title: Pivot task increases knee frontal plane loading compared with sidestep and drop-jump.
abstract: The purpose of this study was to assess kinematic and kinetic differences between three tasks (drop-jump, sidestep cutting, and pivot tasks) commonly used to evaluate anterior cruciate ligament risk factors. Nineteen female collegiate soccer athletes from a Division I institution participated in this study. Participants performed a drop-jump task, and two unanticipated tasks, sidestep cutting and pivot. Repeated-measures analyses of variance were conducted to assess differences in the kinematic and kinetic parameters between tasks. The pivot task had lower knee flexion (-41.2 ± 8.8°) and a higher valgus angle (-7.6 ± 10.1°) than the sidestep (-53.9 ± 9.4° and -2.9 ± 10.0°, respectively) at maximum vertical ground reaction force. The pivot task (0.8 ± 0.3 multiples of body weight) had higher peak posterior ground reaction force than the drop-jump (0.3 ± 0.06 multiples of body weight) and sidestep cutting (0.3 ± 0.1 multiples of body weight), as well as higher internal varus moments (0.72 ± 0.3 N · m/kg · m) than the drop-jump (0.14 ± 0.07 N · m/kg · m) and sidestep (0.17 ± 0.5 N · m/kg · m) at peak stance. During the pivot task, the athletes presented a more erect posture and adopted strategies that may place higher loads on the knee joint and increase the strain on the anterior cruciate ligament.
authors.affiliation: Sports Medicine Assessment, Research & Testing Laboratory, George Mason University, Fairfax, Virginia 22030, USA. ncortes@gmu.edu
authors.forename: Nelson
authors.initials: N
authors.lastname: Cortes
authors.forename: James
authors.initials: J
authors.lastname: Onate
authors.forename: Bonnie
authors.initials: B
authors.lastname: Van Lunen
mesh_terms: D000293:Adolescent; D016118:Anterior Cruciate Ligament / Q000503:physiopathology; D000070598:Anterior Cruciate Ligament Injuries; D056352:Athletes; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology*; D009068:Movement / Q000502:physiology; D012307:Risk Factors; D012916:Soccer; D014495:Universities; D016474:Weight-Bearing; D055815:Young Adult