Collecting kinematic data on a ski/snowboard track with panning, tilting, and zooming cameras: Is there sufficient accuracy for a biomechanical analysis?

Abstract

For biomechanical research in several sports (e.g. skiing and snowboarding), field experiments are essential because these activities are performed over a great distance and in conditions that could not be reproduced in a controlled laboratory environment. High technical standards in kinematic set-up are necessary to achieve the required accuracy for biomechanical analysis. The purpose of this study was to determine the accuracy of the kinematic data collected in a ski and snowboard field experiment. Eight tests generally used in laboratory settings were adapted to field conditions on a skiing slope to determine the error related to motion capture. The calculated photogrammetric errors in the x-, y-, and z-direction were 11 mm, 9 mm, and 13 mm, respectively. The maximum error caused by soft tissue artifacts was 39 mm. These results indicate that accuracy of kinematic data in the described field experiment was comparable to that found in literature for laboratory experiments. It may be concluded that accurate kinematic data collection for skiing and snowboarding can be performed in a field setting and that these results are accurate enough to serve as input data for further analyses.

Determination of the centre of mass kinematics in alpine skiing using differential global navigation satellite systems

“…Thereafter, a segment length normalisation technique (Smith, 1994) was applied to adjust the computed segment lengths to the measured lengths of the skier's segments. In terms of accuracy, the method used was found to have a mean resultant photogrammetric error of 23 mm with a standard deviation of 10 mm as in an earlier study (Klous et al, 2010;Reid, 2010). The coordinates of the reconstructed body landmarks, control points, video cameras and gates were transformed from the LCS to the global WGS84 coordinate system as detailed in the Appendix.…”

“…position, velocity and acceleration) have been proposed as reference measures representing the athlete's overall movement in space (Schiefermüller, Lindinger, Raschner, & Müller, 2004). While earlier studies mainly used three-dimensional (3D) videobased systems for the reconstruction of the CoM (Federolf, Reid, Gilgien, Haugen, & Smith, 2012;Klous, Müller, & Schwameder, 2010;Raschner et al, 2001;Reid, 2010;Reid et al, 2007;Supej, Kugovnik, & Nemec, 2004), recent approaches have suggested the use of differential global navigation satellite systems (GNSS) (Gilgien, Singer, & Rhyner, 2010;Gilgien, Spörri, Kröll, Crivelli, & Müller, 2014;Gilgien, Spörri, Limpach, Geiger, & Müller, 2014;Lachapelle, Morrison, Ong, & Cole, 2009;Supej, 2010;Supej & Holmberg, 2011;Supej et al, 2013). GNSS systems allow larger capture volumes with reasonable set-up and processing requirements.…”

Three-Dimensional Body and Centre of Mass Kinematics in Alpine Ski Racing Using Differential GNSS and Inertial Sensors

“…Twenty-two joint centers and subject ambient reference points were manually digitized and reconstructed in 3D, as described in detail in References [7,14]. The mean resultant photogrammetric error of this methodology was reported to be 23 mm with a standard deviation of 10 mm [11]. The reconstructed joint center positions were then used to compute the athlete's CoM based on the body segment model of [36].…”

“…Early studies mainly used camera-based stereo photogrammetry to collect kinematic data on a ski-slope and to reconstruct the CoM kinematics [2,3,7,[10][11][12][13]. However, despite advantages in measurement accuracy, these systems are complex to set up and need for time-consuming post processing due to manual digitization.…”

Comparisons of Foot Pressure Patterns between Experienced Skiers and Intermediate Skiers during Alpine Skiing

“…인터스키는 4년마다 각 국을 대표하 는 데몬스트레이터(demonstrator) 1000여명이 참가하여 새 로운 스키 기술과 교수법을 발표하는 인터스키대회(interski congress)를 개최하고 있으며, 이 대회는 월드컵스키대회, 동계올림픽과 함께 3대 동계스포츠 경기로 발전하였다 (Interski-2015(Interski- , 2014 (Gilgien, Spörri, Chardonnens, Kröll, & Müller, 2013;Müller & Schwameder, 2003;Klous, Müller, & Schwameder, 2010;Supej, 2010;Krüger & Edelmann-Nusser, 2010). 또한 스키와 설면 간에 발생하는 접촉압력(contact pressure)을 계산하고, 족저압력측정기와 스키에 장착된 동 력계(dynamometer)에서 나타나는 결과치의 비교를 통해 운 동역학적(kinetic) 분석에 대한 연구영역을 확장시키고 있 다 (Heinrich, Mössner, Kaps, & Nachbauer, 2010;Stricker, Scheiber, Lindenhofer, & Müller, 2010 (Federolf et al, 2008;Supej et al, 2013).…”