The application of inertial measurement units and functional principal component analysis to evaluate movement in the forward 3½ pike somersault springboard dive

The purpose of this study was to evaluate differences in the structure of angular velocity curves and the modes of within-diver variability related to 2 highly skilled divers.

At a glance:

• IMU recording and functional principal component analysis (fPCA) was able to examine repeated quantitative waveforms of dive movement performances.
• fPCA analysis of these waveforms identified lower random variability and greater functional control of a highly skilled international springboard diver.
• Correlations between fPC scores and outcome variables can potentially help better understand how to improve coordination, control, skill and performance.

Full reference and abstract:

Walker, C., Warmenhoven, J., Sinclair, P. J. & Cobley, S. (2019). The application of inertial measurement units and functional principal component analysis to evaluate movement in the forward 3 1/2 pike somersault springboard dive. Sports Biomechanics. 18(2),146-162.

ABSTRACT: Based on technological and analytical advances, the capability to more accurately and finitely examine biomechanical and skill characteristics of movement has improved. The purpose of this study was to use Inertial Measurement Units (IMUs) and Functional Principal Components Analysis (fPCA) to examine the role of movement variability (assessed via angular velocity), on 2 divers (1 international level; 1 national) performing the forward 3½ pike somersault dive. Analysis of angular velocity curves during iveflight identified 5 fPCs, accounting for 96.5% of movement variability. The national diver’s scatter plots and standard deviation of fPC scores illustrated larger magnitudes of angular velocity variability across dive flight. For fPC1 and fPC3, magnitudes of SD variability were 282.6 and 201.5, respectively. The international diver illustrated more consistent angular velocity profiles, with clustering of fPCs scores (e.g., fPC1 & 3 = SD’s of 75.2 & 68.0). To account for lower variability in the international diver, the ability to better coordinate movement sequences and functionally utilise feedback in response to initiation of the somersault position is highlighted. Overall, findings highlight how both IMUs and fPCA can more holistically and finitely examine the biomechanical and skill characteristics of movement sequences with the capability to inform athlete development.

KEYWORDS: Biomechanics; acrobatics; skill acquisition; movement variability; expertise; functional principal component analysis