Lynn Ellenberger1, Julia Jermann2, Stefan Fröhlich3, Walter O Frey4, Jess G Snedeker5, Jörg Spörri6. 1. Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland. Electronic address: lynn.ellenberger@balgrist.ch. 2. Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland. Electronic address: julia.jermann@balgrist.ch. 3. Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland. Electronic address: stefan.froehlich@balgrist.ch. 4. Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland. Electronic address: waltero.frey@balgrist.ch. 5. Biomechanics Laboratory, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; Institute for Biomechanics, ETH Zurich, Zurich, Switzerland. Electronic address: jess.snedeker@hest.ethz.ch. 6. Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland; University Centre for Prevention and Sports Medicine, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland. Electronic address: joerg.spoerri@balgrist.ch.
Abstract
OBJECTIVES: (1) To study the reliability of quantifying rear-chain stabilization capacity during deadbug bridging (DBB), (2) to provide reference values for competitive alpine skiers, and (3) to study associations with age, anthropometrics, maturation, skiing performance and back overuse complaints. DESIGN: Cross-sectional. SETTING: Biomechanical field experiment including questionnaires. PARTICIPANTS: 12 healthy subjects (reliability experiment); 133 skiers of the U16 category and 38 of the elite category (main experiment). MAIN OUTCOME MEASURES: DBB performance was quantified using 3D motion capture as the maximum amplitude of the relative vertical displacement of two pelvis markers (DBBdisplacement). Additionally, in U16 skiers, age, anthropometrics, maturation, skiing performance, and back overuse complaints were assessed. RESULTS: The reliability experiment revealed an ICC(3,1) and 95% CI of 0.81 [0.61, 0.93]. Within-subject SEM was 3.89 mm [3.16 mm, 5.12 mm]. Depending on sex and category, medians of DBBdisplacement in skiers ranged between 29 mm and 45 mm. DBBdisplacement differed between elite and U16 skiers (p < 0.001), but not between sexes. In U16 skiers, DBBdisplacement was independent of age, anthropometrics, and biological maturation, however, associated with skiing performance and back overuse complaints (p < 0.05). CONCLUSION: The proposed approach may be considered an adequate method to quantify athletes' rear-chain stabilization capacity.
OBJECTIVES: (1) To study the reliability of quantifying rear-chain stabilization capacity during deadbug bridging (DBB), (2) to provide reference values for competitive alpine skiers, and (3) to study associations with age, anthropometrics, maturation, skiing performance and back overuse complaints. DESIGN: Cross-sectional. SETTING: Biomechanical field experiment including questionnaires. PARTICIPANTS: 12 healthy subjects (reliability experiment); 133 skiers of the U16 category and 38 of the elite category (main experiment). MAIN OUTCOME MEASURES: DBB performance was quantified using 3D motion capture as the maximum amplitude of the relative vertical displacement of two pelvis markers (DBBdisplacement). Additionally, in U16 skiers, age, anthropometrics, maturation, skiing performance, and back overuse complaints were assessed. RESULTS: The reliability experiment revealed an ICC(3,1) and 95% CI of 0.81 [0.61, 0.93]. Within-subject SEM was 3.89 mm [3.16 mm, 5.12 mm]. Depending on sex and category, medians of DBBdisplacement in skiers ranged between 29 mm and 45 mm. DBBdisplacement differed between elite and U16 skiers (p < 0.001), but not between sexes. In U16 skiers, DBBdisplacement was independent of age, anthropometrics, and biological maturation, however, associated with skiing performance and back overuse complaints (p < 0.05). CONCLUSION: The proposed approach may be considered an adequate method to quantify athletes' rear-chain stabilization capacity.