Validity and Reliability of an Inertial Measurement Unit–based 3-Dimensional Angular Measurement of Cervical Range of Motion

Myofascial trigger points therapy increases neck mobility and reduces headache pain in migraine patients - pilot study

BACKGROUND

This study aimed to evaluate the effects of Ischemic Compression Myofascial Trigger Points (IC-MTrPs) therapy, applied mainly to the upper trapezius muscle (UTM), on: [1] cervical spine range of motion (CS-ROM), and [2] headache characteristics in migraine patients. Reduced CS-ROM can further contribute to musculoskeletal strain and neurological discomfort in migraine sufferers. The application of IC-MTrPs therapy is of particular interest because it targets these trigger points, potentially normalizing muscle tone and improving local blood flow, which may alleviate pain and restore mobility.

DESIGN

A case series employing a repeated-measures design; pilot study.

METHODS

Fifty-three adult female migraine patients were classified into three groups: episodic migraine without aura (MO, n = 31), episodic migraine with aura (MA, n = 15), and chronic migraine (CM, n = 7). Patients underwent seven sessions of IC-MTrPs therapy targeting the shoulder and neck muscles. Assessments were conducted across five sessions: pre-therapy (baseline), post-1st therapy, post-4th therapy, post-7th therapy, and at a 1-month follow-up. Outcome measures included: CS-ROM (assessed using an accelerometer system), subjective headache pain intensity (evaluated via the Visual Analog Scale (VAS)), and calcitonin gene-related peptide (CGRP) concentrations.

RESULTS

CS-ROM for horizontal rotation and forward flexion improved significantly at the 1-month follow-up compared to pre-therapy (baseline) (P < 0.05). Headache intensity during a migraine attacks, as well as headache frequency and duration, significantly decreased at post-7th therapy compared to baseline across all patients (P < 0.05). The highest CGRP concentrations were recorded in CM patients (240.73 ± 79.51 ng/ml). While no significant changes in CGRP levels were observed in patients with MO, CGRP concentration in patients with MA increased significantly at the 1-month follow-up compared to baseline, rising from 151.70 ± 50.85 ng/ml to 176.17 ± 77.21 ng/ml. In patients with CM, the therapy did not result in statistically significant changes in CGRP levels, although reductions in headache frequency and intensity were noted.

CONCLUSIONS

IC-MTrPs therapy proved effective in increasing CS-ROM and alleviating headache characteristics in all migraine subtypes. However, no significant changes in CGRP levels were observed. Distinct characteristics and responses among different migraine subtypes highlight the need for tailored therapeutic approaches.

TRIAL REGISTRATION

The study protocol was retrospectively registered on December 2, 2022, as a clinical trial in the international clinical trial database ClinicalTrials.gov (identifier: NCT05646160).

CLINICAL TRIAL NUMBER

not applicable.

Multi-Planar Cervical Motion Dataset: IMU Measurements and Goniometer

This data descriptor presents a comprehensive and replicable dataset and method for calculating the cervical range of motion (CROM) utilizing quaternion-based orientation analysis from Delsys inertial measurement unit (IMU) sensors. This study was conducted with 14 participants and analyzed 504 cervical movements in the Sagittal, Frontal and Horizontal planes. Validated against a Universal Goniometer and tested for reliability and reproducibility. Analysis showed strong validity in the sagittal plane (R = 0.828 ± 0.051) and moderate in the frontal (R = 0.573 ± 0.138), with limitations in the horizontal plane (R = 0.353 ± 0.122). Reliability was high across all planes (Sagittal: ICC = 0.855 ± 0.065, Frontal: ICC = 0.855 ± 0.015, Horizontal: ICC = 0.945 ± 0.005). Our model for CROM measurements is a valuable tool aiding diagnosis, treatment planning, and monitoring of cervical spine conditions. This study presents an accessible analysis process for biomechanical assessments in cervical and spinal fields. The dataset herein serves as a benchmark for state-of-the-art machine learning models predicting head/neck position, analyzing smoothness of movements, measuring standard motion patterns, and calibrating drift based on movement comparisons.

Reliability of the Moover® 3D Inertial Motion Sensor in Greek Patients With Chronic Neck Pain in a Primary Care Urban Setting

Introduction Neck pain has a high lifetime prevalence and represents a significant health issue. Reduced active cervical range of motion (ACROM) has been found in neck pain patients. Inertial sensor technology can provide objective measurements to assess the impaired ACROM. Purpose Primarily, this study investigated the inter- and intra-rater reliability of the Moover® three-dimensional (3D) inertial motion sensor (Sensor Medica, Rome, Italy) in Greek patients with non-specific chronic neck pain. Secondly, the intra-rater reliability of the Neck Disability Index (NDI) was also assessed. Methods Fifty patients (18 males and 32 females) suffering from non-specific chronic neck pain participated in this study. Two physiotherapists measured separately each participant's ACROM in three planes, within a 48-hour period. The participants' position and the sequence and direction of the three cervical movements (cervical rotation, lateral flexion, and flexion-extension) were standardized. Results The inter-rater reliability intraclass correlation coefficient (ICC) values were good to excellent ranging from 0.77 to 0.95 for the first measurement and 0.85 to 0.95 for the second (p < 0.001). The intra-rater reliability ICC values were moderate to excellent ranging from 0.74 to 0.92 for the first rater and good to excellent ranging from 0.83 to 0.94 for the secondrater (p < 0.001). Intra-rater reliability of the overall NDI was indicated as good, and ICC was 0.80 (95%CI: 0.65-0.89; p < 0.001). ICC values for all sections were significant and ranged from 0.40 to 0.88. Conclusion This study showed the reliability of the Moover 3D inertial sensor for ACROM measurement in Greek patients with chronic neck pain. The NDI scale also showed good intra-rater reliability in the same sample. Both intra- and inter-rater reliability of the Moover 3D were proven to be acceptable over a 48-hour period. The specific sensor might have a potential application in a clinical setting.

Validity of Inertial Measurement Unit (IMU Sensor) for Measurement of Cervical Spine Motion, Compared with Eight Optoelectronic 3D Cameras Under Spinal Immobilization Devices

Background

The assessment of cervical spine motion is critical for out-of-hospital patients who suffer traumatic spinal cord injuries, given the profound implications such injuries have on individual well-being and broader public health concerns. 3D Optoelectronic systems (BTS SmartDX) are standard devices for motion measurement, but their price, complexity, and size prevent them from being used outside of designated laboratories. This study was designed to evaluate the accuracy and reliability of an inertial measurement unit (IMU) in gauging cervical spine motion among healthy volunteers, using a 3D optoelectronic motion capture system as a reference.

Methods

Twelve healthy volunteers participated in the study. They underwent lifting, transferring, and tilting simulations using a long spinal board, a Sked stretcher, and a vacuum mattress. During these simulations, cervical spine angular movements-including flexion-extension, axial rotation, and lateral flexion-were concurrently measured using the IMU and an optoelectronic device. We employed the Wilcoxon signed-rank test and the Bland-Altman plot to assess reliability and validity.

Results

A single statistically significant difference was observed between the two devices in the flexion-extension plane. The mean differences across all angular planes ranged from -1.129° to 1.053°, with the most pronounced difference noted in the lateral flexion plane. Ninety-five percent of the angular motion disparities ascertained by the SmartDX and IMU were less than 7.873° for the lateral flexion plane, 11.143° for the flexion-extension plane, and 25.382° for the axial rotation plane.

Conclusion

The IMU device exhibited robust validity when assessing the angular motion of the cervical spine in the axial rotation plane and demonstrated commendable validity in both the lateral flexion and flexion-extension planes.

Dynamic assessment of spine movement patterns using an RGB-D camera and deep learning

In clinical practice, functional limitations in patients with low back pain are subjectively assessed, potentially leading to misdiagnosis and prolonged pain. This paper proposes an objective deep learning (DL) markerless motion capture system that uses a red-green-blue-depth (RGB-D) camera to measure the kinematics of the spine during flexion-extension (FE) through: 1) the development and validation of a DL semantic segmentation algorithm that segments the back into four anatomical classes and 2) the development and validation of a framework that uses these segmentations to measure spine kinematics during FE. Twenty participants performed ten cycles of FE with drawn-on point markers while being recorded with an RGB-D camera. Five of these participants also performed an additional trial where they were recorded with an optical motion capture (OPT) system. The DL algorithm was trained to segment the back and pelvis into four anatomical classes: upper back, lower back, spine, and pelvis. A kinematic framework was then developed to refine these segmentations into upper spine, lower spine, and pelvis masks, which were used to measure spine kinematics after obtaining 3D global coordinates of the mask corners. The segmentation algorithm achieved high accuracy, and the root mean square error (RMSE) between ground truth and predicted lumbar kinematics was < 4°. When comparing markerless and OPT kinematics, RMSE values were < 6°. This work demonstrates the feasibility of using markerless motion capture to assess FE spine movement in clinical settings. Future work will expand the studied movement directions and test on different demographics.

Cervical Range of Motion Assessment through Inertial Technology: A Validity and Reliability Study

Inertial technology has spread widely for its comfortable use and adaptability to various motor tasks. The main objective of this study was to assess the validity of inertial measurements of the cervical spine range of motion (CROM) when compared to that of the optoelectronic system in a group of healthy individuals. A further aim of this study was to determine the optimal placement of the inertial sensor in terms of reliability of the measure, comparing measurements obtained from the same device placed at the second cervical vertebra (C2), the forehead (F) and the external occipital protuberance (EOP). Twenty healthy subjects were recruited and asked to perform flexion-extension, lateral bending, and axial rotation movements of the head. Outcome measurements of interest were CROM and mean angular velocities for each cervical movement. Results showed that inertial measurements have good reliability (0.75 < ICC < 0.9). Excellent reliability (ICC > 0.9) was found in both flexion and right lateral bending angles. All parameters extracted with EOP placement showed ICC > 0.62, while ICC < 0.5 was found in lateral bending mean angular velocities both for F and C2 placements. Therefore, the optimal sensor's positioning emerged to be EOP. These results suggest that inertial technology could be useful and reliable for the evaluation of the CROM.

Attempt to Make the Upper-Limb Item of Objective Fugl-Meyer Assessment Using 9-Axis Motion Sensors

The Fugl-Meyer Assessment (FMA) has been used as a functional assessment of upper-limb function in stroke patients. This study aimed to create a more objective and standardized evaluation based on an FMA of the upper-limb items. A total of 30 first-ever stroke patients (65.3 ± 10.3 years old) and 15 healthy participants (35.4 ± 13.4 years old) admitted to Itami Kousei Neurosurgical Hospital were included. A nine-axis motion sensor was attached to the participants, and the joint angles of 17 upper-limb items (excluding fingers) and 23 FMA upper-limb items (excluding reflexes and fingers) were measured. From the measurement results, we analyzed the time-series data of each movement and obtained the correlation between the joint angles of each part. Discriminant analysis showed that 17 and 6 items had a concordance rate of ≥80% (80.0~95.6%) and <80% (64.4~75.6%), respectively. In the multiple regression analysis of continuous variables of FMA, a good regression model was obtained to predict the FMA with three to five joint angles. The discriminant analysis for 17 evaluation items suggests the possibility of roughly calculating FMA scores from joint angles.

Reliability of a Wearable Motion Tracking System for the Clinical Evaluation of a Dynamic Cervical Spine Function

Neck pain is a common cause of disability worldwide. Lack of objective tools to quantify an individual's functional disability results in the widespread use of subjective assessments to measure the limitations in spine function and the response to interventions. This study assessed the reliability of the quantifying neck function using a wearable cervical motion tracking system. Three novice raters recorded the neck motion assessments on 20 volunteers using the device. Kinematic features from the signals in all three anatomical planes were extracted and used as inputs to repeated measures and mixed-effects regression models to calculate the intraclass correlation coefficients (ICCs). Cervical spine-specific kinematic features indicated good and excellent inter-rater and intra-rater reliability for the most part. For intra-rater reliability, the ICC values varied from 0.85 to 0.95, and for inter-rater reliability, they ranged from 0.7 to 0.89. Overall, velocity measures proved to be more reliable compared to other kinematic features. This technique is a trustworthy tool for evaluating neck function objectively. This study showed the potential for cervical spine-specific kinematic measurements to deliver repeatable and reliable metrics to evaluate clinical performance at any time points.

Effects of McConnell and Kinesio taping on kinematic variables during stair descent in patients with patellofemoral pain syndrome

BACKGROUND

Studies regarding effects of therapeutic tapings when patients with patellofemoral pain syndrome (PFPS) descend stairs are limited.

OBJECTIVE

The purpose of this study was to investigate the effect of McConnell taping (MT) and Kinesio taping (KT) on kinematic variables when patients with PFPS descend stairs.

METHODS

Fifty PFPS patients were randomly assigned to either the MT group or the KT group. Pain and lower extremities joint angles were measured while descending stairs before and after the intervention. All outcomes measured were analyzed using either paired t tests or independent t tests to compare the difference within or between groups, respectively.

RESULTS

There was a statistically significant difference in both groups in anterior knee pain scale score (p< 0.05). As a result of analysis of lower extremities joint angles at initial contact, loading response, and terminal stance, there were statistically significant within-group differences in hip, knee flexion, abduction and lateral rotation angles in both groups (p< 0.05). There were statistically significant within-group differences in hip flexion, knee flexion, and dorsiflexion angles in pre-swing (p< 0.05). There was a statistically significant difference between the groups in the following events: (1) knee lateral rotation angle at initial contact; (2) hip flexion angle at loading response; (3) and hip flexion at terminal stance angle (p< 0.05).

CONCLUSION

MT and KT were effective in lowering knee pain and improving lower extremities joint angle when patients with PFPS descend stairs. In the comparison between the groups, the MT group showed significantly reduced anterior knee pain and increased range of motion of the lower extremities joint compared to the KT group.

The effect of tablet tilt angles and time on posture, muscle activity, and discomfort at the neck and shoulder in healthy young adults

BACKGROUND

Although young adults regularly perform tablet writing, biomechanics during the tablet writing with different tilt angles has not been studied. The objective of this study was to compare posture, muscle activity, and discomfort at the neck and shoulder between tablet writing with 0° (horizontal) and 30° tablet tilt angles over 40 minutes in healthy young adults.

METHODS

Twenty participants wrote continuously for 40 minutes on a tablet with both tilt angles in a randomized order. Between conditions, there was a 5-minute activity break. Differences in neck and shoulder posture, muscle activity, and discomfort between both tablet tilt angles and changes in the outcomes every 10 minutes over 40 minutes were investigated.

RESULTS

With the tilted tablet, there were lower neck flexion (Z = -4.637, P<0.001), lower shoulder extension (Z = -3.734, P<0.001), and lower neck Visual Analogue Scale (VAS) (left; Z = -4.699, P<0.001 and right; Z = -3.874, P<0.001) as compared to the no tilt condition. However, the right upper trapezius muscle activity was higher in the tilted condition as compared to the no tilt one. Over 40 minutes, the neck VAS (left; χ2(4) = 30.235, P<0.001 and right; χ2(4) = 32.560, P<0.001) and heart rate variability (χ2(4) = 12.906, P = 0.012) showed notable increases after 20 minutes compared to baseline.

CONCLUSION

In conclusion, adjusting the tablet tilt to 30° and limiting time spent to 20 minutes are recommended for young adults during the tablet writing to prevent neck problems.

Concurrent validity and reliability of a smartphone-based application for the head repositioning and cervical range of motion

Objectives

To evaluate the validity and reliability of a smartphone-based application against inertial sensors to measure head repositioning (by using joint position sense –JPS) and cervical range of motion (ROM).

Methods

JPS and cervical ROM were evaluated for neck flexion, extension and both-sides lateral flexion in thirty-one volunteers. Participants were simultaneously evaluated with inertial sensors and the smartphone application. A total of 248 angles were compared for concurrent validity. Inter-tester and intra-tester reliability were evaluated through scoring of images with the smartphone application by two testers, and re-scoring images by the same tester.

Results

Very high correlation was observed between both methods for ROM in all neck movements and JPS in left-side lateral flexion (r>0.9), and high for JPS in the rest of movements (r>0.8). Bland-Altman plots always demonstrated absolute agreement. Inter-and intra-tester reliability was perfect for JPS and ROM in all the neck movements (ICC>0.81).

Conclusions

This smartphone-based application is valid and reliable for evaluating head repositioning and cervical ROM compared with inertial sensors in healthy and young adults. Health professionals could use it in an easier and portable way in field conditions.

A novel virtual reality application for autonomous assessment of cervical range of motion: development and reliability study

Background

Neck pain, one of the most common musculoskeletal diseases, affects 222 million people worldwide. The cervical range of motion (CROM) is a tool used to assess the neck's state across three movement axes: flexo-extension, rotation, and lateral flexion. People with neck pain often have a reduced CROM, and they feel pain at the end-range and/or accompany neck movements with compensatory trunk movements. Virtual reality (VR) setups can track the movement of the head and other body parts in order to create the sensation of immersion in the virtual environment. Using this tracking position information, a CROM assessment can be performed using a VR setup that may be carried out autonomously from the user's home. The objectives of this study were to develop a VR experience that could be used to perform a CROM assessment, and to evaluate the intra-rater and inter-rater reliability of the CROM measures guided by this VR experience. To the best of our knowledge, a study of this type has not been carried out before.

Materials & Methods

A total of 30 asymptomatic adults were assessed using a VR device (HTC Vive Pro Eye™). Two raters provided support with the VR setup, and the participants were guided by the VR experience as they performed the movements. Each rater tested each subject twice, in random order. In addition to a head-mounted display (HMD), a tracker located on the subject's back was used to measure trunk compensatory movements. The CROM was estimated using only the HMD position and this measurement was corrected using the tracker data. The mean and standard deviation were calculated to characterize the CROM. To evaluate the reliability, the interclass correlation coefficients (ICC) were calculated for intra-rater and inter-rater analysis. The standard error of measurement and minimum detectable change were also calculated. The usability of the VR system was measured using the Spanish version of the System Usability Scale.

Results

The mean CROM values in each axis of movement were compatible with those described in the literature. ICC values ranged between 0.86 and 0.96 in the intra-rater analysis and between 0.83 and 0.97 in the inter-rater analysis; these values were between good and excellent. When applying the correction of the trunk movements, both the intra-rater and inter-rater ICC values slightly worsened except in the case of the lateral flexion movement, where they slightly improved. The usability score of the CROM assessment/VR system was 86 points, which is an excellent usability score.

Conclusion

The reliability of the measurements and the usability of the system indicate that a VR setup can be used to assess CROM. The reliability of the VR setup can be affected by slippage of the HMD or tracker. Both slippage errors are additive, i.e., only when the sum of these two errors is less than the compensatory movement do the measurements improve when considering the tracker data.

Effects of McConnell and Kinesio Tapings on Pain and Gait Parameters during Stair Ambulation in Patients with Patellofemoral Pain Syndrome

Background and Objectives: The purpose of this study was to investigate the effects of McConnell and Kinesio tapings on knee pain and gait parameters during stair ambulation in patients with patellofemoral pain syndrome (PFPS). Materials and Methods: We selected 52 young adults suffering from anterior knee pain due to PFPS to participate. Then, we randomly assigned 26 patients to either the McConnell or the Kinesio taping groups. We measured their knee pain and gait parameters during stair ambulation before and after the interventions. For the measured data, we performed a paired t-test to evaluate the amount of change before and after the intervention within the groups and an independent t-test to compare the groups. Results: From the comparison within the groups, we found a significant difference in both groups in the anterior knee pain scale score (p < 0.05) and a significant difference between the groups as well (p < 0.05). As a result of the analysis of the gait parameters while ascending stairs in the comparison within the groups, both groups showed significant differences in all gait variables, except for the double-support stance (p < 0.05), and we found significant differences in all gait variables, except for the double-support stance, in the comparison between the groups (p < 0.05). Regarding the gait variables during stair descent in the comparison within the groups (p < 0.05), both groups showed significant differences in all of the gait variables; we noted significant differences in the double-support stance, step length, velocity, and cadence in the comparison between the groups (p < 0.05). Conclusions: The McConnell and Kinesio tapings were effective in improving knee pain and gait parameters during ambulation in patients with PFPS, but we found that the McConnell taping had a significant impact on pain reduction during stair ambulation, resulting in further improvement in the gait variables.

Angular Kinematics of Chiropractic Supine Cervical Spine Manipulation: Rotational Measures and Comparisons to Doctor and Recipient Perceptions

OBJECTIVES

The primary purposes of this study were to measure axial rotation during supine cervical spinal manipulative therapy (cSMT) and to record recipients' and doctors' perceptions of rotational magnitudes.

METHODS

Experienced doctors of chiropractic (DCs) provided supine cSMT and acted as recipients of cSMT. Participants who received SMT wore inertial measurement units attached to the forehead and sternum for motion capture. Afterward, recipients and DCs completed questionnaires asking about their perceptions of motion. Data were analyzed for magnitudes of axial rotation at peak thrust and correlations with patient and doctor perceptions. Secondary analyses included angular velocity, angular acceleration, and other kinematic variables.

RESULTS

We recorded 23 SMT events with 14 DCs. Rotation at thrust peaks averaged 32.4° (17.4°). Doctors' and recipients' perceptions of rotation were higher than measured values 45% and 50% of the time, respectively. Maximum angular velocity and acceleration averaged 221.9°/s (124.9) and 4786.5°/s² (2456.6), respectively. We found no correlation between perceptions and velocity or acceleration; doctors' perceptions had an inverse correlation with measurements.

CONCLUSION

On average, we found rotation during supine cSMT to be 32°. Both DCs and SMT recipients overestimated rotation compared with actual measurements. These factors should be considered in discussions of rotation and SMT.

Cross-Leg Prediction of Running Kinematics across Various Running Conditions and Drawing from a Minimal Data Set Using a Single Wearable Sensor

The feasibility of prediction of same-limb kinematics using a single inertial measurement unit attached to the same limb has been demonstrated using machine learning. This study was performed to see if a single inertial measurement unit attached to the tibia can predict the opposite leg’s kinematics (cross-leg prediction). It also investigated if there is a minimal or smaller data set in a convolutional neural network model to predict lower extremity running kinematics under other running conditions and with what accuracy for the intra- and inter-participant situations. Ten recreational runners completed running exercises under five conditions, including treadmill running at speeds of 2, 2.5, 3, and 3.5 m/s and level-ground running at their preferred speed. A one-predict-all scheme was adopted to determine which running condition could be used to best predict a participant’s overall running kinematics. Running kinematic predictions were performed for intra- and inter-participant scenarios. Among the tested running conditions, treadmill running at 3 m/s was found to be the optimal condition for accurately predicting running kinematics under other conditions, with R2 values ranging from 0.880 to 0.958 and 0.784 to 0.936 for intra- and inter-participant scenarios, respectively. The feasibility of cross-leg prediction was demonstrated but with significantly lower accuracy than the same leg. The treadmill running condition at 3 m/s showed the highest intra-participant cross-leg prediction accuracy. This study proposes a novel, deep-learning method for predicting running kinematics under different conditions on a small training data set.

The Effect of Rifle Carriage on the Physiological and Accelerometer Responses During Biathlon Skiing

Purpose

Investigate the effect of biathlon rifle carriage on physiological and accelerometer-derived responses during biathlon skiing.

Methods

Twenty-eight biathletes (11F, 17M) completed two XC skiing time-trials (~2,300 m), once with and once without the biathlon rifle, with concurrent measurements of HR, skiing speed and accelerations recorded from three triaxial accelerometers attached at the Upper-spine, Lower-spine and Pelvis. Exercise intensity was quantified from HR, skiing speed as well from accelerometry-derived PlayerLoad™ per minute (PL·min^-1) and average net force (AvF_Net). All metrics were analyzed during Uphill, Flat and Downhill sections of the course. Relationships between accelerometry-derived metrics and skiing speed were examined.

Results

Time-trials were faster for males compared with females (mean difference: 97 ± 73 s) and No-Rifle compared to With-Rifle (mean difference: 16 ± 9 s). HR was greatest during Downhill (183 ± 5 bpm), followed by Uphill (181 ± 5 bpm) and was lowest in the Flat sections (177 ± 6 bpm, p <0.05). For PL·min^-1 and AvF_Net there were 3-way Rifle x Gradient x Sensor-Position interactions. Typically, these metrics were greatest during Uphill and Flat sections and were lowest during Downhill sections. Rifle carriage had no impact on the AvF_Net at the Lower-Spine or Pelvis. Significant positive linear relationships were identified between skiing speed and accelerometer-derived metrics during Uphill, Flat and Downhill skiing (r = 0.12-0.61, p < 0.05).

Conclusions

The accelerometry-derived approach used in this study provides the potential of a novel method of monitoring the external demands during skiing. In particular, AvF_Net with sensors located close to the center of mass displayed greatest utility because it followed the expected response of external intensity where responses were greatest during uphill sections, followed by flats and lowest during downhills. In addition, there were significant positive relationships between AvF_Net and skiing speed ranging from small to large. Accelerometry-derived measures could provide useful estimates of the external demands in XC skiing and biathlon.

The Relationship Between Cardiorespiratory and Accelerometer-Derived Measures in Trail Running and the Influence of Sensor Location

PURPOSE

To examine the relationship between cardiorespiratory and accelerometer-derived measures of exercise during trail running and determine the influence of accelerometer location.

METHODS

Eight trail runners (7 males and 1 female; age 26 [5] y; maximal oxygen consumption [V˙O2] 70 [6] mL·kg-1·min-1) completed a 7-km trail run (elevation gain: 486 m), with concurrent measurements of V˙O2, heart rate, and accelerations recorded from 3 triaxial accelerometers attached at the upper spine, lower spine, and pelvis. External exercise intensity was quantified from the accelerometers using PlayerLoad™ per minute and accelerometry-derived average net force. External exercise volume was calculated using accumulated PlayerLoad and the product of average net force and duration (impulse). Internal intensity was calculated using heart rate and V˙O2-metrics; internal volume was calculated from total energy expenditure (work). All metrics were analyzed during both uphill (UH) and downhill (DH) sections of the trail run.

RESULTS

PlayerLoad and average net force were greater during DH compared with UH for all sensor locations (P ≤ .004). For all accelerometer metrics, there was a sensor position × gradient interaction (F2,1429.003; P <.001). The upper spine was lower compared with both pelvis (P ≤ .003) and lower spine (P ≤ .002) for all accelerometer metrics during both UH and DH running. Relationships between accelerometer and cardiorespiratory measures during UH running ranged from moderate negative to moderate positive (r = -.31 to .41). Relationships were stronger during DH running where there was a nearly perfect correlation between work and impulse (r = .91; P < .001).

CONCLUSIONS

Simultaneous monitoring of cardiorespiratory and accelerometer-derived measures during trail running is suggested because of the disparity between internal and external intensities during changes in gradient. Sensor positioning close to the center of mass is recommended.

Do hip-abduction braces work?-A biomechanical evaluation of a commercially available hip brace

INTRODUCTION

Dislocations of the hip joint are a common and clinically relevant complication following total hip arthroplasty (THA). Hip-abduction braces are currently used following operative or non-operative treatment of THA dislocations to prevent re-dislocations. However, the clinical and biomechanical effectiveness of such braces is still controversial.

MATERIAL AND METHODS

A total of 30 volunteers were measured during standing and during sitting up and down from a chair task wearing a hip brace set at 70°, 90° or no hip flexion limitation. Range of motion of the hip joint was measured in all directions by an inertial sensor system. Further it has been evaluated if the range of motion would be reduced by the additional use of an arthrodesis cushion.

RESULTS

The use of a hip brace set up with flexion limitation did reduce hip ROM in all directions significantly compared to unhinged brace (p < 0.001-0.035). Performing the "sit down and stand-up task" the brace set up at 70° flexion limitation did reduce maximum hip flexion significantly (p = 0.008). However, in most cases the measured hip flexion angles were greater than the settings of the hip brace should have allowed. The additional use of a cushion can further limit hip motion while sitting up and down from a chair.

CONCLUSION

This study has demonstrated that hip-abduction braces reduce hip range of motion. However, we also found that to achieve a flexion limitation of the hip to 90°, the hip brace should be set at a 70° hip flexion limitation.

Real-Time Tracking of Human Neck Postures and Movements

Improper neck postures and movements are the major causes of human neck-related musculoskeletal disorders. To monitor, quantify, analyze, and detect the movements, remote and non-invasive based methods are being developed for prevention and rehabilitation. The purpose of this research is to provide a digital platform for analyzing the impact of human neck movements on the neck musculoskeletal system. The secondary objective is to design a rehabilitation monitoring system that brings accountability in the treatment prescribed, which is shown in the use-case model. To record neck movements effectively, a Smart Neckband integrated with the Inertial Measurement Unit (IMU) was designed. The initial task was to find a suitable position to locate the sensors embedded in the Smart Neckband. IMU-based real-world kinematic data were captured from eight research subjects and were used to extract kinetic data from the OpenSim simulation platform. A Random Forest algorithm was trained using the kinetic data to predict the neck movements. The results obtained correlated with the novel idea proposed in this paper of using the hyoid muscles to accurately detect neck postures and movements. The innovative approach of integrating kinematic data and kinetic data for analyzing neck postures and movements has been successfully demonstrated through the efficient application in a rehabilitation use case with about 95% accuracy. This research study presents a robust digital platform for the integration of kinematic and kinetic data that has enabled the design of a context-aware neckband for the support in the treatment of neck musculoskeletal disorders.

HeadUp: A Low-Cost Solution for Tracking Head Movement of Children with Cerebral Palsy Using IMU

Cerebral palsy (CP) is a common reason for human motor ability limitations caused before birth, through infancy or early childhood. Poor head control is one of the most important problems in children with level IV CP and level V CP, which can affect many aspects of children’s lives. The current visual assessment method for measuring head control ability and cervical range of motion (CROM) lacks accuracy and reliability. In this paper, a HeadUp system that is based on a low-cost, 9-axis, inertial measurement unit (IMU) is proposed to capture and evaluate the head control ability for children with CP. The proposed system wirelessly measures CROM in frontal, sagittal, and transverse planes during ordinary life activities. The system is designed to provide real-time, bidirectional communication with an Euler-based, sensor fusion algorithm (SFA) to estimate the head orientation and its control ability tracking. The experimental results for the proposed SFA show high accuracy in noise reduction with faster system response. The system is clinically tested on five typically developing children and five children with CP (age range: 2–5 years). The proposed HeadUp system can be implemented as a head control trainer in an entertaining way to motivate the child with CP to keep their head up.

Focus on the Scapular Region in the Rehabilitation of Chronic Neck Pain Is Effective in Improving the Symptoms: A Randomized Controlled Trial

Chronic neck pain is a common human health problem. Changes in scapular posture and alteration of muscle activation patterns of scapulothoracic muscles are cited as potential risk factors for neck pain. The purpose of this study was to compare the effects of neck exercise training (NET) with and without scapular stabilization training (SST) on pain intensity, the scapula downward rotation index (SDRI), forward head angle (FHA) and neck range of motion (ROM) in patients with chronic neck pain and scapular dyskinesia. A total of sixty-six subjects with chronic neck pain and scapular dyskinesia were randomly divided into three groups: neck exercise training, n = 24, combined training (NET + SST), n = 24 and a control group, n = 24. Pain intensity, SDRI, FHA and ROM were measured by the numerical rating scale, caliper, photogrammetry and IMU sensor, respectively. When the combined intervention group consisting of NET and SST was compared with NET alone at six weeks, there was a statistically significant difference in pain intensity, SDRI, FHA and cervical ROM for flexion and extension (p ≤ 0.05). Adding scapular exercises to neck exercises had a more significant effect in decreasing pain intensity, SDRI, FHA and increased cervical ROM than neck exercises alone in patients with chronic neck pain. These findings indicate that focus on the scapular posture in the rehabilitation of chronic neck pain effectively improves the symptoms.

Analysis and evaluation of the systems used for the assessment of the cervical spine function: a systematic review

Neck injuries and pathologies are widespread and cause disability. Clinicians use different tools to measure the cervical spine' mobility to diagnose different disorders. There are many reliable assessment methods for this purpose, but their benefits have not been deeply investigated and compared, as well as their measurement results. This review aims to summarise the advantages, accuracy, and reliability, of measurement tools and devices used in studies or trails related to the neck and cervical spine evaluation, to evidence the use of inertial sensors and compare them, to highlight the best assessment systems and their characteristics. A literature review has been performed in a range of five years, to obtain information about cervical spine evaluation. Studies that met the established inclusion criteria were selected and classified according their pathology studied, objectives and methodologies followed when evaluating the cervical spine functionality. Studies were described chronologically highlighting the tools employed, where the motion capture systems and cervical range of motion devices stood out as the most used and reliable methods. Cervical spine assessment studies employing systems with inertial sensors as an accurate method, is not evidenced in the sample. However, they are widely tested and different studies validate these systems for their clinical area use, obtaining high reliability and repeatability. Thereby, this review argues that inertial sensors have proven to be a portable, and easy to use tool for the evaluation of neck and its related pathologies, with a great accuracy level.

Kinematic and perceptual responses in heavy lifting and pulling: Are there differences between males and females?

This study investigated kinematic and perceptual differences between the sexes in a heavy lifting and pulling task. A 20 kg box was lifted from floor to chest height, and a 70 kg mannequin pulled across 20m. The effect of height, mass and average grip strength on kinematics and perceived workload was examined in 42 (19 females, 23 males) healthy individuals. A univariate linear regression analysis found females lifted with greater lumbar extension compared to males (p < 0.001), and adopted more hip (p = 0.006) and knee flexion (p = 0.036) in the pulling task. Females reported a greater perceived workload in both tasks (p < 0.001). After the multivariable analysis, only grip strength remained significant for perceived workload in the lift (p = 0.04), and height for knee flexion in the pull (p = 0.009). This highlights that height and strength are important factors driving kinematics and perceived workload. Clinicians may consider these factors in heavy manual tasks, more so than sex.

Risk assessment in different Judo techniques for children and adolescent athletes

Judo is a combat sport that involves throwing the opponent onto the back. When being thrown, head biomechanics may be related to head injury risk. This study aimed to assess head injury risks associated with four Judo techniques in children and adolescents with different experience levels. Twenty children (<12 years) and 20 adolescents (≥ 12 years) judoka were recruited. Each group was divided into non-expert and expert. Two inertial sensors were fixed on fallers' head and torso. Two backward (o-soto-gari and o-uchi-gari) and two forward (ippon-seoi-nage and tai-otoshi) techniques were performed. Peak of linear and angular head acceleration magnitude, impact time duration, neck angle, and the Gadd Severity Index were assessed. Children did not show differences between techniques or experience levels. In contrast, adolescents showed greater linear acceleration peak in o-soto-gari than tai-otoshi (p = 0.03), greater angular acceleration peak in o-soto-gari and o-uchi-gari than ippon-seoi-nage (p < 0.05), and greater neck flexion in o-uchi-gari than ippon-seoi-nage (p = 0.004). Compared to expert adolescents, non-expert adolescents showed greater angular acceleration peak, impact duration, and the Gadd Severity Index in o-soto-gari (p < 0.05) and greater neck extension in o-uchi-gari (p = 0.02). Current results pointed out higher risks for adolescents judoka while being thrown with backward techniques, especially for non-expert participants. This study highlights the need of training athletes in controlling head and neck during back falls from a young age to become expert judoka in adulthood.