Background: Activity trackers can potentially stimulate users to increase their physical activity behavior. The aim of this study was to examine the reliability and validity of ten consumer activity trackers for measuring step count in both laboratory and free-living conditions.Method: Healthy adult volunteers (n = 33) walked twice on a treadmill (4.8 km/h) for 30 min while wearing ten different activity trackers (i.e. Lumoback, Fitbit Flex, Jawbone Up, Nike+ Fuelband SE, Misfit Shine, Withings Pulse, Fitbit Zip, Omron HJ-203, Yamax Digiwalker SW-200 and Moves mobile application). In free-living conditions, 56 volunteers wore the same activity trackers for one working day. Test-retest reliability was analyzed with the Intraclass Correlation Coefficient (ICC).Validity was evaluated by comparing each tracker with the gold standard (Optogait system for laboratory and ActivPAL for free-living conditions), using paired samples t-tests, mean absolute percentage errors, correlations and Bland-Altman plots.Results: Test-retest analysis revealed high reliability for most trackers except for the Omron (ICC .14), Moves app (ICC .37) and Nike+ Fuelband (ICC .53). The mean absolute percentage errors of the trackers in laboratory and free-living conditions respectively, were: Lumoback (−0.2, −0.4), Fibit Flex (−5.7, 3.7), Jawbone Up (−1.0, 1.4), Nike+ Fuelband (−18, −24), Misfit Shine (0.2, 1.1), Withings Pulse (−0.5, −7.9), Fitbit Zip (−0.3, 1.2), Omron (2.5, −0.4), Digiwalker (−1.2, −5.9), and Moves app (9.6, −37.6). Bland-Altman plots demonstrated that the limits of agreement varied from 46 steps (Fitbit Zip) to 2422 steps (Nike+ Fuelband) in the laboratory condition, and 866 steps (Fitbit Zip) to 5150 steps (Moves app) in the free-living condition.Conclusion: The reliability and validity of most trackers for measuring step count is good. The Fitbit Zip is the most valid whereas the reliability and validity of the Nike+ Fuelband is low.
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Rationale: Although ultrasound has been reported as valid and reliable tool to assess muscle size in older adults1, little is known about intra-rater reliability (intra-RR) and inter-rater reliability (inter-RR) of BodyMetrix in specific to assess small muscles. Therefore, in this study we aimed to assess intra-RR and inter-RR of biceps muscle size (thickness) in elderly.Methods: Thirty elderly (81.9±6.3 years; 80% women; BMI 26.7±5.3 kg/m2) living in a Portuguese nursing home/residence were included. To assess procedural intra-RR and inter-RR, ultrasound measurements were performed by two raters (R1, R2, beginners level) by BodyMetrixTM BX2000, on the biceps of the right arm. R1 repeated the ultrasound measurement once. To assess measurement intra-RR and inter-RR, images were analyzed by three raters (R1, R2, and R3 [experienced level]). Agreement was analyzed by intraclass correlation coefficient. ICC values of 0.50 to 0.75 were considered moderate to good, and >0.75 as good to excellent. Statistical significance was set at p<0.05.Results: Mean muscle thickness at 1st and 2nd measurement (R1) was 23.4±4.5 and 23.7±3.8 mm, respectively. For procedural intra-RR, ICC was 0.630. For inter-RR of image 1 (R1) vs. image 2 (R2), ICC was 0.622. For inter-RR of image 2 (R2) vs. image 3 (R1) ICC was 0.534. For measurement reliability, ICCs for intra-RR of R1 and R2 were 0.865 and 0.766, respectively. ICCs for inter-RR of R1 vs. R2, R2 vs. R3, and R1 vs. R3 were 0.865, 0.800, and 0.815, respectively. All ICCs were statistically significant (p≤0.001).Conclusion: The results of our study indicate that procedural reliability of biceps muscle size as assessed by BodyMetrix in elderly is moderate to good, and measurement reliability is good to excellent. Increasing the level of experience may further improve procedural reliability.
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Literature highlights the need for research on changes in lumbar movement patterns, as potential mechanisms underlying the persistence of low-back pain. Variability and local dynamic stability are frequently used to characterize movement patterns. In view of a lack of information on reliability of these measures, we determined their within- and between-session reliability in repeated seated reaching. Thirty-six participants (21 healthy, 15 LBP) executed three trials of repeated seated reaching on two days. An optical motion capture system recorded positions of cluster markers, located on the spinous processes of S1 and T8. Movement patterns were characterized by the spatial variability (meanSD) of the lumbar Euler angles: flexion–extension, lateral bending, axial rotation, temporal variability (CyclSD) and local dynamic stability (LDE). Reliability was evaluated using intraclass correlation coefficients (ICC), coefficients of variation (CV) and Bland-Altman plots. Sufficient reliability was defined as an ICC ≥ 0.5 and a CV < 20%. To determine the effect of number of repetitions on reliability, analyses were performed for the first 10, 20, 30, and 40 repetitions of each time series. MeanSD, CyclSD, and the LDE had moderate within-session reliability; meanSD: ICC = 0.60–0.73 (CV = 14–17%); CyclSD: ICC = 0.68 (CV = 17%); LDE: ICC = 0.62 (CV = 5%). Between-session reliability was somewhat lower; meanSD: ICC = 0.44–0.73 (CV = 17–19%); CyclSD: ICC = 0.45–0.56 (CV = 19–22%); LDE: ICC = 0.25–0.54 (CV = 5–6%). MeanSD, CyclSD and the LDE are sufficiently reliable to assess lumbar movement patterns in single-session experiments, and at best sufficiently reliable in multi-session experiments. Within-session, a plateau in reliability appears to be reached at 40 repetitions for meanSD (flexion–extension), meanSD (axial-rotation) and CyclSD.
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This study explores how journalists in highspeed newsrooms gather information, how gathering activities are temporally structured and how reliability manifests itself in information-gathering activities.
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This paper outlines an investigation into the updating of fatigue reliability through inspection data by means of structural correlation. The proposed methodology is based on the random nature of fatigue fracture growth and the probability of damage detection and introduces a direct link between predicted crack size and inspection results. A distinct focus is applied on opportunities for utilizing inspection information for the updating of both inspected and uninspected (or uninspectable) locations.
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The aim of this study is to examine the inter-device reliability of an activity tracker on three different levels of aggregation: minute, hour and day.
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Objective: The Tilburg Frailty Instrument (TFI) is an instrument for assessing frailty in community-dwelling older people. Since its development, many studies have been carried out examining the psychometric properties. The aim of this study was to provide a review of the main findings with regard to the reliability and validity of the TFI. Methods: We conducted a literature search in the PubMed and CINAHL databases on May 30, 2020. An inclusion criterion was the use of the entire TFI, part B, referring to the 15 components. No restrictions were placed on language or year of publication. Results: In total, 27 studies reported about the psychometric properties of the TFI. By far, most of the studies (n = 25) were focused on community-dwelling older people. Many studies showed that the internal consistency and test–retest reliability are good, which also applies for the criterion and construct validity. In many studies, adverse outcomes of interest were disability, increased health-care utilization, lower quality of life, and mortality. Regarding disability, studies predominantly show results that are excellent, with an area under the curve (AUC) >0.80. In addition, the TFI showed good associations with lower quality of life and the findings concerning mortality were at least acceptable. However, the association of the TFI with some indicators of health-care utilization can be indicated as poor (eg, visits to a general practitioner, hospitalization). Conclusion: Since population aging is occurring all over the world, it is important that the TFI is available and well known that it is a user-friendly instrument for assessing frailty and its psychometric properties being qualified as good. The findings of this assessment can support health-care professionals in selecting interventions to reduce frailty and delay its adverse outcomes, such as disability and lower quality of life.
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Activity trackers like Fitbit are used for self-tracking of physical activity by an increasing number of individuals. Comparing physical activity scores with peers can contribute to the desired behavioural change. However, for meaningful social comparison a high inter-device reliability is paramount. This study aimed to determine the inter-device reliability of Fitbit activity trackers in measuring steps. Ten activity trackers (Fitbit Ultra) were worn by a single person (male,46 years) during eight consecutive days. Inter-device reliability was assessed on three different levels of aggregation (minutes, hours, days) with various methods, including intra-class correlation coefficient (ICC), Bland-Altman plots, limits of agreement (LOA) and Mixed Model Analysis. Results showed that the inter-device reliability of the Fitbit in measuring steps is good at all levels of aggregation (minutes, hours, days), but especially when steps were measuredper day. This implies that individuals can reliably compare their daily physical activity scores with peers.
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Background To gain insight into the role of plantar intrinsic foot muscles in fall-related gait parameters in older adults, it is fundamental to assess foot muscles separately. Ultrasonography is considered a promising instrument to quantify the strength capacity of individual muscles by assessing their morphology. The main goal of this study was to investigate the intra-assessor reliability and measurement error for ultrasound measures for the morphology of selected foot muscles and the plantar fascia in older adults using a tablet-based device. The secondary aim was to compare the measurement error between older and younger adults and between two different ultrasound machines. Methods Ultrasound images of selected foot muscles and the plantar fascia were collected in younger and older adults by a single operator, intensively trained in scanning the foot muscles, on two occasions, 1–8 days apart, using a tablet-based and a mainframe system. The intra-assessor reliability and standard error of measurement for the cross-sectional area and/or thickness were assessed by analysis of variance. The error variance was statistically compared across age groups and machines. Results Eighteen physically active older adults (mean age 73.8 (SD: 4.9) years) and ten younger adults (mean age 21.9 (SD: 1.8) years) participated in the study. In older adults, the standard error of measurement ranged from 2.8 to 11.9%. The ICC ranged from 0.57 to 0.97, but was excellent in most cases. The error variance for six morphology measures was statistically smaller in younger adults, but was small in older adults as well. When different error variances were observed across machines, overall, the tablet-based device showed superior repeatability. Conclusions This intra-assessor reliability study showed that a tablet-based ultrasound machine can be reliably used to assess the morphology of selected foot muscles in older adults, with the exception of plantar fascia thickness. Although the measurement errors were sometimes smaller in younger adults, they seem adequate in older adults to detect group mean hypertrophy as a response to training. A tablet-based ultrasound device seems to be a reliable alternative to a mainframe system. This advocates its use when foot muscle morphology in older adults is of interest.
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Research shows that power training offers more potential for improving muscle power and physical performance in older adults than strength training. However, the measurement properties of the tests used to assess the effects of power training are unclear. Objective: to review the reliability, validity, and responsiveness of tests used to measure the effects of power training in older adults.
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