Relationship between co-contraction ratio and knee adduction moment in knee osteoarthritis subjects

The purpose of this study was to analyse the effects of ten weeks of different running-retraining programmes on rearfoot strike (RFS) prevalence in adolescents.it is possible to change foot strike pattern in adolescents?A total of 180 children (45.3% girls), aged 13–16 years, participated in this intervention study. The children were randomly assigned to one of three experimental groups (EGs) that each carried out a different retraining programme, based on running technique (n = 39), a 15% increased step frequency (SF) (n = 37) and barefoot training (n = 30), performed for three days each week. A control group (CG) (n = 43) did not perform any retraining. A 2D video-based analysis (240 Hz) was used to determine the RFS.At baseline, no significant differences in RFS prevalence were found between the EGs and the CG in either the left (χ2 = 2.048; p = 0.559) or the right foot (χ2 = 0.898; p = 0.825). In the post-test, no significant differences were found for the left foot (χ2 = 7.102; p = 0.069), but there were significant differences for the right foot (χ2 = 9.239; p = 0.025) were observed. In the re-test, no significant differences were found for either the left foot (χ2 = 2.665; p = 0.273) or the right foot (χ2 = 2.182; p = 0.325). In addition, no group displayed significant changes in RFS prevalence from the pre-test to the re-test. There was a trend towards a reduction in the RFS prevalence in both the increased SF group and the barefoot group.The main finding of this study was that certain running-retraining programmes performed three times per week for ten weeks are not enough to modify the adolescent foot strike pattern (FSP).