A1 Journal article (refereed)
Medial gastrocnemius muscle fascicle function during heel-rise after non-operative repair of Achilles tendon rupture (2023)

van Dijk, K., Khair, R. M., Sukanen, M., Cronin, N. J., & Finni, T. (2023). Medial gastrocnemius muscle fascicle function during heel-rise after non-operative repair of Achilles tendon rupture. Clinical Biomechanics, 105, Article 105977. https://doi.org/10.1016/j.clinbiomech.2023.105977

JYU authors or editors

Publication details

All authors or editors: van Dijk, Koen; Khair, Raad M.; Sukanen, Maria; Cronin, Neil J.; Finni, Taija

Journal or series: Clinical Biomechanics

ISSN: 0268-0033

eISSN: 1879-1271

Publication year: 2023

Publication date: 03/05/2023

Volume: 105

Article number: 105977

Publisher: Elsevier BV

Publication country: Netherlands

Publication language: English

DOI: https://doi.org/10.1016/j.clinbiomech.2023.105977

Publication open access: Openly available

Publication channel open access: Partially open access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/86862


To better understand muscle remodelling in dynamic conditions after an Achilles tendon rupture, this study examined the length of medial gastrocnemius muscle fascicles during a heel-rise at 6- and 12-months after non-operative ATR treatment.

Participants (15 M, 3F) were diagnosed with acute Achilles tendon rupture. Medial gastrocnemius subtendon length, fascicle length and pennation angle were assessed in resting conditions, and fascicle shortening during bi- and unilateral heel-rises.

Fascicle shortening was smaller on the injured side (mean difference [95% CI]: −9. 7 mm [−14.7 to −4.7 mm]; −11.1 mm [−16.5 to −5.8 mm]) and increased from 6- to 12 months (4.5 mm [2.8–6.3 mm]; 3.2 mm [1.4–4.9 mm]) in bi- and unilateral heel-rise, respectively. The injured tendon was longer compared to contralateral limb (2.16 cm [0.54–3.79 cm]) and the length decreased over time (−0.78 cm [−1.28 to −0.29 cm]). Tendon length correlated with fascicle shortening in bilateral (r = −0.671, p = 0.002; r = −0.666, p = 0.003) and unilateral (r = −0.773, p ≤ 0.001; r = −0.616, p = 0.006) heel-rise, at 6- and 12-months, respectively. In the injured limb, the change over time in fascicle shortening correlated with change in subtendon length in unilateral heel-rise (r = 0.544, p = 0.02).

This study showed that the lengths of the injured tendon and associated muscle can adapt throughout the first year after rupture when patients continue physiotherapy and physical exercises. For muscle, measures of resting length may not be very informative about adaptations, which manifest themselves during functional tasks such as unilateral heel-rise.

Keywords: tendons; calcaneal tendon; injuries and disabilities; rehabilitation; muscles; biomechanics

Free keywords: muscle; subtendon; resting length; heel-rise; non-operative treatment

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Ministry reporting: Yes

Reporting Year: 2023

Preliminary JUFO rating: 1

Last updated on 2023-03-10 at 11:51