19 and 20 The additional valgus and internal rotation position have the potential to slightly increase this load, 20, 30 and 32 but play a minor role in terms of ACL-rupture. 19 and 20 A more recent study even suggests that the addition of a valgus collapse pattern to a knee flexion angle of 30° does reduce the length of the ACL compared to the 30° flexed position only, indicating a lower strain on the ACL. 21 Difference between female and male valgus angle during cutting on NT has been reported to be approximate 11°.17 Additionally, Hewett et al.33 identified an 8° difference in valgus angle during

a jump-landing task between participants with an ACL-injured knee and participants with a healthy knee. The current study showed SB431542 mw that there was a tendency towards a lower knee valgus angle by 1.6°–3.2° between different surfaces. Keeping in mind that the knee flexion angle did not significantly change between AT and NT, the implications of these

results are that cutting on AT does not appear to yield an increased ACL-injury risk for the female knee. The decrease in varus angle in combination with the observed decreased knee internal rotation angle and tendency toward an increased ankle inversion could further indicate that cutting on AT might even bear a slightly lower injury potential than cutting on NT. The findings of this study support the literature demonstrating equal7, 9, 13 and 14 and lower knee injury occurrence10 and 12 for female football players on AT and provide, on Hydroxychloroquine in vitro a basic kinematic level, a possible mechanistic explanation. Frontal and transversal knee kinematics are challenging to capture and are susceptible to soft tissue artefacts. To keep this error to a minimum, the Cleveland Clinical Markerset was applied, which uses anatomical landmarks for static calibration in combination with cluster markers for targeting the movement. The 6° of freedom model implemented in V3D uses a least error approach to take

movement artefacts into account. Although, the valgus angles in this study are higher than reported in previous Rolziracetam research,27, 31 and 34 this may be partly due to the higher BMI of the current participants. However, the change in the range of motion of the valgus angle during the early deceleration phase corresponds well with these previous studies. Additionally, the reported intra-individual changes on knee valgus motion between AT and NT are consistent for each participant, which strengthens the confidence, that the demonstrated surface effects occur. The effect of the different surfaces on the ankle is less evident. Even though ankle sprains are among the most common ankle injuries, the mechanisms leading to the injury are unclear. The primary risk factor seems to be having sustained a previous ankle sprain35 and 36 and the majority of ankle sprains present an increased inversion or supination mechanism.