Comparison Of Spine Kinematics Between Dominant And Non-dominant Leg Kicking In Collegiate Women Soccer Players

Abstract

Most kicking research focuses on dominant (D) foot and lower extremity coordination; limited research examines axial skeletal differences between D and non-dominant (ND) kicking. PURPOSE: To compare spine kinematics between D/ND kicking. METHODS: 25 women collegiate level soccer players (19.84±2.54 yrs) performed 12 driven kicks (six each leg) in a random order using self-selected approach angles (AA)/distances (AD). An electromagnetic (EM) tracking system (Motion Monitor, IST, Inc.) captured spine flexion (SFL), lateral flexion (SLFL) and rotation (SRO) calculated at three points, backswing (BS) (kick leg peak extension), ball contact (BC), and end of follow-through (FT) (kick leg peak flexion), were compared between D/ND kicking using adjusted contrasts (a=.016). Ball velocity (BV), measured (SpeedTracX, EMG Comp., Inc) before/with EM sensors secured to participants was analyzed. Paired t-tests (a=.05) compared D/ND repetition time (RT), % cycle BC (%BC), AA, and AD. RESULTS: D BV was significantly greater (P<.001, 95% CI=1.6 to 2.9m/s) than ND; no significant BV differences related to EM sensors. No significant differences for RT (P=.80, 95% CI=-.023 to.029s), AA (P=.76, 95% CI=-3 to 2.2°), and AD (P=.18, 95% CI=-19.0 to 3.5cm) existed. D %BC occurred significantly earlier (P=.03, 95% CI=-10.23 to -.49%) than ND. Mean (±SD) differences (D-ND) for spine positions (degrees):TableCONCLUSION: Greater D leg BV supports prior research. Decreased BS, greater SFL (@ BC and FT) and SRO (@ FT) during D leg kick may reflect a better coordination pattern, forming more trunk tension to ultimately increase BV. Further research is needed to understand D/ND leg differences as well as if multiplanar core training could enhance ND kicking.