Abstract
Objective:To analyse treatment effects of eccentric vs. concentric graded exercise in chronic tennis elbow.Design:Randomized controlled trial.Setting:Primary care in Uppsala County, Sweden.Subjects:A total of 120 subjects with tennis elbow lasting more than three months were recruited from primary care and by advertisement.Intervention:Eccentric (n = 60) or concentric exercise (n = 60), by lowering or lifting a weight, at home daily, for three months with gradually increasing load.Main measures:Pain during muscle contraction and muscle elongation, as well as strength, was assessed at baseline and after one, two, three, six, and 12 months. Function and quality of life was assessed at baseline and after three, six and 12 months.Results:The eccentric exercise group had faster regression of pain, with an average of 10% higher responder rate at all levels of pain reduction, both during muscle contraction and elongation, (p < 0.0001 and p = 0.006, respectively). Significant differences were found in Cox’s analysis from two months onwards (HR 0.78, 95% confidence interval (CI) 0.63-0.96, p < 0.02). This represents an absolute pain reduction of 10% in the eccentric vs. the concentric group and a number-needed-to-treat of 10. The eccentric group also had a greater increase of muscle strength than the concentric (p < 0.02). The differences persisted throughout the follow-up period. There were no significant differences between the groups regarding function or quality of life measures.Conclusion:Eccentric graded exercise reduced pain and increased muscle strength in chronic tennis elbow more effectively than concentric graded exercise.Quotes from study:
In conclusion , an exercise programme for chronic tennis elbow should be designed to gradually put load on the affected painful tissue, and stress the eccentric work phase, but need not exclude the concentric work phase.”
My Comments:
This is a great study, not because I need another blog on tendinopathy, but because it refutes some earlier tendinopathy research that found concentric exercise to be either worthless or aggravating. These researchers found both concentric (lifting a weight) and eccentric (lowering a weight) contractions to be beneficial, with eccentric exercises only being only about 10% better. This backs up my own physical therapy protocols where I make use of regular progressive resistance exercise (combining concentric and eccentric contractions). It also helps to explain why some more recent studies were heavy slow lifting with regular concentric and eccentric contractions are more effective than eccentric only contractions for the treatment of tendinopathy. The big downside of eccentric only contractions is not that they aren’t effective (as this and almost all studies show they are) but that they are tedious to both coach and perform as the patient has to lift the weight with their good arm and lower it with their bad arm. Also, by using normal combined lifts in physical therapy, patients are learning an effective exercise they can continue indefinitely as part of their fitness program. By contrast, eccentric only exercises are more of a “specialty therapy exercise” that patients rarely would nor should wish to continue after their pain resolves.
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