Eccentric or concentric exercises for tendinopathy?
It is currently suggested that isolated eccentric contraction without concentric component is most effective for patients with tendinopathy. More recent studies suggest new loading-based exercise regimes such as isolated concentric training, heavy slow resistance training and concentric/eccentric progressing to eccentric training. Exercise causes an increase in blood flow and collagen synthesis and in the long term leads to hypertrophy, depending of the range of exercise.
Response to different dynamic load regimes is due to the interaction of the parameters. Evidence suggests increased time under load, number of load cycles and loading rate result in a positive adaptive response, such as an increased matrix strength and stiffness and decreased matrix metalloproteinase expression in cultured fibroblasts.
During the eccentric phase, the ground reaction force may fluctuate at a higher frequency; tendon cells could potentially register this modulation, although the magnitude is quite small compared to the total load. It also has been thought that motor unit activation differs between concentric and eccentric exercises, which could produce a difference in load distribution.
The notion of concentric and eccentric contractions mostly applies to the muscle; the tendon is a mechanically passive structure that lengthens when load increases and shortens when load is reduced. It is unknown whether the mode of muscle contraction for a given load and ROM would have a differential effect on tendon tissue
This article provides an inside regarding tendinopathy exercises. It remains unclear if eccentric exercises are the treatment of choice in tendinopathy rehabilitation.
> From: Couppe et al., J Orthop Sports Phys Ther 45 (2016) 853-863. All rights reserved to Journal of Orthopaedic & Sports Physical Therapy.Click here for the Pubmed summary.