"Development and Validation of an Improved Sagittal Plane Device for In" by Sarah Marie Goldrod

Publication Date

12-2023

Date of Final Oral Examination (Defense)

10-19-2023

Type of Culminating Activity

Thesis

Degree Title

Master of Science in Mechanical Engineering

Department Filter

Mechanical and Biomechanical Engineering

Department

Mechanical and Biomedical Engineering

Supervisory Committee Chair

Erin M. Mannen, Ph.D.

Supervisory Committee Member

Trevor Lujan, Ph.D.

Supervisory Committee Member

Sophia Theodossiou, Ph.D.

Abstract

Infants need constant care and support through the first year of life. To minimize the burden of ongoing attending, caregivers frequently use commercial infant products to enable them to carry out daily tasks without holding the baby. An estimated 11,500 infant injuries involving nursery products were treated in emergency rooms in 2021, and 58 deaths were reported in seated nursery products between 2017 and 2019. Head-neck flexion and hyperextension and trunk flexion negatively influence normal breathing and can contribute to positional asphyxia in infants. The body position of infants lying within seated products is an important consideration for safety. Thus, the purpose of this study was to develop an improved testing device that can be easily manufactured, is simple to use, and is validated with human subjects’ data to provide valuable body position information to infant product designers and manufacturers.

First, we developed two anthropometry-based devices to measure the body position of infants in seated products. The newly developed device and three existing devices were used to measure the head-neck, trunk, and torso-pelvis flexion angles in four seated products. Second, a motion capture data collection was conducted to evaluate the body position of 13 infants in the same four seated products. An analysis of the testing device compared to the human subjects data was completed to evaluate the accuracy of each of the devices in measuring infant body position. The CAMI dummy predicted infant head-neck flexion in the seated products the most closely compared to the other sagittal plane devices. This indicates that the three-dimensional shape of the CAMI head better replicates infant head-neck flexion. The 5-segment device generally underestimated trunk flexion angles but provided the closest measurements to infant data, and it was more accurate in predicting the torso-pelvis angles than other measurement devices; though further improvements are necessary. This work is the first to analyze a test-lab-style device to evaluate body position in infant products that could easily be manufactured and implemented into product testing regulations compared to in vivo human subjects’ data.

DOI

https://doi.org/10.18122/td.2169.boisestate

Available for download on Monday, December 01, 2025

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Biomechanics Commons

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