title: The relationships between the center of mass position and the trunk, hip, and knee kinematics in the sagittal plane: a pilot study on field-based video analysis for female soccer players.
abstract: Athletes with non-contact anterior cruciate ligament tears have common features in the sagittal plane; namely, the body's center of mass (COM) is located posterior to the base of support, the trunk and knee joints are extended, and the hip angle is flexed. However, the relationships among these variables have not been assessed in field-based movements. This study sought to determine relationships between distances from the COM to the base of support and the trunk, hip, and knee positions in women while playing soccer. Sixty events (29 single-leg landing and 31 single-leg stopping events) were analyzed using two-dimensional video analysis. The relationships among the measurement variables were determined using the Pearson's product-moment correlation coefficient, and stepwise multiple linear regression models were used to explore the relationships between the COM position and the kinematic variables. The distance from the COM to the base of support displayed a moderate negative relationship with the trunk angle (r = -0.623, p < .0001, r(2) = 0.388) and a strong positive relationship with the limb angle (r = 0.869, p < .0001, r(2) = 0.755). The limb, knee, and trunk angles were selected in the best regression model (adjusted r(2) = 0.953, p < .0001, f(2) = 20.277). These findings suggest that an increased trunk angle and a decreased limb angle at initial contact are associated with a safer COM position. Neuromuscular training may be useful for controlling the trunk and lower limb positions during dynamic activities.
authors.affiliation: Faculty of Health Sciences, Tokyo Ariake University of Medical and Health Sciences, Tokyo, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Sasaki
authors.affiliation: Department of Health and Sports, Niigata University of Health and Welfare, Niigata, Japan.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Nagano
authors.affiliation: Graduate School of Sport Sciences, Waseda University, Saitama, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kaneko
authors.affiliation: Graduate School of Tokyo Ariake University of Medical and Health Sciences, Tokyo, Japan.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Imamura
authors.affiliation: Department of Orthopedic Surgery, Sapporo Medical University, Sapporo, Japan.
authors.forename: Takuma
authors.initials: T
authors.lastname: Koabayshi
authors.affiliation: Faculty of Sport Sciences, Waseda University, Saitama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Fukubayashi
keywords: anterior cruciate ligament; injury prevention; risk factor; two-dimensional assessment