Concurrent Validity of an Automated Footprint Detection Algorithm to Measure Plantar Contact Area During Walking

Background: Monitoring footprints during walking can lead to better identification of foot structure and abnormalities. Current techniques for footprint measurements are either static or dynamic, with low resolution. This work presents an approach to monitor the plantar contact area when walking using high-speed videography. Methods: Footprint images were collected by asking the participants to walk across a custom-built acrylic walkway with a high-resolution digital camera placed directly underneath the walkway. This study proposes an automated footprint identification algorithm (Automatic Identification Algorithm) to measure the footprint throughout the stance phase of walking. This algorithm used coloration of the plantar tissue that was in contact with the acrylic walkway to distinguish the plantar contact area from other regions of the foot that were not in contact. Results: The intraclass correlation coefficient (ICC) demonstrated strong agreement between the proposed automated approach and the gold standard manual method (ICC = 0.939). Strong agreement between the two methods also was found for each phase of stance (ICC > 0.78). Conclusions: The proposed automated footprint detection technique identified the plantar contact area during walking with strong agreement with a manual gold standard method. This is the first study to demonstrate the concurrent validity of an automated identification algorithm to measure the plantar contact area during walking.

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Gait Analysis Using Accelerometry Data from a Single Smartphone: Agreement and Consistency between a Smartphone Application and Gold-Standard Gait Analysis System

Sensors ◽

10.3390/s21227497 ◽

2021 ◽

Vol 21 (22) ◽

pp. 7497

Author(s):

Roy T. Shahar ◽

Maayan Agmon

Keyword(s):

Gait Analysis ◽

Gold Standard ◽

Concurrent Validity ◽

Gait Cycle ◽

Intraclass Correlation ◽

Smartphone Application ◽

Healthy Adults ◽

Community Dwelling ◽

Human Gait ◽

Spatio Temporal

Spatio-temporal parameters of human gait, currently measured using different methods, provide valuable information on health. Inertial Measurement Units (IMUs) are one such method of gait analysis, with smartphone IMUs serving as a good substitute for current gold-standard techniques. Here we investigate the concurrent validity of a smartphone placed in a front-facing pocket to perform gait analysis. Sixty community-dwelling healthy adults equipped with a smartphone and an application for gait analysis completed a 2-min walk on a marked path. Concurrent validity was assessed against an APDM mobility lab (APDM Inc.; Portland, OR, USA). Bland–Altman plots and intraclass correlation coefficients (agreement and consistency) for gait speed, cadence, and step length indicate good to excellent agreement (ICC2,1 > 0.8). For right leg stance and swing % of gait cycle and double support % of gait cycle, results were moderate (0.52 < ICC2,1 < 0.62). For left leg stance and swing % of gait cycle left results show poor agreement (ICC2,1 < 0.5). Consistency of results was good to excellent for all tested parameters (ICC3,1 > 0.8). Thus we have a valid and reliable instrument for measuring healthy adults’ spatio-temporal gait parameters in a controlled walking environment.

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Countermovement Jump Analysis Using Different Portable Devices: Implications for Field Testing

Sports ◽

10.3390/sports6030091 ◽

2018 ◽

Vol 6 (3) ◽

pp. 91 ◽

Cited By ~ 9

Author(s):

Vincenzo Rago ◽

João Brito ◽

Pedro Figueiredo ◽

Thiago Carvalho ◽

Tiago Fernandes ◽

...

Keyword(s):

Gold Standard ◽

Concurrent Validity ◽

Intraclass Correlation ◽

Force Platform ◽

Portable Devices ◽

Countermovement Jump ◽

Good Test ◽

Retest Reliability ◽

Wide Range ◽

Test Retest Reliability

The aim of this study was to analyze the concurrent validity, test–retest reliability, and capacity to detect changes of four different portable devices used to measure a wide range of neuromuscular parameters derived from countermovement jump (CMJ). An accelerometric device (Myotest), a jump mat (Ergojump), an optical device (Optojump), and a smartphone app (MyJump) were simultaneously examined for concurrent validity against gold-standard measures (motion-capture system and a force platform). Twenty-two CMJ-derived variables were collected from 15 healthy male subjects (n = 60 CMJs). Contraction time (CT) and eccentric duration (EccD) measurements obtained from the Myotest were moderately to largely associated with and not different from force platform measurements (r = 0.31 to 0.64, ES = 0.11 to 0.18) and showed moderate test-retest reliability (intraclass correlation coefficient (ICC) = 0.92 to 0.97, coefficient of variation (CV) = 3.8 to 8.0%). Flight time (FT) and jump height (JH) from Ergojump, Optojump, and MyJump showed moderate to strong associations with gold-standard measurements (r = 0.57 to 0.98) and good test–retest reliability (ICC = 0.54 to 0.97, CV = 1.8 to 4.2). However, all portable devices underestimated JH (ES = 1.25 to 2.75). Independent of the instrument used, the analyzed CMJ variables showed good capacity to detect changes (standard error of measurement (SEM) < smallest worthwhile change (SWC)), with the exception of rate of force and rate of power development parameters, which showed marginal capacity (SEM > SWC). The Myotest is preferable to measure temporal parameters during ground contact, whereas Ergojump, Optojump, and MyJump devices may be preferable to measure FT and JH, with the Optojump being the most accurate.

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The Reliability and Concurrent Validity of Digital Inclinometer, Smartphone Applications, and the Cervical Range of Motion Device for Measuring the Cervical Range of Motion

Iranian Rehabilitation Journal ◽

10.32598/irj.18.4.927.1 ◽

2020 ◽

Vol 18 (4) ◽

pp. 405-418

Author(s):

Faezeh Ghorbani ◽

◽

Mojtaba Kamyab ◽

Fatemeh Azadinia ◽

Amir Ahmadi ◽

...

Keyword(s):

Range Of Motion ◽

Gold Standard ◽

Concurrent Validity ◽

Intraclass Correlation ◽

Smartphone Applications ◽

High Agreement ◽

Cervical Range Of Motion ◽

Digital Inclinometer ◽

Direction Of Movement

Objectives: Changes in the Range of Motion (ROM) are essential criteria in determining the severity of spinal disorders and could be effective in predicting pain progression. Instruments to measure the ROM are costly and unavailable in most therapy settings. While there is a tendency in therapists to use their smartphones instead, there is no report to measure the suitability of smartphones to be employed for this purpose. The current study aimed to compare the inter- and intra-rater reliability and concurrent validity of a Cervical Range of Motion (CROM) device (as a gold standard), a digital inclinometer, and smartphones in measuring the CROM in asymptomatic adults. Methods: Twenty-four healthy subjects (11 women, 13 men) aged 22 to 45 years were recruited for this study. Neck movements were assessed per study subject using CROM device, dual digital inclinometer, as well as IOS (for iPhone), and Android applications. Despite the popularity of using smartphone applications, there was no study comparing such applications. Results: The dual inclinometer and iPhone clinometer and compass applications presented acceptable absolute and relative reliability (ICC=0.662-0.913) and (ICC=0.753-0.887), respectively for neck movements in all planes. The reliability of the Android clinometer application in the sagittal and frontal planes was also acceptable (ICC=0.76-0.937); however, the Android compass application used in the horizontal plane indicated the least intraclass correlation coefficient (ICC: 0.202-0.433) in this area. Discussion: All the tested tools differed from the gold standard depending on the direction of movement, confirmed i.e. approved by the Bland-Altman. The dual digital inclinometer presented moderate to high agreement to the CROM device for all motions, except for rotation. The iPhone applications had high to a very high agreement, and the Android application revealed poor to a moderate agreement. These discrepancies should be considered in employing smartphones for diagnosing a cervical disorder and determining a therapeutic plan. However, as phone applications indicated desirable reproducibility, these tools could be used for the follow-up and monitoring of changes in the CROM.

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Validity of the Favero Assioma Duo Power Pedal System for Measuring Power Output and Cadence

Sensors ◽

10.3390/s21072277 ◽

2021 ◽

Vol 21 (7) ◽

pp. 2277

Author(s):

Almudena Montalvo-Pérez ◽

Lidia B. Alejo ◽

Pedro L. Valenzuela ◽

Mario Castellanos ◽

Jaime Gil-Cabrera ◽

...

Keyword(s):

Power Output ◽

Coefficient Of Variation ◽

Gold Standard ◽

Concurrent Validity ◽

The Novel ◽

Power Meter ◽

And Performance ◽

Srm System ◽

External Loads ◽

Strong Agreement

Cycling power meters enable monitoring external loads and performance changes. We aimed to determine the concurrent validity of the novel Favero Assioma Duo (FAD) pedal power meter compared with the crank-based SRM system (considered as gold standard). Thirty-three well-trained male cyclists were assessed at different power output (PO) levels (100–500 W and all-out 15-s sprints), pedaling cadences (75–100 rpm) and cycling positions (seating and standing) to compare the FAD device vs. SRM. No significant differences were found between devices for cadence nor for PO during all-out efforts (p > 0.05), although significant but small differences were found for efforts at lower PO values (p < 0.05 for 100–500 W, mean bias 3–8 W). A strong agreement was observed between both devices for mean cadence (ICC > 0.87) and PO values (ICC > 0.81) recorded in essentially all conditions and for peak cadence (ICC > 0.98) and peak PO (ICC > 0.99) during all-out efforts. The coefficient of variation for PO values was consistently lower than 3%. In conclusion, the FAD pedal-based power meter can be considered an overall valid system to record PO and cadence during cycling, although it might present a small bias compared with power meters placed on other locations such as SRM.

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Reproducibility and Validity of the Myotest for Measuring Step Frequency and Ground Contact Time in Recreational Runners

Journal of Human Kinetics ◽

10.1515/hukin-2015-0003 ◽

2015 ◽

Vol 45 (1) ◽

pp. 19-26 ◽

Cited By ~ 7

Author(s):

Vincent Gouttebarge ◽

Robin Wolfard ◽

Nouschka Griek ◽

Cornelis J. de Ruiter ◽

Julitta S. Boschman ◽

...

Keyword(s):

Gold Standard ◽

Concurrent Validity ◽

Contact Time ◽

Intraclass Correlation ◽

Ground Contact ◽

Step Frequency ◽

Retest Reliability ◽

Ground Contact Time ◽

Recreational Runners ◽

Test Retest Reliability

Abstract The purpose of this study was to assess the reproducibility (test-retest reliability and agreement) and concurrent validity of the Myotest for measuring step frequency (SF) and ground contact time (GCT) in recreational runners. Based on a within-subjects design (test and retest), SF and GCT of 14 participants (11 males, 3 females) were measured at three different running speeds with the Myotest during two test sessions. SF and GCT were also assessed with a foot-mounted accelerometer (Gold Standard, previously validated by comparing to force plate data) during the first test session. Levels of test-retest reliability and concurrent validity were expressed with intraclass correlation coefficients (ICC), agreement with standard errors of measurement (SEM). For SF, test-retest reliability (ICC’s > 0.75) and agreement of the Myotest were considered as good at all running speeds. For GCT, test-retest reliability was found to be moderate at a running speed of 14 km/h and poor at speeds of 10 and 12 km/h (ICC < 0.50). Agreement of the Myotest for GCT at all three running speeds was considered not acceptable given the SEM’s calculated. Concurrent validity of the Myotest with the foot-mounted accelerometer (Gold Standard) at all three running speeds was found to be good for SF (ICC’s > 0.75) and moderate for GCT (0.50 < ICC’s < 0.75). The conclusion of our study is that estimates obtained with the Myotest are reproducible and valid for SF but not for GCT.

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High concurrent validity between digital and analogue algometers to measure pressure pain thresholds in healthy participants and people with migraine: a cross-sectional study

The Journal of Headache and Pain ◽

10.1186/s10194-021-01278-8 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

René F. Castien ◽

Michel W. Coppieters ◽

Tom S. C. Durge ◽

Gwendolyne G. M. Scholten-Peeters

Keyword(s):

Concurrent Validity ◽

Tibialis Anterior Muscle ◽

Intraclass Correlation ◽

Cephalic Region ◽

Limits Of Agreement ◽

Temporal Muscle ◽

Pain Thresholds ◽

Pressure Pain ◽

Pressure Pain Thresholds ◽

Healthy Participants

Abstract Background Pressure pain thresholds (PPTs) are commonly assessed to quantify mechanical sensitivity in various conditions, including migraine. Digital and analogue algometers are used, but the concurrent validity between these algometers is unknown. Therefore, we assessed the concurrent validity between a digital and analogue algometer to determine PPTs in healthy participants and people with migraine. Methods Twenty-six healthy participants and twenty-nine people with migraine participated in the study. PPTs were measured interictally and bilaterally at the cephalic region (temporal muscle, C1 paraspinal muscles, and trapezius muscle) and extra-cephalic region (extensor carpi radialis muscle and tibialis anterior muscle). PPTs were first determined with a digital algometer, followed by an analogue algometer. Intraclass correlation coefficients (ICC3.1) and limits of agreement were calculated to quantify concurrent validity. Results The concurrent validity between algometers in both groups was moderate to excellent (ICC3.1 ranged from 0.82 to 0.99, with 95%CI: 0.65 to 0.99). Although PPTs measured with the analogue algometer were higher at most locations in both groups (p < 0.05), the mean differences between both devices were less than 18.3 kPa. The variation in methods, such as a hand-held switch (digital algometer) versus verbal commands (analogue algometer) to indicate when the threshold was reached, may explain these differences in scores. The limits of agreement varied per location and between healthy participants and people with migraine. Conclusion The concurrent validity between the digital and analogue algometer is excellent in healthy participants and moderate in people with migraine. Both types of algometer are well-suited for research and clinical practice but are not exchangeable within a study or patient follow-up.

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Quantum chemical benchmark databases of gold-standard dimer interaction energies

Scientific Data ◽

10.1038/s41597-021-00833-x ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Alexander G. Donchev ◽

Andrew G. Taube ◽

Elizabeth Decolvenaere ◽

Cory Hargus ◽

Robert T. McGibbon ◽

...

Keyword(s):

Machine Learning ◽

Gold Standard ◽

Training Data ◽

Structure Theory ◽

Cluster Method ◽

Coupled Cluster ◽

Interaction Energies ◽

Gold Standard Method ◽

Representative Subset ◽

Semi Empirical

AbstractAdvances in computational chemistry create an ongoing need for larger and higher-quality datasets that characterize noncovalent molecular interactions. We present three benchmark collections of quantum mechanical data, covering approximately 3,700 distinct types of interacting molecule pairs. The first collection, which we refer to as DES370K, contains interaction energies for more than 370,000 dimer geometries. These were computed using the coupled-cluster method with single, double, and perturbative triple excitations [CCSD(T)], which is widely regarded as the gold-standard method in electronic structure theory. Our second benchmark collection, a core representative subset of DES370K called DES15K, is intended for more computationally demanding applications of the data. Finally, DES5M, our third collection, comprises interaction energies for nearly 5,000,000 dimer geometries; these were calculated using SNS-MP2, a machine learning approach that provides results with accuracy comparable to that of our coupled-cluster training data. These datasets may prove useful in the development of density functionals, empirically corrected wavefunction-based approaches, semi-empirical methods, force fields, and models trained using machine learning methods.

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Evaluation of four different HPLC devices for hemoglobinopathy screening

Turkish Journal of Biochemistry ◽

10.1515/tjb-2019-0484 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Müjgan Ercan Karadağ ◽

Emiş Deniz Akbulut ◽

Esin Avcı ◽

Esra Fırat Oğuz ◽

Saadet Kader ◽

...

Keyword(s):

Gold Standard ◽

High Performance ◽

Public Health Problem ◽

Reference Value ◽

Comparison Study ◽

Gold Standard Method ◽

Blood Samples ◽

Systematic Biases ◽

Hemoglobin Variants ◽

Thalassemia Screening

AbstractObjectiveHemoglobinopathies are a common public health problem in Turkey. In the screening of these disorders in population, cation-exchange high performance liquid chromatography (HPLC) is accepted as the gold standard method. In this study, the aim was to assess four different HPLC devices used in hemoglobinopathy screening.Materials and methodsA total of 58 blood samples were analyzed with four different HPLC methods (Bio-Rad variant II, Agilent 1100, Tosoh G8 and Trinity Ultra2 trademarks).ResultsThe comparison study demonstrated a good correlation between the results of each HPLC analyzer and the reference value obtained by averaging all the HbA2 results belonging to the methods tested in the study [ (Tosoh G8 (r=0.988), Bio-Rad variant II (r=0.993), Agilent 1100 (r=0.98) and Trinity Ultra2 (r=0.992) ]. HbA2 determination in the presence of HbE was interfered in both Bio-Rad variant II and Tosoh G8.ConclusionThe analyzers were found to have compatible HbA2 results but with accompanying different degrees of proportional and systematic biases. HPLC analyzers may be affected by different hemoglobin variants at different HbA2 concentrations, which is an important point to take into consideration during the evaluation of HbA2 results in thalassemia screening.

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Validity of Inertial Sensors for Assessing Balance Kinematics and Mobility during Treadmill-Based Perturbation and Dance Training

Sensors ◽

10.3390/s21093065 ◽

2021 ◽

Vol 21 (9) ◽

pp. 3065

Author(s):

Ernest Kwesi Ofori ◽

Shuaijie Wang ◽

Tanvi Bhatt

Keyword(s):

Concurrent Validity ◽

Inertial Sensors ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Human Motion ◽

Intraclass Correlation Coefficients ◽

Dance Training ◽

Silver Standard ◽

Mean Square Errors ◽

Reactive Balance

Inertial sensors (IS) enable the kinematic analysis of human motion with fewer logistical limitations than the silver standard optoelectronic motion capture (MOCAP) system. However, there are no data on the validity of IS for perturbation training and during the performance of dance. The aim of this present study was to determine the concurrent validity of IS in the analysis of kinematic data during slip and trip-like perturbations and during the performance of dance. Seven IS and the MOCAP system were simultaneously used to capture the reactive response and dance movements of fifteen healthy young participants (Age: 18–35 years). Bland Altman (BA) plots, root mean square errors (RMSE), Pearson’s correlation coefficients (R), and intraclass correlation coefficients (ICC) were used to compare kinematic variables of interest between the two systems for absolute equivalency and accuracy. Limits of agreements (LOA) of the BA plots ranged from −0.23 to 0.56 and −0.21 to 0.43 for slip and trip stability variables, respectively. The RMSE for slip and trip stabilities were from 0.11 to 0.20 and 0.11 to 0.16, respectively. For the joint mobility in dance, LOA varied from −6.98–18.54, while RMSE ranged from 1.90 to 13.06. Comparison of IS and optoelectronic MOCAP system for reactive balance and body segmental kinematics revealed that R varied from 0.59 to 0.81 and from 0.47 to 0.85 while ICC was from 0.50 to 0.72 and 0.45 to 0.84 respectively for slip–trip perturbations and dance. Results of moderate to high concurrent validity of IS and MOCAP systems. These results were consistent with results from similar studies. This suggests that IS are valid tools to quantitatively analyze reactive balance and mobility kinematics during slip–trip perturbation and the performance of dance at any location outside, including the laboratory, clinical and home settings.

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Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.407-408.577 ◽

2009 ◽

Vol 407-408 ◽

pp. 577-581

Author(s):

Shi Chao Xiu ◽

Zhi Jie Geng ◽

Guang Qi Cai

Keyword(s):

Surface Integrity ◽

Contact Area ◽

High Speed ◽

Ground Surface ◽

Depth Of Cut ◽

Grinding Wheel ◽

Grinding Process ◽

Edge Contact ◽

Cylindrical Grinding ◽

Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

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