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
Senia Smoot Reinert, Allison L. Kinney, Kurt Jackson, Wiebke Diestelkamp and Kimberly Bigelow
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.
Jérôme Vaulerin, Frédéric Chorin, Mélanie Emile, Fabienne d’Arripe-Longueville and Serge S. Colson
the absolute difference between both limbs, in centimeters. The same investigator collected WBLT measures for all participants. Postural Stability The SATEL (SATEL, Blagnac, France) platform was used to assess the displacement of the participants’ center of pressure (COP). The COP data were sampled
Ryan Morrison, Kyle M. Petit, Chris Kuenze, Ryan N. Moran and Tracey Covassin
. Future research should aim to include equal male and female student-athletes, with a larger sample over a longer period. Observing baseline changes over a college career would give clinicians a better understanding of how often to collect baseline data, as there are no consistent recommendations
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
Wendy L. Hurley
The agreement of clinical judgments of endfeel between certified athletic trainers and orthopedic surgeons is not known.
To examine agreement of clinical judgments of endfeel between sample populations and explore the influence of clinician technique on sensitivity for determining ACL injury when performing an isolated examination procedure.
Randomized, blinded, controlled clinical trials.
1 orthopedic surgeon, 22 certified athletic trainers, and 12 model patients.
Main Outcome Measures:
Kappa coefficients were calculated to determine the agreement of clinical judgments of endfeel between the 2 populations sampled. Lachman-test sensitivity was measured using true positive and false negative interpretations.
Concurrence was poor for clinical judgments of endfeel. Sensitivity varied according to clinician technique.
Agreement between the 2 populations sampled was influenced by the examiners’ diagnostic skills and their capacity to properly perform and interpret the Lachman test.
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.
Renee Beach Sample, Kurt Jackson, Allison L. Kinney, Wiebke S. Diestelkamp, Senia Smoot Reinert and Kimberly Edginton Bigelow
Falls occur in 33% of older adults each year, some leading to moderate to severe injuries. To reduce falls and fall-related injuries, it is important to identify individuals with subtle risk factors elevating their likelihood of falling. The objective of this study was to determine how postural sway measures differed between fallers and nonfallers under standard and dual-task conditions. Quietstanding posturography measures were collected from 150 older adults during standard, cognitive, manual, and cognitive+manual tasks, and analyzed through traditional and nonlinear analyses. Of the traditional measures, M/L sway range and 95% confidence ellipse sway area showed statistically significant differences in all 4 test conditions between fallers and nonfallers. Although the manual dual task showed the most stable balance, effect sizes demonstrated larger differences between fallers and nonfallers. Nonlinear analysis revealed M/L sample entropy and M/L α-scaling exponent differentiating between fallers and nonfallers, with the cognitive task demonstrating larger differences. Based on the results, it is recommended to: (1) apply M/L sway range and 95% confidence ellipse area, (2) use the manual task to differentiate between fallers and nonfallers when using traditional analyses, and (3) use the cognitive task and M/L alpha and M/L sample entropy when using nonlinear analyses.
Michael Hutchison, Paul Comper, Lynda Mainwaring and Doug Richards
The baseline / postconcussion neuropsychological (NP) assessment model has been shown to be of clinical value and currently contributes significant information in sport concussion evaluation. Computerized NP batteries are now widely used in elite sport environments and are rapidly becoming more commonly utilized at the community level. With the growth of computerized NP testing, it is important to identify and understand unique characteristics with respect to baseline NP performance. The Automated Neuropsychological Assessment Metrics (ANAM) is a library of computerized NP tests designed to detect speed and accuracy of attention, memory, and thinking ability. This article describes baseline ANAM test scores in a sample of Canadian university athletes and explores the following two factors: (a) performance differences between male and female student-athletes using ANAM tests and (b) the relationship between self-reported history of concussion and baseline NP performance.
Meghan Schreck, Robert Althoff, Meike Bartels, Eco de Geus, Jeremy Sibold, Christine Giummo, David Rubin and James Hudziak
Few studies have explored the relation between withdrawn behavior (WB) and exercise and screen time. The current study used exploratory factor analysis to examine the factor structure of leisure-time exercise behavior (LTEB) and screentime sedentary behavior (STSB) in a clinical sample of youth. Structural equation modeling was employed to investigate the relations between WB and LTEB and STSB, conditional on gender. WB was assessed using the Child Behavior Checklist, and LTEB and STSB were measured using the Vermont Health Behavior Questionnaire. LTEB and STSB emerged as two separate factors. Gender moderated the structure of STSB only. For boys and girls, WB was inversely related to LTEB but not significantly related to STSB. LTEB and STSB are best represented as distinct, uncorrelated constructs. In addition, withdrawn youth may be at risk for poor health outcomes due to lower rates of LTEB. Mental health clinicians, sports psychologists, and related providers may be uniquely qualified to enhance motivation for sports participation in withdrawn youth.