Sports Medicine

, Volume 47, Issue 6, pp 1221–1230

Neuromechanical Modulation of the Achilles Tendon During Bilateral Hopping in Patients with Unilateral Achilles Tendon Rupture, Over 1 Year After Surgical Repair

  • Hiroyuki Oda
  • Kanae Sano
  • Yoko Kunimasa
  • Paavo V. Komi
  • Masaki Ishikawa
Original Research Article

DOI: 10.1007/s40279-016-0629-3

Cite this article as:
Oda, H., Sano, K., Kunimasa, Y. et al. Sports Med (2017) 47: 1221. doi:10.1007/s40279-016-0629-3

Abstract

Background

Patients who have had an Achilles tendon (AT) rupture repaired are potentially at higher risk for re-rupture than those without previous rupture. Little attention has been given to the neuromechanical modulation of muscle–tendon interaction and muscle activation profiles during human dynamic movements after AT rupture repair.

Objective

The purpose of this study was to examine muscle–tendon behavior and muscle activation during bilateral hopping.

Methods

We enrolled nine subjects who had undergone surgical repair of unilateral AT rupture within the past 1–2 years. Subjects performed bilateral hopping while we took ultrasound, kinematic, and electromyogram recordings and measurements. AT behaviors were also recorded. We then compared responses between values obtained from the ruptured AT leg (LEGATR) and non-ruptured AT leg (LEGNOR).

Results

During hopping, the AT stretching amplitudes were greater in the LEGATR than in the LEGNOR, although the peak AT force and stiffness were smaller in the LEGATR than in the LEGNOR. The AT negative mechanical work did not show any significant differences between both legs. However, positive works were significantly lower in the LEGATR than in the LEGNOR. Electromyogram patterns in both soleus and tibialis anterior muscles clearly differed after ground contact for the LEGATR and the LEGNOR.

Conclusions

These results suggest that the repaired ruptured AT can be compliant and have insufficient Young’s modulus, which can influence mechanical responses in muscle activities. The modulation of agonist–antagonist muscle activities corresponding to the different levels of stiffness between the LEGATR and the LEGNOR may not be fully functioning during the pre-activation phase.

Funding information

Funder NameGrant NumberFunding Note
JSPS KAKENHI
  • 26702026

Copyright information

© Springer International Publishing Switzerland 2016

Authors and Affiliations

  1. 1.Graduate School of Sport and Exercise SciencesOsaka University of Health and Sport SciencesOsakaJapan
  2. 2.Riseisha College of Medicine and SportOsakaJapan
  3. 3.Likes Research CenterUniversity of JyväskyläJyväskyläFinland

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