Effects of Eccentric Exercise on Tendon Loading and Ankle Power During a Single-leg Heel Rise and Lowering Task
Abstract
● Documented injury rates among recreational runners range between 25-65%.
● Achilles tendon injuries are among the highest with the incidence in recreational and elite athletes ranging between 6-18%.
● Chronic mid-portion Achilles tendinosis is characterized by pain, localized thickening, and results in degeneration of the tendon and changes in collagen.
● The challenge to is that a significant number of patients (29%) with Achilles tendinopathy do not respond to conservative treatment and require surgical interventions.
● The current conservative treatment modality is an eccentric exercise program. Eccentric loading has better outcomes in strength and pain compared to control groups. However only 12 of the 22 in the experimental group rated themselves as fully recovered after 1 year followup.
● Although much of the literature favors eccentric exercises and suggests that eccentrics be an integral part of the conservative management, little is known about the mechanism behind this favorable effect.
● Current studies suggest that the benefits of eccentric exercises are due to microcirculatory changes around the tendon and tendon remodeling secondary to collagen changes.
● Current research also suggests that tendons need high mechanical loading to promote the healing process.
● Based on this information, it may be that one of the reasons nearly 50% of the patients do not fully recover is that physical therapists are not dosing appropriately (ie higher eccentric loads).