INTRODUCTION: Previous research has demonstrated that ground reaction force (GRF) recorded during eccentric ankle exercise is characterized by greater power in the 8- to 12-Hz bandwidth when compared with that recorded during concentric ankle exercise. Subsequently, it was suggested that vibrations in this bandwidth may underpin the beneficial effect of eccentric loading in tendon repair. However, this observation has been made only in individuals without Achilles tendinopathy. This research compared the force frequency characteristics of eccentric and concentric exercises in individuals with and without Achilles tendinopathy. METHODS: Eleven male adults with unilateral midportion Achilles tendinopathy and nine control male adults without tendinopathy participated in the research. Kinematics and GRF were recorded while the participants performed a common eccentric rehabilitation exercise protocol and a concentric equivalent. Ankle joint kinematics and the frequency power spectrum of the resultant GRF were calculated. RESULTS: Eccentric exercise was characterized by a significantly greater proportion of spectral power between 4.5 and 11.5 Hz when compared with concentric exercise. There were no significant differences between limbs in the force frequency characteristics of concentric exercise. Eccentric exercise, in contrast, was defined by a shift in the power spectrum of the symptomatic limb, resulting in a second spectral peak at 9 Hz, rather than 10 Hz in the control limb. CONCLUSIONS: Compared with healthy tendon, Achilles tendinopathy was characterized by lower frequency vibrations during eccentric rehabilitation exercises. This finding may be associated with changes in neuromuscular activation and tendon stiffness that have been shown to occur with tendinopathy and provides a possible rationale for the previous observation of a different biochemical response to eccentric exercise in healthy and injured Achilles tendons.
INTRODUCTION: Previous research has demonstrated that ground reaction force (GRF) recorded during eccentric ankle exercise is characterized by greater power in the 8- to 12-Hz bandwidth when compared with that recorded during concentric ankle exercise. Subsequently, it was suggested that vibrations in this bandwidth may underpin the beneficial effect of eccentric loading in tendon repair. However, this observation has been made only in individuals without Achilles tendinopathy. This research compared the force frequency characteristics of eccentric and concentric exercises in individuals with and without Achilles tendinopathy. METHODS: Eleven male adults with unilateral midportion Achilles tendinopathy and nine control male adults without tendinopathy participated in the research. Kinematics and GRF were recorded while the participants performed a common eccentric rehabilitation exercise protocol and a concentric equivalent. Ankle joint kinematics and the frequency power spectrum of the resultant GRF were calculated. RESULTS: Eccentric exercise was characterized by a significantly greater proportion of spectral power between 4.5 and 11.5 Hz when compared with concentric exercise. There were no significant differences between limbs in the force frequency characteristics of concentric exercise. Eccentric exercise, in contrast, was defined by a shift in the power spectrum of the symptomatic limb, resulting in a second spectral peak at 9 Hz, rather than 10 Hz in the control limb. CONCLUSIONS: Compared with healthy tendon, Achilles tendinopathy was characterized by lower frequency vibrations during eccentric rehabilitation exercises. This finding may be associated with changes in neuromuscular activation and tendon stiffness that have been shown to occur with tendinopathy and provides a possible rationale for the previous observation of a different biochemical response to eccentric exercise in healthy and injured Achilles tendons.
Authors: Karin Grävare Silbernagel; Peter Malliaras; Robert-Jan de Vos; Shawn Hanlon; Mitchel Molenaar; Håkan Alfredson; Inge van den Akker-Scheek; Jarrod Antflick; Mathijs van Ark; Kenneth Färnqvist; Zubair Haleem; Jean-Francois Kaux; Paul Kirwan; Bhavesh Kumar; Trevor Lewis; Adrian Mallows; Lorenzo Masci; Dylan Morrissey; Myles Murphy; Richard Newsham-West; Richard Norris; Seth O'Neill; Koen Peers; Igor Sancho; Kayla Seymore; Patrick Vallance; Arco van der Vlist; Bill Vicenzino Journal: Sports Med Date: 2021-11-19 Impact factor: 11.136
Authors: Steven J Obst; Luke J Heales; Benjamin L Schrader; Scott A Davis; Keely A Dodd; Cory J Holzberger; Louis B Beavis; Rod S Barrett Journal: Sports Med Date: 2018-09 Impact factor: 11.136
Authors: Arco C van der Vlist; Stephan J Breda; Edwin H G Oei; Jan A N Verhaar; Robert-Jan de Vos Journal: Br J Sports Med Date: 2019-02-04 Impact factor: 13.800