title: Volitional Spine Stabilization During a Drop Vertical Jump From Different Landing Heights: Implications for Anterior Cruciate Ligament Injury.
abstract: BACKGROUND
  Volitional preemptive abdominal contraction (VPAC) during dynamic activities may alter trunk motion, but the role of the core musculature in positioning the trunk during landing tasks is unclear.
  
  
  OBJECTIVE
  To determine whether volitional core-muscle activation incorporated during a drop vertical jump alters lower extremity kinematics and kinetics, as well as trunk and lower extremity muscle activity at different landing heights.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Clinical biomechanics laboratory.
  
  
  METHODS
  Thirty-two young healthy adults, consisting of 17 men (age = 25.24 ± 2.88 years, height = 1.85 ± 0.06 m, mass = 89.68 ± 16.80 kg) and 15 women (age = 23.93 ± 1.33 years, height = 1.67 ± 0.08 m, mass = 89.68 ± 5.28 kg).
  
  
  METHODS
  Core-muscle activation using VPAC.
  
  
  METHODS
  We collected 3-dimensional ankle, knee, and hip motions, moments, and powers; ground reaction forces; and trunk and lower extremity muscle activity during 0.30- and 0.50-m drop vertical-jump landings.
  
  
  RESULTS
  During landing from a 0.30-m height, VPAC performance increased external oblique and semitendinosis activity, knee flexion, and knee internal rotation and decreased knee-abduction moment and knee-energy absorption. During the 0.50-m landing, the VPAC increased external oblique and semitendinosis activity, knee flexion, and hip flexion and decreased ankle inversion and hip-energy absorption.
  
  
  CONCLUSIONS
  The VPAC performance during landing may protect the anterior cruciate ligament during different landing phases from different heights, creating a protective advantage just before ground contact and after the impact phase. Incorporating VPAC during high injury-risk activities may enhance pelvic stability, improve lower extremity positioning and sensorimotor control, and reduce anterior cruciate ligament injury risk while protecting the lumbar spine.
authors.affiliation: Texas Back Institute Research Foundation, Plano.
authors.forename: Ram
authors.initials: R
authors.lastname: Haddas
authors.affiliation: Texas Tech University Health Sciences Center, Center for Rehabilitation Research, School of Health Professions, Lubbock.
authors.forename: Troy
authors.initials: T
authors.lastname: Hooper
authors.affiliation: Texas Tech University Health Sciences Center, Center for Rehabilitation Research, School of Health Professions, Lubbock.
authors.forename: C Roger
authors.initials: CR
authors.lastname: James
authors.affiliation: Texas Tech University Health Sciences Center, Center for Rehabilitation Research, School of Health Professions, Lubbock.
authors.forename: Phillip S
authors.initials: PS
authors.lastname: Sizer
mesh_terms: D000328:Adult; D000843:Ankle Joint / Q000502:physiology; D016118:Anterior Cruciate Ligament / Q000502:physiology*; D000070598:Anterior Cruciate Ligament Injuries / Q000517:prevention & control*; D001696:Biomechanical Phenomena; D015444:Exercise / Q000502:physiology; D005260:Female; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000502:physiology; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology; D013131:Spine / Q000502:physiology; D060726:Torso / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology*; D055815:Young Adult
keywords: clinical biomechanics; core stabilization; rehabilitation