Date of Award


Document Type

Open Access Thesis

Degree Name

Master of Science (MS)



First Advisor

Jacqueline Augustine, Ph.D.

Second Advisor

Kevin Dames, Ph.D.

Third Advisor

Larissa True, Ph.D.


Introduction: Gait retraining interventions are used to modify foot strike parameters associated with musculoskeletal injuries. Such interventions may prove beneficial if gait modifications are maintained long-term and provide a physiological performance benefit. Purpose: The primary purpose of this study was to determine whether female recreational runners can use a smartphone decibel app to self-modify gait mechanics associated with injury. The secondary purpose was to determine if such gait modifications are retained beyond the initial training session. The tertiary purpose was to determine if such gait modifications were associated with improved running economy. Methods: The peak vertical ground reaction force (vGRF), impact transient (IT), maximal instantaneous vertical loading rate (VILR), average vertical instantaneous vertical loading rate (VALR), ground contact time (GCT), and running economy (RE) were collected from subjects during overground and treadmill data collection sessions held Pre-training, Training, and at a 1- week Follow-Up. The gait retraining intervention used a smartphone decibel app to provide biofeedback on the sound intensity of the subject’s footfall. Results: Fifteen female recreational runners were included. There was a significant decrease in vGRF at the Follow-Up Session versus Pre-Training (2.39 vs. 2.34 BW, p = .023) and versus Training Session (2.34 vs. 2.30, p = .047). There was a significant decrease in VILR between Pre-Training versus Training Sessions (69.70 vs. 62.24 BW. s -1 , p = .02) and Pre-Training versus Follow- Up Sessions (69.70 vs. 60.35 BW. s -1 , p = .031). There was not a significant decrease in VO2 among Sessions (p = .308). Conclusions: Results from this study suggest a gait retraining intervention using a Decibel X app may enable recreational runners to benefit from self-modification of gait biomechanics iv associated with musculoskeletal injury long-term without an adverse effect on metabolic performance.