Changing pivoting technique reduces knee valgus moments

Jones, PA; Barber, OR; Smith, L

Abstract

Changing direction is a common action involved in non-contact anterior cruciate ligament injuries in female athletes (Faude et al. [2005]. American Journal of Sports Medicine, 33, 1694-1700), as such actions involve lower limb postures that increase knee valgus moments (KVM) (Cortes et al. [2011]. Journal of Sports Sciences, 29, 83-92). For instance, increased initial foot progression angle (IFPA) may account for the high KVM observed during pivoting (Cortes et al., 2011). Previous research (Dempsey et al. [2009]. American Journal of Sports Medicine, 37, 2194-2200) has shown that a technique modification programme can reduce KVM during cutting. No studies have examined whether a technique modification programme can reduce KVM during pivots. The aim of this study was to investigate the effects of a 6-week technique modification programme on KVM during pivoting. The study was approved by the University’s ethics committee. Ten female netball players (mean ± SD; age: 21.7 ± 3.4 years, height: 1.70 ± 0.03 m, mass: 59.2 ± 4.6 kg) performed 6 trials of pivoting before and after a 6-week, twice per week technique modification programme. For each trial, three-dimensional motion data using Qualisys Pro-Reflex infrared cameras (240Hz) operating through Qualisys Track Manager software v2.8 and ground reaction force 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 12 and 25 Hz, respectively. The time to complete this task (5m approach, 180° turn, and 5m return) was recorded using Brower timing cells (Draper, UT). Following the intervention, paired samples t-tests found that IFPA significantly (P < 0.001, ES = 2.6) reduced from 71 ± 10.6° to 27 ± 22.2° in line with the aims of the programme and was accompanied by a significant (39%) reduction in KVM (0.75 ± 0.43 vs. 0.46 ± 0.37 Nm.kg-1, P = 0.001, ES = 0.73). There was a significant correlation between changes (pre to post) in IFPA and KVM (R2 = 37%, P = 0.028). No significant differences (P = 0.702) in approach velocities (3.20 ± 0.17 vs. 3.23 ± 0.32 m.s-1) were observed between pre and post-tests, but a significant (P = 0.028, ES = 0.74) improvement in performance time (3.15 ± 0.23 vs. 3.02 ± 0.12 s) was observed. The results illustrate that a 6-week technique modification programme can reduce IFPA leading to a reduction in KVM and potential injury risk during pivoting, whilst enhancing performance.

• Presentation Conference Type: Conference Paper (published)
• Conference Name: BASES Annual Conference
• Start Date: Sep 30, 2012
• Publication Date: 2015-12
• Deposit Date: Jul 21, 2023
• Volume: 33: Supplement 1
• DOI: https://doi.org/10.1080/02640414.2015.1110236
• Related Public URLs: https://www.researchgate.net/publication/287198114_Changing_pivoting_technique_reduces_knee_valgus_moments_Day_2_Free_Communications_-_Biomechanics_and_Motor_Behaviour_Journal_of_Sports_Sciences_33sup1_s61-s64