title: Biomechanical Comparison of Single- and Double-Leg Jump Landings in the Sagittal and Frontal Plane.
abstract: BACKGROUND
  Double-leg forward or drop-jump landing activities are typically used to screen for high-risk movement strategies and to determine the success of neuromuscular injury prevention programs. However, research suggests that these tasks that occur primarily in the sagittal plane may not adequately represent the lower extremity biomechanics that occur during unilateral foot contact or non-sagittal plane movements that are characteristic of many multidirectional sports.
  
  
  OBJECTIVE
  To examine the extent to which lower extremity biomechanics measured during a jump landing on a double leg (DL) after a sagittal plane (SAG) movement is representative of biomechanics measured during single-leg (SL) or frontal plane (FRONT) jump landing tasks.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Lower extremity biomechanics were measured in 15 recreationally active females (mean age [±SD], 19.4 ± 2.1 years; mean height, 163.3 ± 5.9 cm; mean weight, 61.1 ± 7.1 kg) while performing SAGDL, SAGSL, FRONTDL, and FRONTSL jump landing tasks. Repeated-measures analyses of variance examined differences in lower extremity biomechanics between the 4 tasks, and linear regressions examined the extent to which an individual's biomechanics during SAGDL were representative of their biomechanics during SAGSL, FRONTDL, and FRONTSL.
  
  
  RESULTS
  Lower extremity kinematics and kinetics differed by condition, with the SAGDL task generally eliciting greater hip and knee flexion angles and lower hip and knee forces than the other tasks (P < .05). Although biomechanics during the SAGDL task were strongly associated with those during the FRONTDL task (R (2), 0.41-0.82), weaker associations were observed between SAGDL and single-leg tasks for hip kinematics (R (2), 0.03-0.25) and kinetics (R (2), 0.05-0.20) and knee abduction moments (R (2), 0.06-0.18) (P < .05).
  
  
  CONCLUSIONS
  Standard double-leg sagittal plane jump landing tasks used to screen for ACL injury risk and the effectiveness of ACL injury prevention programs may not adequately represent the lower extremity biomechanics that occur during single-leg activities.
  
  
  CONCLUSIONS
  These results support further investigation of single-leg multidirectional landings to identify high-risk movement strategies in female athletes playing multidirectional sports.
authors.affiliation: Department of Physical Therapy, High Point University, High Point, North Carolina, USA.; Department of Kinesiology, University of North Carolina at Greensboro, Greensboro, North Carolina, USA.
authors.forename: Jeffrey B
authors.initials: JB
authors.lastname: Taylor
authors.affiliation: Department of Physical Therapy, High Point University, High Point, North Carolina, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Ford
authors.affiliation: Department of Athletic Training, High Point University, High Point, North Carolina, USA.
authors.forename: Anh-Dung
authors.initials: AD
authors.lastname: Nguyen
authors.affiliation: Department of Kinesiology, University of North Carolina at Greensboro, Greensboro, North Carolina, USA.
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Shultz
keywords: anterior cruciate ligament; injury prevention; multidirectional movement; screening