Trunk, pelvis and lower limb coordination between anticipated and unanticipated sidestep cutting in females

Background Emerging research has suggested a plausible relationship may exist between lower limb coordination and musculoskeletal injury. A small number of studies have investigated the link between coordination and anterior cruciate ligament (ACL) injury during sidestep cutting. While prior work has shown unanticipated sidestep cutting to exhibit a more ‘at risk’ kinematic profile compared to anticipated tasks, a detailed understanding of the coordination between multiple joints and how they differ during unanticipated actions is lacking, particularly in females. Research question The purpose of this study was to observe the difference in trunk, pelvis and lower limb coordination and coordination variability during a dynamic, sidestep cutting task under anticipated and unanticipated conditions in a healthy female cohort. Methods Three-dimensional motion analysis data were recorded during anticipated and unanticipated sidestep cutting for nineteen healthy female participants (age, 24 ± 3yrs; height, 164 ± 5 cm; and weight, 58 ± 6 kg). Vector coding methodology was used to calculate coordination and coordination variability values and statistical parametric and non-parametric mapping was used to comprehensively determine differences between anticipated and unanticipated conditions. Results Differences were observed between anticipated and unanticipated conditions in the hip flexion – knee abduction angle (89 % of stance), hip rotation – knee abduction angle (55 % of stance), knee flexion – knee abduction angle (81–83 %, 86 % and 88–89 %) and knee flexion – ankle flexion angle (14–18 %) coupling angles. Differences in coupling angle variability were also observed with only one cluster of significance seen in hip abduction – knee abduction variability (27–30 % of stance). Significance Healthy females exhibit significant differences in lower limb coupling angles and coupling angle variability between anticipated and unanticipated sidestep cutting. Interventions aimed at reducing ACL injury risk may need to consider that anticipated and unanticipated sidestep cutting tasks present unique demands, and therefore should both be trained specifically