Contemporary Acupuncture and Sports Medicine: an overview

Dr. Alejandro Elorriaga Claraco, MD (Spain) Director McMaster University Contemporary Medical Acupuncture Program
Chris O´Connor, RMT, Instructor McMaster CMA Program

Introduction
In Sports Medicine, we are still far from understanding the amazingly complex and delicate neurological connections that make highly precise movements possible. In clinical practice, we need to oversimplify these millions of coordinated electrical impulses into a small number of measurable outputs in order to be able to approach the study of the dysfunctions of the musculoskeletal system of the athlete.

Although we usually intervene as a result of unpleasant neurological information experienced by the athlete (nociception, pain), we know that functional restoration, i.e. optimal movement patterns, is indeed our ultimate treatment goal. However, this quest for optimal motor function is full of pitfalls and difficulties due to the elusive nature of most of the sensory signalling generated by the locomotor system, such as proprioception and kinesthesia. Even nociceptive signals can be quite elusive as well as the brain sometimes is unable to interpret correctly the origin of a noxius stimulus from myofascial origin, e.g. trigger points and referred pain patterns.

Therefore, any therapeutic tool with a potential effect on musculoskeletal sensory and motor signals could be of great practical value for the clinician dealing with sports injuries and related problems. Contemporary acupuncture (or electro-acupuncture) is one of such a tool.

Contemporary acupuncture: neuro-reactive sites and neuromodulation
Contemporary acupuncture can be defined as a therapeutic method in which fine solid needles are inserted into specific neuro-reactive sites of the body for the purpose of inducing autonomic, sensory and/or motor neuromodulatory responses. Neuromodulation is the property of the nervous system to regulate its own activity in response to exogenous or endogenous stimuli, and is an integral part of the nervous system modus operandi, i.e. feedback mechanisms allow for finer modulation of efferent neurological responses as well as for filtering and selection of afferent neurological signals.

Neuro-reactive sites in general can be defined as any area of the body where there is somatic and/or autonomic sensory or motor innervation. These include skin, fascias, muscles, tendons, periosteum, joint capsules, ligaments, nerve trunks, arterial vessels, and peripheral neurovascular bundles. Specific (or preferential) neuro-reactive sites for contemporary acupuncture stimulation are associated with areas of the musculoskeletal system rich in specialized sensory receptors such as muscle spindles, Golgi tendon organs, ligament receptors, Paciniform and Ruffini’s receptors (joint capsules), deep pressure endings (within muscle belly), and free nerve endings (muscle and fascia). Also the motor nerves themselves are preferential targets for eletrostimulation through acupuncture needles.

Defined in this manner, the vast number of potential neuro-reactive or insertion sites available to contemporary acupuncture practitioners requires a great working knowledge of gross and functional neuroanatomy. A thorough technical description of these sites is beyond the scope of this overview article.

Neuromodulatory responses triggered by the insertion of acupuncture needles in the human body are now starting to be understood. In the last 35 years, we have learnt a great deal about the possible nature of these responses from studies in animal models. In recent years, the use of functional Magnetic Resonance Imaging has opened a new window into the understanding of the neurological responses to acupuncture in humans.

A great deal of the existing research in acupuncture has been devoted to the mechanisms of acupuncture analgesia. Nowadays, specific applications of acupuncture in the arena of sports medicine are beginning to be explored, and there are already preliminary studies of the effects of acupuncture on strength, aerobic conditioning, flexibility, and sport performance.

The author of this article has a personal experience of twenty years in the field of sports medicine having treated many thousands of athletes with injuries, as well as having developed a “performance care model” integrating acupuncture and manual interventions (soft tissue techniques) for the purpose of optimizing movement performance in physically active people. Some of this anecdotal evidence is shared with the reader in this article.

Contemporary acupuncture mechanisms: a neurological model
Contemporary Acupuncture interventions are based on a contemporary neurological model that allows for best integration of functional diagnosis and treatment interventions in sports medicine. In simple terms, contemporary electroacupuncture provides a physiological non noxius physical stimulus that triggers existing reflexes at the local tissue level, at spinal segmental level, and at supraspinal levels (brain stem, thalamus, and hipothalamus). An in depth review of these mechanisms is beyond the scope of this overview but a summary will be useful in order to understand the possible range of applications in sports medicine.

Physiological response to contemporary acupuncture interventions include: local tissue responses (vasodilation, release of nitric oxide, tissue healing), segmental modulation of nociceptive and proprioceptive signals (dorsal horn integrative and filtering mechanisms, spinal descending inhibitory systems), segmental modulation of autonomic and visceral signals (viscero-somatic, somato-visceral reflexes), and suprasegmental modulation of autonomic, endocrine & immune functions, as well as modulation of miscellaneous central functions such as those associated with the activities of the limbic system (neurological, neurohumoral, neuroendocrine, and neuroimmune responses).

The technical aspects related to each of those families of mechanisms will take several volumes to explore, and at the end we would not have a whole or acurate picture since this discipline is still in development. Therefore the rest of this article will simply focus on making some practical comments on the applications of contemporary acupuncture on sports medicine.

Contemporary Acupuncture and acute injuries
Acute injuries are easier to treat since the body responds mobilizing well known healing mechanisms that can be optimized by specific neurostimulation. The role of acupuncture at this stage is to tone down the high sympathetic activity triggered by the injury, both at the site of damage and centrally, as well as optimize the local healing mechanisms and reduce the motor inhibition and the discomfort from the tissue nociceptive activity. Though I am not aware of gold standard studies for this applications, my experience with hundreds of cases (plus hundreds more from colleagues in the sport world) allow me to state that well design contemporary acupuncture inputs are of great value in the recovery of acute injuries such as ankle sprains, muscle tears, or contusions. The most relevant mechanisms would be local and spinal segmental. In this respect, is worth noticing that some authors (Andersson and Lundeberg) have compared the physiologic benefits of sustained physical exercise with those of repeated acupuncture treatment due to the fact that both stimulate the same muscle afferents producing similar spinal segmental neuromodulatory responses.

Contemporary Acupuncture and subacute and chronic injuries
Effectiveness of acupuncture in subacute and chronic injuries will depend on the clinician’s ability to define the true levels of the dysfunction and to address them in a multilevel integrated manner. Having said that, many studies on the use of acupuncture on chronic musculoskeletal conditions (most of the time in non athletic populations) such as myofascial pain, low back pain, lateral epicondylitis, or knee osteoarthritis have shown promising results. Unfortunately, the uneven range of methodological and clinical quality of these studies precludes at the present time any definite judgment on the true value of acupuncture on these conditions.

For instance, in a study blood flow on the trapezius muscle improved in fibromyalgia patients with local acupuncture stimulation, but not on healthy controls, indicating a homeostatic effect which supports the notions above expressed of acupuncture being a physiological intervention.

Several controlled trials using acupuncture for back pain conclude that acupuncture has been shown to be superior to various control interventions, but not enough data are currently available to support its efficacy over sham acupuncture needling. Regarding lateral elbow pain, a Cochrane systematic review compiled in November 2001 reviewed the literature and determined that only four randomized controlled trials met their methodological search standards. Of the four, two showed a positive effect.

Likewise, four of seven studies on knee osteoarthritis found acupuncture to have a positive effect on pain, on the other three the effects were neutral. No studies reported acupuncture as having a negative effect on pain associated with knee osteoarthritis.
These reviews are provided with the references at the end of this article.

Contemporary Acupuncture and motor neuromodulation
The least know application of acupuncture in sports medicine relates to its ability to restore motor activity when this has been impaired due to motor inhibition secondary to segmental nociception or long standing somatic dysfunctions without clinical signs of pain. Abnormal proprioceptive information is often the underlying problem. In general, a great deal of proprioceptive information related to the control of movement in a given area is processed segmentally and intersegmentally, such as the reciprocal inhibition and autogenous inhibition reflexes. Therefore, the genesis of non noxious signals from the affected segment, preferably through electrical stimulation of motor nerves with acupuncture needles, could be a great way to restore segmental and intersegmental flow of proprioceptive information with the result of improved sensory-motor integration resulting in normalization of motor output in the segment.

Recently, a pilot study showed that in a group of individuals with chronic functional ankle instability, a single session of acupuncture electro-stimulation produced significant changes in strength, proprioception, balance, perceived discomfort, and the number of reported episodes of giving way, with all the improvements still remaining one month post treatment. The only explanation for this spectacular clinical improvement is the segmental normalization of sensory-motor activity with elimination of the prior regional motor inhibition.

Indeed, the author has provided segmental motor interventions thousands of times to both athletes and non athletes, and has found it to be the single most valuable therapeutic strategy in the treatment of movement disorders.

Discussion of the different techniques available to accomplish this is again beyond the scope of this article but as a quick summary they involve treating agonists and antagonistic muscles, involved joints, motor and sensory nerves, and affected spinal segments. The clinical results are often astounding as the ankle instability study shown, even producing at times improvement of athletic performance (best personal marks) due to the restoration of optimal sensory-motor integration, joint mechanics, and soft tissue mechanics.

Mid range and high frequencies (15-20 Hz and up) reinforce the segmental effects of these inputs, while low frequencies (2-4 Hz) engage supraspinal mechanisms in the neuromodulation of the segmental and intersegmental activities.

Miscellaneous applications of acupuncture in sports medicine
Muscle activity and potential changes in strength following acupuncture have been examined in one study. The investigators suggested that acupuncture is able to influence neuromuscular activity since electromyographic changes were detected after 15 minutes needling of the muscle belly. This coincides with this author’s experience as described above.

Ehrlic and Haber investigated the influence of acupuncture administered once per week over a 5-week period on anaerobic threshold and work capacity during exercise in healthy young, untrained males. At the end, individuals in the acupuncture treatment group had higher maximal exercise capacity and were able to perform higher workloads at the onset of blood lactate accumulation (OBLA) than individuals in the placebo group. Also, individuals who received acupuncture demonstrated lower heart rates than controls at various submaximal and maximal levels.

These results indicate once again the physiological and functional nature of the response to acupuncture treatment. Acupuncture is a functional intervention and not just a passive modality. There are still other areas of acupuncture in sports under investigation such as improving flexibility, speed, and coordination but insufficient data preclude any conclusions at this point.

Only clinician’s experiences and future studies will be able to elucidate the true value of all the many promising application of contemporary electro-acupuncture in sports medicine.

References
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