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Running man.

Doctoral defence of Adam Kositsky, MSc, 10.3.2023: Semitendinosus structure and function in healthy and anterior cruciate ligament reconstructed individuals  

The doctoral dissertation in the field of Biomechanics will be examined at the Faculty of Science, Forestry and Technology, Kuopio Campus and online.

What is the topic of your doctoral research? Why is it important to study the topic?

The semitendinosus is an atypically structured muscle split into two connecting segments, a design not seen in any other human extremity muscle. Functionally, semitendinosus contributes to forward progression during locomotion. Clinically, semitendinosus has a long distal tendon that is routinely harvested for surgical reconstructions. In particular, the tendon is commonly used for reconstructing the anterior cruciate ligament of the knee, a procedure increasing in frequency, particularly in younger individuals, due to the rising number of anterior cruciate ligament ruptures. After this reconstruction, individuals generally have impaired function of their knee. As such, there is a need for further information on the basic structure and function of semitendinosus and how the muscle adapts post-reconstruction.

What are the key findings or observations of your doctoral research?

Four main findings resulted from the studies conducted for this thesis. First, ultrasonography is a reliable and valid method for assessing the dimensions of the semitendinosus muscle and tendon. Second, despite its unusual design, the two separate neuromuscular compartments appear to work in tandem with each another to function as one whole muscle. Third, generic assumptions used in computational and electromyographic analyses are likely not valid for semitendinosus, particularly after anterior cruciate ligament reconstruction. Finally, considerable morphological alterations of the semitendinosus muscle are seen after its distal tendon is harvested for anterior cruciate ligament reconstruction, but these morphological adaptations do not fully explain the long-term loss of knee function also evident after the surgery.

How can the results of your doctoral research be utilised in practice?

Overall, the results can be used to inform clinical and research settings with the aim of progressing treatment and rehabilitation after anterior cruciate ligament reconstruction. More specifically, ultrasonography can be used as a cost-effective and more accessible alternative to magnetic resonance imaging for assessing semitendinosus morphology, and the insight gained on the structure and function of the semitendinosus muscle will hopefully aid in restoring normal knee joint function in the anterior cruciate ligament reconstructed knee.

What are the key research methods and materials used in your doctoral research?

Both healthy individuals and those who had undergone anterior cruciate ligament reconstruction with a distal semitendinosus tendon autograft participated in the studies conducted for this thesis. Methods included multiple imaging modalities (ultrasonography, magnetic resonance imaging, shear-wave elastography), strength testing (isokinetic dynamometry), and computational analyses (musculoskeletal modelling).

The doctoral dissertation of Adam Kositsky, MSc, entitled Semitendinosus structure and function in healthy and anterior cruciate ligament reconstructed individuals is a joint project with Griffith University (Australia) and  will be examined at the Faculty of Science, Forestry and Technology, Kuopio Campus. The opponent will be Professor Keith Baar, University of California - Davis, USA, and the custos will be Senior Researcher Lauri Stenroth, University of Eastern Finland. Language of the public defence is English.

For more information, please contact:

Adam Kositsky,