Energetic Analysis of Landing: A Novel Approach to Understanding Anterior Cruciate Ligament Injuries Public Deposited

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  • March 22, 2019
  • Norcross, Marc F.
    • Affiliation: School of Medicine, Department of Allied Health Sciences, Curriculum in Human Movement Science
  • Energetic analysis of landing combines kinematic and kinetic parameters across the landing period that have traditionally been evaluated independently and at discrete time points. This coupling of the kinematics and kinetics of multiple joints provides a more comprehensive description of the complex multi-segmental mechanics that occur during landing and in proposed anterior cruciate ligament (ACL) injury mechanisms. The purpose of this investigation was to utilize this form of analysis to 1) elucidate new knowledge regarding biomechanical factors that contribute to sagittal plane energy absorption (EA) patterns that are associated with high risk landing biomechanics related to ACL injury; 2) explore relationships between frontal and sagittal plane EA, and ACL-related landing biomechanics; and 3) clarify previous research regarding potential sex differences in lower extremity EA strategies. 82 volunteer subjects (41 males, 41 females; age = 20.1 ± 2.4 years; height = 1.74 ± 0.10 m; mass = 70.3 ± 16.1 kg) were included in this research study. Subjects had peak isometric strength measured prior to completing double leg jump landing and drop landing tasks during which biomechanics and were assessed. It was found that greater sagittal and frontal plane EA during the 100 ms after ground contact were indicative of biomechanical profiles that likely result in greater ACL loading due to sagittal and frontal plane mechanisms, respectively. However, there is no association between the magnitudes of sagittal and frontal plane EA during landing. Additionally, no sex differences in EA strategy were identified after controlling for initial joint kinematics indicating that landing posture, not sex, influences EA strategy. Finally, the combination of multi-factorial biomechanical parameters is predictive of EA at the hip and ankle, but not at the knee and suggests that interventions aimed at reducing total lower extremity EA and thereby potentially decreasing knee joint loading during landing must facilitate changes across the entire kinetic chain. The results of this investigation provide significant information for understanding the way in which multi-joint lower extremity movement patterns during landing, quantified using EA analyses, affects ACL loading, and provides much-needed evidence for specific biomechanical factors that should be targeted in ACL injury prevention programs.
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  • ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Interdisciplinary Human Movement Science (School of Medicine).
  • Blackburn, J. Troy
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  • University of North Carolina at Chapel Hill

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