Limits Of Agreement Analysis Research Articles

A single trunk-mounted wearable sensor to measure motor performance in triathletes during competition

The objective of this research was to validate a single, trunk-mounted wearable sensor (Optimeye S5, Catapult Australia, Melbourne) to measure the cadence of swimming strokes, cycling pedals and running strides in a triathlon. While similar validations have been performed in swimming and running, it is a novel application in cycling, and thus, across a whole triathlon. Seven triathletes were recruited to participate in a sprint distance triathlon which was filmed and simultaneously measured by a single, trunk-mounted wearable sensor. To validate the wearable sensor, individual swimming strokes, cycling pedal strokes and running strides were manually counted by viewing the wearable sensor data and video footage. While analysing cycling data, changes in cycling subtask performances were noticed, thus, a secondary analysis in cycling was conducted to investigate. The 95% limits of agreement analysis indicated the sensor validly measured swimming strokes (mean bias = −0.034 strokes), cycling pedal strokes (mean bias = −0.09 strokes) and running strides (mean bias = 0.00 strides) with minimal to no bias ( p > 0.05). Further analysis of cycling revealed the wearable sensor is an acceptably valid tool to measure the duration of out of saddle riding (mean bias = 0.08 s), however, significant differences in the duration of in saddle riding (mean bias = −0.5 s) and coasting were identified (mean bias = 0.39 s). A single trunk mounted wearable sensor is a valid tool to measure movement cadence in a triathlon, however, further validation is required to generate a full understanding of cycling subtask performances.

Translating digital anthropometry measurements obtained from different 3D body image scanners.

Body image scanners are used in industry and research to reliably provide a wealth of anthropometric measurements within seconds. The demonstrated utility of the scanners drives the current proliferation of more commercially available devices that rely on their own reference body sites and proprietary algorithms to output anthropometric measurements. Since each scanner relies on its own algorithms, measurements obtained from different scanners cannot directly be combined or compared. To develop mathematical models that translate anthropometric measurements between the three popular commercially available scanners. A unique database that contained 3D scanner measurements in the same individuals from three different scanners (Styku, Human Solutions, and Fit3D) was used to develop linear regression models that translate anthropometric measurements between each scanner. A limits of agreement analysis was performed between Fit3D and Styku against Human Solutions measurements and the coefficient of determination, bias, and 95% confidence interval were calculated. The models were then applied to normalized scanner data from four different studies to compare the results of a k-means cluster analysis between studies. A scree plot was used to determine the optimal number of clusters derived from each study. Correlations ranged between R2 = 0.63 (Styku and Human Solutions mid-thigh circumference) to R2 = 0.97 (Human Solutions and Fit3D neck circumference). In general, Fit3D had better agreement with Human Solutions compared to Styku. The widest disagreement was found in chest circumference (Fit3D (bias = 2.30, 95% CI = [-3.83, 8.43]) and Styku (bias = -5.60, 95% CI = [-10.98, -0.22]). The optimal number of body shape clusters in each of the four studies was consistently 5. The newly developed models that translate measurements between the scanners Styku and Fit3D to predict Human Solutions measurements make it possible to standardize data between scanners allowing for data pooling and comparison.

Reliability, Usefulness, and Validity of Field-Based Vertical Jump Measuring Devices.

Comyns, TM, Murphy, J, and O'Leary, D. Reliability, usefulness, and validity of field-based vertical jump measuring devices. J Strength Cond Res 37(8): 1594-1599, 2023-The purpose of this study was to examine the test-retest reliability, usefulness, and validity of field-based devices, in determining jump height (JH) during a countermovement jump (CMJ). Twenty-one male (22.8 ± 2.4 years; 1.82 ± 0.07 m; 86.0 ± 10.4 kg) and 7 female field sport athletes (20.5 ± 1.5 years; 1.65 ± 0.06 m; 65.4 ± 7.2 kg) performed 3 CMJs with data simultaneously recorded using a force plate (criterion measure), Optojump, Output Capture, and Push-Band 2.0. Reliability was determined by intraclass correlation (ICC) and coefficient of variation (CV) analyses. Usefulness was assessed by comparing typical error (TE) with the smallest worthwhile change (SWC), and the validity analyses involved repeated measures analysis of variance with post hoc analysis, Pearson correlation coefficient ( r ), coefficient of determination, and Bland-Altman 95% limits of agreement analyses. All 3 field-based devices were deemed reliable in assessing CMJ height as the respective ICCs ≥ 0.80 and the CV ≤ 10%. Only the Optojump and Output Capture devices were rated as "good" at detecting the SWC in performance (Optojump SWC: 1.44 > TE: 1.04; Output Capture SWC: 1.47 > TE: 1.05). The Output Capture device demonstrated acceptable validity for CMJ height assessment, whereas the Push-Band 2.0 showed systematic bias when compared with the criterion force plate data. Systematic difference was also evident for the Optojump potentially due to the optical switching-cell position on the Optojump. Although all 3 devices showed excellent reliability, the Optojump and Output Capture devices offer practitioners a cost effective, reliable, and valid method of assessing the smallest worthwhile change in CMJ performance in an applied setting.

Accuracy and Precision of a Novel Photogate System to Measure Toe Clearance on Stairs

Background: Toe clearance on stairs is typically measured using optoelectronic systems, though these are often constrained to the laboratory, due to their complex setups. Here we measured stair toe clearance through a novel prototype photogate setup and compared this to optoelectronic measurements. Methods: Twelve participants (age 22 ± 3 years) completed 25 stair ascent trials, each on a seven-step staircase. Toe clearance over the fifth step edge was measured using Vicon and the photogates. Twenty-two photogates were created in rows through laser diodes and phototransistors. The height of the lowest photogate broken at step-edge crossing was used to determine photogate toe clearance. A limits of agreement analysis and Pearson's correlation coefficient compared the accuracy, precision and relationship between systems. Results: We found a mean difference of -1.5 mm (accuracy) between the two measurement systems, with upper and lower limits (precision) of 10.7 mm and -13.8 mm, respectively. A strong positive correlation was also found (r = 70, n = 12, p = 0.009) between the systems. Discussion: The results suggest that photogates could be an option for measuring real-world stair toe clearances, where optoelectronic systems are not routinely used. Improvements to the design and measurement factors may help to improve the precision of the photogates.

Overestimation of maximal aerobic speed by the Université de Montréal track test and a 1500-m-time trial in soccer.

Introduction: Maximal aerobic speed (MAS), usually measured by cardiopulmonary exercise testing (CPET) on a treadmill, is gaining popularity in soccer to determine aerobic performance. Several field tests are used to estimate MAS, although, gold standard methods are still not clarified. Therefore, this work aims 1) to compare two different CPET based methods to assess MAS and 2) to investigate the convergent validity of two common field tests to estimate MAS in soccer. Methods: Thirteen trained male soccer players completed an CPET on a treadmill to determine two VO2-kinetic based definitions of MAS (MASPlateau = speed at onset of VO2-plateau = gold standard; MAS30s = first speed of 30-s-interval of VO2max), the Université de Montreal Track Test (UMTT; VUMTT = speed of the last stage), and a 1500-m-time trial (1500-m-TT; V1500m = average speed). MASPlateau, MAS30s, VUMTT, and V1500m were compared using ANOVA. Additionally, limits of agreement analysis (LoA), Pearson’s r, and ICC were calculated between tests. Results: MAS30s, VUMTT, and V1500m significantly overestimated MASPlateau by 0.99 km/h (ES = 1.61; p < 0.01), 1.61 km/h (ES = 2.03; p < 0.01) and 1.68 km/h (ES = 1.77; p < 0.01), respectively, with large LoA (-0.21 ≤ LoA≤3.55), however with large-to-very large correlations (0.65 ≤ r ≤ 0.87; p ≤ 0.02; 0.51 ≤ ICC≤ 0.85; p ≤ 0.03). Discussion: The overestimation and large LoA of MASPlateau by all estimates indicate that 1) a uniform definition of MAS is needed and 2) the UMTT and a 1500-m-TT seem questionable for estimating MAS for trained soccer players on an individual basis, while regression equations might be suitable on a team level. The results of the present work contribute to the clarification of acquisition of MAS in soccer.

Poster 118: The Accuracy of a Smartphone App in Measuring Shoulder Range of Motion

Objectives:Measuring shoulder movements, specifically range of motion (ROM) of the shoulder joint is an important clinical parameter related to glenohumeral disorders and for functional evaluation of the shoulder before and after treatment, which may include surgery. Currently shoulder ROM measurements are performed in an office setting by the provider or alternatively may be performed by a physical therapist, traditionally with the use of a goniometer. The purpose of this study was to determine the accuracy of a smartphone-based digital ROM tool in assessing active shoulder ROM, compared to traditional goniometry measured by a physical therapist in an office setting.Methods:A prospective, non-blinded study was conducted at a single institution (University of St. Augustine, Austin< TX). Thirty (30) eligible and consenting participants with normal shoulder ROM were recruited. Each participant self-assessed their active shoulder ROM using the smartphone App. A physical therapist concurrently measured each participant’s active shoulder ROM using a hand-held goniometer. This concurrent data collection was designed for greater efficiency and minimal bias. Forward flexion (FF), abduction (AB) external rotation (ER), internal rotation (IR) and extension (EX) were measured. Agreement between the smartphone App and goniometric measurements, as well as intra-rater reliability (precision) was assessed using intraclass correlation coefficients (ICC) and Limits of Agreement analysis. Each measurement was performed in duplicate to assess precision. Statistical analysis was performed using R (https://www.r-project.org/)Results:Data were analyzed for 60 shoulders (30 right, 30 left) from 30 participants (mean age was 31.4, 92% female.) The inter-rater reliability between the two methods was excellent for all movements, with ICC ranging from 0.9 to 0.96. For all movements except AB, the mean difference in the measurements between PT and App was less than 1.3 degrees, and the difference was within 6 degrees of the mean differences for 80% of the participants. For AB, the mean difference was 2.08, and the difference was within 15 degrees of the mean difference for 80% of the participants. The intra-rater reliability or precision ranged from good to excellent. For all movements except IR, both PT and App showed excellent intra-rater reliability (ICCs > 0.90). For IR, good intra-rater reliability (ICCs >= 0.75) was observed.Conclusions:These data provide evidence that the smartphone App can be a reliable and valid tool for measuring shoulder ROM. Smartphone Apps enable self-assessment of ROM by patients at the convenience of their home and allow for remote monitoring at zero visit cost to the patient.

Cardiorespiratory fitness in police recruits: Assessing the validity of the 20-meter shuttle run test for recruitment purposes.

Although the 20-meter shuttle run test (20MSR) is frequently used by police organisations for recruitment purposes, to our knowledge no study has yet assessed the accuracy of this test to estimate maximal oxygen consumption (VO2max) in police recruits. The primary objective of this study was to assess the validity of the 20MSR as a predictor of VO2max in police cadets. 49 police cadets completed both an indirect calorimetry VO2max assessment and a 20MSR. Based on their results, estimated VO2max was calculated using an established equation. Furthermore, two models estimating the VO2max was also developed using the final stage completed and sex as independent variables in the first model (model A) as well as the final half-stage completed and sex in the second model (model B). A strong and significant bivariate correlation was found between measured VO2max and the final stage completed at the 20MSR (r = 0.874, p < 0.001). Nevertheless, limits of agreement analysis showed relatively large agreement errors between measured VO2max and estimated VO2max based on the established equation (0.46±6.29 ml·min-1·kg-1), model A (0.00±5.58 ml min-1 kg-1), and model B (0.00±5.48 ml min-1·kg-1). Although the 20MSR can be a useful tool to estimate cardiorespiratory fitness for research and conditioning purposes, the large agreement errors found in this study suggest that results at the 20MSR should be interpreted with caution when making "pass or fail" decisions.

Comparison of segmental lean tissue mass in individuals with spinal cord injury measured by dual energy X-ray absorptiometry and predicted by bioimpedance spectroscopy.

Observational. To compare two methods for predicting segmental (arms, legs, trunk) lean tissue mass (LTM: non-bone fat-free mass) from bioimpedance spectroscopy (BIS) against LTM measured from dual energy X-ray absorptiometry (DXA) in individuals with acute spinal cord injury (SCI). Austin Health Victorian Spinal Cord Service, Victoria, Australia. Fourteen participants (two female), within 8 weeks of traumatic SCI had BIS measured following an overnight fast and within 24 h of DXA scanning. Total body fat-free mass (FFM, body weight minus fat mass) and segmental LTM were predicted from BIS using manufacturer's proprietary software and a previously established SCI-specific prediction method. Appendicular LTM (ALM) was calculated from the sum of the LTM of the arms and legs. Agreement and strength of relationships with DXA for predicted LTM measures using both approaches were assessed using Lin's concordance coefficient and limits of agreementanalysis (LOA). The BIS proprietary method performed better than the SCI-specific prediction method in predicting DXA LTM, demonstrating substantial concordance for total body FFM (rc = 0.80), ALM (rc = 0.78), arm (rc = 0.76) and leg LTM (rc = 0.65) and a smaller bias and LOA for ALM (+0.8 vs. -3.4 kg; LOA -4.9-6.4 vs. -11.9-5.1 kg), arm (+0.02 vs. -0.3 kg; LOA -1.1-1.1 kg vs. -2.2-1.6 kg) and leg (+0.4 vs. -1.4 kg; LOA -2.0-2.8 vs. -5.6-2.8) LTM. BIS can be used to accurately predict total body FFM, segmental LTM and ALM in individuals with acute SCI.

Accuracy of self-reported BMI using objective measurement in high school students.

Self-reported measures for body mass index (BMI) are considered a limitation in research design, especially when they are a primary outcome. Studies have found some populations to be quite accurate when self-reporting BMI; however, there is mixed research on the accuracy of self-reported measurements in adolescents. The aim of this study is to examine the accuracy of self-reported BMI by comparing it with measured BMI in a sample of U.S. adolescents and to understand gender differences. This cross-sectional study collected self-reported height and weight measurements of students from five high schools in four states (Tennessee, South Dakota, Kansas and Florida). Trained researchers took height and weight of students for an objective measurement. BMI was calculated from both sources and categorized (underweight, normal, overweight and obese) using the Centers for Disease Control and Prevention's BMI-for-age percentiles. Participants (n 425; 51⋅0 % female) had a mean age of 16⋅3 years old, and the majority were White (47⋅5 %). Limits of agreement (LOA) analysis revealed that BMI and weight were underreported, and height was overreported in the overall sample, in females, and in males. LOA analysis was fair for BMI in all three groups. Overall agreement in BMI categorisation was considered substantial (Κ 0⋅71, P < 0⋅001). As BMI increased, more height and weight inaccuracies led to decreased accuracy in BMI categorisation, and the specificity of obese participants was low (50⋅0 %). This study's findings suggest that using self-reported values to categorize BMI is more accurate than using continuous BMI values when self-reported measures are used in health-related interventions.

Nix Pro Color Sensor Provides Comparable Color Measurements to Hunterlab Colorimeter

ObjectivesMeat color is the most important quality attribute that influences consumer purchase decisions. Monitoring color to maximize shelf life and consumer acceptability is routinely used in meat science research. The HunterLab MiniScan EZ (HunterLab) colorimeter is the widely used industry standard for objectively measuring meat color. This device can collect tristimulus values of CIE L* (lightness), a* (redness), and b* (yellowness) for color measurements based on the light reflectance from the meat surface. While the HunterLab colorimeter serves as an accurate measure of meat color, it is relatively expensive and bulky. The Nix Pro Color Sensor (Nix) colorimeter is a less expensive and smaller handheld device that can capture the CIE L*, a*, b* values which can be downloaded to a smartphone app. However, limited research has been performed to compare the efficiency of these colorimeters for measuring beef color. Therefore, the objective of this study was to investigate the capabilities of the Nix colorimeter as an additional resource for objective fresh beef color measurements.Materials and MethodsThe longissimus dorsi muscle from one side of A maturity beef carcasses (n = 200) were evaluated using the HunterLab and Nix colorimeters. Carcasses were allowed approximately 1 h to bloom after being ribbed (between the 12th and 13th rib) prior to color measurements. Three (technical replicate) scans were obtained using the HunterLab colorimeter (illuminant A and 10° standard observer) and the mean readings were recorded. A series of independent technical replication (3, 5, 7, and 9) scans were obtained using the Nix colorimeter with illuminant A and 10° standard observer as well. The differences in color measurements between colorimeters were analyzed by using the Bland Altman Limits of Agreement and CORR (correlation) procedure of SAS with α &lt; 0.05.ResultsCorrelation between the HunterLab and Nix was highest for a* value (redness) with 3 scans (r = 0.85, P &lt; 0.01), followed by 7, 5, and 9 scans (r = 0.84, 0.82, and 0.82, respectively; P &lt; 0.01). Additionally, L* values (lightness) were highly correlated for all the scanning series (r = 0.79–0.81; P &lt; 0.01). Similar to a* values, 3 scans with the Nix for b* values (yellowness) demonstrated the best correlation with HunterLab (r = 0.83; P &lt; 0.01), whereas the 5, 7, and 9 scans were still highly correlated (r = 0.79–0.82; P &lt; 0.01). The Bland Altman Limits of Agreement analysis indicated that the mean difference in a* values using 3 scans of both colorimeters was –1.68, whereas it was –0.91 for L* values and 0.25 for b* values. Moreover, the analysis indicated good agreement between the Nix and the Hunterlab colorimeters for all the color parameters.ConclusionThree replicate scans using the Nix was highly correlated with color measurements using the HunterLab colorimeter and can serve as an acceptable additional resource for objectively measuring beef color. The Nix provides an opportunity for a less expensive, more mobile, and multipurpose device. Although these colorimeters are not equivalent, the Nix could be an adequate method for objective beef color measurements and is comparable to the HunterLab.

Reliability of measurement of active trunk movement in wheelchair basketball players.

The study aim was to assess the reliability to active trunk movements measurement in four sitting positions in wheelchair basketball players and to check their trunk movements in these positions. Eighteen volunteer wheelchair basketball athletes, with a minimum of five years’ training experience, were asked to perform the maximum range of active trunk movement in three planes in four sitting positions (in a sports wheelchair with straps, without straps, on a table with feet on the floor, on a table without foot support). The range of movement was measured by the Kinect for Windows V2 sensor twice (with one-week interval). To assess the reliability, different statistical methods were used for each movement: significance of differences between the results (p-value), interclass correlation coefficient (ICC) and minimal detectable change (MDC). The limits of agreement analysis (LOA) were calculated. Differences between trunk movements in four positions were checked by the MANOVA (Wilk’s Lambda and ETA2 were calculated if data were normally distributed). The significance level was set at α < .05. Friedman ANOVA and non-parametric Wilcoxon test with the Bonferroni correction were applied when data were not normally distributed. The significance level after Bonferroni correction was set at α < .013 (α = p/k, where p = .05, k–number of positions = 4). The measurement of active trunk movement in each plane was reliable (p > .05, no differences between the results, “very good”ICC, between .96-.99). In the position with straps, the trunk movement was significantly bigger than in other positions (p < .05), except for the position without straps (p > .05). The Kinect for Windows V2 sensor measured active trunk movement in a reliable manner and it can be recommended as a reliable tool for measuring trunk function. Utilizing straps by wheelchair basketball players increases their trunk movement.

Repeatability and Agreement of Various High-Speed Macrotexture Measurement Devices

Five high-speed macrotexture measurement devices were tested on a variety of asphalt and Portland cement concrete pavement surfaces to evaluate their repeatability and their pairwise agreement. Experiments were run under three speed conditions: highway speed, varying constant speeds, and various acceleration and deceleration profiles. Data were processed and reduced per current industry standards. A novel approach for outlier removal from line laser devices was developed. The pairwise device agreement was evaluated using a limits of agreement analysis. The results demonstrate good repeatability for each of the devices tested. The agreement analysis showed that not all high-speed distance triangulation devices can be used interchangeably for all pavement surfaces. Data acquisition speed was found to be a factor in macrotexture parameter calculation for two of the five devices. The effect of speed was found to be worse on randomly textured surfaces than on transversely textured surfaces. Finally, acceleration was shown to have an effect on the parameters produced by one of the devices, giving further credence to the fact that care should be taken to gather high-quality datasets for the critical pavement characteristic of macrotexture.

Parent and child ratings of child behaviour following mild traumatic brain injury

ABSTRACTBackground: Mild traumatic brain injury (mTBI) in children is most commonly associated with parent-reported child behaviour problems. The extent to which parent and child ratings align is unknown.Objectives: To examine differences in child behaviour and patterns of recovery over the first 12 months following mTBI based on parent and child self-report.Methods: Ninety-nine children (8–15 years) with mTBI and one of their parents completed the Behavioural Assessment Scale for Children – version 2 to assess child hyperactivity, anxiety and depression at baseline, 1, 6 and 12 months post-injury. Differences between ratings from parents and children were evaluated using Bland–Altman limits of agreement analyses. Child recovery over time was examined using mixed models repeated measures analyses.Results: Parent and child ratings for child hyperactivity, anxiety and depression differed significantly at baseline and these differences remained constant at each follow-up. Parents tended to report more child hyperactivity, anxiety and depression. Over time, parents and children reported fewer child hyperactivity and anxiety problems.Conclusions: Parents and children have poor agreement in ratings of child behaviour yet there is general agreement in patterns of recovery in the year following mTBI. Findings show the importance of considering both parent and self-report of child behaviour.

Accuracy and precision of loadsol® insole force-sensors for the quantification of ground reaction force-based biomechanical running parameters

Force plates represent the “gold standard” in measuring running kinetics to predict performance or to identify the sources of running-related injuries. As these measurements are generally limited to laboratory analyses, wireless high-quality sensors for measuring in the field are needed. This work analysed the accuracy and precision of a new wireless insole forcesensor for quantifying running-related kinetic parameters. Vertical ground reaction force (GRF) was simultaneously measured with pit-mounted force plates (1 kHz) and loadsol® sensors (100 Hz) under unshod forefoot and rearfoot running-step conditions. GRF data collections were repeated four times, each separated by 30 min treadmill running, to test influence of extended use. A repeated-measures ANOVA was used to identify differences between measurement devices. Additionally, mean bias and Bland–Altman limits of agreement (LoA) were calculated. We found a significant difference (p < .05) in ground contact time, peak force, and force rate, while there was no difference in parameters impulse, time to peak, and negative force rate. There was no influence of time point of measurement. The mean bias of ground contact time, impulse, peak force, and time to peak ranged between 0.6% and 3.4%, demonstrating high accuracy of loadsol® devices for these parameters. For these same parameters, the LoA analysis showed that 95% of all measurement differences between insole and force plate measurements were less than 12%, demonstrating high precision of the sensors. However, highly dynamic behaviour of GRF, such as force rate, is not yet sufficiently resolved by the insole devices, which is likely explained by the low sampling rate.

Goldmann applanation tonometer versus ocular response analyzer for measuring intraocular pressure after congenital cataract surgery.

To compare intraocular pressure measured using the Goldmann applanation tonometer with that measured using the ocular response analyzer after congenital cataract surgery. This study included 113 eyes of 64 patients who underwent lensectomy and vitrectomy. In all, 36 eyes remained aphakic after surgery. Intraocular lens implantation was performed at the time of surgery in 47 eyes and secondarily in 30 eyes. Corneal hysteresis, corneal resistance factor, and cornea-compensated intraocular pressure were measured. The influences of independent factors on the difference between the cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer were investigated using linear regression analyses. Agreement between the two tonometers was investigated using the Bland and Altman and 95% limits of agreement analysis. Central corneal thickness, corneal hysteresis, and corneal resistance factor were 591.2 ± 53.3 µm, 10.83 ± 2.27 mmHg, and 11.36 ± 2.14 mmHg, respectively. Cornea-compensated intraocular pressure (16.75 ± 4.82 mmHg) was significantly higher than intraocular pressure measured with Goldmann applanation tonometer (14.41 ± 2.27 mmHg, p < 0.001). Central corneal thickness (p = 0.02) and corneal hysteresis (p < 0.001) were identified as the main predictors of difference between cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer readings. A 95% limits of agreement for cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer was between -4.86 and 9.53 mmHg in the entire group. Cornea-compensated intraocular pressure showed the best agreement with intraocular pressure measured with Goldmann applanation tonometer in the primary pseudophakic subgroup as compared to the other subgroups. The Goldmann applanation tonometer and ocular response analyzer cannot be used interchangeably for measuring intraocular pressure after congenital cataract surgery. The difference between the cornea-compensated intraocular pressure and intraocular pressure measured with Goldmann applanation tonometer was primarily affected by central corneal thickness and corneal hysteresis. Among the subgroups, the primary pseudophakic subgroup had the thinnest cornea and the highest corneal hysteresis values and demonstrated the best agreement between the two tonometers.

Bedside quantification of fat-free mass in acute spinal cord injury using bioelectrical impedance analysis: a psychometric study.

Psychometric. Assess the validity of bioimpedance-based measures of fat-free mass (FFM) in acute SCI and of current definitions of obesity based on body mass index (BMI). Australia. All admissions within eight weeks of a new traumatic SCI were screened. 29% were eligible. 71% of those consented. Twenty participants (18 male) completed deuterium dilution (DD) and bioimpedance-based measurements of FFM. Thirteen also underwent dual-energy x-ray absorptiometry. Strength of relationships and agreement were examined using Lin's concordance coefficient and limits of agreement analysis, respectively. Sensitivity and specificity were calculated for three BMI cutoffs for obesity, using percentage fat mass (%FM) obtained from DD as reference. Median time since injury was 41 days (IQR 28-48). FFM from DD and DXA were highly correlated but not identical. Concordance and agreement between DD and seven bioimpedance-based predictive equations are presented. The best-fitting equation demonstrated a low bias (+0.6 kg) and moderate dispersion (±5.2 kg). The cutoff for overweight in able-bodied people (BMI ≥25 kg/m2) provided sensitivity of 43.8%, compared to 25% for the cut-off for obesity (BMI ≥30 kg/m2). FM from bioimpedance gave the highest sensitivity (88.9%). BMI demonstrates poor specificity to classify obesity in acute SCI. Present findings support the utility of bioimpedance-based measurements for estimating FFM in acute SCI for group comparisons. These results are generalizable to traumatic SCI 4-8 weeks post injury; however, the present data reflect a high proportion of high cervical injuries. Further research is indicated to establish validity for assessment of individuals and for longitudinal monitoring. The present study was funded by a grant from the Institute for Safety, Compensation and Recovery Research (ISCRR Project #NGE-E-13-078). M Panisset was supported by an Australian Postgraduate Award. K Desneves was supported by the Austin Medical Research Foundation.

How valid and accurate are measurements of golf impact parameters obtained using commercially available radar and stereoscopic optical launch monitors?

The application of measurement technology in golf is increasing. In particular, measures of golf performance are valuable to coaches, golfers, club-fitters and equipment manufacturers. Commercially available launch monitors, such as the TrackMan Pro IIIe and Foresight GC2+HMT, offer bespoke instantaneous methods to measure such parameters. Uncertainty in the outputs, however, is not well established nor independently verified. This study aimed to determine the degree of agreement between parameters from two launch monitors with measurements taken using a benchmark system. A total of 240 shots were collected with a driver, 7-iron and utility wedge. Shots were simultaneously tracked by each system and outputs compared using Limits of Agreement analysis. In addition, two reference grades were defined based on different levels of agreement; research and coaching grade. Agreement between the launch monitors and the benchmark system was noticeably stronger for ball parameters with greater variability in clubhead parameters. Furthermore, for both launch monitors, the strength of agreement for several parameters varied between clubs. The majority of ball parameters from both launch monitors fell within the research reference grade, but caution is needed for the use of clubhead parameters within a research environment. For coaches and clubfitters, the results suggest the launch monitor parameters are largely of sufficient quality.

Variability in measurement of Pithomyces chartarum spore counts

AIMSTo examine the agreement between spore counts of Pithomyces chartarum measured in a single aliquot of wash water with counts from multiple aliquots from the same 60 g pasture sample, and between spore counts measured in an individual 60 g pasture sample with counts from three 60 g pasture samples selected from the same 200 g paddock sample.MATERIALS AND METHODSFour Waikato dairy farms were visited once weekly from early January to late May 2013. One paddock, with 40 sampling sites, was selected per farm. At each visit, ∼200 g of pasture was collected per site. Spore counting was undertaken using a standard method, except that three separate 60 g pasture samples per 200 g paddock sample was counted; and for each 60 g pasture sample, spores were counted in 10 aliquots of wash water. The relationship between the results of a single aliquot and 6–10 aliquots of wash water from the same 60 g grass sample were assessed by calculating 95% prediction intervals. Limits of agreement analysis was used to assess the agreement between counts from one, two or three aliquots per 60 g pasture sample compared with 10 aliquots, and between counts from one and three 60 g pasture samples from the same 200 g paddock sample.RESULTSComparing spore counts from individual aliquots with multiple aliquots resulted in large prediction intervals and 95% limits of agreement, which increased with increasing spore count. For an individual aliquot count of 2 spores, the 95% prediction interval for the count from 10 aliquots was 3–49 spores, and for an individual count of 10 spores the 95% prediction interval was 28–222 spores. Increasing the number of aliquots counted improved agreement. For a total count of 10 spores measured in 10 aliquots, the 95% limits of agreement, based on a single aliquot, were 2–50 spores, and for three aliquots were 5–20 spores. The agreement in spore counts measured in one compared with three 60 g pasture samples was moderate and also decreased with increasing spore count; the 95% limits of agreement were 4–14.5 for a mean spore count of 10.CONCLUSIONS AND CLINICAL RELEVANCEMeasuring the spore counts of three aliquots of wash water per 60 g grass sample improved repeatability, and should be used as the standard technique, particularly when determining whether to start or finish facial eczema control programmes.

Abstract P4-02-12: Tomosynthesis as an alternative to magnetic resonance imaging (MRI) in assessing invasive lobular carcinoma (ILC) multifocality

Abstract Introduction Invasive lobular carcinoma is associated with a higher rate of multifocality than other types of breast cancer. Breast MRI is commonly performed in patients diagnosed with ILC to assess for additional disease prior to formulating a management plan. MRI may be both time consuming and costly and can delay treatment. Recently tomosynthesis has become an adjunct in the assessment and diagnosis of breast cancer. It is readily available at the time of mammography therefore providing information at the one stop clinic. We proposed that it may be possible to use tomosynthesis to assess for multifocality in ILC in place of MRI. Method A retrospective review of all cases of ILC diagnosed at a single regional screening unit over a 3-year period was performed. Patients having surgery as primary treatment were included. Ninety-eight patients were identified, 29 having both MRI and tomosynthesis in addition to mammography and ultrasound scan as part of their assessment. Histological data was used to compare the two imaging modalities. Bland and Altman limits of agreement analysis was performed to assess the difference between MRI and tomosynthsis in these patients. An acceptable difference (the difference in values that is unlikely to influence management) was set at 5mm. Results The Bland and Altman limits of agreement analysis produced three graphs to demonstrate the difference between MRI and Tomosynthesis, MRI and histology size and Tomosynthesis and histology size. It shows that the average difference between MRI and Tomosynthesis = 3.8mm (95% limits of agreement: –19.2 to 26.8mm). The percentage of 'acceptable' differences (defined as ≤ 5mm) was 72% for MRI and tomosynthesis suggesting that there is good concordance between the two. Tumours measuring &amp;gt;30mm on MRI are perceived as smaller under Tomosynthesis. The analysis demonstrated the average difference between MRI and histology values is -1.3 mm (95% limits of agreement = – 33.2 to 30.6)compared with an average difference between Tomosynthesis and histology of -5.1 mm (95% limits of agreement = – 27.7 to 17.5). The percentage of 'acceptable' differences (defined as ≤ 5 mm) was 48% for both MRI vs histology and Tomosynthesis vs histology, suggesting that neither is superior when compared to final histology results. In three patients there were multifocal cancers identified on histology that had not been detected by any imaging modality. In one patient there were MRI images that suggested a second tumour which was not present on histological examination. The same is true for a patient diagnosed with a second cancer identified by tomosynthesis but not found in the specimen. A third patient was diagnosed with a second tumour by both image modalities but again not present on histology. In one case tomosysnthesis detected a true second cancer that was not identified on MRI. Conclusion We believe this preliminary study suggests that tomosynthesis is equivocal to MRI for assessing multifocality in ILC. If confirmed the implications would be a shorter investigative pathway with reduced delays and costs. A larger mutli-centre trial to assess the use of tomosynthesis to replace MRI in patients with ILC is warranted. Citation Format: Holt RE, Topps A, Lim YY, Gandhi A. Tomosynthesis as an alternative to magnetic resonance imaging (MRI) in assessing invasive lobular carcinoma (ILC) multifocality [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-02-12.

Concurrent validity and cross-validation of the Brunel Lifestyle Physical Activity Questionnaire.

Given the profoundly negative impact of inactivity on public health, it is important to have valid and reliable measures of lifestyle physical activity (LPA). The Brunel Lifestyle Physical Activity Questionnaire (BLPAQ) was designed to measure planned physical activity (PPA) and unplanned physical activity (UPA). The objective of the present study was to assess the criterion-related validity of the BLPAQ. A correlational design was employed. A sample of British leisure centre users (N=356; age range 18-69 y: mean age 26.5±10.4 y) completed the BLPAQ and two reference measures: the Baecke Questionnaire of Habitual Physical Activity (BQHPA) and the Godin's Leisure-Time Exercise Questionnaire (GLTEQ). MANOVA was used to test for gender differences in LPA. Each measure was also cross-validated using a split-sample approach and the limits of agreement (LoA) method. With the exception of the Moderate and Vigorous dimensions of the GLTEQ in the case of UPA, the remaining scores of the reference instruments were correlated with both PPA and UPA factors (p<0.05). A significant difference in levels of UPA was found between women and men (p=0.039). Furthermore, multiple linear regression analyses demonstrated that the BLPAQ subscales could be predicted by the criterion measures. The LoA analyses demonstrated satisfactory agreement between BLPAQ subscales and those of the BQHPA and GLTEQ. The BLPAQ is a criterion- and cross-validated measure of PPA and UPA that can be used to assess the efficacy of LPA interventions by researchers and practitioners.