Article title: Eccentric exercises; why do they work, what are the problems and how can we improve them? Authors: Rees JD, Wolman RL, Wilson A Publication information: British Journal of Sports Medicine 2009; 43: 242-246 BACKGROUND INFORMATION In sports medicine, there are few injuries seen more frequently than tendinopathies. Common sites for this often disabling condition are the Achilles, patellar, rotator cuff, wrist extensor group, adductor group and hamstring tendons. The exact pathology of tendinopathy is still under study, but it is now generally accepted that a degenerative process predominates, characterized by soft tissue remodeling resulting from a failed healing response (that is, the strain or demands imposed on the tendon exceed its heal- ing capacity). Absent from our current understanding of this condition is a significant inflammatory contribution, which explains the general lack of efficacy of common anti- inflammatory measures for treating these patients. In the last 20+ years, eccentric (ECC) exercise has emerged as a popular treatment Dr. Shawn Thistle is the founder and president of Research Review Service Inc., an online, subscription- based service designed to help busy practitioners to integrate current, relevant scientific evidence into their practice. Shawn graduated from CMCC and holds an Hon- ours Degree in Kinesiology from McMaster University. He also holds a certificate in Contemporary Medi- cal Acupuncture from McMaster University, and is a Certified Active Release Techniques (ART®) Pro- vider. For more information about the Research Review Service, visit www.researchreviewservice.com. approach for a variety of tendinopathies. ECC exercises involve lengthening a muscle/ tendon unit under load (versus concentric exercise which involves a shortening contrac- tion or isometric which involves static holds). The literature to date, although criticized by some, points to the efficacy of ECC exercise for treating tendinopathies, particularly of the Achilles and patellar tendons. Making generalized recommendations for other anatomical sites is difficult at this time due to the quality of published studies. Most uti- lize small sample sizes and have other drawbacks, but taken together a promising picture emerges while pointing to the need for further research. PRACTICAL APPLICATION OF ECC EXERCISE ECC exercise certainly represents a viable treatment option for tendinopathy cases, particu- larly when involving the Achilles (especially chronic mid-tendon cases) and patellar tendons. However, the existing literature cannot specify a protocol for us to use for all tendi- nopathies. Published trials showing positive results of ECC exercise typically employ high repetitions (sets of 12-15) using heavier loads (starting with body weight and sub- sequently adding weight as need), repeated one to two times per day. In other words, these programs impart a large stimulus to the tendon and attempt to overload it in a safe yet aggressive manner. Those who originally proposed this treatment stated that patients should perform these exercises even through pain, although this concept remains con- troversial today. Prudent clinicians who employ ECC exercise with their patients should progress their patients accordingly and monitor compliance, results, and potential adverse reactions carefully. These programs can be challenging and may require extra attention from the supervising doctor or other clinic staff. • For full review – including a discussion of issues surrounding ECC exercise and additional references – please visit www.canadianchiropractor.ca. This brief review is a sample of the content posted weekly on Research Review Service and is one of over 60 reviews available per year of the latest scientific literature in chiropractic. RRS is approved for 4.0 CEUs/year by CMCC. 42 • CANADIAN CHIROPRACTOR | JUNE 2010 www.canadianchiropractor.ca Shawn Thistle, BKin (Hons), DC, CSCS
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