Limited positive effects on jump-landing technique in girls but not in boys after 8 weeks of injury prevention exercise training in youth football

PURPOSE: To evaluate changes in jump-landing technique in football-playing boys and girls after 8 weeks of injury prevention training. METHODS: Four boys’ and four girls’ teams (mean age 14.1 ± 0.8 years) were instructed to use either the original Knee Control injury prevention exercise programme (IPEP) or a further developed IPEP, Knee Control + , at every training session for 8 weeks. Baseline and follow-up testing of jump-landing technique included drop vertical jumps (DVJ), assessed subjectively and with two-dimensional movement analysis, and tuck jump assessment (TJA). RESULTS: Only minor differences in intervention effects were seen between the two IPEPs, and results are therefore presented for both intervention groups combined. At baseline 30% of the boys showed good knee control during the DVJ, normalised knee separation distances of 77–96% (versus hip) and a median of 3 flaws during the TJA. Among girls, 22% showed good knee control, normalised knee separation distances of 67–86% and a median of 4 flaws during the TJA. At follow-up, boys and girls performed significantly more jumps during TJA. No changes in jump-landing technique were seen in boys, whereas girls improved their knee flexion angle at initial contact in the DVJ (mean change + 4.7°, p < 0.001, 95% CI 2.36–6.99, d = 0.7) and their TJA total score (− 1 point, p = 0.045, r = − 0.4). CONCLUSION: The study showed small positive effects on jump-landing technique in girls, but not in boys, after 8 weeks of injury prevention training. LEVEL OF EVIDENCE: Level II. TRIAL REGISTRATION: Clinical Trials gov identifier: NCT03251404 ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00167-019-05721-x) contains supplementary material, which is available to authorized users.