Eccentric vs Concentric strengthening for tendinopathy
Rikke Beyer, Mads Kongsgaard, Birgitte Hougs Kjær, Tommy Øhlenschlæger, Michael Kjær and S. Peter Magnusson. Heavy Slow Resistance Versus Eccentric Training as Treatment for Achilles Tendinopathy : A Randomized Controlled Trial. Am J Sports Med 2015 43: 1704 originally published online May 27, 2015
THERAPY STUDY: Are the results of the trial valid?
What question did the study ask?
1a. R- Was the assignment of patients to physiotherapy treatments randomised?
Yes, Group assignment was randomized by computer generator.
1b. R- Were the groups similar at the start of the trial?
Yes, there were no significant differences between each group with a tendinopathy
2a. A – Aside from the allocated physiotherapy treatment, were groups treated equally?
Yes, other than the different interventions (training protocol and exercises), all individuals were given the same advice about exercise management and progression.
2b. A – Were all patients who entered the trial accounted for? – and were they analysed in the groups to which they were randomised?
Yes, the investigators explained the reasons why some individuals did not continue with the study (i.e. lack of time, didn’t turn up, moved away, partial Achilles rupture, accompanying back or ankle pain etc.)
- M – Were measures objective or were the patients and clinicians kept “blind” to which treatment was being received?
Yes, a single blind method was used whereby an independent investigator analysed the results. It was impossible to blind the subjects based on the nature of the study.
What were the results?
Improvements in pain, function and structural appearance were all considered. The authors could also have evaluated strength
How large was the treatment effect?
Significant improvements were made in both groups between weeks 0 and 52. There were no significant differences between the two intervention groups. Measures were self reported VAS and ultrasound
How precise was the estimate of the treatment effect?
Results show that intervention groups showed a statistically significant improvement. Confidence intervals varied depending on objective measure.
Will the results help me in caring for my patient? (ExternalValidity/Applicability)
Yes and no, this study examined patients with mid-portion tendinopathies, so we may not be able to generalise these results to a patient with an insertional tendinopathy. Subjects included in the study were athletes (58); many physiotherapy patients we treat are sedentary and/or only active on weekends.
Are the likely treatment benefits greater than the potential harms and costs?
Yes, Outcomes are good with minimal risk of harm.
It has been well established that eccentric loading provides clinical improvement, pain reduction and improvements in function.1,2 When the unilateral heel drop exercise used in the study above is performed, force on the tendon is a function of the patient’s body weight. Forces can then be modulated by adding weight to a back pack to be worn while performing the exercise. In addition to reductions in pain and improved function, a study has shown increased biosynthesis of collagen, Type I.3 There are a limited number of studies comparing eccentric loading with other types of exercise. While it is clear that loading confers significant clinical changes, based on available literature, we cannot delineate the role of type of contraction from the number of repetitions and load magnitude, recovery time, etc. This study adds to the evidence that perhaps more focus should be placed on a broader rehabilitation approach that looks at different exercise dosing parameters such as size of loading, speed and frequency of loading.
- Kingma JJ, de Knikker R, Wittink HM, Takken T. Eccentric overload training in patients with chronic achilles tendinopathy: A systematic review. Br J Sports Med. 2007;41:e3.
- Sussmilch-Leitch SP, Collins NJ, Bialocerkowski AE, Warden SJ, Crossley KM. Physical therapies for achilles tendinopathy: Systematic review and meta-analysis. J Foot Ankle Res. 2012;5:15.
- Langberg H, Ellingsgaard H, Madsen T, et al. Eccentric rehabilitation exercise increases peritendinous type i collagen synthesis in humans with achilles tendinosis. Scand J Med Sci Sports. 2007;17:61-66.