NATA-BOC Therapeutic Intervention and Modalities 2 — Questions and Answers

Question 1: An athletic trainer is considering using therapeutic ultrasound on an athlete's chronic patellar tendinopathy. Which parameter settings would be most appropriate?

1 MHz, continuous mode, 1.5 W/cm2
3 MHz, continuous mode, 1.0 W/cm2 (Correct answer)
1 MHz, pulsed 20%, 0.5 W/cm2
3 MHz, pulsed 50%, 2.0 W/cm2

Correct answer: 3 MHz, continuous mode, 1.0 W/cm2

The patellar tendon is a superficial structure, so 3 MHz (penetration depth 1-2 cm) is appropriate. Continuous mode provides thermal effects that benefit chronic conditions by increasing tissue extensibility and blood flow.

Therapeutic ultrasound parameter selection depends on tissue depth and treatment goals. Frequency: 1 MHz penetrates 3-5 cm (deep structures — hip joint, deep muscles), while 3 MHz penetrates 1-2 cm (superficial structures — tendons, superficial muscles, scar tissue). The patellar tendon is superficial, making 3 MHz the correct choice. Mode: continuous delivers sustained thermal energy (appropriate for chronic conditions), while pulsed mode emphasizes non-thermal effects (appropriate for acute conditions). Intensity for thermal effects: 0.5-2.0 W/cm2. The effective radiating area (ERA) of the sound head should be at least half the treatment area. Treatment time depends on the treatment area relative to the ERA. An intensity of 1.0 W/cm2 in continuous mode at 3 MHz provides adequate heating for a chronic tendon condition without excessive temperature rise.

Question 2: Which contraindication would prevent an athletic trainer from applying electrical stimulation?

Previous surgery at the treatment site (healed)
Active deep vein thrombosis in the treatment area (Correct answer)
Mild muscle guarding in the cervical region
Chronic lateral epicondylitis

Correct answer: Active deep vein thrombosis in the treatment area

Active deep vein thrombosis (DVT) is an absolute contraindication for electrical stimulation. Muscle contractions induced by electrical stimulation could dislodge the thrombus, causing a potentially fatal pulmonary embolism.

Absolute contraindications for electrical stimulation include: active DVT or thrombophlebitis (risk of embolism), over the carotid sinus area (risk of cardiac arrhythmia or hypotension), over the transthoracic area in patients with cardiac pacemakers (interference with pacemaker function), over the pregnant uterus, over active hemorrhage, and directly over cancerous tissue. Relative contraindications include: impaired sensation (risk of burns), skin irritation or breakdown, confusion or inability to report sensation, and metal implants (depending on modality). Previous healed surgical sites are not contraindicated — electrical stimulation is actually commonly used post-surgically for muscle re-education. Muscle guarding and chronic tendinopathy are common indications for electrical stimulation. Athletic trainers must thoroughly screen for contraindications before applying any modality.

Question 3: An athletic trainer applies ice massage to an athlete's medial epicondylitis. What is the typical duration for ice massage treatment?

3-5 minutes
5-10 minutes (Correct answer)
15-20 minutes
25-30 minutes

Correct answer: 5-10 minutes

Ice massage is typically applied for 5-10 minutes due to the direct contact of ice on skin. The intense cold application provides faster cooling than ice bags, and the CBAN sequence (Cold, Burning, Aching, Numbness) is usually completed within this timeframe.

Ice massage involves direct application of ice to the skin in slow, circular or longitudinal strokes. Because there is no barrier between the ice and skin, cooling occurs rapidly. The treatment duration of 5-10 minutes is sufficient to produce: analgesia (pain relief through numbness), decreased local metabolism, vasoconstriction, and reduced muscle spasm. The patient typically progresses through the CBAN sequence: Cold sensation, Burning sensation, Aching sensation, Numbness (at which point treatment should end). This is shorter than the 15-20 minutes typically used for ice bag application, which has a barrier (towel, plastic bag) between the ice and skin that slows heat transfer. Ice massage is particularly effective for treating small, well-defined areas such as the medial or lateral epicondyle, patellar tendon, and Achilles tendon. Contraindications include Raynaud's disease, cold allergy, and impaired sensation.

Question 4: Which therapeutic modality uses alternating current at frequencies of 4,000 Hz to achieve deeper tissue penetration for pain management?

TENS (Transcutaneous Electrical Nerve Stimulation)
Interferential current (IFC) (Correct answer)
Galvanic stimulation
Russian stimulation

Correct answer: Interferential current (IFC)

Interferential current uses medium-frequency alternating currents (typically 4,000 Hz) from two channels that intersect in the tissue, producing a beat frequency at the treatment depth that achieves deeper penetration with less skin resistance.

Interferential current therapy uses two medium-frequency sinusoidal currents (typically 4,000 and 4,100 Hz) applied through two electrode channels. Where the currents intersect (interference zone), they produce a beat frequency equal to the difference between the two carrier frequencies (in this example, 100 Hz). The advantage of IFC: medium-frequency currents encounter less skin impedance than low-frequency currents (TENS), allowing greater current delivery to deeper tissues with less patient discomfort. The beat frequency can be adjusted to target different physiological effects: 1-10 Hz for endorphin release, 90-130 Hz for pain gate mechanism, and 10-50 Hz for muscle stimulation. TENS uses low-frequency current (2-150 Hz). Galvanic stimulation uses direct current. Russian stimulation uses medium-frequency current (2,500 Hz) in bursts designed for muscle strengthening.

Question 5: An athletic trainer decides to use iontophoresis to deliver dexamethasone to treat an athlete's plantar fasciitis. Which electrode carries the medication?

The anode (positive electrode)
The cathode (negative electrode) (Correct answer)
Either electrode depending on the tissue being treated
A neutral electrode placed between the anode and cathode

Correct answer: The cathode (negative electrode)

Dexamethasone is a negatively charged ion and is delivered under the cathode (negative electrode). In iontophoresis, like charges repel — the negative electrode repels the negatively charged drug into the tissue.

Iontophoresis uses direct current to drive ionized medications through the skin via electromotive force. The principle is 'like repels like' — a negatively charged medication is placed under the negative electrode (cathode), and the current repels it into the tissue. A positively charged medication goes under the positive electrode (anode). Common medications and their polarity: Dexamethasone (negative/cathode) — anti-inflammatory for tendinopathy, plantar fasciitis, bursitis; Lidocaine (positive/anode) — local anesthetic; Acetic acid (negative/cathode) — calcium deposit dissolution; Calcium chloride (positive/anode) — muscle spasm reduction. Treatment parameters: typically 40-80 mA-minutes (intensity multiplied by time), with current density not exceeding 0.5 mA/cm2 to avoid burns. Contraindications include skin irritation/breakdown, metal implants in the current path, and allergy to the medication.

Question 6: During a moist heat pack application, how many layers of toweling should be placed between the pack and the patient's skin?

1-2 layers
6-8 layers (Correct answer)
10-12 layers
No layers; direct contact is recommended

Correct answer: 6-8 layers

Six to eight layers of commercial toweling should be placed between the hydrocollator pack and the skin. This provides adequate insulation to prevent burns while allowing therapeutic heat transfer to the tissue.

Hydrocollator moist heat packs are stored at 160-170 degrees F (71-77 degrees C) and can cause severe burns if applied directly to the skin. The standard recommendation is 6-8 layers of commercial terry cloth toweling. Commercial hot pack covers typically provide 4 layers, so 1-2 additional towels may be needed. The layers serve as: thermal insulation to prevent burns, a barrier that allows gradual heat transfer, and protection against moisture. Important clinical considerations: the patient should feel comfortable warmth, not excessive heat; always check the skin after 5 minutes; never allow the patient to lie on top of the pack (compresses the toweling and reduces insulation); treatment duration is typically 15-20 minutes. Contraindications include impaired sensation, acute inflammation, active bleeding, and compromised circulation. Patients on blood thinners may be more susceptible to burns and require additional monitoring.

NATA-BOC Therapeutic Intervention and Modalities 2

An athletic trainer is considering using therapeutic ultrasound on an athlete's chronic patellar tendinopathy.
Which parameter settings would be most appropriate?