A Comparison of Joint Kinetics Produced by Two-Dimensional and Three-Dimensional Motion Analysis During the First Stance Phase of the Sprint Start

Abstract

Motion analysis has significantly improved in recent years with three-dimensional (3D) analysis becoming more popular. Direct comparison between two-dimensional (2D) and 3D analysis is limited within previous literature, as is the analysis of the sprint start, with the majority of research being 2D. Evidence suggests complex movements such as the sprint start require 3D analysis. The aim of this study was to compare 2D and 3D joint kinetics during the first stance phase of the sprint start. Kinematic and ground reaction force data were collected from three well trained athletes during the first stance phase of maximal effort sprint starts. A standard inverse dynamic analysis was used to calculate joint kinetics for both methods. Differences between the two methods of analysis were lowest at the ankle (8.7%), followed by the knee (9.2%) and hip (25.4%). At each joint throughout stance, the 2D analysis showed lower moment magnitudes. The frontal plane accounted for 17.0 – 23.9% and the transverse plane 7.2 – 15.3% of the net 3D moments. Both 2D and 3D joint kinetics were higher than previously published 2D joint kinetics for the first stance phase. Substantial joint kinetics were seen outside of the sagittal plane highlighting the importance of this comparison.