Wireless Tri-axial Accelerometer Research Articles

Objective psychomotor laparoscopic skills evaluation using a low-cost wearable device based on accelerometry: construct and concurrent validity study.

Motion analysis of surgical maneuvers provides useful quantitative information for the objective evaluation of the surgeons. However, surgical simulation laboratories for laparoscopic training do not usually integrate devices that help quantify the level of skills of the surgeons due to their limited resources and the high costs of new technologies. The purpose of this study is to present the construct and concurrent validity of a low-cost motion tracking system, based on a wireless triaxial accelerometer, employed to objectively evaluate psychomotor skills of surgeons during laparoscopic training. An accelerometry system, a wireless three-axis accelerometer with appearance of wristwatch, was placed on the dominant hand of the surgeons to register the motion during the laparoscopy practice with the EndoViS simulator, which simultaneously recorded the motion of the laparoscopic needle driver. This study included the participation of 30 surgeons (6 experts, 14 intermediates and 10 novices) who performed the task of intracorporeal knot-tying suture. Using 11 motion analysis parameters (MAPs), the performance of each participant was assessed. Subsequently, the scores of the three groups of surgeons were statistically analyzed. In addition, a validity study was conducted comparing the metrics between the accelerometry-tracking system and the EndoViS hybrid simulator. Construct validity was achieved for 8 of the 11 metrics examined with the accelerometry system. Concurrent validity demonstrated that there is a strong correlation between the results of the accelerometry system and the EndoViS simulator in 9 of 11 parameters, showing reliability of the accelerometry system as an objective evaluation method. The accelerometry system was successfully validated. This method is potentially useful to complement the objective evaluation of surgeons during laparoscopic practice in training environments such as box-trainers and simulators.

Does total knee arthroplasty affect pelvic movements? A prospective comparative study.

Pathology in any segment of the spine-pelvis-lower extremity may impair the global postural balance, leading to compensatory alterations in other parts. The aim of this study was to compare the pelvic movements of patients suffering from knee osteoarthritis with patients who underwent total knee arthroplasty and healthy controls. This study was performed at the Department of Orthopedics and Traumatology Clinic of a Cankiri State Hospital between April 2021 and February 2022. This study included 84 participants. Of them, 31 patients who underwent total knee arthroplasty between 2018 and 2020 years were selected as the total knee arthroplasty group, while 28 patients with knee osteoarthritis were selected as the knee osteoarthritis group. In the control group, there were 25 healthy individuals. Exclusion criteria from the study included any kind of neurological disease, an inability to walk a distance of 100 m unassisted, or a history of surgery to the lower limb. Pelvic movements (i.e., tilt, rotation, and obliquity) and gait parameters (i.e., "gait velocity," "cadence," and "stride length") were assessed using a wireless tri-axial accelerometer. Total knee arthroplasty and control groups had decreased minimum anterior tilt of the pelvis, decreased maximum anterior tilt, and decreased oblique range of the pelvis compared with the knee osteoarthritis group. In comparison with the control group, gait velocity and length of stride during gait were remarkably lower in both knee osteoarthritis and total knee arthroplasty groups. In this study, total knee arthroplasty was found to affect pelvic movements. It was thought that total knee arthroplasty changed these variables, probably owing to the frontal and sagittal plane alignment correction through surgery.

ASEMPTOMATİK FİZİKSEL İNAKTİF YETİŞKİNLERDE GÖVDE KAS KUVVETİ İLE PELVİK SALINIMLAR ARASINDAKİ İLİŞKİ

Purpose: Pelvis and trunk structure are body segments that are integrated with each other. Collaboration between pelvic mobility and trunk muscles plays a significant role in walking and energy consumption. The aim of this study is to investigate the relationship between trunk muscle strength and pelvic oscillations.
 Methods: Twenty-eight healthy individuals volunteered for the study (16 women, 12 men; mean age 24.46 ± 2.97 yrs., height 172.03 ± 9.41cm, weight 67.78 ± 16.31 kg). Pelvic oscillations were measured by using a wireless tri-axial accelerometer. Trunk muscle strength was evaluated with Isokinetic Dynamometer (Cybex Humac Norm Testing & Rehabilitation System, USA). The trunk extensors and flexors were tested concentrically at 60°s. Statistically, the direction and level of the relationship were examined by using Spearman Correlation Analysis.
 Results: Correlation analysis showed significant relationships between concentric strength of trunk flexion and anterior-posterior pelvic tilt (r=-0.419 p

Classification of kneeling and squatting in workers wearing protective equipment: development and validation of a rule-based model using wireless triaxial accelerometers

Several professions in industries, such as petroleum, manufacturing, construction, mining, and forestry require prolonged work tasks in awkward postures, increasing workers’ risks for musculoskeletal pain and injury. Therefore, we developed and validated a rule-based model for classifying unilateral and bilateral kneeling and squatting based on 15 individuals wearing personal protective equipment and using three wireless triaxial accelerometers. The model provided both high sensitivity and specificity for classifying kneeling (0.98; 0.98) and squatting (0.96; 0.91). Hence, this model has the potential to contribute to increased knowledge of physical work demands and exposure thresholds in working populations with strict occupational safety regulations. Practitioner summary: Our results indicate that this rule-based model can be applied in a human-factors perspective enabling high-quality quantitative information in the classification of occupational kneeling and squatting, known risk factors for musculoskeletal pain, and sick leave. This study is adapted for working populations wearing personal protective equipment and aimed for long-term measurements in the workplace.

Detection of kneeling and squatting during work using wireless triaxial accelerometers

Occupational kneeling and squatting are well-documented risk factors for knee disorders. A method using 3 wireless accelerometers to detect and discriminate kneeling and squatting during work were developed based on data from a semi-standardised laboratory protocol. The method was tested for validity under free-living working conditions. The developed method showed high sensitivity (88–99%) and specificity (98–99%) for detection of kneeling and squatting during the semi-standardised laboratory conditions. During free-living working conditions, kneeling showed very high sensitivity (94%) and specificity (99%), while squatting results were non-conclusive due to limited duration of squatting during the free-living working conditions. This method shows great promise for long-term technical measurement of kneeling and squatting during normal working conditions using wireless accelerometers. The method opens up possibilities for using technical measurements to provide valid exposure assessments and intervention evaluations of kneeling and squatting, as well as increased feasibility for technical measurements in large cohort studies. Practitioner summary: Quantification of kneeling and squatting during work is important for prevention, but limited by either imprecise or costly methods. This study developed and validated an inexpensive wireless accelerometer-based measurement method that can be used by practitioners and researchers for long-term measurements of kneeling and squatting during free-living working conditions.

The effects of electromyography-triggered neuromuscular electrical stimulation plus tilt sensor functional electrical stimulation training on gait performance in patients with subacute stroke: a randomized controlled pilot trial.

The effects of electromyography-triggered neuromuscular electrical stimulation and tilt sensor functional electrical stimulation on ankle dorsiflexion during walking are unclear. This study investigated whether combined electrical stimulation training affects gait performance in patients with stroke. Thirty-six patients were randomly assigned to a control (n = 13), electromyography-triggered neuromuscular electrical stimulation training (single electrical stimulation group, n = 12), or a combined electromyography-triggered neuromuscular electrical stimulation and tilt sensor functional electrical stimulation training (combined electrical stimulation group, n = 11) group. Both experimental groups undertook 60-minute interventions for two weeks. All patients' gait performances were evaluated according to walking speed and trunk acceleration during 10-meter walking tests undertaken pre-intervention and at two weeks post-intervention. A wireless triaxial accelerometer measured trunk acceleration, and the root mean square values of the vertical, mediolateral, and anterioposterior planes were calculated from randomly selected 10-step sequences. Compared with baseline, the 10-meter walking tests improved significantly after two weeks in the single and combined electrical stimulation groups. In the combined electrical stimulation group, the 10-meter walking tests scores and root mean square of the mediolateral plane improved significantly compared with those in the control group. Electromyography-triggered neuromuscular electrical stimulation and tilt sensor functional electrical stimulation training may improve body perturbation stability and walking quality.

CSM 2019 American Academy of Sports Physical Therapy Poster Presentations (Abstracts SPO1–SPO132)

CSM 2019 American Academy of Sports Physical Therapy Poster Presentations (Abstracts SPO1–SPO132)

On using wearable tri-axial accelerometers to examine the striking phase kinematics of expert specialist drag flickers on-field

ABSTRACTAnalysing player kinematics during a match using “gold-standard” 3D video-based motion analysis techniques is a difficult prospect indeed. The development of small, wireless, wearable sensors offers the potential to reduce the challenges of measuring kinematics during match-play without hindering performance. The present study examined the viability of using wireless tri-axial accelerometers to examine whether key performance measures of drag flicks executed by expert specialist drag-flickers are predicted by the kinematics of the striking phase. Linear mixed models were used to examine whether the speed and accuracy of players’ drag flicks were predicted by the duration of stick-ball contact, and the kinematics of the lead lower limb at stick-ball contact and ball release. Results revealed that stick and lead lower limb kinematics significantly predicted shot accuracy but not shot speed. Shorter drag-time predicted more accurate flicks (p = 0.03) as did a more vertical leg at stick-ball contact (p = 0.016) and a more horizontal thigh at ball release (p = 0.001). This may indicate that there are more ways to produce fast drag flicks than accurate ones. This study illustrates that wireless tri-axial accelerometers can be used on-field to measure the effects of kinematics on key performance measures.

A Study on Efficacy of Wavelet Transform for Damage Identification in Reinforced Concrete Buildings

Structural damage and its extent can be detected by vibration-based techniques to avoid failure or to minimize maintenance. Among different damage identification techniques, modal curvature approaches are widely researched and applied one. On the contrary, wavelet transformation (WT) methods are gaining popularity in damage identification of real life buildings because of their suitability for non-stationary signals and non-dependency on baseline data. This paper presents a novel approach utilizing complex continuous wavelet to effectively locate change in physical properties of reinforced concrete (RC) buildings by virtue of variation in frequency and mode shapes due to small change in mass and stiffness. In this paper, the effect of variation of mass and stiffness of a building on the modal parameters is established analytically using theequation of motion for a multi-degree freedom system under forced vibration condition. A 3-D finite element model was developed for predicting the modal frequencies and mode shapes of the scaled down six storey RC building and the effect of addition of mass on a particular level of structure on the modal parameters was studied. Further, acceleration time histories were recorded with variation in mass on 3rd story of building using wireless tri-axial accelerometers and the time histories were processed to arrive at Curvature Damage Factor and wavelet coefficients for identification of the additional load on the particular floor. Vibration responses from all floors of RC building in ambient and loaded conditions were analyzed for frequency response spectra (FRS). Mode shapes were drawn for unloaded case and loaded cases. It was observed that the modal frequency of building decreases with the increase in mass at floors. It is observed that CDF approach could detect the change in mass in both numerical and experimental results. However, CDF algorithm could not detect the addition of load in case 1, 2 and 3, i.e. when load was less than 25 kg, i.e. only 2.6% of floor mass (960 kg). The acquired data for the above stated load cases were analyzed using complex Gaussian ‘cgau5’ wavelet in MATLAB toolbox to determine the singularity in the signal in terms of wavelet coefficient modulus. It is observed that the WT approach is able to precisely locate the change in physical parameters of the RC model building. However, it is seen that additional load could not be detected in case where only 9 kg, i.e. 0.93% of the total floor mass, was placed on 3rd floor. From the research work, it is observed that CDF technique is inefficient in damage detection and always demand prior baseline information, which is usually difficult to obtain in practice. However, the wavelet transform-based approach more accurately detects the location of change without relying on intact state vibration data.

Trunk Movement Quantification of Adult with and without Mental Disability during Gardening Task Using Wireless Tri-Axial Accelerometer

Trunk Movement Quantification of Adult with and without Mental Disability during Gardening Task Using Wireless Tri-Axial Accelerometer

A Pilot Study Using Entropy as a Noninvasive Assessment of Running.

Running performance is influenced by the interaction of biomechanical and physiological factors. Miniaturized accelerometers worn by athletes can be used to quantify mechanical aspects of running and as a noninvasive tool to assess training status and progression. The aim of this study was to define and validate a method to assess running regularity and allow the estimation of an individual's oxygen uptake (V̇O2) and/or blood lactate-[La]b-based on data collected with accelerometers and heart rate. Male adolescent endurance athletes completed an incremental submaximal aerobic stage test where V̇O2 and [La]b were measured. The test was terminated when [La]b concentration at the end of the stage exceeded 4 mmol/L. Two wireless triaxial accelerometers were placed on participants' right shank and lower back throughout the test. The root mean square (RMS) and sample entropy (SampEn) were calculated for the vertical, mediolateral, and anteroposterior components of acceleration. There were significant positive correlations of acceleration and entropy variables with [La]b and V̇O2, with moderate to high coefficients (r = .43-.87). RMS of the shank acceleration was the most highly related with both physiological variables. When the accelerometer was attached on the trunk, SampEn of the vertical acceleration had the strongest relationship with V̇O2 (r = .76, P < .01). The described method analyzing running complexity may allow an assessment of gait variability, which noninvasively tracks V̇O2 and/or [La]b, allowing monitoring of fatigue or training readiness for trained adolescent individuals.

Trunk kinematics and low back pain during pruning among vineyard workers-A field study at the Chateau Larose-Trintaudon.

The prevalence of low back disorders is dramatically high in viticulture. Field measurements that objectively quantify work exposure can provide information on the relationship between the adopted trunk postures and low back pain. The purposes of the present study were three-fold (1) to carry out a kinematics analysis of vineyard-workers’ pruning activity by extracting the duration of bending and rotation of the trunk, (2) to question separately the relationship between the duration of forward bending or trunk rotation with low back pain intensity and pressure pain sensitivity and (3) to question the relationship between the combined duration of forward bending and trunk rotation on low back pain intensity and pressure pain sensitivity. Fifteen vineyard-workers were asked to perform pruning activity for 12 minutes with a wireless triaxial accelerometer placed on their trunk. Kinematic analysis of the trunk showed that vineyard-workers spent more than 50% of the time with the trunk flexed greater than 30° and more than 20% with the trunk rotated greater than 10°. These results show that pruning activity lead to the adoption of forward bended and rotated trunk postures that could significantly increase the risk of work related musculoskeletal disorders in the low back. However, this result was mitigated by the observation of an absence of significant association between the duration of forward bending and trunk rotation with low back pain intensity or pressure pain sensitivity. Even if prospective field measurements and studies assessing the effects of low back pain confounders are needed, this field study provides new genuine information on trunk kinematics during pruning activity.

A Hybrid Temporal Reasoning Framework for Fall Monitoring

This paper presents a real-time method for detecting a fall at different phases using a wireless tri-axial accelerometer and reports the classification performance when the sensor is placed on different body parts. The proposed hybrid framework combines a rule-based knowledge representation scheme with a time control mechanism and machine-learning-based activity classification. Real-time temporal reasoning is performed using a standard rule-based inference engine. The framework is validated for fall detection performance, false alarm evaluation, and comparison with a highly cited baseline method. Based on a data set with 14 fall types (280 falls) collected from 16 subjects, the highest accuracy values of 86.54%, 87.31%, and 91.15% are obtained for fall detection at pre-impacts, impacts, and post-impacts, respectively. Without post-impact activity information, the side of the waist and chest are the best sensor positions, followed by the head, front of the waist, wrist, ankle, thigh, and upper arm. With post-impact activity information, the best sensor position is the side of the waist, followed by the head, wrist, front of the waist, thigh, chest, ankle, and upper arm. Most false alarms occur during transitions of lying postures. The proposed method is more robust to a variety of fall and activity types and yields better classification performance and false alarm rates compared with the baseline method. The results provide guidelines for sensor placement when developing a fall monitoring system.

Tool Condition Monitoring and Remaining Useful Life Prognostic Based on a Wireless Sensor in Dry Milling Operations.

Tool breakage causes losses of surface polishing and dimensional accuracy for machined part, or possible damage to a workpiece or machine. Tool Condition Monitoring (TCM) is considerably vital in the manufacturing industry. In this paper, an indirect TCM approach is introduced with a wireless triaxial accelerometer. The vibrations in the three vertical directions (x, y and z) are acquired during milling operations, and the raw signals are de-noised by wavelet analysis. These features of de-noised signals are extracted in the time, frequency and time–frequency domains. The key features are selected based on Pearson’s Correlation Coefficient (PCC). The Neuro-Fuzzy Network (NFN) is adopted to predict the tool wear and Remaining Useful Life (RUL). In comparison with Back Propagation Neural Network (BPNN) and Radial Basis Function Network (RBFN), the results show that the NFN has the best performance in the prediction of tool wear and RUL.

Effect of Visual and Somatosensory Information Inputs on Postural Sway in Patients With Stroke Using Tri-Axial Accelerometer Measurement

Background: Posture balance control is the ability to maintain the body’s center of gravity in the minimal postural sway state on a supportive surface. This ability is obtained through a complicated process of sensing the movements of the human body through sensory organs and then integrating the information into the central nervous system and reacting to the musculoskeletal system and the support action of the musculoskeletal system. Motor function, including coordination, motor, and vision, vestibular sense, and sensory function, including proprioception, should act in an integrated way. However, more than half of stroke patients have motor, sensory, cognitive, and emotional disorders for a long time. Motor and sensory disorders cause the greatest difficulty in postural control among stroke patients. Objects: The purpose of this study is to determine the effect of visual and somatosensory information on postural sway in stroke patients and carrying out a kinematic analysis using a tri-axial accelerometer and a quantitative assessment. Methods: Thirty-four subjects posed four stance condition was accepted various sensory information for counterbalance. This experiment referred to the computerized dynamic posturography assessments and was redesigned four condition blocking visual and somatosensory information. To measure the postural sway of the subjects’ trunk, a wireless tri-axial accelerometer was used by signal vector magnitude value. Ony-way measure analysis of variance was performed among four condition. Results: There were significant differences when somatosensory information input blocked (p<.05). Conclusion: The sensory significantly affecting the balance ability of stroke patients is somatosensory, and the amount of actual movement of the trunk could be objectively compared and analyzed through quantitative figures using a tri-axial accelerometer for balance ability.

Study of acceleration of center of mass during sit-to-stand and stand-to-sit in patients with stroke.

[Purpose] The purpose of this study was to compare the center of mass during sit-to-stand and stand-to-sit activities in the timed up and go test between healthy subjects and patients with stroke. [Subjects and Methods] Thirty healthy participants and thirty patients with stroke volunteered for this study. Acceleration of the center of mass was measured using a wireless tri-axial accelerometer during sit-to-stand and stand-to-sit activities in the timed up and go test. Accelerometer data were analyzed using BTS G-studio software. [Results] The phase duration was significantly longer and the anterior-posterior, mediolateral, and vertical acceleration ranges were significantly lower during sit-to-stand for patients with stroke than for healthy controls. Further, phase duration and the mediolateral acceleration range during stand-to-sit differed significantly between healthy controls and subjects with stroke. [Conclusions] During training for the sit-to-stand activity, the focus should be all three balance dimensions, but during training for the stand-to-sit activity, the focus should be on improving mediolateral balance and asymmetrical foot positioning should be recommended.

Diagnosis of knee osteoarthritis and gait variability increases risk of falling for osteoporotic older adults: The GAINA study

ObjectivesTo examine the relationship between history of falling, and musculoskeletal disease, bone mass, muscle strength, muscle mass, kyphosis, and gait speed and variability in osteoporotic older adults. MethodsThe GAINA study, which began in 2014, is a population-based prospective study of subject cohorts from the town of Hino, Tottori Prefecture, Japan. Participants were recruited from among individuals who had an annual town-sponsored medical check-up in 2014, between May and June. A total 223 of residents were screened for our study. Inclusion criteria were osteoporotic older adults who had: (1) a ≤70% young adult mean (YAM) bone mass as assessed using quantitative ultrasound (QUS) methods, (2) a prior hip fracture or vertebral fracture, (3) fragility fractures other than hip and vertebral fractures and <80% YAM of bone mass. From the total screened, 91 residents (mean age, 76.0 ± 8.0 years; 22 men and 69 women) met the eligibility criteria. History of falling, diagnosis of musculoskeletal disease, bone mass, grip strength, muscle mass, kyphosis, and gait speed were assessed. Gait variability analysis was based on acceleration in three directions: mediolateral (ML), vertical (VT), and anteroposterior (AP) using a wireless triaxial accelerometer. Subjects were classified as belonging to a nonfall group or fall group based on their history of falling. ResultsDuring the previous 12 months, 26 falls were reported by 16 subjects (5 men and 11 women). Sixteen of the 91 included patients (17.6%) fell (22% men and 15% women), and 8 of the 16 subjects reported multiple falls. In a multivariable analysis, diagnosis of knee osteoarthritis and higher gait variability had a significant independent relationship with falling in these osteoporotic adults. ConclusionsDiagnosis of knee osteoarthritis and gait variability are associated with previous falls in osteoporotic older adults. Accelerometry-based gait analysis may be a useful tool with which to assess the risk of falling in this population.

Comparison between a center of mass and a foot pressure sensor system for measuring gait parameters in healthy adults.

[Purpose] The purpose of this study was to determine the relationship between an accelerometer system and a foot pressure sensor system for measuring gait characteristics during walking in healthy adults. [Subjects and Methods] Thirty-five healthy participants with no neurological, musculoskeletal, or cardiopulmonary disorders volunteered for this study. Gait characteristics were measured while participants walked freely along a 10-m walkway using two different measurement systems simultaneously. The first analysis system was based on center of mass using a wireless tri-axial accelerometer and the second system was a foot pressure sensor system. [Results] There was a significant and high correlation between the two systems with respect to gait velocity and cadence. The stride length as a percentage of the stride height measured with the center of mass system was significantly and highly correlated with stride length and stride velocity that was measured with the foot pressure system. Furthermore, stride length from the center of mass system was significantly and highly correlated with stride length and stride velocity from the foot pressure system. [Conclusion] A gait analysis based on a center of mass system is a valid method to assess the effectiveness of therapeutic interventions in a clinical setting.

Lower-leg compression, running mechanics, and economy in trained distance runners.

The efficacy of and mechanisms behind the widespread use of lower-leg compression as an ergogenic aid to improve running performance are unknown. The purpose of this study was to examine whether wearing graduated lower-leg compression sleeves during exercise evokes changes in running economy (RE), perhaps due to altered gait mechanics. Sixteen highly trained male distance runners completed 2 separate RE tests during a single laboratory session, including a randomized-treatment trial of graduated calf-compression sleeves (CS; 15-20 mm Hg) and a control trial (CON) without compression sleeves. RE was determined by measuring oxygen consumption at 3 constant submaximal speeds of 233, 268, and 300 m/min on a treadmill. Running mechanics were measured during the last 30 s of each 4-min stage of the RE test via wireless triaxial 10-g accelerometer devices attached to the top of each shoe. Ground-contact time, swing time, step frequency, and step length were determined from accelerometric output corresponding to foot-strike and toe-off events. Gait variability was calculated as the standard deviation of a given gait variable for an individual during the last 30 s of each stage. There were no differences in VO2 or kinematic variables between CON and CS trials at any of the speeds. Wearing lower-leg compression does not alter the energetics of running at submaximal speeds through changes in running mechanics or other means. However, it appears that the individual response to wearing lower-leg compression varies greatly and warrants further examination.

Analyzing Body Movements within the Laban Effort Framework Using a Single Accelerometer

This article presents a study on analyzing body movements by using a single accelerometer sensor. The investigated categories of body movements belong to the Laban Effort Framework: Strong—Light, Free—Bound and Sudden—Sustained. All body movements were represented by a set of activities used for data collection. The calculated accuracy of detecting the body movements was based on collecting data from a single wireless tri-axial accelerometer sensor. Ten healthy subjects collected data from three body locations (chest, wrist and thigh) simultaneously in order to analyze the locations comparatively. The data was then processed and analyzed using Machine Learning techniques. The wrist placement was found to be the best single location to record data for detecting Strong—Light body movements using the Random Forest classifier. The wrist placement was also the best location for classifying Bound—Free body movements using the SVM classifier. However, the data collected from the chest placement yielded the best results for detecting Sudden—Sustained body movements using the Random Forest classifier. The study shows that the choice of the accelerometer placement should depend on the targeted type of movement. In addition, the choice of the classifier when processing data should also depend on the chosen location and the target movement.