Publication Date

5-2024

Date of Final Oral Examination (Defense)

January 2024

Type of Culminating Activity

Dissertation

Degree Title

Doctor of Philosophy in Biomedical Engineering

Department Filter

Mechanical and Biomechanical Engineering

Department

Mechanical and Biomedical Engineering

Supervisory Committee Chair

Erin M. Mannen, Ph.D.

Supervisory Committee Member

Tyler Brown, Ph.D.

Supervisory Committee Member

Trevor Lujan, Ph.D.

Supervisory Committee Member

Sophia Theodossiou, Ph.D.

Supervisory Committee Member

Omiya Hassan, Ph.D.

Abstract

Motor skills, like rolling, are an important part of an infant’s cognitive and motor development by facilitating interactions with others and their surrounding environment. Additionally, an infant’s musculoskeletal and motor development is largely affected by their environment and in the U.S., infants spend a majority of their time in commercial infant products, including those at an incline. The biomechanical impacts of infants spending time at an incline is an understudied area, and almost 12,000 emergency room visits occur each year due to injuries involving commercial infant products. Therefore, the overall objective of this study was to understand how an infant’s muscle utilization and coordinated movements are affected by varying mechanical environments.

We first created methodology that allowed for the accurate identification of infant rolling coordinated movements through video alone. This validated video-based methodology allows both researchers and clinicians to identify infant rolling movements quickly and effectively without the use of motion capture technology. Second, the muscle utilization of the different coordinated movements was quantified on a firm flat surface, providing a baseline for comparison when looking at rolling in different mechanical environments. Finally, how rolling is affected by different mechanical environments, specifically seatback incline, was determined. We identified how rolling techniques and muscle utilization change at varying seatback inclines and for the various coordinated movements of rolling.

Our results indicate that each coordinated movement of rolling can be identified between different reviewers with substantial agreement, expanding the accessibility of infant rolling identification for research and clinical diagnoses. We also determined that each coordinated movement has a unique muscle utilization pattern, and these muscle utilization patterns can change based on the mechanical environment in which an infant is placed. In the mechanical environments we tested, we also discovered a new coordinated movement that was not exhibited on the flat surface alone. Furthermore, we found that at inclines of just 10° infants exhibited significantly higher erector spinae muscle activation and significantly lower abdominal muscle activation when compared to the flat surface. With these increasing inclines, an infant’s choice in rolling maneuver also significantly changed. When testing with a seatback angle of 0°, comparable to the flat surface, an infant’s hamstring and quadricep muscle activation was significantly higher than that of the flat surface, indicating that infants are interacting with products independent of the incline.

This body of work is the first that we know of that (1) identifies the coordinated movements of rolling with video-based methodology, (2) defines the muscle utilization patterns of infant rolling on a flat surface, and (3) determines how rolling is affected by different mechanical environments. Results from this study can provide more insight into motor development and may inform the juvenile products industry to mitigate unexpected rolling and potential injuries within commercial infant products.

DOI

https://doi.org/10.18122/td.2221.boisestate

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