Abstract
BackgroundExcessive knee valgus moments are considered to be a risk factor for non-contact injuries in female athletes. Knee injuries are highly prevalent in netballers and are significant in terms of cost and disability. The aim of the study was to identify if changes in external ankle support mechanisms effect the range of motion and loading patterns at the ankle and knee joint during a sidestep cutting manoeuvre in high performance netball players.MethodsNetballers with no previously diagnosed ankle or knee injury (n = 10) were recruited from NSW Institute of Sport netball programme. Kinematic and kinetic data were collected simultaneously using a 3-D Motion Analysis System and a force platform to measure ground reaction forces. Players performed repeated side step cutting manoeuvres whilst wearing a standard netball shoe, the same shoe with a lace-up brace and a high-top shoe.ResultsThe brace condition significantly reduced ankle joint ROM in the sagittal plane by 8.9° ± 2.4 when compared to the standard netball shoe (p = 0.013). No other significant changes were seen between conditions for either kinematic or kinetic data. All shoe conditions did however produce knee valgus moments throughout the cutting cycle that were greater than those considered excessive in the previous literature (0.59 Nm/kg-Bwt).ConclusionsThe results show that an external ankle support brace can be used to reduce the ROM at the ankle in the sagittal plane without affecting the loading of the joints of the lower limb. Internal varus moments generated at the knee during the task were however greater than values reported in the literature to classify excessive knee joint moments, regardless of the condition. All netballers exhibited lower extremity patterns and alignments previously associated with increased peak external valgus moments including; increasing hip abduction, peak hip flexion and internal rotation during early contact and high laterally directed ground reaction forces. Increased external valgus knee loads have been strongly linked to the development of non-contact injuries at the knee in female athletes and could highlight a potential mechanism for the development non-contact knee injuries in netballers performing side step cutting tasks.
Highlights
Excessive knee valgus moments are considered to be a risk factor for non-contact injuries in female athletes
The brace condition was shown to significantly reduce the range of motion (ROM) at the ankle in the sagittal plane when compared to the standard shoe condition (39.7° ± 8.4° vs. 48.6° ± 10.6°, p = 0.013) (Table 1)
The brace condition significantly reduced ankle joint range of motion in the sagittal plane by 8.9° ± 2.4° throughout ground contact of the side step cut, when compared to the standard netball shoe. These results differ from previous research that has investigated the effect of ankle bracing in a netball specific landing task [13] in that no restriction of motion in the frontal plane at the ankle was observed in the current study
Summary
Excessive knee valgus moments are considered to be a risk factor for non-contact injuries in female athletes. Excessive external knee valgus moments are thought to be a significant factor in placing the female knee at greater risk of ACL injury [9] Added to this is the finding that female athletes are two to eight times more likely to sustain a non-contact ACL injury when compared to male athletes [7,10]. Restricting the ankle motion in the frontal plane using prophylactic ankle braces [16] and custom foot orthotics [17] has been linked to increased peak external rotation moments at the knee joint during vertical landing [16] and running tasks [17], which may have the potential to contribute to the development of knee injuries through altered knee loading [9,18]. Studies have showed that wearing high top shoes in certain ankle strain situations brought about delayed muscular pre-activation timing, decreased amplitudes of muscle activity and changed proprioceptive feedback, which may have a detrimental effect on establishing and maintaining functional ankle joint stability [19]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
