How early should you brake during a 180° turn? A kinetic comparison of the antepenultimate, penultimate, and final foot contacts during a 505 change of direction speed test

Dos'Santos, Thomas ORCID: https://orcid.org/0000-0003-2715-0116, Thomas, Christopher and Jones, Paul (2021) How early should you brake during a 180° turn? A kinetic comparison of the antepenultimate, penultimate, and final foot contacts during a 505 change of direction speed test. Journal of Sports Sciences, 39 (4). pp. 395-405. ISSN 0264-0414

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Abstract

The aim of the study was to compare ground reaction force (GRF) characteristics between the antepenultimate foot contact (APFC), penultimate foot contact (PFC), and final foot contact (FFC), and to examine the relationships between APFC, PFC, and FFC GRF characteristics with 505 change of direction (COD) speed performance. Twenty university male soccer players performed three COD trials, whereby GRFs were collected over the aforementioned foot contacts. Greater peak braking forces in shorter ground contact times were demonstrated over the APFC compared to the PFC and FFC (p ≤ 0.011, d = 0.96–7.82), while APFC mean GRFs were greater than the PFC (p ≤ 0.001, d = 1.86–7.57). Faster 505 performance was associated with greater APFC peak and mean vertical, horizontal, and resultant braking GRFs (r2 = 21.6–54.5%), greater FFC mean HGRFs (r2 = 38.8%), more horizontally orientated peak resultant APFC and PFC GRFs (r2 = 22.8–55.4%), and greater APFC, PFC, and FFC mean horizontal to vertical GRF ratios (r2 = 32.0–61.9%). Overall, the APFC plays a more pivotal role in facilitating deceleration compared to the PFC for effective 505 performance. Practitioners should develop their athletes’ technical ability to express force horizontally across all foot contacts and coach braking strategies that emphasise greater magnitudes of posteriorly directed APFC GRFs to facilitate faster 505 performance.