A comparison of braking characteristics between pre-planned and unanticipated changing direction tasks in female soccer players: An exploratory study

Jones, P; Stones, S; Smith, L

Abstract

Changing direction is a common action involved in non-contact anterior cruciate ligament injuries in female soccer players (Faude et al. [2005]. Am J Sports Med, 33, 1694-1700). Most biomechanical studies into changing direction focus on final contact, but little is known about the role of penultimate contact. Previous research (Graham-Smith et al. [2009, July]. Paper presented at the 5th UK Strength and Conditioning Association Conference, Bedford) found significantly greater knee extensor moments, vertical and horizontal ground reaction forces (GRF) during penultimate compared to final contact during pre-planned pivots in male soccer players. No previous research has identified whether such deceleration strategies occur during unanticipated cutting and pivoting. The aim of this study was to compare braking characteristics between pre-planned and unanticipated cutting (90⁰) and pivoting (180⁰ turn). The study was approved by the University’s ethics committee. Ten female soccer players (mean ± SD; age: 22.1±1.9 years, height: 1.62 ± 0.06, mass: 62.6 ± 8.5 kg) performed 6 trials each of pre-planned and unanticipated cutting and pivoting. For each trial, three-dimensional motion data using Qualysis ‘Pro reflex’ infrared cameras (240Hz) operating through QTrac Manager software v2.8 and GRF data from two AMTI force platforms (1200Hz) were collected. Joint coordinate and force data were smoothed with a Butterworth low pass digital filter with cut-off frequencies of 12Hz and 25Hz, respectively. A 2 × 2 factorial ANOVA for the factors of contact (penultimate vs. final) and task (pre-planned vs. unanticipated) revealed a significant interaction for peak vertical (cut: P = 0.001; η2 = 0.76; pivot: P = 0.019, η2 = 0.48) and resultant GRF (cut: P = 0.001, η2 = 0.70; pivot: P = 0.024, η2 = 0.49). Tukey’s post hoc analysis revealed significant (P < 0.05) increases in peak vertical GRF from penultimate to final contact during unanticipated tasks, which remained unchanged during pre-planned tasks. More pronounced (P < 0.05) increases in resultant GRF during unanticipated tasks (cut 14%; pivot 34%) compared to pre-planned (cut 3%; pivot 4%) were observed. Significantly (P = 0.038, η2 = 0.42) greater final/ penultimate peak horizontal GRF ratio was observed during unanticipated pivots (1.25) compared to pre-planned (0.89). The results illustrate that less braking takes place during penultimate contact of unanticipated cutting and pivoting compared to pre-planned; highlighting the need to develop players anticipatory skills to allow more time for technical adjustments prior to final contact to help lower hazardous knee joint loads during final contact.

Citation

Jones, P., Stones, S., & Smith, L. (2013, September). A comparison of braking characteristics between pre-planned and unanticipated changing direction tasks in female soccer players: An exploratory study. Poster presented at BASES Annual Conference, St Georges Park, Burton

• Presentation Conference Type: Poster
• Conference Name: BASES Annual Conference
• Conference Location: St Georges Park, Burton
• Start Date: Sep 30, 2013
• Deposit Date: Jul 21, 2023
• Related Public URLs: https://www.researchgate.net/publication/280923425_A_comparison_of_braking_characteristics_between_pre-planned_and_unanticipated_changing_direction_tasks_in_female_soccer_players_An_exploratory_study