Kiss goodbye to the ‘kissing knees’: no association between frontal plane inward knee motion and risk of future non-contact ACL injury in elite female athletes

Agnethe NILSTAD, Erich PETUSHEK, Kam-Ming MOK, Roald BAHR, Tron KROSSHAUG*

*Corresponding author for this work

Research output: Journal PublicationsJournal Article (refereed)peer-review

22 Citations (Scopus)


The aim of this study was to investigate if frontal plane knee and hip control in single-leg squats or vertical drop jumps with an overhead target were associated with future non-contact anterior cruciate ligament (ACL) injury in elite female athletes. Of the 429 handball and 451 football athletes (age 21.5 ± 4.0 years, height 169.6 ± 6.4 cm, body weight 67.1 ± 8.0 kg), 722 non-injured and 56 non-contact ACL injured participants were eligible for analysis. We calculated lateral pelvic tilt, frontal plane knee projection angle, medial knee position, and side-to-side asymmetry in these from 2D videos recorded at baseline, and recorded any new ACL injuries prospectively. None of the aforementioned variables in either screening task were different or could discriminate between injured and non-injured athletes (all p values >.05 and Cohen’s d values < .27). Two-dimensional video assessment of frontal plane knee and hip control during both a single-leg squat and vertical drop jump was unable to identify individuals at increased risk of non-contact ACL injury, thus should not be used for screening.
Original languageEnglish
Pages (from-to)65-79
Number of pages15
JournalSports Biomechanics
Issue number1
Early online date28 Apr 2021
Publication statusPublished - 2023

Bibliographical note

Funding Information:
The Oslo Sports Trauma Research Center has been established at the Norwegian School of Sport Sciences through generous grants from the Royal Norwegian Ministry of Culture, the South-Eastern Norway Regional Health Authority, the International Olympic Committee, the Norwegian Olympic Committee & Confederation of Sport, and Norsk Tipping AS. This study also received financial support from The Norwegian Fund for Post-Graduate Training in Physiotherapy. We thank Maya Rosvoll, Sólveig Þórarinsdóttir, Camilla Christensen and Jørn Erik Strand for their contributions to the video analyses. A special thanks to Inge Dehli Andersen for valuable help with data acquisition. We also acknowledge all athletes in the Norwegian female soccer and handball premier league for their participation in the study.

Publisher Copyright:
© 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.


  • sports inqury
  • injury prevention
  • risk screening
  • motion analysis
  • single-leg squat
  • vertical drop jump


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