Validation of a Device to Accurately Monitor Knee Kinematics during Dynamic Movements

The incidence of anterior cruciate ligament (ACL) injury in athletes who play multidirectional sports has increased over recent times. Female athletes are at a higher risk of sustaining the ACL injury when compared to their male counterparts involved in the same sport. Various intrinsic (anatomical and hormonal) and extrinsic (biomechanical) factors have been identified that contribute to the increased risk of injury. Sex differences in the kinematics and kinetics of the lower extremity between males and females have been identified while performing various physical tasks has been a topic of discussion since a long time. While it’s difficult to control the anatomical and hormonal factors, identifying and modifying the biomechanical factors that contribute to the ACL injury is possible. Wearable sensors involving inertial measurement units (IMUs) have been developed to monitor lower extremity motion and help in assistance with rehabilitation. The purpose of this study was to validate a set of wearable IMUs against a 3D motion analysis system to monitor the lower extremity motion during jumps and runs in a laboratory and to determine whether IMUs could be used to estimate ground reaction force at landing. An average difference of 5°-10° for flexion, 4°-6° abduction and internal rotation was reported during jump and run. The results of this study showed that correlation between ground reaction force and tibial acceleration is poor when data from all the subjects were included together. However, the correlation was improved when subjects were examined individually. A strong correlation was observed between the resultant ground reaction force and the resultant tibial acceleration during jumping and running between both the legs for the eight subjects when examined individually.Master of Science in EngineeringMechanical Engineering, College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttps://deepblue.lib.umich.edu/bitstream/2027.42/146786/1/49698122_Thesis report_Ruchika Tadakala_36771515 edited (2).pdfDescription of 49698122_Thesis report_Ruchika Tadakala_36771515 edited (2).pdf : Thesi

Providing Real-Time Exercise Feedback to Patients Undergoing Physical Therapy

Musculoskeletal conditions, often requiring rehabilitation, affect one-third of the U.S. population annually. RehabBuddy is a rehabilitation assistance system that extends the reach of a physical rehabilitation specialist beyond the clinic. This thesis presents a system that uses body-worn motion sensors and a mobile application that provides the patient with assistance to ensure that home exercises are performed with the same precision as under clinical supervision. Assisted by a specialist in the clinic, the wearable sensors and user interface developed allow the capture of individualized exercises unique to the patient's physical abilities. Beyond the clinical setting, the system can assist patients by providing real-time corrective feedback to repeat these exercises through a correct and complete arc of motion for the prescribed number of repetitions. An inertial measurement unit (IMU) is used on the body part to be exercised to capture its pose. Presented is a kinematics data processing approach to defining custom exercises with flexibility in terms of where it is worn and the nature of the exercise, as well as real-time corrective feedback parameters. This thesis goes through the engineering approach, initial student investigator trials, and presents new preliminary subject data from subject trials currently ongoing at the University of Kentucky. The system is tested on multiple exercises performed by multiple subjects. It is then demonstrated how it can improve exercise adherence by assisting patients in reaching the full prescribed range of motion and avoid overextension, assist in adherence to the ideal plane of motion, and affect hold time.MSComputer Engineering, College of Engineering & Computer ScienceUniversity of Michigan-Dearbornhttp://deepblue.lib.umich.edu/bitstream/2027.42/169159/1/Ella Reimann Final Thesis.pd

User Interface Design and Validation for the Automated Rehabilitation System

In current physical rehabilitation protocols, patients typically perform exercises with intermittent feedback or guidance following the initial demonstrations from the physiotherapist. Although many patient-centered systems have been developed for home rehabilitation, few systems have been developed to aid the physiotherapist as well as patients in the rehabilitation clinic. This thesis designs and validates the user interface of an Automated Rehabilitation System (ARS), tailored for both patients and therapists in the clinical setting. The ARS was designed using an iterative design process, developed with physiotherapists and patients in a knee and hip replacement clinic. ARS consists of body-worn inertial measurement units which are used to continuously estimate the patient's pose. The estimated pose is graphically represented as an animation and overlaid with the instructed motion on a visual display shown to the patient during exercise performance. ARS allows physiotherapists to quantitatively measure patient movement, assess recovery progress, and manage and schedule patient exercise regimens. For patients, ARS provides visual feedback and a novel exercise guidance feature to aid them while exercising. As an initial "proof of concept", two user studies were conducted with healthy participants to evaluate the usability of the visual guidance tool. Motion data was collected by the inertial measurement unit sensors and used to evaluate quality of motion, comparing user performance with and without visual feedback and with or without exercise guidance. The quantitative and qualitative results of the studies confirmed that performing the exercises with the visual guidance tool promotes more consistent exercise performance and proper technique with healthy participants. Following the user studies with healthy participants, system requirements and design requirements were derived through a focus group with 13 physiotherapists. The physiotherapists were presented with an early version of ARS and were asked to discuss how they envisioned the system could potentially be used in their current workflow and whether such a system could improve their current protocol. The physiotherapists provided comments on both the physiotherapist and patient interface of the system. The physiotherapists felt the physiotherapist interface would be useful for patient assessment and provided suggestions on how the data could be better displayed to fit their current workflow. The physiotherapists also felt the patient interface would be helpful for patients to learn the exercise motion, but they expressed concerns as to whether the patient population would be able to comprehend the guidance component of the patient interface. Following adaptations of the interface to incorporate physiotherapist feedback, the patient interface was evaluated in a user study with 26 outpatients in the clinical setting. Patients were asked to wear the inertial measurement unit sensors during their exercise session and were instructed to use the ARS interface for a subset of the exercises in their exercise regimen. At the end of the exercise session, patients were asked to complete questionnaires and participate in a semi-structured interview where the researchers asked the patients to discuss their experiences using ARS while exercising. The results show that performing the exercises with the visual guidance tool improves the quality of exercise performance and that patients had a positive experience exercising with ARS. Finally, a pilot study was conducted with two healthy participants to evaluate the effects of different forms of feedback on exercise performance. Participants were instructed to perform four different exercises and were shown a different feedback method for each exercise. The results of this pilot study showed that additional feedback from ARS may improve range of motion and increase consistency in exercise performance, and is worth further investigation in future work