Effect of joint rotation correction when measuring elongation of the gastrocnemius medialis tendon and aponeurosis

Publikationen: Beitrag in FachzeitschriftZeitschriftenaufsätzeForschungBegutachtung

AutorInnen

  • Adamantios Arampatzis
  • Gianpiero De Monte
  • Kiros Karamanidis

Forschungseinrichtungen

Details

It is well known that during maximal plantar flexion contractions the ankle joint rotation overestimates the actual elongation of the tendon and aponeurosis. The aim of this study was to examine the influence of the curve length changes of the Achilles tendon on the joint rotation corrected elongation and strain of the gastrocnemius medialis (GM) tendon and aponeurosis. Nine subjects (age: 29.4+/-5.7 years, body mass: 78.8+/-6.8 kg, body height: 178+/-4 cm) participated in the study. The subjects performed maximal voluntary isometric plantarflexion contractions in the prone position on a Biodex-dynamometer. Ultrasonography (Aloka SSD 4000) was used to visualize the muscle belly of the GM muscle-tendon unit. To calculate the curve length changes of the Achilles tendon its surface contour was reconstructed using a series of small reflective skin markers having a diameter of 2.5mm. The elongation of the GM tendon and aponeurosis was calculated (a) as the difference of the measured and the passive (due to joint rotation) displacement of the tendon and aponeurosis and (b) as the difference of the measured displacement and the length changes of the reconstructed Achilles tendon surface contour. The absolute difference between the elongation obtained by both methods were 1.2+/-0.4mm. These differences were due to the higher changes in length obtained by the reconstruction of the tendon curved surface contour as compared to the changes observed in the passive displacement of the digitised point at the aponeurosis. Without correcting for angle joint rotation, the measured elongation clearly overestimates the actual elongation of the GM tendon and aponeurosis. After the passive displacement correction the calculated elongation still overestimates the actual elongation of the GM tendon and aponeurosis. However, this overestimation has a negligible effect on the examined in vivo strain ( approximately 0.3%) of the tendon and aponeurosis.

OriginalspracheEnglisch
ZeitschriftJournal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology
Jahrgang18
Heft3
Seiten (von - bis)503-508
Seitenumfang6
ISSN1050-6411
DOIs
PublikationsstatusVeröffentlicht - 01.06.2008

ID: 18685

DOI

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