scholarly journals A Video-Based Method to Quantify Stroke Synchronisation in Crew Boat Sprint Kayaking

2018 ◽  
Vol 65 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Cheryl Sihui Tay ◽  
Pui Wah Kong
Keyword(s):  
Video Camera ◽  
Single Gender ◽  
Phase Duration ◽  
Rater Reliability ◽  
Intra Class Correlation ◽  
National Team ◽  
Timing Difference ◽  
The Mean ◽  
Zero Offset ◽  
Standard Error Of Measurement

AbstractThe study aimed to quantify stroke synchronisation in two-seater crew boat sprint kayaking (K2) using a video-based method, and to assess the intra- and inter-rater reliabilities of this method. Twelve sub-elite sprint kayakers (six males and six females) from a national team were paired into six single-gender K2 crews. The crews were recorded at 120 Hz with a sagittal-view video camera during 200-m time trials. Video analysis identified four meaningful positions of a stroke (catch, immersion, extraction and release). The timing difference (termed “offset”) between the front and back paddlers, within each K2, at each stroke position was calculated, with zero offset indicating perfect synchronisation. Results showed almost perfect intra-rater reliability of this method. The intra-class correlation (ICC) ranged from .87 to 1.00, and standard error of measurement ( SEM) from 0 to 5 milliseconds (ms). Inter-rater reliability was substantial to almost perfect (ICC .72 – .94, SEM 2 – 6 ms). On average, 35 strokes were analysed for each crew and the mean offset was 17 ms, or 5.7% of water phase duration. Crews were more synchronised at the catch (11 ms, 3.8%) than the release (21 ms, 7.2%). However, the stroke synchronisation profiles of the six sub-elite crews varied considerably from each other. For example, the best performing male and female crews had directly contrasting profiles. This suggests that there is no universal stroke synchronisation profile for well-trained sprint kayakers. This video-based method may aid future investigations on improving performance.

Is the location of the signal intensity weighted centroid a reliable measurement of fluid displacement within the disc?

2018 ◽  
Vol 63 (4) ◽  
pp. 453-460 ◽  
Author(s):  
Vahid Abdollah ◽  
Eric C. Parent ◽  
Michele C. Battié
Keyword(s):  
Signal Intensity ◽  
Water Distribution ◽  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Region Of Interest ◽  
Rater Reliability ◽  
Fluid Displacement ◽  
Intraclass Correlation Coefficients ◽  
The Mean ◽  
Standard Error Of Measurement

Abstract Degenerated discs have shorter T2-relaxation time and lower MR signal. The location of the signal-intensity-weighted-centroid reflects the water distribution within a region-of-interest (ROI). This study compared the reliability of the location of the signal-intensity-weighted-centroid to mean signal intensity and area measurements. L4-L5 and L5-S1 discs were measured on 43 mid-sagittal T2-weighted 3T MRI images in adults with back pain. One rater analysed images twice and another once, blinded to measurements. Discs were semi-automatically segmented into a whole disc, nucleus, anterior and posterior annulus. The coordinates of the signal-intensity-weighted-centroid for all regions demonstrated excellent intraclass-correlation-coefficients for intra- (0.99–1.00) and inter-rater reliability (0.97–1.00). The standard error of measurement for the Y-coordinates of the signal-intensity-weighted-centroid for all ROIs were 0 at both levels and 0 to 2.7 mm for X-coordinates. The mean signal intensity and area for the whole disc and nucleus presented excellent intra-rater reliability with intraclass-correlation-coefficients from 0.93 to 1.00, and 0.92 to 1.00 for inter-rater reliability. The mean signal intensity and area had lower reliability for annulus ROIs, with intra-rater intraclass-correlation-coefficient from 0.5 to 0.76 and inter-rater from 0.33 to 0.58. The location of the signal-intensity-weighted-centroid is a reliable biomarker for investigating the effects of disc interventions.

scholarly journals Validity and Reliability of a New Optoelectronic System for Measuring Active Range of Motion of Upper Limb Joints in Asymptomatic and Symptomatic Subjects

2019 ◽  
Vol 8 (11) ◽  
pp. 1851
Author(s):  
Rodrigo Martín-San Agustín ◽  
Jose A. García-Vidal ◽  
German Cánovas-Ambit ◽  
Aurelio Arenas-Della Vecchia ◽  
Manuel López-Nicolás ◽  
...  
Keyword(s):  
Upper Limb ◽  
Pearson Correlation ◽  
Minimal Detectable Change ◽  
Validity And Reliability ◽  
Optoelectronic System ◽  
Rater Reliability ◽  
Intra Class Correlation ◽  
Active Range Of Motion ◽  
Upper Limb Movements ◽  
Standard Error Of Measurement

The aim of this study was to evaluate the validity of the Veloflex infrared dynamic angle-meter (Veloflex-IDA) and the intra- and inter-rater reliability when measuring the ranges of motion (ROMs) of the upper limb joints. Thirty-five healthy and 20 symptomatic participants were evaluated. Twelve upper limb movements were measured in two sessions with the Veloflex-IDA, which is a device composed of a camera that tracks the trajectory of retro-reflective markers. In addition, a goniometer was used in the first session to evaluate concurrent validity. Validity and agreement were evaluated by Pearson correlation coefficient (r) and Bland–Altmann plots. Intra- and inter-rater reliability were evaluated using intra-class correlation (ICC), standard error of measurement (SEM), and minimal detectable change (MDC). Both instruments showed excellent correlation for all movements (r range from 0.992 to 0.999). The intra- and inter-rater reliability were excellent (ICC range from 0.95 to 0.99 and 0.90 to 0.98, respectively). Intra-rater reliability showed SEMs <1.38% and <5.19% and inter-rater reliability SEMs <2.26% and <5.22% for asymptomatic and symptomatic, respectively. Veloflex-IDA is a valid and reliable alternative to measure the upper limb joints’ ROM and it can be used in clinical practice and research after basic training.

scholarly journals Intra- and Inter-Rater Reliability of Strength Measurements Using a Pull Hand-Held Dynamometer Fixed to the Examiner’s Body and Comparison with Push Dynamometry

Diagnostics ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1230
Author(s):  
Javier González-Rosalén ◽  
Josep Carles Benítez-Martínez ◽  
Francesc Medina-Mirapeix ◽  
Alba Cuerda-Del Pino ◽  
Antonio Cervelló ◽  
...  
Keyword(s):  
Body Composition ◽  
Standard Error ◽  
Healthy Subjects ◽  
Isometric Strength ◽  
Rater Reliability ◽  
Intra Class Correlation ◽  
Standard Error Of Measurement ◽  
Error Of Measurement

Hand held dynamometers (HHDs) are the most used method to measure strength in clinical sitting. There are two methods to realize the assessment: pull and push. The purpose of the present study was to evaluate the intra- and inter-rater reliability of a new measurement modality for pull HHD and to compare the inter-rater reliability and agreement of the measurements. Forty healthy subjects were evaluated by two assessors with different body composition and manual strength. Fifteen isometric tests were performed in two sessions with a one-week interval between them. Reliability was examined using the intra-class correlation (ICC) and the standard error of measurement (SEM). Agreement between raters was examined using paired t-tests. Intra- and inter-rater reliability for the tests performed with the pull HHD showed excellent values, with ICCs ranging from 0.991 to 0.998. For tests with values higher than 200 N, push HHD showed greater differences between raters than pull HHD. Pull HHD attached to the examiner’s body is a method with excellent reliability to measure isometric strength and showed better agreement between examiners, especially for those tests that showed high levels of strength. Pull HHD is a new alternative to perform isometric tests with less rater dependence.

Ratio imaging of intracellular ion concentration

1992 ◽  
Vol 50 (2) ◽  
pp. 1160-1161
Author(s):  
Stephen R. Bolsover
Keyword(s):  
Individual Cell ◽  
Video Camera ◽  
Field Of View ◽  
Ion Concentration ◽  
Fluorescence Signal ◽  
Ion Imaging ◽  
Ratiometric Fluorescence ◽  
Ratio Imaging ◽  
The Mean ◽  
The Many

The field of intracellular ion concentration measurement expanded greatly in the 1980's due primarily to the development by Roger Tsien of ratiometric fluorescence dyes. These dyes have many applications, and in particular they make possible to image ion concentrations: to produce maps of the ion concentration within living cells. Ion imagers comprise a fluorescence microscope, an imaging light detector such as a video camera, and a computer system to process the fluorescence signal and display the map of ion concentration.Ion imaging can be used for two distinct purposes. In the first, the imager looks at a field of cells, measuring the mean ion concentration in each cell of the many in the field of view. One can then, for instance, challenge the cells with an agonist and examine the response of each individual cell. Ion imagers are not necessary for this sort of experiment: one can instead use a system that measures the mean ion concentration in a just one cell at any one time. However, they are very much more convenient.

Development and Validation of an Instrument to Assess Horseback Mobility in Hippotherapy

2021 ◽  
pp. 003151252110365
Author(s):  
Alessandra V. Prieto ◽  
Kênnea Martins Almeida Ayupe ◽  
Ana C. A. Abreu ◽  
Paulo J. B. Gutierres Filho
Keyword(s):  
Correlation Coefficient ◽  
Factor Structure ◽  
Internal Consistency ◽  
Rater Reliability ◽  
Intra Class Correlation ◽  
Exploratory Factor Analyses ◽  
Excellent Internal Consistency ◽  
Development And Validation ◽  
Functional Gain ◽  
Intra Class Correlation Coefficient

Improvement in rider mobility represents an important functional gain for people with disabilities undergoing hippotherapy. However, there is no validated measuring instrument to track and document the rider's progress in riding activities. In this study, we aimed to develop and establish validity evidence for an instrument to assess hippotherapy participants’ mobility on horseback. We report on this development through the stages of: (a) content validation, (b) construct validation, (c) inter- and intra-rater reliability and (d) internal consistency analysis. We evaluated its factor structure with exploratory factor analyses, calculated values for inter- and intra-rater reliability using the intra-class correlation coefficient, and calculated its internal consistency using Cronbach's alpha. We followed recommendations by the Guidelines for Reporting Reliability and Agreement Studies. We found good inter-rater reliability (intra-class correlation coefficient – ICC = 0.991–0.999) and good intra-rater reliability (ICC = 0.997–1.0), and there was excellent internal consistency (Cronbach's α = 0.937–0.999). The instrument’s factor structure grouped its three domains into one factor. As this instrument is theoretically consistent and has been found to be appropriate and reliable for its intended use, it is now available for the measurement of horseback mobility among hippotherapy riders.

scholarly journals Development of new 9-ball test protocols for assessing expertise in cue sports

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jing Wen Pan ◽  
John Komar ◽  
Pui Wah Kong
Keyword(s):  
Power Control ◽  
Video Analysis ◽  
Test Performance ◽  
Absolute Error ◽  
Group Differences ◽  
Intra Class Correlation ◽  
National Team ◽  
Alignment Angle ◽  
Overall Performance ◽  
Ball Test

Abstract Background This study aimed to develop new test protocols for evaluating 9-ball expertise levels in cue sports players. Methods Thirty-one male 9-ball players at different playing levels were recruited (recreational group, n = 8; university team, n = 15; national team, n = 8). A 15-ball test was administered to indicate overall performance by counting the number of balls potted. Five skill tests (power control, cue alignment, angle, back spin, and top spin) were conducted to evaluate specific techniques by calculating error distances from pre-set targets using 2D video analysis. Results Intra-class correlation analyses revealed excellent intra-rater and inter-rater reliability in four out of five skill tests (ICC > 0.95). Significant between-group differences were found in 15-ball test performance (p <  0.001) and absolute error distances in the angle (p <  0.001), back spin (p = 0.006), and top spin tests (p = 0.045), with the recreational group performing worst while the national team performing best. Greater inter-trial variability was observed in recreational players than the more skilled players (p <  0.005). Conclusions In conclusion, the 9-ball test protocols were reliable and could successfully discriminate between different playing levels. Coaches and researchers may employ these protocols to identify errors, monitor training, and rank players.

Liquid Sheet Disintegration and Atomization Process on a Simplified Airblast Atomizer

1993 ◽  
Vol 115 (3) ◽  
pp. 461-466 ◽  
Author(s):  
G. Lavergne ◽  
P. Trichet ◽  
P. Hebrard ◽  
Y. Biscos
Keyword(s):  
High Speed ◽  
Swirling Flow ◽  
Video Camera ◽  
Frequency Instability ◽  
Liquid Sheet ◽  
Processing Unit ◽  
Spray Formation ◽  
High Speed Video Camera ◽  
The Mean ◽  
Component Phase

Liquid sheet break-up in coflowing shear flow is the mean by which liquids are atomized in practical injectors for gas turbine combustors. The present study explores experimentally the mechanisms of liquid sheet instabilities and spray formation. Experiments are conducted on four airblast geometries. A high-speed video camera associated with an image processing unit was used to study the liquid sheet instabilities. A microphone and a frequency analyzer were used to track the disintegration frequency. Instability amplitude and disintegration length of the liquid sheet were measured. A two-component Phase Doppler Particle Analyzer was used to characterize the resultant spray. The spatial distribution of the particle size is influenced by the swirling flow field. These experimental results will be used to assess models of fuel sheet instabilities and disintegration.

scholarly journals Guideline for Selecting Types of Reliability and Suitable Intra-class Correlation Coefficients in Clinical Research

2021 ◽  
Author(s):  
Khalil Taherzadeh Chenani ◽  
Farzan Madadizadeh
Keyword(s):  
Clinical Research ◽  
Correlation Coefficients ◽  
Reliability Test ◽  
Research Information ◽  
Rater Reliability ◽  
Intra Class Correlation ◽  
Medical Researchers ◽  
Different Types ◽  
Test Retest Reliability ◽  
Cluster Correlation

Introduction: Reliability is an integral part of measuring the reproducibility of research information. Intra-cluster correlation coefficient (ICC) is one of the necessary indicators for reliability reporting, which can be misleading in terms of its diversity. The main purpose of this study was to introduce the types of reliability and appropriate ICC indices.  Methods: In this tutorial article, useful information about the types of reliability and indicators needed to report the results, as well as the types of ICC and its applications were explained for dummies. Results: Three general types of reliability include inter-rater reliability, test-retest reliability, and intra-rater reliability was presented. 10 different types of ICC were also introduced and explained. Conclusion: The research results may be misleading if any of the reliability types and calculation criteria types are chosen incorrectly. Therefore, to make the results of the study more accurate and valuable. Medical researchers must seek help from relevant guidelines such as this study before conducting reliability analysis.  

Evaluation and validation of a patient completed psoriatic arthritis flare questionnaire

2021 ◽  
pp. jrheum.201317
Author(s):  
Philip S. Helliwell ◽  
William Tillett ◽  
Robin Waxman ◽  
Laura C. Coates ◽  
Mel Brooke ◽  
...  
Keyword(s):  
Psoriatic Arthritis ◽  
Disease Activity ◽  
Loss Of Function ◽  
Intra Class Correlation ◽  
The Mean ◽  
Definition Of ◽  
Multiple Domains ◽  
Intra Class Correlation Coefficient ◽  
Symptoms And Signs ◽  
Patient Opinion

Objective Evaluation of a psoriatic arthritis (PsA), multidimensional, patient completed disease flare questionnaire (FLARE). Methods The FLARE questionnaire was administered to 139 patients in a prospective observational study. The ‘gold standard’ of flare was based on patient opinion. Test-retest was evaluated by intra-class correlation coefficient (ICC). Disease activity was measured by the PASDAS, GRACE, CPDAI and DAPSA. Results The most common symptoms of a PsA flare were musculoskeletal, followed by fatigue, frustration, loss of function and an increase in cutaneous symptoms. The test-retest ICC for the FLARE questionnaire was 0.87 (95% CI 0.72 – 0.94). The optimum cut-off to identify a flare of disease was 4/10 (sensitivity 0.82, specificity 0.76; area under curve 0.85). For those patients scoring 4 or above, the mean score for the composite measures was as follows (score for those not reporting a flare in brackets): PASDAS, 5.3 ± 1.3 (3.1 ± 1.6); GRACE, 4.5 ± 1.2 (2.2 ± 1.4); CPDAI, 8.9 ± 2.5 (4.7 ± 3.1); DAPSA, 38.2 ± 20.3 (16.8 ± 14.9). In a new flare the increase in composite measure score was calculated as follows; 1 for PASDAS and GRACE, 2 for CPDAI, 7 for DAPSA. Moderate agreement was found between the definition of flare using the cut-off of 4, indicated by subjects in a separate question. Conclusion A PsA flare displays escalation of symptoms and signs across multiple domains; the FLARE questionnaire has external validity both in terms of composite disease activity and overall patient opinion of the state of their condition.

scholarly journals Non-contact physiological monitoring of preterm infants in the Neonatal Intensive Care Unit

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Mauricio Villarroel ◽  
Sitthichok Chaichulee ◽  
João Jorge ◽  
Sara Davis ◽  
Gabrielle Green ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Heart Rate ◽  
Respiratory Rate ◽  
Preterm Infants ◽  
Neonatal Intensive Care ◽  
Mean Absolute Error ◽  
Vital Signs ◽  
Absolute Error ◽  
Video Camera ◽  
The Mean

AbstractThe implementation of video-based non-contact technologies to monitor the vital signs of preterm infants in the hospital presents several challenges, such as the detection of the presence or the absence of a patient in the video frame, robustness to changes in lighting conditions, automated identification of suitable time periods and regions of interest from which vital signs can be estimated. We carried out a clinical study to evaluate the accuracy and the proportion of time that heart rate and respiratory rate can be estimated from preterm infants using only a video camera in a clinical environment, without interfering with regular patient care. A total of 426.6 h of video and reference vital signs were recorded for 90 sessions from 30 preterm infants in the Neonatal Intensive Care Unit (NICU) of the John Radcliffe Hospital in Oxford. Each preterm infant was recorded under regular ambient light during daytime for up to four consecutive days. We developed multi-task deep learning algorithms to automatically segment skin areas and to estimate vital signs only when the infant was present in the field of view of the video camera and no clinical interventions were undertaken. We propose signal quality assessment algorithms for both heart rate and respiratory rate to discriminate between clinically acceptable and noisy signals. The mean absolute error between the reference and camera-derived heart rates was 2.3 beats/min for over 76% of the time for which the reference and camera data were valid. The mean absolute error between the reference and camera-derived respiratory rate was 3.5 breaths/min for over 82% of the time. Accurate estimates of heart rate and respiratory rate could be derived for at least 90% of the time, if gaps of up to 30 seconds with no estimates were allowed.

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