title: Kinematic analysis of hip and knee rotation and other contributors to ballet turnout.
abstract: Turnout, or external rotation (ER) of the lower extremities, is essential in ballet. The purpose of this study was to utilise physical examination and a biomechanical method for obtaining functional kinematic data using hip and knee joint centres to identify the relative turnout contributions from hip rotation, femoral anteversion, knee rotation, tibial torsion, and other sources. Ten female dancers received a lower extremity alignment assessment, including passive hip rotation, femoral anteversion, tibial torsion, weightbearing foot alignment, and Beighton hypermobility score. Next, turnout was assessed using plantar pressure plots and three-dimensional motion analysis; participants performed turnout to ballet first position on both a plantar pressure mat and friction-reducing discs. A retro-reflective functional marker motion capture system mapped the lower extremities and hip and knee joint centres. Mean total turnout was 129±15.7° via plantar pressure plots and 135±17.8° via kinematics. Bilateral hip ER during turnout was 49±10.2° (36% of total turnout). Bilateral knee ER during turnout was 41±5.9° (32% of total turnout). Hip ER contribution to total turnout measured kinematically was less than expected compared to other studies, where hip ER was determined without functional kinematic data. Knee ER contributed substantially more turnout than expected or previously reported. This analysis method allows precise assessment of turnout contributors.
authors.affiliation: a Department of Dance, Claire Trevor School of the Arts , University of California, Irvine , Irvine , CA , USA.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Quanbeck
authors.affiliation: b Division of Athletic Training , School of Applied Health Sciences and Wellness, Ohio University , Athens , OH , USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Russell
authors.affiliation: c University of Minnesota Medical School , Minneapolis , MN , USA.
authors.forename: Sara C
authors.initials: SC
authors.lastname: Handley
authors.affiliation: d James R. Gage Center for Gait and Motion Analysis, Gillette Children's Specialty Healthcare , 200 East University Avenue, St. Paul , MN , USA.
authors.forename: Deborah S
authors.initials: DS
authors.lastname: Quanbeck
mesh_terms: D000293:Adolescent; D000328:Adult; D001696:Biomechanical Phenomena; D003615:Dancing; D005260:Female; D005269:Femur; D005528:Foot; D006615:Hip; D006621:Hip Joint; D006801:Humans; D007717:Knee; D007719:Knee Joint; D035002:Lower Extremity; D009068:Movement; D010808:Physical Examination; D016059:Range of Motion, Articular; D012399:Rotation; D013977:Tibia; D055815:Young Adult
keywords: Dance; biomechanics; kinesiology; lower extremity; motion analysis