title: Technique analysis in elite athletes using principal component analysis.
abstract: The aim of this study was to advance current movement analysis methodology to enable a technique analysis in sports facilitating (1) concurrent comparison of the techniques between several athletes; (2) identification of potentially beneficial technique modifications and (3) a visual representation of the findings for feedback to the athletes. Six elite cross-country skiers, three world cup winners and three national elite, roller ski skated using the V2 technique on a treadmill while their movement patterns were recorded using 41 reflective markers. A principal component analysis performed on the marker positions resulted in multi-segmental "principal" movement components (PMs). A novel normalisation facilitated comparability of the PMs between athletes. Additionally, centre of mass (COM) trajectories were modelled. We found correlations between the athletes' performance levels (judged from race points) and specific features in the PMs and in the COM trajectories. Plausible links between COM trajectories and PMs were observed, suggesting that better performing skiers exhibited a different, possibly more efficient use of their body mass for propulsion. The analysis presented in the current study revealed specific technique features that appeared to relate to the skiers' performance levels. How changing these features would affect an individual athlete's technique was visualised with animated stick figures.
authors.affiliation: a Department of Physics , University of Oslo , Oslo , Norway.|b Department of Physical Performance , Norwegian School of Sport Sciences , Oslo , Norway.
authors.forename: Øyvind
authors.initials: Ø
authors.lastname: Gløersen
authors.affiliation: b Department of Physical Performance , Norwegian School of Sport Sciences , Oslo , Norway.
authors.forename: Håvard
authors.initials: H
authors.lastname: Myklebust
authors.affiliation: b Department of Physical Performance , Norwegian School of Sport Sciences , Oslo , Norway.
authors.forename: Jostein
authors.initials: J
authors.lastname: Hallén
authors.affiliation: b Department of Physical Performance , Norwegian School of Sport Sciences , Oslo , Norway.|c Department of Neuroscience, Faculty of Medicine , Norwegian University of Science and Technology , Trondheim , Norway.|d Department of Sport Science , University of Innsbruck , Innsbruck , Austria.
authors.forename: Peter
authors.identifier: http://orcid.org/0000-0002-0266-6813
authors.initials: P
authors.lastname: Federolf
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D005080:Exercise Test; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology; D011187:Posture / Q000502:physiology; D025341:Principal Component Analysis; D012865:Skiing / Q000502:physiology*; D013996:Time and Motion Studies
keywords: Elite sport; cross-country ski skating; motion analysis; principal component analysis; principal movements; segment coordination patterns