Award Date

12-1-2012

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Kinesiology and Nutrition Sciences

First Committee Member

John A. Mercer

Second Committee Member

Janet S. Dufek

Third Committee Member

Richard D. Tandy

Fourth Committee Member

Daniel L. Young

Number of Pages

66

Abstract

Shock attenuation (SA) has been well studied in activities such as walking and running (Chu, et al. 2004; Derrick, et al. 2004; Mercer, et al. 2003); however, there is a lack of research regarding SA during landing. Furthermore, there is lack of information regarding which structures attenuate shock. The purpose of this study was to examine SA among the leg-hip, hip-head, and leg-head segments during landing. Each subject (n=10, Age 26.3 ± 2.71 years, Height 1.68 ± 0.08 m, Mass 70.49 ± 16.03 kg) was instrumented with accelerometers at the leg, hip and forehead. Subjects then performed landings from three heights: 30cm, 60cm, and 90cm. For each height, subjects completed 5 landing trials. Rest was provided between each trial. Order of conditions was randomized to account for fatigue and learning. During each landing, accelerations were recorded at 1000 Hz for the leg, hip, and head respectively using light-weight accelerometers. Data were reduced by identifying the peak impact accelerations for the leg (PkLeg), hip (PkHip), and head (PkHead). After peak impact accelerations were identified, SA was calculated for three locations using the following formulas: Total (between leg and head) = [1-PkHd/PkLeg]*100, Lower (between leg and hip) = [1-PkHip/PkLeg]*100, Upper (between hip and head) = [1-PkHd/PkHip]*100. Peak impact accelerations as well as SA were the dependent variables. There were three levels of independent variable height (30 cm, 60 cm, and 90 cm) and location (leg, hip, and head for peak impact accelerations; total, lower, and upper-body for SA). Variables were compared using repeated measures ANOVA (α=0.05). It was determined that there was an interaction between height and location for peak impact acceleration (p0.05). Peak impact accelerations across all locations increased with an increase in height (p0.05) With an overall increase in peak impact accelerations at all locations, and an increase in total and lower-body SA, but not upper-body SA, it appears the lower extremity is primarily responsible for the attenuation of the impacts resulting from landing

Keywords

Acceleration (Mechanics); Accelerometry; Attenuation (Physics); Biomechanics; Human mechanics; Landing; Shock (Mechanics)

Disciplines

Biomechanics | Kinesiology

File Format

pdf

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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