Main author: Guðni Rafn Harðarson
Institution or Company: Háskóli Íslands
Co-Authors, Institution or Company:
Kristin Briem, Háskóli Íslands. Haraldur Björn Sigurðsson, University of Delaware.
Objective: Knee-movement in the frontal-plane is used during drop-jump (DJ) to screen for knee-injury (KI) [1]. Injury-prevention programs (IPP) decrease the incidence of KI [2]. The aim of this study was to describe the effect of an IPP, on medial knee displacement (MKD) during a DJ, comparing athletes who partook in the IPP to control group (CG) and to examine the effect of age on MKD.
Methods: Prospective laboratory study. In phase one (P1) female participants (n=114, age=9-12) performed ten DJs. In phase two (P2) they returned (age=14-18). Nineteen partook in the intervention group (IG). Data was recorded with an eight-camera motion-capture system. MKD was the displacement of the distal-femur from initial-contact (IC) to peak medial-position before the lowest position of the pelvis during landing. A linear model was created, MKD normalized by femur length (FL) as the dependent-variable, and the intervention and phases as the independent-variables.
Results: There was a main effect of phase (p<0.01) where transitioning to P2 showed an increase of 0.0044 (0.0005-0.0083) FLs. However, this was increased for the intervention group by 0.0127 (0.0048-0.0207) FLs (p<0.01). The models R^2 is 0.441 and the fixed effect coefficient is 0.016.
Conclusions: Although different MKD in P2 compared to P1 shows that MKD increases with age, IPP did not influence MKD in this model. IPP may reduce the risk of KI by affecting other factors.
References
[1] Redler, L. H. et al. (2016). Phys Sportsmed., 44(1), 46–52.
[2] L. A. Donnell-Fink et al. (2015) PLoS One, 10(12),
