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Understanding the Nature of Measurement Error When Estimating Energy Expenditure and Physical Activity via Physical Activity Recall

David R. Paul, Ryan McGrath, Chantal A. Vella, Matthew Kramer, David J. Baer, and Alanna J. Moshfegh

-living physical activity patterns. 13 Although DLW and accelerometers have been used extensively, these techniques pose some disadvantages, such as cost, participant burden, within-participant measurement error, and short time frame of measurement. 10 , 12 , 14 , 15 Physical activity questionnaires (PAQs) have

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Error-Correction Processing in Timing Lights for Measuring Sprint Performance: Does It Work?

Stefan Altmann, Steffen Ringhof, Benedikt Becker, Alexander Woll, and Rainer Neumann

. This causes measurement errors (MEs), as researchers and coaches usually seek to capture the athlete’s torso during sprint testing. 2 To improve measurement accuracy, systems employing error correction processing (ECP) algorithms—termed “postprocessing timing” in the previous research 1 —have been

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Modeling Errors in Physical Activity Recall Data

Sarah M. Nusser, Nicholas K. Beyler, Gregory J. Welk, Alicia L. Carriquiry, Wayne A. Fuller, and Benjamin M.N. King

Background:

Physical activity recall instruments provide an inexpensive method of collecting physical activity patterns on a sample of individuals, but they are subject to systematic and random measurement error. Statistical models can be used to estimate measurement error in activity recalls and provide more accurate estimates of usual activity parameters for a population.

Methods:

We develop a measurement error model for a short-term activity recall that describes the relationship between the recall and an individual’s usual activity over a long period of time. The model includes terms for systematic and random measurement errors. To estimate model parameters, the design should include replicate observations of a concurrent activity recall and an objective monitor measurement on a subsample of respondents.

Results:

We illustrate the approach with preliminary data from the Iowa Physical Activity Measurement Study. In this dataset, recalls tend to overestimate actual activity, and measurement errors greatly increase the variance of recalls relative to the person-to-person variation in usual activity. Statistical adjustments are used to remove bias and extraneous variation in estimating the usual activity distribution.

Conclusions:

Modeling measurement error in recall data can be used to provide more accurate estimates of long-term activity behavior.

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Reliability of 2-Dimensional Video Assessment of Frontal-Plane Dynamic Knee Valgus During Common Athletic Screening Tasks

Allan Munro, Lee Herrington, and Michael Carolan

Context:

Two-dimensional (2D) video analysis of frontal-plane dynamic knee valgus during common athletic screening tasks has been purported to identify individuals who may be at high risk of suffering knee injuries such as anterior cruciate ligament tear or patellofemoral pain syndrome. Although the validity of 2D video analysis has been studied, the associated reliability and measurement error have not.

Objective:

To assess the reliability and associated measurement error of a 2D video analysis of lower limb dynamic valgus.

Design:

Reliability study.

Participants:

20 recreationally active university students (10 women age 21.5 ± 2.3 y, height 170.1 ± 6.1 cm, weight 66.2 ± 10.2 kg, and 10 men age 22.6 ± 3.1 y, height 177.9 ± 6.0 cm, weight 75.8 ± 7.9 kg).

Main Outcome Measurement:

Within-day and between-days reliability and measurement-error values of 2D frontal-plane projection angle (FPPA) during common screening tasks.

Interventions:

Participants performed single-leg squat and drop jump and single-leg landings from a standard 28-cm step with standard 2D digital video camera assessment.

Results:

Women demonstrated significantly higher FPPA in all tests except the left single-leg squat. Within-day ICCs showed good reliability and ranged from .59 to .88, and between-days ICCs were good to excellent, ranging from .72 to .91. Standard error of measurement and smallest detectable difference values ranged from 2.72° to 3.01° and 7.54° to 8.93°, respectively.

Conclusions:

2D FPPA has previously been shown to be valid and has now also been shown to be a reliable measure of lower extremity dynamic knee valgus. Using the measurement error values presented along with previously published normative data, clinicians can now make informed judgments about individual performance and changes in performance resulting from interventions.

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Recommendations to Improve the Accuracy of Estimates of Physical Activity Derived From Self Report

Barbara E. Ainsworth, Carl J. Caspersen, Charles E. Matthews, Louise C. Mâsse, Tom Baranowski, and Weimo Zhu

Context:

Assessment of physical activity using self-report has the potential for measurement error that can lead to incorrect inferences about physical activity behaviors and bias study results.

Objective:

To provide recommendations to improve the accuracy of physical activity derived from self report.

Process:

We provide an overview of presentations and a compilation of perspectives shared by the authors of this paper and workgroup members.

Findings:

We identified a conceptual framework for reducing errors using physical activity self-report questionnaires. The framework identifies 6 steps to reduce error: 1) identifying the need to measure physical activity, 2) selecting an instrument, 3) collecting data, 4) analyzing data, 5) developing a summary score, and 6) interpreting data. Underlying the first 4 steps are behavioral parameters of type, intensity, frequency, and duration of physical activities performed, activity domains, and the location where activities are performed. We identified ways to reduce measurement error at each step and made recommendations for practitioners, researchers, and organizational units to reduce error in questionnaire assessment of physical activity.

Conclusions:

Self-report measures of physical activity have a prominent role in research and practice settings. Measurement error may be reduced by applying the framework discussed in this paper.

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Harmonizing Monitor- and Report-Based Estimates of Physical Activity Through Calibration

Gregory J. Welk

measurement error in physical activity. The studies use different approaches and target different populations but provide examples of how relatively simple calibration procedures can be used to promote harmonization of physical activity outcomes. It is important to acknowledge that the examples and

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Critical Review of Measurement Practices in the Study of Automatic Associations of Sedentary Behavior, Physical Activity, and Exercise

Zachary Zenko and Panteleimon Ekkekakis

susceptibility to random measurement error (i.e., reliability, in some cases, below commonly acceptable standards, such as less than 50% true variance); (b) typically low, or even near-zero, intercorrelations with each other; (c) generally low correlations with measures of explicit attitudes and behavior; (d

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Measurement Error in Studies of the Built Environment: Validating Commercial Data as Objective Measures of Neighborhood Destinations

Paula Louise Hooper, Nicholas Middleton, Matthew Knuiman, and Billie Giles-Corti

Background:

There is increasing focus on the influence of neighborhood destinations on a variety of health behaviors. Commercial databases, integrated with Geographic Information Systems (GIS), are popular sources of destination information for public health researchers. However, the suitability and accuracy of these data for public health research purposes has been generally unexplored.

Methods:

This study validated the presence and number of a broad range of destination types listed within an Australian-based commercial database (Yellow Pages), thought to be important for encouraging health behaviors, against those identified via field audit. The study was conducted in and around 5 housing developments within the RESIDential Environments project across metropolitan Perth, Western Australia.

Results:

Overall agreement of the count of destinations listed within the Yellow Pages ranged from 0.29–0.76, depending on the study area, the timing of the data extract and the geocoding methods used. Results also indicated considerable variation between different extracts from the same commercial dataset, and appreciable over- and under-counting of different destination types compared with field audit findings.

Conclusions:

The choice of database and extraction time and methods, have important implications in the quantification of neighborhood destination mix and robustness of associations with public health behaviors.

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Criterion and Construct Validity of an Isometric Midthigh-Pull Dynamometer for Assessing Whole-Body Strength in Professional Rugby League Players

Nick Dobbin, Richard Hunwicks, Ben Jones, Kevin Till, Jamie Highton, and Craig Twist

Purpose: To examine the criterion and construct validity of an isometric midthigh-pull dynamometer to assess whole-body strength in professional rugby league players. Methods: Fifty-six male rugby league players (33 senior and 23 youth players) performed 4 isometric midthigh-pull efforts (ie, 2 on the dynamometer and 2 on the force platform) in a randomized and counterbalanced order. Results: Isometric peak force was underestimated (P < .05) using the dynamometer compared with the force platform (95% LoA: −213.5 ± 342.6 N). Linear regression showed that peak force derived from the dynamometer explained 85% (adjusted R 2 = .85, SEE = 173 N) of the variance in the dependent variable, with the following prediction equation derived: predicted peak force = [1.046 × dynamometer peak force] + 117.594. Cross-validation revealed a nonsignificant bias (P > .05) between the predicted and peak force from the force platform and an adjusted R 2 (79.6%) that represented shrinkage of 0.4% relative to the cross-validation model (80%). Peak force was greater for the senior than the youth professionals using the dynamometer (2261.2 ± 222 cf 1725.1 ± 298.0 N, respectively; P < .05). Conclusion: The isometric midthigh pull assessed using a dynamometer underestimates criterion peak force but is capable of distinguishing muscle-function characteristics between professional rugby league players of different standards.

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Variability in Submaximal Self-Paced Exercise Bouts of Different Intensity and Duration

Ciaran O’Grady, Louis Passfield, and James G. Hopker

Purpose: Rating of perceived exertion (RPE) as a training-intensity prescription has been extensively used by athletes and coaches. However, individual variability in the physiological response to exercise prescribed using RPE has not been investigated. Methods: Twenty well-trained competitive cyclists (male = 18, female = 2, maximum oxygen consumption = 55.07 [11.06] mL·kg−1·min−1) completed 3 exercise trials each consisting of 9 randomized self-paced exercise bouts of either 1, 4, or 8 minutes at RPEs of 9, 13, and 17. Within-athlete variability (WAV) and between-athletes variability (BAV) in power and physiological responses were calculated using the coefficient of variation. Total variability was calculated as the ratio of WAV to BAV. Results: Increased RPEs were associated with higher power, heart rate, work, volume of expired oxygen (VO2), volume of expired carbon dioxide (VCO2), minute ventilation (V E), deoxyhemoglobin (ΔHHb) (P < .001), and lower tissue saturation index (ΔTSI%) and ΔO2Hb (oxyhaemoglobin; P < .001). At an RPE of 9, shorter durations resulted in lower VO2 (P < .05) and decreased ΔTSI%, and the ΔHHb increased as the duration increased (P < .05). At an RPE of 13, shorter durations resulted in lower VO2, V E, and percentage of maximum oxygen consumption (P < .001), as well as higher power, heart rate, ΔHHb (P < .001), and ΔTSI% (P < .05). At an RPE of 17, power (P < .001) and ΔTSI% (P < .05) increased as duration decreased. As intensity and duration increased, WAV and BAV in power, work, heart rate, VO2, VCO2, and VE decreased, and WAV and BAV in near-infrared spectroscopy increased. Conclusions: Self-paced intensity prescriptions of high effort and long duration result in the greatest consistency on both a within- and between-athletes basis.