Thermal modalities are perhaps the most widely used and readily available of all treatment options for the rehabilitation professional. Undeniably, a hot or cold modality is used either in the physical therapy clinic setting or athletic training room more than any other treatment modality. Further, these heat or cold modalities can be used on people of all ages, activity levels and stage of injury. Reasons for using thermal modalities are most notably for pain and swelling reduction, as well as improving range of motion. There are a host of options for the clinician to choose from when deciding which type of modality to use, but these options go beyond hot packs and ice bags. Shortwave diathermy, ultrasound and cold compression units are other thermal resources at the clinician's disposal.

Clinical Application of Cold Modalities

By far, the most common cold modality is ice in some form. It's cheap and readily available-"ice it" has been a timeless instruction after injury. Ice is often used to offset pain, swelling and dysfunction associated with minor athletic trauma.¹Researchers have found that cold leads to pain relief through altered nerve conduction velocity, inhibition of nociceptors, reduction in spasm, reduced metabolic enzyme levels, reduced inflammation and increased pain tolerance.^2,3For acute injuries, it is recommended that ice immersion be used when possible. For example, ice water immersion would be appropriate after an ankle sprain. Knight and Londeree have previously proposed using "cryokinetics," cold application with exercise, as an effective means of treating these injuries.⁴It is suggested that the athlete be placed in an ice water immersion bath for three to four minutes, followed by exercise that may include gait training or ankle range-of-motion exercises for a few minutes. The process would then repeat for a total treatment time of 20 minutes.

Cryokinetics could also be used with success in thigh contusions, elbow injuries and wrist injuries. Following the above treatment with compression and elevation to further reduce swelling is advocated for acute injuries. Ice immersion of the elbow is an excellent treatment for pitchers following practices or games. If ice immersion is not possible or available, multiple icing sessions per day following an acute injury are advocated for pain relief if anything, but potentially for swelling reduction when coupled with compression and elevation.

Cold whirlpool is very popular for athletes. This author has experience at the Division I level as well as with Major League Baseball and the National Football League. Athletes routinely get in cold tubs after practices or games to "get their legs back" and help with post-exercise leg soreness. It is believed that the cold immersion results in rapid cooling and subsequent systemic vasoconstriction that will ultimately reduce pain and limit secondary hypoxic injury from the waste products built up with vigorous exercise.

Patterson has found that cold whirlpool immersion can reduce power, speed, range of motion and agility for up to 30 minutes after application.¹Therefore, it is recommended that cold whirlpool only be used after exercise. Contrast therapy has been used for years in athletes, mostly after exercise. The theory behind it is that through contrast, there is vasodilation and vasoconstriction that "pumps" waste products to enhance recovery. Little evidence supports contrast therapy, but it is commonly used.

Ice massage is incredibly effective for treating superficial soft-tissue injuries. It is an excellent choice for Achilles and patellar tendon injuries, medial collateral ligament injuries, "shin splints," and tendonitis of the ankle, knee, elbow and shoulder. In cases of tendonitis, it behooves the clinician to ensure that a true inflammatory condition exists. In cases of chronic tendinopathy, there is no inflammation present. Therefore, ice is not likely to be useful. Ice massage has also been used with success for analgesia in patients with patellofemoral pain. Ice massage seems be more effective because the application can be focused on a specific spot and analgesia is achieved faster compared to an ice bag.

In cases of deep-muscle contusions, as in a thigh bruise, it is ­suggested that the athlete ice several times a day with the muscle on stretch to minimize the risk of myositis ossificans. Placing the muscle on stretch with ice minimizes the risk of pooling of blood. A complement to the proposed treatment is to place a pad over the area with compressive wrapping to further compress the region and reduce the risk of pooling. Once the acute phase is over, active exercise followed by stretching and ice in the stretched position is advised.

There is little evidence supporting electrical stimulation with ice or compression and ice.^5,6 ore research is needed on the effects of vasopneumatic devices on swelling compared to compression with compressive wraps. Unfortunately, it is difficult to quantify the placebo effect with modalities. Regardless, it is safe to assume that ice in any capacity is helpful for pain relief.

Clinical Application of Heat Modalities

It is generally accepted that heat modalities are used to increase local or systemic circulation and promote vasodilation with the goal of increasing tissue temperature. Moist and dry heat are commonly used, but two other modalities are worth noting. Shortwave diathermy has made a comeback recently-it was more common in previous decades as a deep-heating modality to help with chronic inflammation. It is beyond the scope of this review to discuss all relevant studies on diathermy, but previous researchers have found it may increase circulation and change tissue temperature as well as decrease pain and swelling, particularly in those with chronic joint pain.⁷

Another common heating modality, and possibly the most controversial, is therapeutic ultrasound. Ultrasound is a widely used and potentially abused modality for deep heating. Draper and colleagues have previously concluded that 3 MHz ultrasound heats faster than the 1 MHz frequency and that a treatment area of no more than twice the size of the ultrasound head is most effective for heating tissue.⁸

A generally accepted dogma in rehabilitation is "heat before, ice after." Moist hot packs are an excellent preparatory treatment to use prior to soft-tissue treatment or myofascial release to promote blood flow and relaxation. Similar to cold whirlpool, a hot whirlpool is an effective means for systemic vasodilation. Furthermore, it may be helpful for increasing nerve excitation prior to activity.

In cases of chronic inflammation, it may be more advantageous to use hot packs, thermal ultrasound or diathermy if available. Much like a degenerative joint that responds well to heat and/or exercise, degenerative tendons respond similarly and should be treated as such. Ice is not advocated for chronic tendinopathies and little research supports using ice for chronic conditions.

Thermal ultrasound can be used to heat tissue prior to joint or soft-tissue mobilization. Ultrasound over the anterior capsule of the shoulder, or a chronic tendinopathy of the Achilles or patellar tendons is a possibility as a preparatory treatment prior to exercise. Using thermal ultrasound is potentially helpful not only due to the thermal effects, but also due to the proposed mechanical effect of facilitating collagen deposition and increasing vascular permeability. Perhaps the best way to heat tissue is through exercise. Placing an athlete on a bike, upper-body ergometer, or sending him on a jog is a great way to promote systemic heating through increases in blood flow and increased body temperature. A good rule is to ensure that the athlete breaks a sweat to determine if he is adequately warmed up.

Finally, the concept of "total end range time (TERT)," previously advocated by McClure et al, uses sustained stretch with heat, exercise and ice for increasing and maintaining soft-tissue extensibility.⁹Basically, the use of TERT involves heating tissue for 20 minutes with a sustained stretch, then exercising for 20 minutes, and finally icing for 20 minutes in the "new" range. Even though the McClure et al study used splinting to increase extensibility in a stiff joint, the concept can be applied clinically as the clinician "splints" the joint with a sustained stretch while using thermal modalities and exercise. The TERT formula can be used with success in stiff knees and shoulders following surgical procedures.

Thermal modalities are a cost-effective means to help with an array of conditions for diagnoses across the lifespan. Although the mechanisms are not well understood, they have historically been and will continue to be a widely used and clinically effective option in the treatment plan.

References

1. Patterson, S., Udermann, B., Doberstein, S., & Reineke, D. (2008). The effects of cold whirlpool on power, speed, agility, and range of motion. Journal of Sports Science Medicine, 7, 387-394.

2. Algafly, A., & George, K. (2007). The effect of cryotherapy on nerve conduction velocity, pain threshold, and pain tolerance. British Journal of Sports Medicine, 41, 365-369.

3. Schaser, K., Disch, A., Stover, J., et al. (2007). Prolonged superficial cryotherapy attenuates microcirculatory impairment, regional inflammation, and muscle necrosis after closed soft-tissue injury in rats. American Journal of Sports Medicine, 35, 93-102.

4. Knight, K., & Londeree, B. (1980). Comparison of blood flow in the ankle of uninjured subjects during therapeutic applications of heat, cold and exercise. Medical Science of Sports Exercise, 12, 76-80.

5. Hubbard, T., & Denegar, C. (2004). Does cryotherapy improve outcomes with soft-tissue injury? Journal of Athletic Training, 39, 278-279.

6. Bleakley, C., McDonough, S., & MacAuley, D. (2004). The use of ice in the treatment of acute soft-tissue injury: A systematic review of randomized controlled trials. American Journal of Sports Medicine, 32, 251-261.

7. Jan, M., Chai, H., Wang, C., et al. (2006). Effects of repetitive shortwave diathermy for reducing synovitis in patients with knee osteoarthritis: An ultrasonographic study. Physical Therapy, 86, 236-244.

8. Draper, D., Castel, J., & Castel, D. (1995). Rate of temperature increase in human muscle during 1 MHz and 3 MHz continuous ultrasound. Journal of Orthopedic Sports Physical Therapy, 22, 142-149.

9. McClure, P., Blackburn, L., & Dusald, C. (1994). The use of splints in the treatment of joint stiffness: Biologic rationale and an algorithm for making clinical decisions. Physical Therapy, 74, 1101-1107.

Dan Lorenz is a sports medicine specialist at Providence Medical Center in Kansas City, KS, as well as an adjunct faculty member at Rockhurst University in Kansas City, MO.