  • Bone and wound healing

  • Plantar wart management

US Contraindications

  • Bleeding or active infection

  • Deep vein thrombosis or thrombophlebitis

  • Cancer

  • External fixation devices

  • Around eyes, heart, skull, genitals, or central nervous system tissue

  • Over the trunk during pregnancy

US Precautions

  • Epiphyseal plates

  • Fracture or bone pathology

  • Injury in the acute inflammatory phase


Phonophoresis involves the use of therapeutic US to assist the diffusion of topical medications through the skin and into the target tissues. Improving cellular permeability is the main proposed mechanism, and both thermal and nonthermal parameters may be used depending on the treatment goal. Common medications used are topical analgesics and anti-inflammatories. Medication absorption is influenced by the following:

  • Water content of skin

  • Patient age

  • Thickness of skin

  • Vascularity

Ultrasonic Osteogenesis Stimulator

Ultrasonic osteogenesis stimulators use low-intensity pulsed US to facilitate fracture healing. These devices are separate machines from traditional therapeutic US machines with different settings. Treatment duration is 20 minutes/day.

Electrical Stimulation

Electrical stimulation uses electrical current delivered via wired electrodes to create cellular changes in the target tissue. Different therapeutic effects are achieved by manipulating the following parameters: waveform, modulation, intensity, duration, frequency, polarity, and electrode placement ( Table 44.1 ). Equipment used includes therapeutic electrical generators, both portable and nonportable, and electrodes. Modern devices have preprogrammed parameters to ensure patient safety and ease of use. Electrical stimulation has the following therapeutic effects:

  • Increased cellular metabolism via mitochondrial stimulation

  • Pain modulation

  • Elicit muscle contraction to increase blood flow locally

  • Stimulation of sensory, motor, and/or nerve fibers

Table 44.1
Electrical Stimulation Treatment Parameters
Goal Pain Management Wound Healing Edema Reduction Muscle Strengthening
Method TENS IFC High-Voltage NMES
Sensory Motor Hyperstimulation Sensory Motor Sensory Motor Low Rate Medium Frequency (Russian)
Current type Alternating Alternating Alternating Alternating Alternating Pulsed direct Pulsed direct Direct Direct
Pulse frequency (Hz) 50–110 1–5 1–4 50–100 1–5 80–105 4–10 35–80 2500
Phase duration (μsec) 50–125 200–500 250–10 msec Machine default Machine default Fixed 250 200–300 Machine default
Intensity Comfortable paresthesia, no muscle contraction Visible muscle contraction Highest tolerable noxious sensation Highest tolerable paresthesia, no muscle contraction Highest comfortable muscle contraction Below motor threshold Visible muscle contraction Maximum tolerable muscle contraction Maximum tolerable muscle contraction
Electrode placement Bipolar Bipolar Monopolar with point probe Quadripolar or bipolar with premodulated current Quadripolar or bipolar with premodulated current Monopolar Monopolar Bipolar Bipolar
Duty cycle (on:off) 100% 100% 100% 100% 100% 100% 1:1 with low on ramp 10s:50s with 1–2s on ramp 10–15s: 50–120s with 0.5–2s on ramp
Treatment duration 30–60 minutes, continuous 40–60 minutes 2 × 30 seconds for each point; 10–20 points max 20–30 minutes 20–30 minutes 60 minutes/day 5 days/week 30 minutes 8–10 repetitions 8–10 repetitions

Types of Current

  • Direct/monophasic

    • Continuous, unidirectional flow of charged particles

    • Electrodes represent positive and negative poles to facilitate current flow in one direction

  • Alternating/biphasic

    • Continuous bidirectional flow of charged particles

    • Current flow moves toward one pole of the circuit then changes direction to the opposite pole; no polar effects

  • Pulsatile

    • Discontinuous delivery of electrical current

    • Can be direct or alternating

    • Has an on period and an off period, stimulating electrical current delivery in “pulses”

Electrode Placement

  • Monopolar

    • Large dispersive pad placed away from treatment area and a small active pad placed over the treatment area

    • Used for polar effects such as wound healing, edema reduction, and medication delivery

  • Bipolar

    • Two pads of the same size

    • Treatment area between the electrodes

  • Quadripolar

    • Two pairs of electrodes with alternating currents that bisect each other

    • Treatment area between the electrodes where the current intersects

Methods of Electrical Stimulation

  • Transcutaneous electrical nerve stimulation (TENS). The main goal of TENS is pain modulation:

    • High-rate (sensory) TENS achieves fast-acting, short-duration pain management through stimulation of large-diameter (A-beta) nerve fibers

    • Low-rate (motor) TENS achieves slow-acting, long-duration pain management through stimulation of smaller-diameter (A-delta) nerve fibers

    • Noxious (hyperstimulation) TENS achieves pain management through stimulation of the smallest (C) nerve fibers

  • Interferential current (IFC). The main goal of IFC is pain modulation.

  • High-voltage The main goal of high-voltage is to use the polar effects for wound healing and edema reduction.

    • High rate (sensory) used for wound healing.

    • Low rate (motor) used for edema reduction.

  • Neuromuscular electrical stimulation (NMES). The main goal of NMES is muscular strengthening via increased alpha motor neuron recruitment. Larger fast-twitch fibers are recruited first and are more easily fatigued, resulting in muscular strengthening. The muscle strengthening is amplified if voluntary muscle contraction is combined with electrical stimulation. This is also used for stimulation of denervated muscle via regeneration of alpha motor neurons.

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