Technological advances regarding Inertial Measurements Units (IMUs) have positioned this type of sensor as an alternative for camera-based motion capture. This study introduces a new IMU based system (IMUsys) to measure hip and knee flexion angles. PURPOSE: To validate the use of a five-sensor IMUsys for the measurement of knee and hip flexion angles during gait in adults and pediatrics at two different time points. METHODS: Bilateral hip and knee flexion patterns (LH, RH, LK, and RK) of twenty-two healthy participants (12 adults and 10 pediatric) between the ages of 8 – 35 years were investigated. Participants performed two 1-min gait trials on a treadmill at self-selected speeds at two different time points. Data were analyzed using linear regression coefficients, the root mean square error (RMSE), the mean absolute error (MAE), and Bland & Altman plots. RESULTS: A strong relationship (r2> 0.94) between the IMUsys and the camera-based system was found across all condition. RMSEs [LH < 10°, RH < 10°, LK > 10°, RK > 10°] were found across all condition. Repeatability coefficients [LH ≤ 5°, RH ≤ 5°, LK > 10°, RK < 10°] were found across all condition. CONCLUSION: The validity of the IMUsys was maintained across age groups with different segment proportion, and during prolonged use. However, the large errors observed for knee flexion measurements should be considered when using the IMUsys.
","abstract_html":"<p>Technological advances regarding Inertial Measurements Units (IMUs) have positioned this type of sensor as an alternative for camera-based motion capture. This study introduces a new IMU based system (IMU<sub>sys</sub>) to measure hip and knee flexion angles. PURPOSE: To validate the use of a five-sensor IMU<sub>sys</sub> for the measurement of knee and hip flexion angles during gait in adults and pediatrics at two different time points. METHODS: Bilateral hip and knee flexion patterns (LH, RH, LK, and RK) of twenty-two healthy participants (12 adults and 10 pediatric) between the ages of 8 – 35 years were investigated. Participants performed two 1-min gait trials on a treadmill at self-selected speeds at two different time points. Data were analyzed using linear regression coefficients, the root mean square error (RMSE), the mean absolute error (MAE), and Bland & Altman plots. RESULTS: A strong relationship (<em>r</em><sup>2</sup>> 0.94) between the IMU<sub>sys</sub> and the camera-based system was found across all condition. RMSEs [LH < 10°, RH < 10°, LK > 10°, RK > 10°] were found across all condition. Repeatability coefficients [LH ≤ 5°, RH ≤ 5°, LK > 10°, RK < 10°] were found across all condition. CONCLUSION: The validity of the IMU<sub>sys</sub> was maintained across age groups with different segment proportion, and during prolonged use. However, the large errors observed for knee flexion measurements should be considered when using the IMU<sub>sys</sub>.</p>","abstract_has_math":false,"creators":["Park, Joonsun"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Dr. Nuno Oliveira","Dr. Paul Donahue","Dr. Zhanxin Sha"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020-12-01T08:00:00Z","date_published":"2020-12-01T08:00:00Z","updated_at":"2026-07-24T05:45:19Z","subjects":["biomechanics","gait","inertial measurement units","lower limb","validation","Kinesiotherapy","Other Rehabilitation and Therapy","Physical Therapy","Rehabilitation and Therapy","Sports Sciences","Translational Medical Research"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aquila.usm.edu/masters_theses/790","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Nuno Oliveira","Dr. Paul Donahue","Dr. Zhanxin Sha"]},{"key":"dc:creator","label":"Author","values":["Park, Joonsun"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2020-10-12T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["biomechanics","gait","inertial measurement units","lower limb","validation","Kinesiotherapy","Other Rehabilitation and Therapy","Physical Therapy","Rehabilitation and Therapy","Sports Sciences","Translational Medical Research"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://aquila.usm.edu/masters_theses/790"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Technological advances regarding Inertial Measurements Units (IMUs) have positioned this type of sensor as an alternative for camera-based motion capture. This study introduces a new IMU based system (IMUsys) to measure hip and knee flexion angles. PURPOSE: To validate the use of a five-sensor IMUsys for the measurement of knee and hip flexion angles during gait in adults and pediatrics at two different time points. METHODS: Bilateral hip and knee flexion patterns (LH, RH, LK, and RK) of twenty-two healthy participants (12 adults and 10 pediatric) between the ages of 8 – 35 years were investigated. Participants performed two 1-min gait trials on a treadmill at self-selected speeds at two different time points. Data were analyzed using linear regression coefficients, the root mean square error (RMSE), the mean absolute error (MAE), and Bland & Altman plots. RESULTS: A strong relationship (r2> 0.94) between the IMUsys and the camera-based system was found across all condition. RMSEs [LH < 10°, RH < 10°, LK > 10°, RK > 10°] were found across all condition. Repeatability coefficients [LH ≤ 5°, RH ≤ 5°, LK > 10°, RK < 10°] were found across all condition. CONCLUSION: The validity of the IMUsys was maintained across age groups with different segment proportion, and during prolonged use. However, the large errors observed for knee flexion measurements should be considered when using the IMUsys.
"]},{"key":"dc:title","label":"Title","values":["Validation of an Inertial-Measurement-Unit System for Calculating Hip and Knee Flexion Angles During Gait"]}]}],"canonical_facts":{"dc:contributor":["Dr. Nuno Oliveira","Dr. Paul Donahue","Dr. Zhanxin Sha"],"dc:creator":["Park, Joonsun"],"dc:date.available":["2020-10-12T07:00:00Z"],"dc:description.abstract":["Technological advances regarding Inertial Measurements Units (IMUs) have positioned this type of sensor as an alternative for camera-based motion capture. This study introduces a new IMU based system (IMUsys) to measure hip and knee flexion angles. PURPOSE: To validate the use of a five-sensor IMUsys for the measurement of knee and hip flexion angles during gait in adults and pediatrics at two different time points. METHODS: Bilateral hip and knee flexion patterns (LH, RH, LK, and RK) of twenty-two healthy participants (12 adults and 10 pediatric) between the ages of 8 – 35 years were investigated. Participants performed two 1-min gait trials on a treadmill at self-selected speeds at two different time points. Data were analyzed using linear regression coefficients, the root mean square error (RMSE), the mean absolute error (MAE), and Bland & Altman plots. RESULTS: A strong relationship (r2> 0.94) between the IMUsys and the camera-based system was found across all condition. RMSEs [LH < 10°, RH < 10°, LK > 10°, RK > 10°] were found across all condition. Repeatability coefficients [LH ≤ 5°, RH ≤ 5°, LK > 10°, RK < 10°] were found across all condition. CONCLUSION: The validity of the IMUsys was maintained across age groups with different segment proportion, and during prolonged use. However, the large errors observed for knee flexion measurements should be considered when using the IMUsys.
"],"dc:identifier":["https://aquila.usm.edu/masters_theses/790"],"dc:subject":["biomechanics","gait","inertial measurement units","lower limb","validation","Kinesiotherapy","Other Rehabilitation and Therapy","Physical Therapy","Rehabilitation and Therapy","Sports Sciences","Translational Medical Research"],"dc:title":["Validation of an Inertial-Measurement-Unit System for Calculating Hip and Knee Flexion Angles During Gait"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:45:19Z"}