Author ORCID Identifier

https://orcid.org/0009-0002-2991-7384

Semester

Summer

Date of Graduation

2026

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Stephen M. Cain

Committee Member

Nicholas Szczecinski

Committee Member

JuHyeong Ryu

Committee Member

Jean McCrory

Committee Member

Melissa Morrow

Abstract

Manual wheelchair users with spinal cord injury (SCI) face chronic, repetitive shoulder demands that far exceed those of able-bodied daily life, placing them at high risk for rotator cuff pathology and long-term upper extremity dysfunction. Despite this burden, existing research has relied predominantly on brief laboratory assessments that capture only a narrow part of real-world mechanical demands, leaving critical gaps in the identification of true injury risk factors. This dissertation developed and applied inertial measurement unit (IMU)-based methods and novel algorithms to characterize arm use, mobility, and environmental context during a full week of free living behavior in 25 manual wheelchair users with SCI. Participants wore eight Axivity IMUs positioned bilaterally on the wrists, upper arms, thorax, wheelchair frame, and wheel hubs across seven consecutive days. A movement-based synchronization algorithm was developed to resolve inter-sensor clock drift, which reached up to 9.25 seconds over 160 hours, enabling reliable multi-sensor, multi-day analysis without hardware connectivity or participant-initiated calibration. Three domains of daily wheelchair life were then characterized. Daily mobility was highly intermittent, with nearly 94% of events lasting under 215 seconds and participants averaging 428 starts and stops per day. Steady-state propulsion accounted for only 22% of total daily distance, and real-world stroke patterns diverged substantially from clinical guidelines, with the arc technique dominating despite recommendations favoring the semicircular pattern. Most critically, activities of daily living, including transfers, reaching, self-care, and object manipulation contributed 63.9% of total daily shoulder exposure at significantly higher loading rates than propulsion, with dominant-arm asymmetry offering a sensor-derived explanation for the lateralized rotator cuff pathology documented in longitudinal imaging studies. A supplementary investigation using an accessibility survey further linked environmental barriers to elevated non mobility shoulder exposure, pointing toward built-environment modification as a clinically relevant injury prevention strategy. Collectively, these findings indicate that shoulder injury prevention in manual wheelchair users must extend beyond optimizing propulsion mechanics to address the high-load, asymmetric demands of daily living activities and the environmental conditions that shape them. The methodological tools, mobility profiling frameworks, and shoulder exposure metrics developed here establish a critical foundation for the longitudinal, environmentally valid research needed to translate these findings into evidence-based strategies for preserving long-term upper-extremity health in this population.

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