scholarly journals Optimization of IMU Sensor Placement for the Measurement of Lower Limb Joint Kinematics

Sensors ◽  
2020 ◽  
Vol 20 (21) ◽  
pp. 5993
Author(s):  
Wesley Niswander ◽  
Wei Wang ◽  
Kimberly Kontson
Keyword(s):  
Lower Limb ◽  
Sensor Placement ◽  
Joint Kinematics ◽  
The Body ◽  
Timed Up And Go ◽  
Functional Movement ◽  
Sensor Position ◽  
Optical Motion ◽  
Measurement Units ◽  
Optical Motion Capture

There is an increased interest in using wearable inertial measurement units (IMUs) in clinical contexts for the diagnosis and rehabilitation of gait pathologies. Despite this interest, there is a lack of research regarding optimal sensor placement when measuring joint kinematics and few studies which examine functionally relevant motions other than straight level walking. The goal of this clinical measurement research study was to investigate how the location of IMU sensors on the lower body impact the accuracy of IMU-based hip, knee, and ankle angular kinematics. IMUs were placed on 11 different locations on the body to measure lower limb joint angles in seven participants performing the timed-up-and-go (TUG) test. Angles were determined using different combinations of IMUs and the TUG was segmented into different functional movements. Mean bias and root mean square error values were computed using generalized estimating equations comparing IMU-derived angles to a reference optical motion capture system. Bias and RMSE values vary with the sensor position. This effect is partially dependent on the functional movement analyzed and the joint angle measured. However, certain combinations of sensors produce lower bias and RMSE more often than others. The data presented here can inform clinicians and researchers of placement of IMUs on the body that will produce lower error when measuring joint kinematics for multiple functionally relevant motions. Optimization of IMU-based kinematic measurements is important because of increased interest in the use of IMUs to inform diagnose and rehabilitation in clinical settings and at home.

scholarly journals Validation method for body-mounted sensor attachments

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Katharina Schmidt ◽  
David Hochmann
Keyword(s):  
Evaluation Method ◽  
Tracking System ◽  
The Body ◽  
Exploratory Research ◽  
Body Segment ◽  
Validation Method ◽  
Sensor Position ◽  
Validation Parameters ◽  
Measurement Units ◽  
Soft Tissue Artifact

AbstractSmall sensor devices like inertial measurement units enable mobile movement and gait analysis, whereby existing systems differ in data acquisition, data processing, and gait parameter calculation. Concerning the validation, recent studies focus on the captured motion and the influence of sensor positioning with respect to the accuracy of the computed biomechanical parameters in comparison to a reference system. Although soft tissue artifact is a major source of error for skin-mounted sensors, there are no investigations regarding the relative movement between the body segment and sensor attachment itself. The aim of this study is to find an evaluation method and to determine parameters that allow the validation of various sensor attachment types and different sensor positionings. The analysis includes the comparison between an adhesive and strap attachment variant as well as the frontal and lateral sensor placement. To validate different attachments, an optical marker-based tracking system was used to measure the body segment and sensor position during movement. The distance between these two positions was calculated and analyzed to determine suitable validation parameters. Despite the exploratory research, the results suggest a feasible validation method to detect differences between the attachments, independent of the sensor type. To have representative and statistically validated results, further studies that involve more participants are necessary.

scholarly journals IMU gyroscopes are a valid alternative to 3D optical motion capture system for angular kinematics analysis in tennis

2020 ◽  
pp. 175433712096544 ◽  
Author(s):  
Gabriel Delgado-García ◽  
Jos Vanrenterghem ◽  
Emilio J Ruiz-Malagón ◽  
Pablo Molina-García ◽  
Javier Courel-Ibáñez ◽  
...  
Keyword(s):  
Angular Velocity ◽  
Motion Capture ◽  
Correlation Coefficients ◽  
Strong Relationship ◽  
System Level ◽  
Optical Motion ◽  
Measurement Units ◽  
The Difference ◽  
Optical Motion Capture ◽  
Level Of Agreement

Whereas 3D optical motion capture (OMC) systems are considered the gold standard for kinematic assessment in sport science, they present some drawbacks that limit its use in the field. Inertial measurement units (IMUs) incorporating gyroscopes have been considered as a more practical alternative. Thus, the aim of the study was to evaluate the level of agreement for angular velocity between IMU gyroscopes and an OMC system for varying tennis strokes and intensities. In total, 240 signals of angular velocity from different body segments and types of strokes (forehand, backhand and service) were recorded from four players (two competition players and two beginners). The angular velocity of the IMU gyroscopes was compared to the angular velocity from the OMC system. Level of agreement was evaluated by correlation coefficients, magnitudes of errors in absolute and relative values and Bland-Altman plots. Differences between both systems were highly consistent within players’ skill (i.e. along the broad range of velocities) and axes ( x, y, z). Correlations ranged from 0.951 to 0.993, indicating a very strong relationship and concordance. The magnitude of the differences ranged from 4.4 to 35.4 deg·s−1. The difference relative to the maximum angular velocity achieved was less than 5.0%. The study concluded that IMUs and OMC systems showed comparable values. Thus, IMUs seem to be a valid alternative to detect meaningful differences in angular velocity during tennis groundstrokes in field-based experimentation.

New Method of Evaluating Muscular Strength of Lower Limb Using MEMS Acceleration and Gyro Sensors

2013 ◽  
Vol 25 (1) ◽  
pp. 153-161
Author(s):  
Shinsuke Yoshioka ◽  
◽  
Akinori Nagano ◽  
Dean C. Hay ◽  
Izumi Tabata ◽  
...  
Keyword(s):  
Lower Limb ◽  
Muscular Strength ◽  
Mechanical Load ◽  
Micro Electro Mechanical Systems ◽  
Diverse Range ◽  
Home Setting ◽  
Mems Sensor ◽  
System Method ◽  
Optical Motion ◽  
Optical Motion Capture

The purpose of this study was to develop a home-use method of evaluating muscular strength of the lower limb of a physically diverse range of people. Through a survey of previous findings regarding the mechanical load of daily activities, we propose that rapidly standing from an initial low squat posture is an appropriate movement to evaluate muscular strength of the lower limb. Additionally, we define a new index of muscular strength of the lower limb called “muscular strength margin.” This index shows the muscular strength relative to the minimum required muscular strength for activities of daily living. For easy measurement in a home setting, we utilize Micro-Electro-Mechanical Systems (MEMS) acceleration and gyro sensors to measure muscle strength. The MEMS sensor method highly correlates (r = 0.996) with optical motion capture system method, indicating that the MEMS sensor method has sufficient reliability for home use. The validity of the method developed in this study was verified through kinematic and kinetic analyses of 98 subjects whose age ranged from 14 to 98 yrs and from data of previous studies.

scholarly journals A Lightweight Exoskeleton-Based Portable Gait Data Collection System

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 781
Author(s):  
Md Rejwanul Haque ◽  
Masudul H. Imtiaz ◽  
Samuel T. Kwak ◽  
Edward Sazonov ◽  
Young-Hui Chang ◽  
...  
Keyword(s):  
Data Collection ◽  
Motion Capture ◽  
Lower Limb ◽  
Joint Angle ◽  
Motion Capture System ◽  
Collection System ◽  
Data Collection System ◽  
Optical Motion ◽  
Lower Limb Movement ◽  
Optical Motion Capture

For the controller of wearable lower-limb assistive devices, quantitative understanding of human locomotion serves as the basis for human motion intent recognition and joint-level motion control. Traditionally, the required gait data are obtained in gait research laboratories, utilizing marker-based optical motion capture systems. Despite the high accuracy of measurement, marker-based systems are largely limited to laboratory environments, making it nearly impossible to collect the desired gait data in real-world daily-living scenarios. To address this problem, the authors propose a novel exoskeleton-based gait data collection system, which provides the capability of conducting independent measurement of lower limb movement without the need for stationary instrumentation. The basis of the system is a lightweight exoskeleton with articulated knee and ankle joints. To minimize the interference to a wearer’s natural lower-limb movement, a unique two-degrees-of-freedom joint design is incorporated, integrating a primary degree of freedom for joint motion measurement with a passive degree of freedom to allow natural joint movement and improve the comfort of use. In addition to the joint-embedded goniometers, the exoskeleton also features multiple positions for the mounting of inertia measurement units (IMUs) as well as foot-plate-embedded force sensing resistors to measure the foot plantar pressure. All sensor signals are routed to a microcontroller for data logging and storage. To validate the exoskeleton-provided joint angle measurement, a comparison study on three healthy participants was conducted, which involves locomotion experiments in various modes, including overground walking, treadmill walking, and sit-to-stand and stand-to-sit transitions. Joint angle trajectories measured with an eight-camera motion capture system served as the benchmark for comparison. Experimental results indicate that the exoskeleton-measured joint angle trajectories closely match those obtained through the optical motion capture system in all modes of locomotion (correlation coefficients of 0.97 and 0.96 for knee and ankle measurements, respectively), clearly demonstrating the accuracy and reliability of the proposed gait measurement system.

scholarly journals OpenSense: An open-source toolbox for Inertial-Measurement-Unit-based measurement of lower extremity kinematics over long durations

2021 ◽  
Author(s):  
Mazen Al Borno ◽  
Johanna O'Day ◽  
Vanessa Ibarra ◽  
James Dunne ◽  
Ajay Seth ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Open Source ◽  
Motion Capture ◽  
Joint Kinematics ◽  
Natural Environments ◽  
Joint Angles ◽  
Inertial Measurement ◽  
Optical Motion ◽  
Optical Motion Capture ◽  
Over Time

Background: The ability to measure joint kinematics in natural environments over long durations using inertial measurement units (IMUs) could enable at-home monitoring and personalized treatment of neurological and musculoskeletal disorders. However, drift, or the accumulation of error over time, inhibits the accurate measurement of movement over long durations. We sought to develop an open-source workflow to estimate lower extremity joint kinematics from IMU data that was accurate, and capable of assessing and mitigating drift. Methods: We computed IMU-based estimates of kinematics using sensor fusion and an inverse kinematics approach with a constrained biomechanical model. We measured kinematics for 11 subjects as they performed two 10-minute trials: walking and a repeated sequence of varied lower-extremity movements. To validate the approach, we compared the joint angles computed with IMU orientations to the joint angles computed from optical motion capture using root mean square (RMS) difference and Pearson correlations, and estimated drift using a linear regression on each subject's RMS differences over time. Results: IMU-based kinematic estimates agreed with optical motion capture; median RMS differences over all subjects and all minutes were between 3-6 degrees for all joint angles except hip rotation and correlation coefficients were moderate to strong (r = 0.60 to 0.87). We observed minimal drift in the RMS differences over ten minutes; the average slopes of the linear fits to these data were near zero (-0.14 to 0.17 deg/min). Conclusions: Our workflow produced joint kinematics consistent with those estimated by optical motion capture, and could mitigate kinematic drift even in the trials of continuous walking without rest, obviating the need for explicit sensor recalibration (e.g. sitting or standing still for a few seconds or zero-velocity updates) used in current drift-mitigation approaches. This could enable long-duration measurements, bringing the field one step closer to estimating kinematics in natural environments.

scholarly journals Proposed Mobility Assessments with Simultaneous Full-Body Inertial Measurement Units and Optical Motion Capture in Healthy Adults and Neurological Patients for Future Validation Studies: Study Protocol

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5833
Author(s):  
Elke Warmerdam ◽  
Robbin Romijnders ◽  
Johanna Geritz ◽  
Morad Elshehabi ◽  
Corina Maetzler ◽  
...  
Keyword(s):  
Motion Capture ◽  
Healthy Adults ◽  
Response To Treatment ◽  
Inertial Measurement Units ◽  
Mobility Patterns ◽  
Inertial Measurement ◽  
Neurological Patients ◽  
Optical Motion ◽  
Measurement Units ◽  
Optical Motion Capture

Healthy adults and neurological patients show unique mobility patterns over the course of their lifespan and disease. Quantifying these mobility patterns could support diagnosing, tracking disease progression and measuring response to treatment. This quantification can be done with wearable technology, such as inertial measurement units (IMUs). Before IMUs can be used to quantify mobility, algorithms need to be developed and validated with age and disease-specific datasets. This study proposes a protocol for a dataset that can be used to develop and validate IMU-based mobility algorithms for healthy adults (18–60 years), healthy older adults (>60 years), and patients with Parkinson’s disease, multiple sclerosis, a symptomatic stroke and chronic low back pain. All participants will be measured simultaneously with IMUs and a 3D optical motion capture system while performing standardized mobility tasks and non-standardized activities of daily living. Specific clinical scales and questionnaires will be collected. This study aims at building the largest dataset for the development and validation of IMU-based mobility algorithms for healthy adults and neurological patients. It is anticipated to provide this dataset for further research use and collaboration, with the ultimate goal to bring IMU-based mobility algorithms as quickly as possible into clinical trials and clinical routine.

scholarly journals Exploring the Role of Wearable Technology in Sport Kinematics and Kinetics: A Systematic Review

Sensors ◽  
2019 ◽  
Vol 19 (7) ◽  
pp. 1597 ◽  
Author(s):  
Yewande Adesida ◽  
Enrica Papi ◽  
Alison H McGregor
Keyword(s):  
Performance Enhancement ◽  
Angular Rate ◽  
Wearable Technology ◽  
Optical Motion ◽  
Measurement Units ◽  
And Performance ◽  
Optical Motion Capture ◽  
Flex Sensors ◽  
Kinematics And Kinetics

The aim of this review was to understand the use of wearable technology in sport in order to enhance performance and prevent injury. Understanding sports biomechanics is important for injury prevention and performance enhancement and is traditionally assessed using optical motion capture. However, such approaches are limited by capture volume restricting assessment to a laboratory environment, a factor that can be overcome by wearable technology. A systematic search was carried out across seven databases where wearable technology was employed to assess kinetic and kinematic variables in sport. Articles were excluded if they focused on sensor design and did not measure kinetic or kinematic variables or apply the technology on targeted participants. A total of 33 articles were included for full-text analysis where participants took part in a sport and performed dynamic movements relating to performance monitored by wearable technologies. Inertial measurement units, flex sensors and magnetic field and angular rate sensors were among the devices used in over 15 sports to quantify motion. Wearable technology usage is still in an exploratory phase, but there is potential for this technology to positively influence coaching practice and athletes’ technique.

scholarly journals Lower Back Injury Prevention and Sensitization of Hip Hinge with Neutral Spine Using Wearable Sensors during Lifting Exercises

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5487
Author(s):  
Florian Michaud ◽  
Manuel Pérez Soto ◽  
Urbano Lugrís ◽  
Javier Cuadrado
Keyword(s):  
Wearable Sensors ◽  
Sport Performance ◽  
Core Stability ◽  
Herniated Disc ◽  
Neutral Position ◽  
Big Box ◽  
Optical Motion ◽  
Measurement Units ◽  
Optical Motion Capture ◽  
Lower Back Injury

The popularization and industrialization of fitness over the past decade, with the rise of big box gyms and group classes, has reduced the quality of the basic formation and assessment of practitioners, which has increased the risk of injury. For most lifting exercises, a universal recommendation is maintaining a neutral spine position. Otherwise, there is a risk of muscle injury or, even worse, of a herniated disc. Maintaining the spine in a neutral position during lifting exercises is difficult, as it requires good core stability, a good hip hinge and, above all, observation of the posture in order to keep it correct. For this reason, in this work the authors propose the prevention of lumbar injuries with two inertial measurement units. The relative rotation between two sensors was measured for 39 voluntary subjects during the performance of two lifting exercises: the American kettlebell swing and the deadlift. The accuracy of the measurements was evaluated, especially in the presence of metals and for fast movements, by comparing the obtained results with those from an optical motion capture system. Finally, in order to develop a tool for improving sport performance and preventing injury, the authors analyzed the recorded motions, seeking to identify the most relevant parameters for good and safe lifting execution.

Exploring relationships between pianists’ body movements, their expressive intentions, and structural elements of the music

2011 ◽  
Vol 16 (1) ◽  
pp. 19-40 ◽  
Author(s):  
Marc R. Thompson ◽  
Geoff Luck
Keyword(s):  
Music Performance ◽  
The Body ◽  
Musical Score ◽  
Structural Elements ◽  
Piano Performance ◽  
Body Movements ◽  
Optical Motion ◽  
Optical Motion Capture ◽  
Performance Conditions ◽  
Biomechanical Factors

Body movements during music performance have been found to be indicative of the performer’s musical intentionality, and contribute to an observer’s perception of expressive playing. This study investigates the effect of structural elements of the score, and the playing of different levels of expression on body movements during a piano performance. Pianists were required to play the same piece in four different performance conditions. Their movements were tracked by an optical motion capture system, and the comparisons that were made between specific parts of the body used, performance condition, and musical score locations were subsequently statistically examined. We found that the head and shoulders exhibited more movement per measure, as well as larger differences between each condition, than the fingers, wrists and lower back. Differences between performance conditions were observed primarily at structurally significant portions of the score, and biomechanical factors also played a role. Moreover, our data supports the view that performers equate playing without expression to playing without nonessential movements.

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