Table 1 PICOS framework used to define inclusion and exclusion criteria of studies
Population | For the purpose of this review, male, female and sex refers to individuals assigned male or female at birth based on biological characteristics Healthy women – No restrictions were placed regarding reproductive status and hormonal contraception (HC) usage Healthy males (as a control for sex comparison of biomechanics) Age 18–40 years (children and pre/adolescent populations were excluded to control for the effect of puberty or changes during adolescence) Competing in or familiar with jump landing / cutting dominant, field / court based invasion games / sports Performance level: Tier 1 minimum – Tier 5 [67]—Healthy, recreationally active and elite athletes No history of ACL injury |
Intervention/method | A specific intervention was not investigated but participants were required to meet the population criteria above Studies must have examined biomechanical surrogates of non-contact ACL injury risk injury during pre-planned or unplanned change of direction tasks, with 3D motion and/or GRF analysis (inclusive of pre and/or unplanned tasks) Studies which adhered to the following change of direction task criteria were included: A preceding approach run of a minimum of 3 steps containing a subsequent change in direction > 20° The decision was made to omit tasks that included a split/ false step or hop or that omitted an approach run in line with previous COD definitions [68, 69] Omission of an approach run would not truly replicate the loading parameters of non-contact ACL injury situations due to the absence of a deceleration (as deceleration has been identified as the component where most noncontact ACL ruptures occur) (Donelon et al., 2020 [45]) |
Comparator | To determine the effect of sex: A direct between group comparison of a biomechanical surrogate of non-contact ACL injury risk between females and males (acting as a control) |
Outcome | Precise mean and SD provided for injury risk factors between males and females Biomechanics:  Knee abduction, rotation, flexion moments / impulse (knee joint loads) [45, 70,71,72,73,74]  Proximal anterior tibial shear [75] Technical, kinetic, or kinematic determinants of surrogates of injury risk (knee joint loads) [36, 70, 76] at initial contact (IC) (first instance of ground contact in COD) and peak value obtained during stance (across the full cutting cycle 0–100%) related to quadriceps, ligament, trunk, and leg dominance, such as:  Vertical/posterior GRF/ impulse  Initial or peak  Lateral trunk flexion/rotation angle  Hip internal rotation angle  Knee valgus / internal rotation angle  Knee flexion / hip flexion  Foot progression angles  Rearfoot/ forefoot strike  Coordination changes  Asymmetries |
Study design |  Peer review full article in English, examining humans from the year 2000 onwards due to a lack of 3D motion analysis research before this date  Direct assessment of change of direction biomechanics (with surrogates of injury) between healthy males and females |
Other data extraction | The following data were extracted and recorded in a spreadsheet: (1) Author names, publication year and country of origin (2) Sample size and participant characteristics including sport(s), playing level/status, training history, strength history/status/profile, reproductive status(females), hormonal contraception usage (3) Angle of COD task (4) Anticipatory nature of COD task (planned/unplanned) (5) If unanticipated, method and timing of stimulus presentation (6) Approach velocity prior to COD (7) How approach velocity was controlled for / calculated (8) Rest period between trials (if stated) (9) How risk factor (ACL surrogate) was assessed (methods) (10) Reliability and familiarisation stated for outcome measures / tasks (11) Outcome measures (mean, SD,) (12) Any other empirical data available for a variable that could mitigate any sex differences in surrogate injury risk identified (e.g. strength or experience / playing time) (13) For female populations, information relating to:   a. Reproductive status   b. Menstrual cycle phase   c. Hormonal contraception use |