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Thomas Dos’Santos, Paul A. Jones, Jonathan Kelly, John J. McMahon, Paul Comfort and Christopher Thomas

athletes. 19 Variations in IMTP kinetics reported across the literature may be partially explained by methodological differences. 2 , 8 , 13 , 16 , 18 Early research used a sampling frequency of 500 Hz and 600 Hz, 8 , 13 whereas more recent investigations have implemented a sampling frequency of 1000 Hz

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Senia Smoot Reinert, Allison L. Kinney, Kurt Jackson, Wiebke Diestelkamp and Kimberly Bigelow

movement quality because they only give the maximum displacement of COP. However, newer nonlinear analysis methods, such as sample entropy, allow us to describe movement quality. Sample entropy quantifies the underlying regularity of human movements and has been used to study phenomena such as the effect

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Megan S. Patterson and Patricia Goodson

compulsive exercise scores? Based on the tripartite model and previous literature, the investigators expect relationships with peers and family members to significantly impact compulsive exercise scores in the sample. They also hypothesize that having greater body dissatisfaction and exercising more

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Daniel J. Madigan, Thomas Curran, Joachim Stoeber, Andrew P. Hill, Martin M. Smith and Louis Passfield

 al., 2011 ). Notably, Gotwals et al. ( 2010 ) also found coach pressure to predict perfectionistic strivings and perfectionistic concerns in a sample of late-adolescent athletes. Although current findings are suggestive of a link between coach pressure and athlete perfectionism, several issues remain

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Joseph Hamill, Graham E. Caldwell and Timothy R. Derrick

Researchers must be cognizant of the frequency content of analog signals that they are collecting. Knowing the frequency content allows the researcher to determine the minimum sampling frequency of the data (Nyquist critical frequency), ensuring that the digital data will have all of the frequency characteristics of the original signal. The Nyquist critical frequency is 2 times greater than the highest frequency in the signal. When sampled at a rate above the Nyquist, the digital data will contain all of the frequency characteristics of the original signal but may not present a correct time-series representation of the signal. In this paper, an algorithm known as Shannon's Sampling Theorem is presented that correctly reconstructs the time-series profile of any signal sampled above the Nyquist critical frequency. This method is superior to polynomial or spline interpolation techniques in that it can reconstruct peak values found in the original signal but missing from the sampled data time-series.

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Rand Wilcox, Travis J. Peterson and Jill L. McNitt-Gray

, meaning the probability of detecting a true difference. A positive feature of standard methods for comparing means is that they control the type I error probability reasonably well when observations are sampled from populations of individuals that have identical means, variances, skewness, and so forth

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Thomas Dos’Santos, Paul A. Jones, Jonathan Kelly, John J. McMahon, Paul Comfort and Christopher Thomas

Purpose:

Skeletal-muscle function can be evaluated using force–times curves generated via the isometric midthigh pull (IMTP). Various sampling frequencies (500–1000 Hz) have been used for IMTP assessments; however, no research has investigated the influence of sampling frequency on IMTP kinetics. Therefore, the purpose of this study was to investigate the influence of sampling frequency on kinetic variables during the IMTP, including peak force, time-specific force values (100, 150, and 200 ms), and rate of force development (RFD) at 3 time bands (0–100, 0–150, 0–200 ms).

Methods:

Academy rugby league players (n = 30, age 17.5 ± 1.1 y, height 1.80 ± 0.06 m, mass 85.4 ± 10.3 kg) performed 3 IMTP trials on a force platform sampling at 2000 Hz, which was subsequently down-sampled to 1500, 1000, and 500 Hz for analysis.

Results:

Intraclass correlation coefficients (ICC) and coefficients of variation (CV) demonstrated high within-session reliability for all force and RFD variables across all sampling frequencies (ICC ≥ .80, CV ≤ 10.1%). Repeated-measures analysis of variance revealed no significant differences (P > .05, Cohen d ≤ 0.009) in kinetic variables between sampling frequencies. Overall, high reliability was observed across all sampling frequencies for all kinetic variables, with no significant differences (P > .05) for each kinetic variable across sampling frequencies.

Conclusions:

Practitioners and scientists may consider sampling as low as 500 Hz when measuring peak force, time-specific force values, and RFD at predetermined time bands during the IMTP for accurate and reliable data.

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Laura D. Ellingson, Paul R. Hibbing, Gregory J. Welk, Dana Dailey, Barbara A. Rakel, Leslie J. Crofford, Kathleen A. Sluka and Laura A. Frey-Law

data collection. Procedures At the initial visit, participants were fitted with a wrist-worn tri-axial accelerometer (ActiGraph GT3X+, dynamic range ±6 g, sampling rate 30 Hz) to wear on their non-dominant wrist 24 hrs/day for a week (including sleep and showering). Participants were instructed to

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Steve Hansen, Spencer J. Hayes and Simon J. Bennett

The current study examined the effect of interocular delay in a manual aiming task that required accurate end-point placement, but not precise control of a grip aperture. Participants aimed in binocular, monocular, or alternating monocular vision conditions. For the latter, 25ms monocular samples were provided to alternate eyes without delay (0ms), or a delay of 25 or 50ms. The interocular delay resulted in a longer movement time, caused by a longer time-to-peak and time-after-peak velocity, and a reduction in peak velocity. We suggest that the change in kinematics reflect a strategic response to preserve terminal aiming accuracy and variability when faced with an informational perturbation. These findings indicate that the response to the interocular delay between alternating monocular samples depends on the task-specific information used to control that behavior.

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Lindsy Kass and Roger Carpenter

Purpose:

To compare blood lactate concentration ([Bla]) at 15 s and 45 s during the 1-min rest period between each stage of an incremental test in rowers and to establish the validity of using interchangeable sampling times.

Methods:

Seventeen male club rowers (mean ± SD, age 28.8 ± 5.7 years, height 186.9 ± 5.1 cm, body mass 85.4 ± 6.6 kg) performed an incremental rowing ergometer test, consisting of five stages of 4 min corresponding to approximately 80% HRmax. A 10-µL earlobe blood sample was collected from each subject at 15 s and again at 45 s in the final minute of each test stage and analyzed in duplicate. A maximum of 10 s was allowed for blood collection.

Results:

Statistical analysis using limits of agreement and correlation indicated a high level of agreement between the two [Bla] samples for all fve test stages (agreement >95%, confidence intervals [CI] = -0.5 to 1.5, r = .97, P < .05).

Conclusion:

These results suggest that a sampling time between 15 s and 45 s may be recommended for the valid assessment of the [Bla] threshold in rowing performance monitoring. This extends the current sampling time of 30 s used by physiologists and coaches for National and club-level Rowers.