Choice of low-pass filter influences practical interpretation of ball kicking motions: the effect of a time-frequency filter method

Augustus, Simon, Amca, Arif, Hudson, Penny E. and Smith, Neal A. (2020) Choice of low-pass filter influences practical interpretation of ball kicking motions: the effect of a time-frequency filter method. Sports Biomechanics. pp. 1-18. ISSN 1476-3141

[img] Text (This is an Accepted Manuscript of an article published by Taylor & Francis in Sports Biomechanics on 02 September 2020, available online: https://doi.org/10.1080/14763141.2020.1805507)
Manuscript_Kicking_Augustus_Amca_Hudson_Smith_Final SportsBiomec filter kick.docx - Accepted Version
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Abstract

When studying ball kicking, conventional low-pass filters may distort kick leg kinematics near the time of foot-to-ball contact, leading to flawed practical interpretation of the skill. Time-frequency filters are a viable alternative, but are not widely used. This study compared a fractional Fourier filter (FrFF) with conventional filters (CF) methods for estimating common parameters used to define kicking performance. Instep kicks from 23 experienced soccer players were captured by 3D motion analysis (1000Hz), and kick leg foot velocities, knee angular velocities and ankle dorsi-plantarflexion angles compared between the FrFF and variations of a Butterworth CF. The FrFF and CFs using a higher cut-off frequency (> 70 Hz) successfully detected lower leg motion prior to, during and following impact, whereas CFs with low cut-off frequencies (< 20Hz) attenuated motion near impact. Truncating data at impact provided valid pre-impact kinematics, but ignored information thereafter. Rather than decelerating the lower leg to conserve accuracy, ‘kicking through the ball’ should be considered a valid coaching cue. Further, controlling ankle plantarflexion to ensure efficient impact mechanics may be important for skilled kicking. Practitioners should consider how choice of filter will affect their data, and use of time-frequency methods can help inform empirically grounded coaching practices.

Item Type: Article
Additional Information: 38th International Society of Biomechanics in Sport Conference postponed until 2022
Uncontrolled Keywords: Soccer, football, instep kick, fractional Fourier filter, impact.
Subjects: L Education > L Education (General)
Q Science > Q Science (General)
Q Science > QC Physics
Divisions: Research Centres > CCASES
Event Title: 38th International Society of Biomechanics in Sport Conference
Event Location: Liverpool, UK
Event Dates: 21-25 July 2020 Postponed until 2022
Related URLs:
Depositing User: Neal Smith
Date Deposited: 07 Aug 2020 08:32
Last Modified: 24 Sep 2020 13:21
URI: http://eprints.chi.ac.uk/id/eprint/5279

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