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Dylan Kobsar, Chad Olson, Raman Paranjape and John M. Barden

A single triaxial accelerometer has the ability to collect a large amount of continuous gait data to quantitatively assess the control of gait. Unfortunately, there is limited information on the validity of gait variability and fractal dynamics obtained from this device. The purpose of this study was to test the concurrent validity of the variability and fractal dynamic measures of gait provided by a triaxial accelerometer during a continuous 10 minute walk in older adults. Forty-one healthy older adults were fitted with a single triaxial accelerometer at the waist, as well as a criterion footswitch device before completing a ten minute overground walk. The concurrent validity of six outcome measures was examined using intraclass correlation coefficients (ICC) and 95% limits of agreement. All six dependent variables measured by the accelerometer displayed excellent agreement with the footswitch device. Mean parameters displayed the highest validity, followed by measures of variability and fractal dynamics in stride times and measures of variability and fractal dynamics in step times. These findings suggest that an accelerometer is a valid and unique device that has the potential to provide clinicians with valid quantitative data for assessing their clients’ gait.

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Abderrehmane Rahmani, Georges Dalleau, Fabrice Viale, Christophe A. Hautier and Jean-René Lacour

This study determined the validity and reliability of the kinematic device developed by Bosco et al. (1995) by comparing its peak force, peak velocity, and peak power measurements to data obtained simultaneously with a force platform placed under the subject’s feet. Fifteen international downhill skiers performed maximal half-squats on a guided barbell with masses of 60–180 kg. The coefficient of correlation (r) between the two peak forces (r = 0.85–0.95, p < .001), the two peak velocities (r = 0.74–0.91, p < .001), and the two peak powers (r = 0.85–0.95, p < .001) indicated that the kinematic device measurements were valid. The trial-to-trial reliability of half-squat exercises measured by the kinematic device gave an intraclass coefficient of correlation (CR) of: 0.70-0.90 for peak force, 0.62-0.90 for peak velocity, and 0.57-0.91 for peak power. There were no statistical differences between the two trials. The standard error of the means (SEM%) was less than 5% for peak force, less than 4% for peak velocity, and less than 7% for power. The high CR and low SEM% indicate that the kinematic device is reliable. The movement recorded by the kinematic device accurately described the action measured by the force platform.

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Saurabh Sharma and M. Ejaz Hussain

can be established by its measurement properties, such as validity and reliability. A vast majority of people in India and abroad (544 million) speak and understand Hindi well, as it is a national language. 10 The SPADI original and its translations (Greek, Spanish, Thai, Tamil, etc.) have undergone

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Kai-Yu Ho, Brenda Benson Deaver, Tyrel Nelson and Catherine Turner

that typically has a lower camera sampling frequency than other computer-based 2D motion analysis. As individuals with ACLR may exhibit more knee valgus 2 and there is limited data regarding the reliability/validity of using MAA to measure knee movement, it is necessary for validation of using a MAA

Open access

Robert W. Cox, Rodrigo E. Martinez, Russell T. Baker and Lindsay Warren

measuring ankle plantar flexion. The purpose of this study was 2-fold: (1) to assess the validity of the Clinometer Smartphone Application™ for use in the ankle (ie, plantar flexion) and (2) to assess the validity of the inclinometer procedures used to measure ankle plantar flexion. Methods A blinded

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Joonkoo Yun and Dale A. Ulrich

The purposes of this tutorial are threefold: (a) to clarify the meaning of measurement validity, (b) to provide appropriate validation procedures for use by researchers in adapted physical activity, and (c) to raise the awareness of the limitations of the traditional views on measurement validity. Several validation procedures are described with specific examples from adapted physical activity research based on traditional approaches of providing validity evidence. Conceptual and empirical limitations of the traditional validity framework are discussed. We recommend that several categories of validity evidence should be reported in research studies. We encourage practicing the unified concept of measurement validity (Messick, 1993, 1995) in adapted physical activity research and practice.

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Roel De Ridder, Julien Lebleu, Tine Willems, Cedric De Blaiser, Christine Detrembleur and Philip Roosen

needed to obtain the gait parameters. This aspect is really important to facilitate technology adoption. 7 However, before using them for clinical interpretation, we need to define their reliability and validity. The latter can be done by comparing the spatiotemporal parameters of gait obtained from the

Open access

Richard A. Brindle, David Ebaugh and Clare E. Milner

is unclear whether the peak force during a hip abductor eccentric strength test occurs before or after the leg begins to lower. For measures to be useful in clinical decision making, they need to be both reliable and valid. Substantial intrarater reliability of a hip abductor eccentric strength test

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Ricky Watari, Blayne Hettinga, Sean Osis and Reed Ferber

The purpose of this study was to validate measures of vertical oscillation (VO) and ground contact time (GCT) derived from a commercially-available, torso-mounted accelerometer compared with single marker kinematics and kinetic ground reaction force (GRF) data. Twenty-two semi-elite runners ran on an instrumented treadmill while GRF data (1000 Hz) and three-dimensional kinematics (200 Hz) were collected for 60 s across 5 different running speeds ranging from 2.7 to 3.9 m/s. Measurement agreement was assessed by Bland-Altman plots with 95% limits of agreement and by concordance correlation coefficient (CCC). The accelerometer had excellent CCC agreement (> 0.97) with marker kinematics, but only moderate agreement, and overestimated measures between 16.27 mm to 17.56 mm compared with GRF VO measures. The GCT measures from the accelerometer had very good CCC agreement with GRF data, with less than 6 ms of mean bias at higher speeds. These results indicate a torsomounted accelerometer provides valid and accurate measures of torso-segment VO, but both a marker placed on the torso and the accelerometer yield systematic overestimations of center of mass VO. Measures of GCT from the accelerometer are valid when compared with GRF data, particularly at faster running speeds.

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Loren Z.F. Chiu, Brian K. Schilling, Andrew C. Fry and Lawrence W. Weiss

Displacement-based measurement systems are becoming increasingly popular for assessment of force expression variables during resistance exercise. Typically a linear position transducer (LPT) is attached to the barbell to measure displacement and a double differentiation technique is used to determine acceleration. Force is calculated as the product of mass and acceleration. Despite the apparent utility of these devices, validity data are scarce. To determine whether LPT can accurately estimate vertical ground reaction forces, two men and four women with moderate to extensive resistance training experience performed concentric-only (CJS) and rebound (RJS) jump squats, two sessions of each type in random order. CJS or RJS were performed with 30%, 50%, and 70% one-repetition maximum parallel back squat 5 minutes following a warm-up and again after a 10-min rest. Displacement was measured via LPT and acceleration was calculated using the finite-difference technique. Force was estimated from the weight of the lifter-barbell system and propulsion force from the lifter-barbell system. Vertical ground reaction force was directly measured with a single-component force platform. Two-way random average-measure intraclass correlations (ICC) were used to assess the reliability of obtained measures and compare the measurements obtained via each method. High reliability (ICC > 0.70) was found for all CJS variables across the load-spectrum. RJS variables also had high ICC except for time parameters for early force production. All variables were significantly (p < 0.01) related between LPT and force platform methods with no indication of systematic bias. The LPT appears to be a valid method of assessing force under these experimental conditions.