Influence of lower limb asymmetry on the two-handed backhand stroke in female tennis players

This study explored the influence of lower limb asymmetry on the kinematic characteristics of the tennis two-handed backhand (2HB) stroke in skilled female players. It included 14 right-handed tennis players. Lower limb symmetry was assessed using the hurdle step test (HDS) from the Functional Movement Screen (FMS™). Based on the results, participants were divided into two groups: eight in the symmetric (SYM) group and six in the asymmetric (ASYM) group. Motion capture cameras recorded both groups performing backhand strokes. Data were analysed to measure linear and angular displacement of the trunk and lower limb segments throughout the preparation, acceleration, and follow-through phases. Differences in selected mean kinematics were assessed using independent t-tests. The ASYM group demonstrated a less closed stance in the initial backswing, less linear movement towards the left, and greater dependence on internal rotation of the left hip during acceleration The ankle having greater external rotation, resulted in more leg twist. The ASYM group also exhibited a greater forward lean at impact, with the follow-through characterised by continued forward lean, and greater leftward movement of both the trunk and lower limbs. SYM and ASYM grouping resulted in 11 significant mean differences in 2HB kinematics. Lower extremity symmetry assessed in the HDS task in skilled female tennis players may be an indicator of trunk, pelvis, and lower extremity technique in the 2HB.