Evidence-based research has confirmed the effect of therapeutic modalities for pain relief in a variety of patient populations. Michelle, a patient who is attending physical therapy in an outpatient setting for left hip pain during dance class, receives ultrasound from Catherine A. Grumbein PT, DPT.
By Catherine A. Grumbein, PT, DPT
Physical therapists are often faced with the challenge of returning athletes back to sports when they seek relief for a variety of ailments. Pain is the number one reason patients seek physical therapy. There are many sources of pain, including referred, radicular, phantom, acute, chronic, and neurogenic, to name a few. As physical therapists, pain management begins with identifying the source of pain; decreasing chemical, mechanical, and psychological causes of pain; and facilitating tissue healing. It is also known that gender differences play a role in the rehabilitation process. These gender differences are another factor that contributes to physical therapists’ challenges in getting athletes back to their sport.
Techniques and resources we utilize to help decrease our patients’ pain are quite extensive, but modalities have been a common entity in the treatment of pain. Modalities are one of many treatment options that can be used not only for our pain management patients, but our female athletic population. First, we must recognize that gender differences play a role in the rehabilitation process and pain management in physical therapy. These differences are what dictate which modality of choice we as physical therapists should implement during therapy.
Effects of Gender
It has been readily researched that female athletes have a higher incidence than men of musculoskeletal injuries due to biomechanical alignment, hormonal influences, and neuromuscular factors. For example, ligamentous laxity and a decreased intercondylar notch may result in increased ACL and meniscus tears, strains, and sprains in females compared to their male counterparts.1 Increased progesterone or estrogen, too, increases the ligamentous laxity in the female population, making female athletes more susceptible to injuries. Female athletes tend to have a wider pelvis, an increased Q angle, femoral anteversion, increased tibial torsion, abduction at the knee, and increased ankle eversion attributing to biomechanical differences, setting female athletes at a higher rate of injury.2 These anatomical differences often place greater risk of injury for the female athlete. Furthermore, neuromuscular differences play a role in the risk of injury between genders.
One of the biggest reasons for sports performance differences in men and women is glucose use and skeletal muscle fiber type.2 Women tend to have a greater proportion of Type 1 fibers and greater capillary density. This leads to the ability to hold off fatigue, better tissue perfusion, and greater capacity for glucose and fatty acid oxidation.2 Men have a higher glycolytic capacity, meaning they can burn through more glucose in the absence of oxygen, which lends itself to better performance for short-intense bursts of effort. This is related to a higher percentage of Type II fibers. This is one reason male athletes tend to be faster and stronger in athletic competition.2
[sidebar float=”right” width=”250″]Product Resources
The following companies provide products for pain management:
Accelerated Care Plus
www.acplus.com
Amrex Electrotherapy Equipment
www.amrexusa.com
Ari-Med Pharmaceuticals
www.ari-med.com
Battle Creek Equipment Company
www.battlecreekequipment.com
Dynatronics Corp
www.dynatronics.com
Everyway4all
www.everyway4all.com
JTECH Medical
www.jtechmedical.com
LiteCure
www.litecure.com
Mettler Electronics
www.mettlerelectronics.com
OPTP
www.optp.com
Parker Laboratories
www.parkerlabs.com
PHS Medical by Pivotal Health Solutions
www.phsmedicalsolutions.com
Roscoe Medical/Compass Health Brands
www.roscoemedical.com
Sore No More
www.sorenomore.com
Southwest Technologies
www.elastogel.com[/sidebar]
Targeting Pain Symptoms
Now that we have explored the differences between gender that play a role in injuries in athletes, what treatment modality options are available if an injury does occur in the female athlete? In order to understand which modality is most beneficial for the athletic population, it is also necessary to explore which pain theory the modality of use is targeting.
Transcutaneous Electrical Neuromuscular Stimulation (TENS) is a modality that works on the premise of gate control theory. First described by Melzack and Wall in 1965, the Gate Control Theory of Pain depends on the relative amount of traffic in two different sensory pathways, which carry information from the sensory organs to the brain. Without any stimulation, both large and small nerve fibers are quiet and the inhibitory interneuron blocks the signal in the projection neuron that connects to the brain. Therefore, the “gate is closed,” and the athlete will have no perception of pain. With non-painful stimulation, large nerve fibers are activated which activates the inhibitory interneuron, which then blocks the signal in the projection neuron that connects to the brain. Therefore, the “gate is closed,” and the athlete will have no perception of pain. With pain stimulation, small nerve fibers become active. They activate the projection neurons and block the inhibitory interneuron. Since the inhibitory interneuron is blocked, it cannot block the output of the projection neuron that connects with the brain. Therefore, the “gate is open,” and pain is experienced.
TENS is readily available, easy to apply to a variety of patient populations, and provides an analgesic effect to patients. It is a modality I use with my female athletes in hopes of providing another resource for pain modification besides the use of medication. TENS, however, is still inconclusive in the success of treating chronic pain patients, and may provide differences in pain relief between genders.
When treating female athletes with TENS in the clinic, I use the Dynatronics Solaris 709 Plus (Dynatronics Corp, Salt Lake City) on the premodulation setting. This conventional or high-frequency, low-intensity setting is one of the most common parameters for TENS. The stimulation parameters include a high frequency typically above 100Hz and a short pulse duration of 50-80?s. This combination of parameters stimulates the Group II (Aß) afferent nerve fibers. Conventional TENS produces a sensation of comfortable paraesthesia (pins and needles) with no muscle contraction. I use the premodulation setting as it is a faster onset for pain relief, but often analgesia is typically of a shorter duration of relief compared to an acupuncture-like or low frequency/high intensity TENS. With acupuncture-like TENS, a low frequency, usually 1-4Hz, and a high intensity—high enough to produce visible muscle contractions—and a long pulse duration about 200?s is used. Acupuncture-like TENS primarily stimulates the Group III (Ad) and IV (C) nociceptive fibers and small motor fibers. The user will therefore experience paraesthesia and muscle contraction. This mode of TENS is believed to operate primarily through the release of endogenous opioids via the descending pain-suppression system.
TENS is a staple technology among PT clinics, and therapists have several suppliers they can turn to for this technology. Everyway4all, based in Chino, Calif, offers the iStim EV-820 TENS Machine. The iStim EV-820 uses a 9-volt battery and provides five modes with adjustable pulse width, pulse rate, and treatment timer. Amrex-Zetron Inc, Paramount, Calif, also provides a line of TENS units that includes the SpectrumMicro-1000micro current generator for acute and chronic pain. The company’s portable models are the AdvanTeq2000 and Z-Stim 100.
In the past, I have also utilized Russian TENS with a base frequency of 2500Hz, burst of 50Hz, ramp of 2, 10:30 on/off initially moving to a 10:10 on/off time, to improve the strength of the targeted muscle.
In addition to TENS, Ultrasound (US) can be used for a variety of female athletes who may have ligamentous or soft tissue injuries. Ultrasound has both thermal and non-thermal properties that can facilitate tissue healing. Ultrasound works on the basis of converting the electrical energy from the generator into ultrasound vibrations.3 The vibrations are used to provide deep heat and micro-massage to tissue. This deep heat and micro-massage relieves pain, clears up bruises, increases blood flow, and provides perhaps faster healing; all are reasons why I use US for my athletes. The unit I typically use is also from Dynatronics, the solarius 709 model. The parameters I use include 1 MHz, at which the ultrasound penetrates up to about 1.5 inches in muscle; and to about 6.0 inches in fat.3 If I implement 3 MHz, only about 1/3 as far depth as 1 MHz is reached.3 This makes it good to use on very shallow tissue areas such as hands or ankle injuries. Typically, I utilize a duty cycle pulsed waveform of 50% if I do not wish to have thermal effects during my treatment. Most researchers agree that pulsing the ultrasound is beneficial because it allows for more intense micro-massage to be delivered with less possibility of damage from excess heat. Ultrasound also is a fast modality to use, allows hands-on application allowing for more time with patients, is inexpensive, non-invasive, and non-painful.
Michelle works on improving her strength and neuromuscular control as she performs a plank. She is able to resist sight pressures improving her neuromuscular control of abdominal and lower quarter musculature.
Hot and Cold Treatment
Other modalities that are beneficial in treating female athletes include superficial use of cold and heat. Cryotherapy is easy to administer, and reduces mild inflammation, spasticity, and pain.
It is effective as it works on the principle that immediate vasoconstriction of cutaneous vessels, decrease of blood flow, and decrease of nerve-conduction velocity of sensory and motor fibers in proportion to the degrees and duration of temperature change can increase the pain threshold and therefore decrease sensation of pain via gate theory.3 When using cryotherapy, if swelling and pain is involved, I use the Game Ready GRPRO2.1 model from Concord, Calif-based Game Ready. The GRPRO2.1 has a temperature setting as low as 34 degrees Fahrenheit with a choice of low, medium, or high compression. Typically, I utilize the low compression setting, which is between 5-15mmHg. It also has circumferential wraps around multiple anatomic parts—shoulder, ankle, neck, leg, etc—to provide compression and cooling. If I am utilizing a cold pack instead of compression, I use Chattanooga ColPac reusable gel packs that come in a variety of sizes and shapes.
Heat or thermal therapy vasodilates vessels, has a direct reflex activation of smooth muscle of blood vessels by cutaneous thermoreceptors, indirect activation of local spinal cord reflexes by cutaneous thermoreceptors, or local release of chemical mediators of inflammation.3 Heat increases the pain threshold by reducing ischemia and muscle spasm, and increasing blood flow. Like cryotherapy, it is easily administered, reduces pain, and is cost-effective.
Several manufacturers offer a range of hot and cold therapy products designed especially for use in the PT clinic. Among them is Battle Creek Equipment Company, Fremont, Ind, which offers Thermophore Moist Heat Packs in a range of sizes to deliver heat that penetrates into tissues and stimulates circulation. The company also offers Ice It! reusable cold packs, which remain flexible when frozen and can be purchased in contoured, joint-specific designs as well as multiple use designs.
Elasto-Gel therapy products from Southwest Technologies, North Kansas City, Mo, are another option for hot and cold therapy solutions designed to provide moist heat and soothing cold. Elasto-Gel products are reusable, microwavable, available in more than 40 shapes and sizes, and manufactured so they can conform to contoured areas and move with the wearer.
Topical Analgesics
Some therapists may also find that topical agents are a useful option for managing pain among female athletes. Topical analgesics are relatively affordable, easy to apply, and can be used in the clinic or by the patient at home. Natural ingredients are popular in some topicals manufactured for the temporary relief from pain, such as the active ingredients in Sore No More Pain Relieving Gel from Sore No More, Moab, Utah. Available in sizes from 2-ounce jars to 1-gallon jugs, Sore No More products use menthol, capsaicin, and witch hazel in combination with six natural plant extracts. Flexall topical pain-relieving gels from Ari-Med Pharmaceuticals, Tempe, Ariz, are also available in formulations that include menthol, eucalyptus, peppermint, thyme, and camphor in an aloe vera base. Flexall gel formulas are greaseless and are made to absorb quickly.
Back on Their Feet
Every patient and athlete we treat is unique, and modalities are just one option in the PT toolkit that can aid in the management of pain. As physical therapists, it is our job to get our patients “back on their feet,” and while there is an array of products that allow us to tailor the approach we use in treating pain symptoms, our solutions benefit when they consider the physiological variable of gender. PTP
Catherine A. Grumbein, PT, DPT, is clinical supervisor for The Physical Therapy & Wellness Institute’s Montgomeryville, Pa, location. She earned a Bachelor’s Degree in Kinesiology and a Doctorate of Physical Therapy from the New York Institute of Technology in Old Westbury, NY. Catherine is a member of the APTA and has a strong interest in manual therapy, including cervical and temporomandibular treatments. For more information, contact [email protected].
References
1. Lindle RS, Metter EJ, Lynch NA, et al. Age and gender comparisons of muscle strength in 654 women and men aged 20–93 years. J Appl Physiol. 1997;83(5):1581-1587.
2. Harmon KG, Ireland ML. Gender differences in noncontact anterior cruciate ligament injuries. Clin Sports Med. 2001;19(2):87-302.
3. Dutton M. Dutton’s Orthopedic Examination, Evaluation, and Intervention. 3rd ed. 2013; McGraw-Hill.
