Eleftherios Kellis is a professor of Kinesiology at the Department of Physical Education and Sports Sciences of Serres at the Aristotle University of Thessaloniki, where he currently teaches kinesiology and biomechanics. His main research interests include the hamstring and trunk core muscle biomechanics, 3D ultrasound and related techniques and soccer injury biomechanics.  He acts as reviewer for several scientific journals in the field of sport and exercise sciences. He has been awarded a best researcher award of the Aristotle University of Thessaloniki, for the years 2014-, 2015, 2016 and 2019. According to the bibliographic data base “Scopus”, as in May 2023, he has 137 publications in international scientific journals, 4441 references to his work and h-index 37. He is also ranked according to the annual assessment of Stanford (https://doi.org/10.1371 /journal.pbio.3000918) at number 167 in the world, in the subject area “sports sciences”.