Validity and sensitivity of an inertial measurement unit-driven biomechanical model of motor variability for gait

Motor variability in gait is frequently linked to fall risk, yet field-based biomechanical joint evaluations are scarce. We evaluated the validity and sensitivity of an inertial measurement unit (IMU)-driven biomechanical model of joint angle variability for gait. Fourteen healthy young adults completed seven-minute trials of treadmill gait at several speeds and arm swing amplitudes. Joint kinematics were estimated by IMU- and optoelectronic-based models using OpenSim. We calculated range of motion (ROM), magnitude of variability (meanSD), local dynamic stability (λmax), persistence of ROM fluctuations (DFAα), and regularity (SaEn) of each angle over 200 continuous strides, and evaluated model accuracy (e.g., RMSD: root mean square difference), consistency (ICC2,1: intraclass correlation), biases, limits of agreement, and sensitivity to within-participant gait responses (effects of Speed and Swing). RMSDs of joint angles were 1.7–7.5° (pooled mean of 4.8°), excluding ankle inversion. ICCs were mostly good–excellent in the primary plane of motion for ROM and in all planes for meanSD and λmax, but were poor–moderate for DFAα and SaEn. Modeled Speed and Swing responses for ROM, meanSD, and λmax were similar. Results suggest that the IMU-driven model is valid and sensitive for field-based assessments of joint angles and several motor variability features.

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Validity and Sensitivity of an Inertial Measurement Unit-Driven Biomechanical Model of Motor Variability for Gait

Sensors ◽

10.3390/s21227690 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7690

Author(s):

Christopher A. Bailey ◽

Thomas K. Uchida ◽

Julie Nantel ◽

Ryan B. Graham

Keyword(s):

Dynamic Stability ◽

Inertial Measurement Unit ◽

Joint Angle ◽

Intraclass Correlation ◽

Biomechanical Model ◽

Measurement Unit ◽

Local Dynamic ◽

Motor Variability ◽

Inertial Measurement ◽

Local Dynamic Stability

Motor variability in gait is frequently linked to fall risk, yet field-based biomechanical joint evaluations are scarce. We evaluated the validity and sensitivity of an inertial measurement unit (IMU)-driven biomechanical model of joint angle variability for gait. Fourteen healthy young adults completed seven-minute trials of treadmill gait at several speeds and arm swing amplitudes. Trunk, pelvis, and lower-limb joint kinematics were estimated by IMU- and optoelectronic-based models using OpenSim. We calculated range of motion (ROM), magnitude of variability (meanSD), local dynamic stability (λmax), persistence of ROM fluctuations (DFAα), and regularity (SaEn) of each angle over 200 continuous strides, and evaluated model accuracy (RMSD: root mean square difference), consistency (ICC2,1: intraclass correlation), biases, limits of agreement, and sensitivity to within-participant gait responses (effects of speed and swing). RMSDs of joint angles were 1.7–7.5° (pooled mean of 4.8°), excluding ankle inversion. ICCs were mostly good to excellent in the primary plane of motion for ROM and in all planes for meanSD and λmax, but were poor to moderate for DFAα and SaEn. Modelled speed and swing responses for ROM, meanSD, and λmax were similar. Results suggest that the IMU-driven model is valid and sensitive for field-based assessments of joint angle time series, ROM in the primary plane of motion, magnitude of variability, and local dynamic stability.

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Tibial Accelerations During the Single-Leg Hop Test: Influence of Fixation

Journal of Sport Rehabilitation ◽

10.1123/jsr.2020-0309 ◽

2020 ◽

pp. 1-4

Author(s):

Hannah W. Tucker ◽

Emily R. Tobin ◽

Matthew F. Moran

Keyword(s):

Correlation Coefficient ◽

Intraclass Correlation Coefficient ◽

Repeated Measures ◽

Inertial Measurement Unit ◽

Intraclass Correlation ◽

Return To Sport ◽

Fixation Method ◽

Measurement Unit ◽

Inertial Measurement ◽

Hop Test

Context: Performance on single-leg hopping (SLH) assessments is commonly included within return-to-sport criteria for rehabilitating athletes. Triaxial accelerometers have been used to quantify impact loading in a variety of movements, including hopping; however, they have never been attached to the tibia during SLH, and their method of fixation has not been investigated. Objective: The purpose of this study was to quantify triaxial accelerations and evaluate the influence of the fixation method of a lightweight inertial measurement unit (Blue Trident) mounted to the tibia during SLH performance. Design: Single cohort, repeated-measures experimental design. Participants: Sixteen healthy participants (10 females and 6 males; 20 [0.9] y; 1.67 [0.08] m; 66.0 [8.5] kg) met the inclusion criteria, volunteered, and completed this study. Interventions: Participants performed 2 sets of 3 SLH trials with an inertial measurement unit (1500 Hz) fixated to the tibia, each set with 1 of 2 attachment methods (double-sided tape [DST] with athletic tape and silicon strap [SS] with Velcro adhesion). Main Outcome Measures: Hop distance, peak tibial acceleration (PTA), time to PTA, and the acceleration slope were assessed during each hop landing. Results: Repeated-measures analysis of variance determined no significant effect of the attachment method on hop metrics (P = .252). Across 3 trials, both fixation methods (DST and SS) had excellent reliability values (intraclass correlation coefficient: .868–.941) for PTA and acceleration slope but not for time to PTA (intraclass correlation coefficient: .397–.768). The PTA for DST (27.22 [7.94] g) and SS (26.21 [10.48] g) was comparable and had a moderate, positive relationship (DST: r = .72, P < .01; SS: r = .77, P < .01) to SLH distance. Conclusions: Tibial inertial measurement units with triaxial accelerometers can reliably assess PTA during performance of the SLH, and SS is a viable alternative tibial attachment to DST.

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Valid and Reliable Barbell Velocity Estimation Using an Inertial Measurement Unit

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18179170 ◽

2021 ◽

Vol 18 (17) ◽

pp. 9170

Author(s):

Steffen Held ◽

Ludwig Rappelt ◽

Jan-Philip Deutsch ◽

Lars Donath

Keyword(s):

Inertial Measurement Unit ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Velocity Estimation ◽

Measurement Unit ◽

Systematic Bias ◽

Validity And Reliability ◽

Inertial Measurement ◽

Intraclass Correlation Coefficients ◽

Reliability Indicators

The accurate assessment of the mean concentric barbell velocity (MCV) and its displacement are crucial aspects of resistance training. Therefore, the validity and reliability indicators of an easy-to-use inertial measurement unit (VmaxPro®) were examined. Nineteen trained males (23.1 ± 3.2 years, 1.78 ± 0.08 m, 75.8 ± 9.8 kg; Squat 1-Repetition maximum (1RM): 114.8 ± 24.5 kg) performed squats and hip thrusts (3–5 sets, 30 repetitions total, 75% 1RM) on two separate days. The MCV and displacement were simultaneously measured using VmaxPro® and a linear position transducer (Speed4Lift®). Good to excellent intraclass correlation coefficients (0.91 < ICC < 0.96) with a small systematic bias (p < 0.001; ηp2 < 0.50) for squats (0.01 ± 0.04 m·s−1) and hip thrusts (0.01 ± 0.05 m·s−1) and a low limit of agreement (LoA < 0.12 m·s−1) indicated an acceptable validity. The within- and between-day reliability of the MCV revealed good ICCs (0.55 < ICC < 0.91) and a low LoA (<0.16 m·s−1). Although the displacement revealed a systematic bias during squats (p < 0.001; ηp2 < 0.10; 3.4 ± 3.4 cm), no bias was detectable during hip thrusts (p = 0.784; ηp2 < 0.001; 0.3 ± 3.3 cm). The displacement showed moderate to good ICCs (0.43 to 0.95) but a high LoA (7.8 to 10.7 cm) for the validity and (within- and between-day) reliability of squats and hip thrusts. The VmaxPro® is considered to be a valid and reliable tool for the MCV assessment.

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An inertial measurement unit tracking system for body movement in comparison with optical tracking

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/0954411920921695 ◽

2020 ◽

Vol 234 (7) ◽

pp. 728-737

Author(s):

Rui Li ◽

Barclay Jumet ◽

Hongliang Ren ◽

WenZhan Song ◽

Zion Tsz Ho Tse

Keyword(s):

Inertial Measurement Unit ◽

Tracking System ◽

Low Cost ◽

Optical Tracking ◽

Measurement Unit ◽

Joint Movement ◽

Joint Angles ◽

Optical Tracking System ◽

Microelectromechanical System ◽

Inertial Measurement

The recent advancement of motion tracking technology offers better treatment tools for conditions, such as movement disorders, as the outcome of the rehabilitation could be quantitatively defined. The accurate and fast angular information output of the inertial measurement unit tracking systems enables the collection of accurate kinematic data for clinical assessment. This article presents a study of a low-cost microelectromechanical system inertial measurement unit-based tracking system in comparison with the conventional optical tracking system. The system consists of seven microelectromechanical system inertial measurement units, which could be mounted on the lower limbs of the subjects. For the feasibility test, 10 human participants were instructed to perform three different motions: walking, running, and fencing lunges when wearing specially designed sleeves. The subjects’ lower body movements were tracked using our inertial measurement unit-based system and compared with the gold standard—the NDI Polaris Vega optical tracking system. The results of the angular comparison between the inertial measurement unit and the NDI Polaris Vega optical tracking system were as follows: the average cross-correlation value was 0.85, the mean difference of joint angles was 2.00°, and the standard deviation of joint angles was ± 2.65°. The developed microelectromechanical system–based tracking system provides an alternative low-cost solution to track joint movement. Moreover, it is able to operate on an Android platform and could potentially be used to assist outdoor or home-based rehabilitation.

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Monitoring of Hip and Knee Joint Angles Using a Single Inertial Measurement Unit During Lower Limb Rehabilitation

IEEE Sensors Journal ◽

10.1109/jsen.2015.2503765 ◽

2016 ◽

Vol 16 (6) ◽

pp. 1557-1564 ◽

Cited By ~ 21

Author(s):

Vincent Bonnet ◽

Vladimir Joukov ◽

Dana Kulic ◽

Philippe Fraisse ◽

Nacim Ramdani ◽

...

Keyword(s):

Knee Joint ◽

Lower Limb ◽

Inertial Measurement Unit ◽

Measurement Unit ◽

Joint Angles ◽

Inertial Measurement ◽

Limb Rehabilitation ◽

Lower Limb Rehabilitation

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Validity and Reliability of a New Device to Measure Type of Actions in Indoor Sports

International Journal of Sports Medicine ◽

10.1055/a-1244-9985 ◽

2020 ◽

Author(s):

Carlos Lago-Fuentes ◽

Paolo Aiello ◽

Mauro Testa ◽

Iker Muñoz ◽

Marcos Mecías Calvo

Keyword(s):

Coefficient Of Variation ◽

Inertial Measurement Unit ◽

High Reliability ◽

Intraclass Correlation ◽

Measurement Unit ◽

Validity And Reliability ◽

Inertial Measurement ◽

New Device ◽

Standing Up ◽

Indoor Sports

AbstractThe purpose of this study was to analyze the validity and the reliability of the intensity ranges, number of actions and changes of direction measured by a commercial inertial measurement unit. Eleven elite youth futsal players performed a circuit with different type of displacements as sprinting, running at low-medium intensity, standing up and changes of direction. Data recorded by the Overtraq system were compared with video-analyzer during the six trials of each player. Standard error mean, Intraclass Correlation Coeficient and Coefficient of variation, were calculated to analyze the reliability of the device, as well as the Root Mean Square Error and Confidence Interval with correlation of Pearson for its validity. The results reported good validity for three intensity ranges (R2>0.7) with high reliability (Intraclass Correlation Coeficient: 0.8–0.9), especially for high intensity actions (Intraclass Correlation Coeficient: 0.95, Coefficient of Variation: 3.06%). Furthermore, the validity for the number of different actions was almost perfect (96.3–100%), with only small differences regarding changes of activity (mean error: 2.0%). The Overtraq system can be considered as a valid and reliable technology for measuring and monitoring actions at different intensities and changes of direction in futsal, likewise common actions for other indoor sports.

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Variability in Baseball Throwing Metrics During a Structured Long-Toss Program: Does One Size Fit All or Should Programs Be Individualized?

Sports Health A Multidisciplinary Approach ◽

10.1177/1941738119869945 ◽

2019 ◽

Vol 11 (6) ◽

pp. 535-542 ◽

Cited By ~ 3

Author(s):

Nels D. Leafblad ◽

Dirk R. Larson ◽

Glenn S. Fleisig ◽

Stan Conte ◽

Stephen A. Fealy ◽

...

Keyword(s):

High School ◽

Coefficient Of Variation ◽

Inertial Measurement Unit ◽

Intraclass Correlation ◽

Measurement Unit ◽

Level Of Evidence ◽

Inertial Measurement ◽

Ball Velocity ◽

Maximum Effort ◽

Level 3

Background: The variability of throwing metrics, particularly elbow torque and ball velocity, during structured long-toss programs is unknown. Hypotheses: (1) Elbow torque and ball velocity would increase as throwers progressed through a structured long-toss program and (2) intrathrower reliability would be high while interthrower reliability would be variable. Study Design: Descriptive laboratory study. Level of Evidence: Level 3. Methods: Sixty healthy high school and collegiate pitchers participated in a structured long-toss program while wearing a validated inertial measurement unit, which measured arm slot, arm velocity, shoulder rotation, and elbow varus torque. Ball velocity was assessed by radar gun. These metrics were compared within and between all pitchers at 90, 120, 150, and 180 ft and maximum effort mound pitching. Intra- and interthrower reliabilities were calculated for each metric at every stage of the program. Results: Ball velocity significantly changed at each progressive throwing distance, but elbow torque did not. Pitching from the mound did not place more torque on the elbow than long-toss throwing from 120 ft and beyond. Intrathrower reliability was excellent (intraclass correlation coefficient >0.75) throughout the progressive long-toss program, especially on the mound. Ninety-one percent of throwers had acceptable interthrower reliability (coefficient of variation <5%) for ball velocity, whereas only 79% of throwers had acceptable interthrower reliability for elbow torque. Conclusion: Based on trends in elbow torque, it may be practical to incorporate pitching from the mound earlier in the program (once a player is comfortable throwing from 120 ft). Ball velocity and elbow torque do not necessarily correlate with one another, so a degree of caution should be exercised when using radar guns to estimate elbow torque. Given the variability in elbow torque between throwers, some athletes would likely benefit from an individualized throwing program. Clinical Relevance: Increased ball velocity does not necessarily equate to increased elbow torque in long-toss. Some individuals would likely benefit from individualized long-toss programs for rehabilitation.

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Evaluation of head posture using an inertial measurement unit

Scientific Reports ◽

10.1038/s41598-021-99459-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mustafa Al-Yassary ◽

Kelly Billiaert ◽

Gregory S. Antonarakis ◽

Stavros Kiliaridis

Keyword(s):

Inertial Measurement Unit ◽

Electronic Device ◽

Intraclass Correlation ◽

Measurement Unit ◽

Index Test ◽

In Vitro Test ◽

Inertial Measurement ◽

Head Posture

AbstractAn inertial measurement unit (IMU) is an electronic device that measures and track the orientation of a body. We conducted this study in accordance with the STARD guidelines to evaluate the accuracy of IMU (index test) for measuring head posture compared to the current gold standard using a cervical range of motion (CROM) device. The reproducibility of the hunter and mirror-guided head posture was also evaluated. In vitro and in vivo tests were carried out to assess the validity of the IMU. To assess reproducibility, thirty healthy young adults were asked to look at four different locations in two different sessions while the head posture was recorded. Excellent correlation (r = 0.99; p < 0.001) was found between the IMU and CROM device with an absolute mean difference of 0.45° ± 0.58° (p = 0.85) for the in vitro test and 0.88° ± 1.20° (p = 0.99) for the in vivo test. For the reproducibility test, moderate to good correlation coefficients were found (r = 0.55 to 0.89; all p < 0.05) between the two sessions. The intraclass correlation coefficient ranged from moderate to excellent reliability (ICC from 0.74 to 0.96). These results suggest that the IMU sensors, when calibrated correctly, can be adequate to analyze head posture.

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