Biomechanical and performance differences between female soccer athletes in National Collegiate Athletic Association Divisions I and III

Abstract

Context: The recent increase in women's varsity soccer participation has been accompanied by a lower extremity injury rate that is 2 to 6 times that of their male counterparts.

Objective: To define the differences between lower extremity biomechanics (knee abduction and knee flexion measures) and performance (maximal vertical jump height) between National Collegiate Athletic Association Division I and III female soccer athletes during a drop vertical jump.

Design: Mixed 2 x 2 design.

Setting: Research laboratory.

Patients or other participants: Thirty-four female collegiate soccer players (Division I: n = 19; Division III: n = 15) participated in the study. The groups were similar in height and mass.

Intervention(s): Each subject performed a maximal vertical jump, followed by 3 drop vertical jumps.

Main outcome measure(s): Kinematics (knee abduction and flexion angles) and kinetics (knee abduction and flexion moments) were measured with a motion analysis system and 2 force platforms during the drop vertical jumps.

Results: Knee abduction angular range of motion and knee abduction external moments were not different between groups (P > .05). However, Division I athletes demonstrated decreased knee flexion range of motion (P = .038) and greater peak external knee flexion moment (P = .009) compared with Division III athletes. Division I athletes demonstrated increased vertical jump height compared with Division III (P = .008).

Conclusions: Division I athletes demonstrated different sagittal-plane mechanics than Division III athletes, which may facilitate improved performance. The similarities in anterior cruciate ligament injury risk factors (knee abduction torques and angles) may correlate with the consistent incidence of anterior cruciate ligament injury across divisions.

Keywords: knee flexion angle; knee valgus; lower extremity; women's soccer.

Figure 1. Locations of reflective markers during data collection. Medial knee and ankle markers were removed after the static trial. Sacrum, left posterior superior iliac spine, left mid tibia, and right heel markers are not visible in this view.

Figure 2. A, Data from reflective marker locations collected simultaneously with 2 force platforms. B, C, Skeletal segments created using external marker locations.

Figure 3. A, Athlete's standing position. B, Drop vertical jump maneuver starting position on top of a 31-cm box. C, Maximal vertical excursion of the athlete's center of mass (COM). Vertical jump height calculated from COM = COMc − COMa.

Figure 4. Knee flexion and abduction joint angles in Division I and Division III female soccer players during drop vertical jump.

Figure 5. Knee flexion and knee abduction joint moments in Division I and Division III female soccer players during drop vertical jump.