Details

Autor(en) / Beteiligte

• Tsaopoulos, Dimitrios E
• Baltzopoulos, Vasilios
• Richards, Paula J
• Maganaris, Constantinos N

Titel

In vivo changes in the human patellar tendon moment arm length with different modes and intensities of muscle contraction

Ist Teil von

• Journal of biomechanics, 2007-01, Vol.40 (15), p.3325-3332

Ort / Verlag

United States: Elsevier Ltd

Erscheinungsjahr

2007

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Abstract The purpose of this study was to examine the effect of different muscle contraction modes and intensities on patellar tendon moment arm length ( d PT ) . Five men performed isokinetic concentric, eccentric and passive knee extensions at an angular velocity of 60 deg/s and six men performed gradually increasing to maximum effort isometric muscle contractions at 90 ∘ and 20 ∘ of knee flexion. During the tests, lateral X-ray fluoroscopy imaging was used to scan the knee joint. The d PT differences between the passive state and the isokinetic concentric and extension were quantified at 15 ∘ intervals of knee joint flexion angle. Furthermore, the changes of the d PT as a function of the isometric muscle contraction intensities were determined during the isometric knee extension at 90 ∘ and 20 ∘ of knee joint flexion. Muscle contraction-induced changes in knee joint flexion angle during the isometric muscle contraction were also taken into account for the d PT measurements. During the two isometric knee extensions, d PT increased from rest to maximum voluntary muscle contraction (MVC) by 14–15%. However, when changes in knee joint flexion angle induced by the muscle contraction were taken into account, d PT during MVC increased by 6–26% compared with rest. Moreover, d PT increased during concentric and eccentric knee extension by 3–15%, depending on knee flexion angle, compared with passive knee extension. These findings have important implications for estimating musculoskeletal loads using modelling under static and dynamic conditions.