Biomechanical Investigation of Elite Place-Kicking

Authors

Chase M. Pfeifer, University of Nebraska-LincolnFollow

Date of this Version

11-2015

Document Type

Article

Citation

Pfeifer, Chase M. Biomechanical Investigation of Elite Place-Kicking. Diss. U of Nebraska-Lincoln, 2015.

Comments

A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of the Requirements For the Degree of Doctor of Philosophy, Major: Biomedical Engineering, Under the Supervision of Professors Jeff A. Hawks and Shane M. Farritor. Lincoln, Nebraska: November, 2015

Copyright (c) 2015 Chase M. Pfeifer

The author would also like to acknowledge additional advisors, Dr. Judith M. Burnfield, and Dr. Timothy J. Gay.

Abstract

Many studies aim to understand the fundamentals of kicking commonly displayed by soccer players [4,6,10,16,17,18,24,25,28,29,30,34,36,38,40]. Of those studies, most are limited to a two-dimensional (2D) analysis using high-speed cameras for position tracking or utilizing electromyography to observe the activity of select muscles [4,6,18,25,29,36]. The few studies that investigate kicking using a three-dimensional (3D) model are limited in their position tracking capabilities and focus mainly on joint flexion potentials and foot speed.

This dissertation is a comprehensive biomechanical analysis (kinematic and EMG) of the field-goal place-kicking techniques of four elite kickers in American football. Data were compared and contrasted with ball flight trajectories created using a motorized mechanical place-kicker to elucidate the influence of impact location on ball flight. A novel tracking software was developed to quantify ball flight trajectory. Human subject testing revealed that the ideal timing of proximal-to-distal motion (application of the summation of speed principle) plays a key role in achieving maximum kicking potential. However, the quality of a place kick cannot be determined solely on foot speed but also other impact conditions such as foot orientation, impact location, and the energy created by the kicking leg through impact. The findings emerging from human subjects’ testing were reinforced by data emerging from the mechanical kicker, demonstrating that impact location is the driving factor influencing the football's flight. These findings correlate with the results of the human subject testing.

To the author’s knowledge, this work is the first published study to date that comprehensively analyzed kinematic and electromyography patterns generated by elite American football place kickers and compared these data to patterns emerging from a motorized mechanical model of place kicking.

Advisors: Jeff A. Hawks, Shane M. Farritor