Typical Error Of Measurement Research Articles

Baseline Cardiac Autonomic Predictors Of Blood Pressure Response To Standardized Endurance Training In Hypertensive Women

Although international recommendations corroborate the antihypertensive effects of regular endurance training (ET), interindividual responses are widely heterogeneous, differing between responders (RE) and non-responders (NR). Previous studies have shown the decrease in the activity of the autonomic nervous system (ANS) is involved in the ET-induced reduction of blood pressure (BP). However, it is not yet known whether this mechanism is related to the variability of BP response. PURPOSE: Associate baseline ANS variables with interindividual BP responses in hypertensive women undergoing ET. METHODS: Forty-four women performed 12 weeks of ET on cycle ergometer (50 min.day-1, 3 days.week-1 at 60-70% heart rate reserve). Pre and post ET 20 min beat-to-beat BP waveforms were recorded by finger photoplethysmography and ANS was assessed by heart rate (HR) variability (HRV) recorded from HR monitor and analyzed in the time and frequency domain. Participants were identified as RE by a magnitude of reduction in systolic BP (SBP) greater than the typical error (TE) of measurement (1xTE=7.4 mmHg) and participants with changes less or increase greater than 1xTE as NR. Associations between baseline HRV variables and changes (Δ) in BP after ET were analyzed using Pearson’s correlation coefficient and multiple linear regression. Student's t-test to comparisons RE vs. NR. Receiver operator characteristic (ROC) curve to identify predictors cut-off values for RE and NR discrimination. RESULTS: Ten individuals were considered RE (Δ=-15.6±7.6 mmHg) and 34 NR (Δ=4.3±7.9 mmHg). SBP changes were correlated with: SDNN (r=0.395; p=0.008), RMSSD (r=0.384; p=0.010), LF (r=0.318; p=0.036) and HF (r=0.348; p=0.02). SDNN was able to predict 15.6% of variance in SBP changes (β=0.39, p=0.008). Compared to RE, NR demonstrated greater SDNN (29.6±21.4 vs. 16.1±4.9, p=0.09), RMSSD (32.7±27.3 vs. 17.4±8.6, p=0.013) and LF (591±1380 vs. 110±71, p=0.001) and HF (668±1340 vs. 154±164, p=0.012). For SDNN, a cut-off value of 18.7 discriminated RE and NR with good accuracy (AUC=0.81, sensitivity=80%, specificity=76%, p=0.03). CONCLUSION: Baseline cardiac autonomic function can predict interindividual SBP responses to ET. Predictors cut-off values could be used to determine whether patients with hypertension are likely to benefit from ET.

Validity and Reliability of a New Test of Change of Direction in Fencing Athletes.

The aim of this study was to validate a new test of change of direction (COD) for fencer athletes and to establish its relationship with selected measures of physical fitness. Thirty-nine fencer athletes participated to this study (age: 20.8 ± 3.0 years). They performed the new specific fencing COD test (SFCODT) on two separate occasions to establish its reliability. In addition, assessment of COD, jumping ability (i.e., squat jump, countermovement jump, five jump test), sprint time (e.g., 5-m, 10-m and 20-m), isokinetic concentric and eccentric quadriceps, and hamstring force tests were assessed. To establish SFCODT’s construct validity, two subgroups were identified based on their international and national fencing results: High- vs. low-ranked fencer athletes. Reliability, validity, and sensitivity of the SFCODT were established from the intraclass correlation coefficient (ICC), typical error of measurement (TEM), smallest worthwhile change (SWC), and receiving operator characteristic (ROC) analysis. The ICC of SFCODT was excellent at >0.95, and the TEM was < 5%. Based on the usefulness analysis, the ability to detect small performance changes can be rated as “good” in fencer athletes (SWC > TEM). SFCODT was very largely associated with the COD test and moderate to very large associated with jumping ability, sprint time, and isokinetic strength. High-ranked fencer athletes were better than low-ranked fencer athletes on SFCODT (p < 0.01). The area under the ROC curve was 0.76. In conclusion, the SFCODT is a highly reliable, valid, and sensitive test. Therefore, the SFCODT could be used by practitioners to evaluate specific CODS performance in fencer athletes.

Joint position error after neck protraction-retraction movements in healthy office workers: a cross-sectional study.

Since the upper cervical spine (UCS) has been regarded to be distinct from the lower cervical spine (LCS), joint position error (JPE) needs to be tested separately for both regions. The purpose of this study was to investigate the JPE after cervical protraction/retraction movements, involving opposite movements of extension and flexion for the UCS and LCS. These movements are frequently performed during office work. Cervical JPEs were tracked in thirty healthy office workers while performing four tests of cervical pro-retraction movements with variations in vision and movement direction, and assessed using the Kinect head tracker (Microsoft Corp), placed in front of each participant. The JPE was expressed in constant (CE), absolute (AE) and variable errors (VE). Multilevel linear models evaluated main and interaction effects of vision, movement direction, cervical region and sex. Slightly larger JPEs have been found in the UCS. Vision showed no effect on any outcome variable. No effect exceeded typical measurement errors reported for the Kinect head tracker. This study showed, that JPEs after pro-retraction movements of the head and neck may differ for UCS and LCS. The differences were small and not beyond measurement error reported for the Kinect.

Machine Learning vs. Physics-Based Modeling for Real-Time Irrigation Management

Real-time monitoring of soil matric potential has now become a common practice for precision irrigation management. Some crops, such as cranberries, are susceptible to both water and anoxic stresses. Excessive variations in soil matric potential in the root zone may reduce plant transpiration, due to either saturated or dry soil conditions, thereby reducing productivity. A timely supply of the right amount of water is, therefore, fundamental for efficient irrigation management. In this paper, we compare the capabilities of a machine learning-based model and a physics-based model to predict soil matric potential in the root zone. The machine learning model is a random forest algorithm, while the physics-based model is a two-dimensional solver of Richards equation (HYDRUS 2D). After training and calibration on a dataset collected in a cranberry field located in Quebec (Canada), the performance of the two models is evaluated for 30 different time frames of 72-h soil matric potential forecasts. The results highlight that both models can accurately forecast the soil matric potential in the root zone. The machine learning-based model can achieve better performance when compared to the physics-based model, but forecasting accuracy decreases rapidly toward the end of the 72-h lead time, while the error for the Richards equation-based model does not increase with time and remain small compared to the typical measurement error.

Reliability and Minimal Detectable Change of the Styku 3D Body Scanner

ABSTRACT The objective of this study was to assess the reliability and minimal detectable change (MDC) of the Styku S100 3-dimensional (3D) scanner. Thirty-three participants completed two visits separated by 1–3 days; at each visit, two scans were performed. Intra-class correlation co-efficients (ICCs) and MDC values based on a 90% confidence interval (MDC90) were calculated. For body fat percentage, within-day ICC and MDC90 values were 0.997 and 1.1%, respectively, and these values changed to 0.989 and 2% when using single scans on separate days. For 21 circumference sites, 10 of the within-day ICCs were ≥ 0.99 and 20 of the MDC90 values were < 2 cm. Comparatively, five ICCs were ≥ 0.99 and 15 MDC90 values were < 2 cm when using single scans on separate days. In conclusion, between-visit differences of 1-2% for body fat percentage and 1–2 cm for most circumference values are needed to exceed typical measurement error.

Reliability of gastrointestinal barrier integrity and microbial translocation biomarkers at rest and following exertional heat stress.

PurposeExertional heat stress adversely distrupts (GI) barrier integrity and, through subsequent microbial translocation (MT), negativly impacts health. Despite widespread application, the temporal reliability of popular GI barrier integity and MT biomarkers is poorly characterised.MethodFourteen males completed two 80‐min exertional heat stress tests (EHST) separated by 7–14 days. Venous blood was drawn pre, immediately‐ and 1‐hr post both EHSTs. GI barrier integrity was assessed using the serum Dual‐Sugar Absorption Test (DSAT), Intestinal Fatty‐Acid‐Binding Protein (I‐FABP) and Claudin‐3 (CLDN‐3). MT was assessed using plasma Lipopolysaccharide Binding Protein (LBP), total 16S bacterial DNA and Bacteroides DNA.ResultsNo GI barrier integrity or MT biomarker, except absolute Bacteroides DNA, displayed systematic trial order bias (p ≥ .05). I‐FABP (trial 1 = Δ 0.834 ± 0.445 ng ml−1; trial 2 = Δ 0.776 ± 0.489 ng ml−1) and CLDN‐3 (trial 1 = Δ 0.317 ± 0.586 ng ml−1; trial 2 = Δ 0.371 ± 0.508 ng ml−1) were increased post‐EHST (p ≤ .01). All MT biomarkers were unchanged post‐EHST. Coefficient of variation and typical error of measurement post‐EHST were: 11.5% and 0.004 (ratio) for the DSAT 90‐min postprobe ingestion; 12.2% and 0.004 (ratio) at 150‐min postprobe ingestion; 12.1% and 0.376 ng ml−1 for I‐FABP; 4.9% and 0.342 ng ml−1 for CLDN‐3; 9.2% and 0.420 µg ml−1 for LBP; 9.5% and 0.15 pg µl−1 for total 16S DNA; and 54.7% and 0.032 for Bacteroides/total 16S DNA ratio.ConclusionEach GI barrier integrity and MT translocation biomarker, except Bacteroides/total 16S ratio, had acceptable reliability at rest and postexertional heat stress.

Variability of regional quadriceps echo intensity in active young men with and without subcutaneous fat correction.

Quantifying echo intensity (EI), a proposed measure of muscle quality, is becoming increasingly popular. Additionally, much attention has been paid to regional differences in other ultrasonically evaluated measures of muscle morphology and architecture. However, the variability of regional (proximal, middle, distal) EI of the vastus lateralis, rectus femoris, and lateral and anterior vastus intermedius has yet to be determined. Twenty participants (40 limbs), were evaluated on 3 occasions, separated by 7 days. Intersession variability of EI with and without subcutaneous fat correction was quantified. Furthermore, the interchangeability of corrected EI across regions was evaluated. Variability of regional quadriceps EI was substantially lower with subcutaneous fat correction (intraclass correlation coefficient (ICC) = 0.81-0.98, coefficient of variation (CV) = 4.5%-16.8%, typical error of measure (TEM) = 0.13-0.49) versus raw values (ICC = 0.69-0.98, CV = 7.7%-42.7%, TEM = 0.14-0.68), especially when examining the vastus intermedius (ICC = 0.81-0.95, CV = 7.1%-16.8%, TEM = 0.23-0.49 vs. ICC = 0.69-0.92, CV = 22.9%-42.7%, TEM = 0.31-0.68). With the exception of the rectus femoris and vastus intermedius (p ≥ 0.143, effect size (ES) ≤ 0.18), corrected EI was greater for proximal and distal regions when compared with the midpoint (p ≤ 0.038, ES = 0.38-0.82). Researchers and practitioners should utilize subcutaneous fat thickness correction to confidently evaluate EI at all regions of the quadriceps. Regional EI cannot be used interchangeably for the vastus muscles, likely because of an increase in fibrous content towards the myotendinous junctions. Novelty Regional quadriceps echo intensity was reliable with and without correction for subcutaneous fat thickness. Intersession variability of regional quadriceps echo intensity was substantially improved following subcutaneous fat correction. Quadriceps echo intensity increased towards myotendinous junctions in the vastus muscles.

Variability of concentric angle-specific isokinetic torque and impulse assessments of the knee extensors

Objective: Length-tension relationships are widely reported in research, rehabilitation and performance settings; however, several isometric contractions at numerous angles are needed to understand these muscular outputs. Perhaps a more efficient way to determine torque-angle characteristics is via isokinetic dynamometry; however, little is known about the variability of isokinetic measurements besides peak torque and optimal angle. This paper examines the variability of angle-specific isokinetic torque and impulse measures. Approach: Three sessions of concentric (60°·s−1) knee extensions were performed by both limbs of 32 participants. Assessments were repeated on three occasions, separated by 5–8 d. To quantify variability, the standardized typical error of measurement (TEM) was doubled and thresholds of 0.2–0.6 (small), 0.6–1.2 (moderate), 1.2–2.0 (large), 2.0–4.0 (very large) and >4.0 (extremely large) were applied. Additionally, variability was deemed large when the intraclass correlation coefficient (ICC) was <0.67 and coefficient of variation (CV) > 10%; moderate when ICC > 0.67 or CV < 10% (but not both); and small when both ICC > 0.67 and CV < 10%. Main results: Isokinetic torque and angular impulse show small to medium variability (ICC = 0.75–0.96, CV = 6.4%–15.3%, TEM = 0.25–0.53) across all but the longest (100°) and shortest (10°) muscle lengths evaluated. However, moderate to large variability was found for the optimal angle (ICC = 0.58–0.64, CV = 7.3%–8%, TEM = 0.76–0.86), and torque and impulse at the beginning and end of the range of motion (ICC = 0.57–0.85, CV = 11–42.9%, TEM = 0.40–0.89). Intersession variability of isokinetic torque and impulse were small to moderate at medium (90–20°) joint angles. Significance: Researchers and practitioners can examine the muscle torque-angle relationship and activity-specific torque outputs within these ranges, without resorting to more strenuous and time-consuming isometric evaluations.

Lower Extremity Strength Profile in Ambulatory Adults with Cerebral Palsy and Spastic Diplegia: Norm Values and Reliability for Hand-Held Dynamometry.

The handheld dynamometer (HHD) is a well-accepted tool to assess muscle strength in children with cerebral palsy (CP), though reliability is not tested for adults with CP and no normative data are available. To present strength levels of lower extremity muscle groups and test-retest reliability of HHD measurements in ambulatory adults with CP and typically developed (TD) adults. Case-control study. Human motion laboratory. Fifty-four adults with CP (28 men; Gross Motor Function Classification System [GMFCS] level I/II/III: n = 25/20/9; mean age (SD) = 38 (7) year) and 62 TD adults (31 men; mean age (SD) = 37 (5) year). Not applicable. Maximum strength levels were obtained during voluntary isometric contraction of eight lower extremity muscle groups in adults with CP and spastic diplegia and TD adults using HHD. Three trials were performed per muscle group per leg. Test-retest reliability was investigated by calculating intraclass correlation coefficient (ICC), coefficient of variation (CV), and typical error of measurement (TEM). Force and torque levels were significantly lower in all eight lower extremity muscle groups. Excellent ICC levels were observed in TD, GMFCS I and II (>0.90), and moderate to excellent (0.82-0.97) in GMFCS III. CV and TEM were higher in adults with CP compared to TD adults, especially in GMFCS III. No subtypes other than adults with CP and spastic diplegia were included. Lower extremity strength profiles demonstrate substantial muscle weakness in ambulatory adults with CP compared to TD adults, which highlights the importance to address muscle weakness in this population group. These strength profiles may serve as norm values for clinicians and researchers. In addition, HHD showed to be reliable to assess lower extremity strength in adults with CP.

Certified reduced basis method in geosciences

One of the biggest challenges in Computational Geosciences is finding ways of efficiently simulating high-dimensional problems. In this paper, we demonstrate how the RB method can be gainfully exploited to solve problems in the Geosciences. The reduced basis method constructs low-dimensional approximations to (high-dimensional) solutions of parametrized partial differential equations. In contrast to other widely used geoscientific reduction techniques, the reduced basis method reduces the Galerkin approximation space, and not the physical space and is consequently much less restrictive. Another advantage of the method is that for the problems considered in this paper, the method provides a bound to the error in the reduced order approximation, thus permitting an objective evaluation of the approximation quality. Using a geothermal conduction problem, we demonstrate that depending on the model, we obtain a maximum speed-up of three orders of magnitude with an approximation error that is very small in comparison with typical measurement errors. This significant reduction of the cost of the forward simulation allows performing uncertainty quantification, inversions, and parameter studies for larger and more complex models than currently possible.

Ecological Validity and Reliability of an Age-Adapted Endurance Field Test in Young Male Soccer Players.

Castagna, C, Krustrup, P, D'Ottavio, S, Pollastro, C, Bernardini, A, and Araújo Póvoas, SC. Ecological validity and reliability of an age-adapted endurance field test in young male soccer players. J Strength Cond Res 33(12): 3400-3405, 2019-The purpose of this study was to examine the reliability and the association with relevant match activities (ecological validity) of an age-adapted field test for intermittent high-intensity endurance known as Yo-Yo intermittent recovery level 1 children's test (YYIR1C) in young male soccer players. Twenty-eight young male outfield soccer players (age 11.1 ± 0.9 years, height 142 ± 4.4 cm, body mass 37.0 ± 5.9 kg) with at least 2 years of experience in soccer competitions were tested twice using YYIR1C and an age-adapted competitive small-sided game (i.e., 9v9), 7 days apart in a random order. The YYIR1C performance showed an excellent relative (intraclass correlation coefficient = 0.94) and a good absolute reliability (typical error of measurement as percentage of the coefficient of variation = 5.1%). Very large and significant associations were found between YYIR1C performance and match high-intensity activity (r = 0.53). Large correlations were found between YYIR1C and match sprinting (r = 0.42) and high-intensity metabolic power (r = 0.46) distances. Match total distance was largely associated with YYIR1C (r = 0.30). The results of this study showed that YYIR1C may be considered a valid and reliable field test for assessing intermittent high-intensity endurance in young male soccer players. Because of the relevance of aerobic fitness in youth soccer, future studies testing the sensitiveness of YYIR1C are necessary.

Reliability and Validity of a New Eccentric Hamstring Strength Measurement Device

ObjectiveTo investigate the reliability and establish validity of a new eccentric hamstring strength measurement device. DesignA randomized double-crossover trial with intraclass correlation coefficients to analyze the outcomes. Participants attended 4 sessions, 7 days apart. They were randomly allocated into 2 groups. Session 1 was a familiarization session for all participants on the new eccentric hamstring strength measurement device and isokinetic dynamometer. The following 3 sessions were used to measure knee flexor (hamstring) eccentric strength on the isokinetic dynamometer and a further test-retest measurement using the new eccentric hamstring strength measurement device. SettingInstitute of Technology Carlow, third level educational institution. ParticipantsMale intercollegiate field-sport players completed the trial (N=19). Participants were 21±2 years, weighed 78.6±4.6 kg, and were 179.6±6.4 cm in height. InterventionsN/A. Main Outcome MeasuresPeak torque (Nm) was recorded by the isokinetic device, and peak force (N) was recorded by the new eccentric hamstring strength measurement device and used to test for significant interdevice correlations (>0.7). Intraclass correlation coefficients were calculated using the peak force recorded from 2 separate trials of the new eccentric hamstring strength measurement device. ResultsHigh test-retest reliability was observed from the new eccentric hamstring strength measurement device, intraclass coefficient (ICC)=.910 (confidence interval [CI], .76-.96) and .914 (CI, .78-.96) for left and right peak forces, respectively. Typical error of measurement between trials was calculated to be 14.65 and 17.29N for the left and right limbs, respectively. Minimum detectable change (MDC) was also calculated to be 40.62N (MDC%=14.68%) and 39.63N (MDC%=13.31%) for left and right limbs, respectively. The interdevice correlation showed good validity, ICC=.823 (CI, .58-.93) and .840 (CI, .58-.93) for left and right peak torque/forces, respectively. Conclusion(s)The new eccentric hamstring strength measurement device is a reliable and valid device that provides an objective measurement of eccentric hamstring strength that may be used in combination with a comprehensive assessment to inform rehabilitation and management.

Development of a Mobile Phone App for Measuring Striking Response Time in Combat Sports: Cross-Sectional Validation Study.

BackgroundTReaction is a mobile app developed to determine strike response time at low cost and with easy application in combat sports. However, the validity and accuracy of the response time obtained by the TReaction app has not yet been evaluated.ObjectiveThis study aimed to test the validity and reliability of the TReaction app in measuring motor response time in combat sports.MethodsA total of two athletes performed 59 strikes to assess the response time upon visual stimulus using the TReaction app simultaneously with a high-speed camera. Accuracy of the measure was verified using a computer simulator programmed to discharge visual stimuli and obtain the response time. Pearson correlation, Student t test for dependent samples, and the Bland-Altman analysis were performed. Accuracy was verified using the intraclass correlation coefficient. Effect size (g) and the typical error of measurement (TEM) were calculated. The significance level was set at P<.05.ResultsNo significant difference (P=.56) was found between both systems. The methods presented a very strong correlation (r=0.993). The magnitude of differences was trivial (g<0.25), and TEM was 1.4%. These findings indicate a high accuracy between the computer screen and the mobile app measures to determine the beginning of the task and the response time.ConclusionsOur findings suggest that the TReaction app is a valid tool to evaluate the response time in combat sports athletes.

Variability of Multiangle Isometric Force-Time Characteristics in Trained Men.

Oranchuk, DJ, Storey, AG, Nelson, AR, Neville, JG, and Cronin, JB. Variability of multiangle isometric force-time characteristics in trained men. J Strength Cond Res 36(1): 284-288, 2022-Measurements of isometric force, rate of force development (RFD), and impulse are widely reported. However, little is known about the variability and reliability of these measurements at multiple angles, over repeated testing occasions in a homogenous, resistance-trained population. Thus, understanding the intersession variability of multiangle isometric force-time characteristics provides the purpose of this article. Three sessions of isometric knee extensions at 40°, 70°, and 100° of flexion were performed by 26 subjects across 51 limbs. All assessments were repeated on 3 occasions separated by 5-8 days. Variability was qualified by doubling the typical error of measurement (TEM), with thresholds of 0.2-0.6 (small), 0.6-1.2 (moderate), 1.2-2.0 (large), 2.0-4.0 (very large), and >4.0 (extremely large). In addition, variability was deemed large when the intraclass correlation coefficient (ICC) was <0.67 and coefficient of variation (CV) >10%; moderate when ICC >0.67 or CV <10% (but not both); and small when both ICC >0.67 and CV <10%. Small to moderate between-session variability (ICC = 0.68-0.95, CV = 5.2-18.7%, TEM = 0.24-0.49) was associated with isometric peak force, regardless of angle. Moderate to large variability was seen in early-stage (0-50 ms) RFD and impulse (ICC = 0.60-0.80, CV = 22.4-63.1%, TEM = 0.62-0.74). Impulse and RFD at 0-100 ms, 0-200 ms, and 100-200 ms were moderately variable (ICC = 0.71-0.89, CV = 11.8-42.1%, TEM = 0.38-0.60) at all joint angles. Isometric peak force and late-stage isometric RFD and impulse measurements were found to have low intersession variability regardless of joint angle. However, practitioners need to exercise caution when making inferences about early-stage RFD and impulse measures due to moderate-large variability.

Computationally efficient modelling of hip replacement separation due to small mismatches in component centres of rotation

Patient imaging and explant analysis has shown evidence of edge loading of hard-on-hard hip replacements in vivo. Experimental hip simulator testing under edge loading conditions has produced increased, clinically-relevant, wear rates for hard-on-hard bearings when compared to concentric conditions. Such testing, however, is time consuming and costly. A quick running computational edge loading model (Python Edge Loading (PyEL) - quasi-static, rigid, frictionless), capable of considering realistic bearing geometries, was developed. The aim of this study was to produce predictions of separation within the typical experimental measurement error of ∼0.5 mm. The model was verified and validated against comparable finite element (FE) models (including inertia and friction) and pre-existing experimental test data for 56 cases, covering a variety of simulated cup orientations, positions, tissue tensions, and loading environments. The PyEL model agreed well with both the more complex computational modelling and experimental results. From comparison with the FE models, the assumption of no inertia had little effect on the maximum separation prediction. With high contact force cases, the assumption of no friction had a larger effect (up to ∼5% error). The PyEL model was able to predict the experimental maximum separations within ∼0.3 mm. It could therefore be used to optimise an experimental test plan and efficiently investigate a much wider range of scenarios and variables. It could also help explain trends and damage modes seen in experimental testing through identifying the contact locations on the liner that are not easily measured experimentally.

Variability of Regional Quadriceps Architecture in Trained Men Assessed by B-Mode and Extended-Field-of-View Ultrasonography.

Regional muscle-architecture measures are reported widely; however, little is known about the variability of these measurements in the rectus femoris, vastus lateralis, and anterior and lateral vastus intermedius. The aim of this study was to quantify this variability. Regional muscle thickness, pennation angle (PA), and calculated and extended-field-of-view-derived fascicle length (FL) were quantified in 26 participants using ultrasonography across 51 limbs on 3 occasions. To quantify variability, the typical error of measurement (TEM) was multiplied by 2, and thresholds of 0.2-0.6 (small), 0.6-1.2 (moderate), 1.2-2.0 (large), 2.0-4.0 (very large), and >4.0 (extremely large) were applied. In addition, variability was deemed large when the intraclass correlation coefficient (ICC) was <.67 and coefficient of variation (CV) >10%, moderate when ICC > .67 or CV < 10% (but not both), and small when both ICC > .67 and CV < 10%. Muscle thickness of all muscles and regions had low to moderate variability (ICC = .88-.98, CV = 2.4-9.3%, TEM = 0.15-0.47). PA of the proximal and distal vastus lateralis had low variability (ICC = .85-.96, CV = 3.8-8%) and moderate to large TEM (TEM = 0.42-0.83). PA of the rectus femoris was found to have moderate to very large variability (ICC = .38-.74, CV = 11.4-18.5%, TEM = 0.61-1.29) regardless of region. Extended-field-of-view-derived FL (ICC = .57-.94, CV = 4.1-11.5%, TEM = 0.26-0.88) was superior to calculated FL (ICC = .37-.84, CV = 7.4-17.9%, TEM = 0.44-1.33). Variability of muscle thickness was low in all quadriceps muscles and regions. Only rectus femoris PA and FL measurements were highly variable. The extended-field-of-view technique should be used to assess FL where possible. Inferences based on rectus femoris architecture should be interpreted with caution.

A Method for Calibrating a Digital Image Correlation System for Full-Field Strain Measurements during Large Deformations

Numerous variables can introduce errors into the measurement chain of a digital image correlation (DIC) system. These can be grouped into two categories: measurement quality and the correlation principle. Although previous studies have attempted to investigate each error source in isolation, there are still no comprehensive, standardized procedures for calibrating DIC systems for full-field strain measurement. The aim of this study, therefore, was to develop an applied experimental method that would enable a DIC practitioner to perform a traceable full-field measurement calibration to evaluate the accuracy of a particular system setup in a real-world environment related to their specific application. A sequence of Speckle Pattern Boards (SPB) that included artificial deformations of the speckle pattern were created, allowing for the calibration of in-plane deformations. Multiple deformation stages (from 10% to 50%) were created and measured using the GOM ARAMIS system; the results were analysed and statistical techniques were used to determine the accuracy. The measured strain was found to be slightly over-estimated (nominally by 0.02%), with a typical measurement error range of 0.34% strain at a 95% confidence interval. Location within the measurement volume did not have a significant effect on error distributions. It was concluded that the methods developed could be used to calibrate a DIC system in-situ for full-field measurements of large deformations. The approach could also be used to benchmark different DIC systems against each other or allow operators to better understand the influence of particular measurement variables on the measurement accuracy.

Interindividual variability and individual responses to exercise training in adolescents with obesity.

This study investigated the impact of exercise training on interindividual variability and response rates in body composition and cardiometabolic outcomes in adolescents with obesity. Postpubertal males and females (n = 143) were randomly assigned to 6 months of a diet-only control or aerobic, resistance, or combined exercise training. Body composition indices were percentages of body fat mass and lean body mass and waist circumference. Biomarkers of cardiometabolic health were systolic blood pressure and plasma fasting glucose, triglycerides, and high-density lipoprotein cholesterol. Interindividual variability was examined by comparing the standard deviation of individual responses (SDIR) to a smallest robust change (SRC). The typical error of measurement was used to classify responses. SDIR exceeded the SRC for percent body fat mass in all exercise groups (SRC = 1.04%; aerobic SDIR = 1.50%; resistance SDIR = 1.22%; combined SDIR = 2.29%), percent lean body mass (SRC = 1.38%; SDIR = 3.2%,), systolic blood pressure (SRC = 2.06 mm Hg; SDIR = 4.92 mm Hg) in the resistance group, and waist circumference (SRC = 2.33 cm; SDIR = 4.09 cm), and fasting glucose (SRC = 0.08 mmol/L; SDIR = 0.28 mmol/L) in the combined group. However, half of the reported variables (11/21) did not have a positive SDIR. Importantly, adverse response rates were significantly lower in all 3 exercise groups compared with control for body composition. Although exercise had a small influence on interindividual variability for indices of body composition, the rate of adverse responses did not increase for any outcome. Novelty Interindividual variability and individual responses to exercise training have not been investigated in adolescents with obesity. Six months of exercise training does not increase interindividual variability in adolescents with obesity. Exercise created a positive, uniform shift in responses.

The Fatigue and Fitness Test for Teams (FFITT): A practical option for monitoring athletes in a team as individuals

We developed the Fatigue and Fitness Test for Teams (FFITT) to address the challenges of monitoring players in a team simultaneously. The test, which takes 8 min for the entire team, incorporates subjective measures of well-being (RTT-Q), and objective measures of the autonomic system (HRR60s) and neuromuscular function (SLJ). The aim of this study was to present the rationale for the FFITT as a novel athlete monitoring protocol and to measure the reliability of each component of the test. The internal consistency of the RTT-Q questions ranged from α = 0.69–0.92. All questions had an α > 0.83, with one exception of question ‘Rate the well-being/stress your school/university/work is causing you to feel’ which had an α = 0.69. The reliability of the HRR60s and SLJ was high (R = 0.92, and 0.91 respectively). The absolute typical error of measurement (TEM) of the SLJ was 8 cm and HRR60s was 3 beats. When expressed relatively the CVTEM of HRR60s was 8.4% and SLJ was 3.0%. Based on the TEM the HRR60s and SLJ could detect medium and large changes in fatigue and fitness. In absolute terms this equates to more than 5 bpm (HRR60s) and more than 13 cm (SLJ). The FFITT has the potential to satisfy both scientific principles and the coach’s demands of a practical monitoring protocol for frequent use in a team.

Whole-body dual-energy X-ray absorptiometry demonstrates better reliability than segmental body composition analysis in college-aged students.

Dual-energy X-ray absorptiometry (DXA) is rapidly becoming more accessible and popular as a technique to monitor body composition. The reliability of DXA has been examined extensively using a number of different methodological approaches. This study sets up to investigate the accuracy of measuring the parameters of body composition (BC) by means of the whole-body and the segmental DXA method analysis with the typical error of measurement (TEM) that allows for expressing the error in the units of measure. The research was implemented in a group of 63 participants, all of whom were university students. Thirty-eight males (22.6±2.9 years, average body mass 77.5±8.4 kg) and 25 females (21.4±2.0 years, average body mass 58.6±7.2 kg) were recruited. The measured parameters included body mass (BM), fat-free mass (FFM), body fat (BF), bone mineral content (BMC), bone mineral density (BMD). For the whole-body analysis, the determined TEM was: BM at the level of 0.12 kg in females and 0.29 kg in males; BF 0.25kg and 0.44% females, 0.52 kg and 0.66% males; FFM 0.24 kg females and 0.42 kg males; BMC 0.02 kg females and males; BMD 0.01g/cm2 females and males. The TEM values in the segmental analysis were: BF within the range of 0.04–0.28 kg and 0.68–1.20% in females, 0.10–0.36 kg and 0.72–1.94% in males; FFM 0.08–0.41 kg females and 0.17–0.86 males, BMC 0.00–0.02 kg females and 0.01–0.02 kg males in relation to the body segment (upper limb, trunk, lower limb). The BMD value was at the level of 0.01–0.02g/cm2. The study results showed high reliability in measuring body composition parameters using the DXA method. The whole-body analysis showed a higher accuracy of measurement than the segmental. Only the changes that are greater than the TEM, or the upper bound (95%) of the confidence interval of the measurement can be considered demonstrable when interpreting repeated measurements.