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Alexandra Milligan, Chris Mills and Joanna Scurr

More and more studies are emerging reporting breast kinematics. These studies rarely present effect sizes, power, and variance in the data. Important inferences are drawn from these data, including applications to product design, breast pain assessment, sports performance effects, and more. The aim of the study was to explore the within-participant variance in breast kinematic data during a 5 km run. Multiplanar breast kinematics and within-participant variance, defined by the coefficient of variation, for 10 female participants wearing a low and high level breast support were calculated during a 5 km run. Greater within-participant variance was reported in the high level (mean = 15%) breast support compared with the low level (mean = 12%). Within-participant variance in breast kinematics did not change over the 5 km run. Differences in the magnitude of within-participant variance in breast kinematics were reported between directions of breast movement, with greater levels in the anteroposterior direction compared with mediolateral and vertical. It is important for the progression of this research area that the presence and sources of within-participant variance in breast kinematics are quantified and acknowledged, ensuring that the margin for meaningful differences can be reported.

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Andrew H. Huntley, John L. Zettel and Lori Ann Vallis

A simultaneous turn and step motion is a vital component of many complex movements and may provide insight into age related balance and stability deficits during a weight transfer task. In this study, nine young adults and ten healthy, community dwelling older adults performed a simultaneous “turn and step” task from a quiet standing position under two self-selected speeds, self-paced and as quickly and efficiently as possible. Whole-body center of mass was estimated to investigate stability, segmental coordination, and variability. Older adults performed the task with greater variability, however they were unable to alter stability nor segmental coordination across the self-selected speeds; absence of this modulation portrays a trade-off between stability and manoeuvrability. An increase in variability with no observed directional differences suggests that the simultaneous turn and step task may be a sensitive discriminatory motor task helpful in elucidating the adoption of altered control strategies used by elderly populations.

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Joel Garrett, Stuart R. Graham, Roger G. Eston, Darren J. Burgess, Lachlan J. Garrett, John Jakeman and Kevin Norton

further analysis into the sensitivity of a SRT, participants were then categorized into “fatigued” (n = 9) and “nonfatigued” (n = 14) groups based on the 8% coefficient of variance (CV) reported in the previous literature for CMJ H . 3 , 7 That is, samples with a score of <92% of baseline were considered

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Roee Holtzer, Cuiling Wang and Joe Verghese

The current study critically assessed the relationship between cognitive functions and gait in nondemented older adults. Quantitative measures of gait (velocity, cadence, and a coefficient of variance in stride length) were assessed in single and dual-task conditions. Three cognitive factors captured the domains of Executive Attention, Verbal IQ, and Memory. Linear regressions showed that Executive Attention was related to velocity in both walking conditions. However, Memory and Verbal IQ were also related to velocity. Memory was related to Cadence in both walking conditions. Executive Attention was related to the coefficient of variance in stride length in both walking conditions. Linear mixed effects models showed that dual-task costs were largest in velocity followed by cadence and the coefficient of variance in stride length. The relationship between cognitive functions and gait depends, in part, on the analytic approach used, gait parameters assessed, and walking condition.

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Wendy A. Pethick, Holly J. Murray, Rob J. Gathercole and Gord G. Sleivert

This case study examines the longitudinal jump data of 1 male and 1 female world-class mogul skier over the course of a quadrennial leading to the 2010 Winter Olympics. Between-subjects standard deviation, smallest worthwhile enhancement, % coefficient of variance, and effect size (ES) were calculated from team jump testing taking place immediately preceding the 2010 Winter Olympics, as this was deemed the point in the quadrennial that the athlete group would be most likely near their best performance. These data were then used to characterize the progression of explosive power of elite mogul skiers over an Olympic quadrennial. Jump data for both the male and the female athlete showed trivial to large improvements in jump performance from Q1 (quadrennial year 1) to Q2, variable changes in performance from Q2 to Q4, and an overall improvement (small to large ES) from Q1 to Q4. Explosive power is a critical component of performance for moguls, and an analysis of the group data (Canadian athletes 2006–2010) shows that of all performance markers, jump testing is the variable that clearly delineates between World Cup and developmental athletes.

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Stephen Crowcroft, Erin McCleave, Katie Slattery and Aaron J. Coutts


To assess measurement sensitivity and diagnostic characteristics of athlete-monitoring tools to identify performance change.


Fourteen nationally competitive swimmers (11 male, 3 female; age 21.2 ± 3.2 y) recorded daily monitoring over 15 mo. The self-report group (n = 7) reported general health, energy levels, motivation, stress, recovery, soreness, and wellness. The combined group (n = 7) recorded sleep quality, perceived fatigue, total quality recovery (TQR), and heart-rate variability. The week-to-week change in mean weekly values was presented as coefficient of variance (CV%). Reliability was assessed on 3 occasions and expressed as the typical error CV%. Week-to-week change was divided by the reliability of each measure to calculate the signal-to-noise ratio. The diagnostic characteristics for both groups were assessed with receiver-operating-curve analysis, where area under the curve (AUC), Youden index, sensitivity, and specificity of measures were reported. A minimum AUC of .70 and lower confidence interval (CI) >.50 classified a “good” diagnostic tool to assess performance change.


Week-to-week variability was greater than reliability for soreness (3.1), general health (3.0), wellness% (2.0), motivation (1.6), sleep (2.6), TQR (1.8), fatigue (1.4), R-R interval (2.5), and LnRMSSD:RR (1.3). Only general health was a “good” diagnostic tool to assess decreased performance (AUC –.70, 95% CI, .61–.80).


Many monitoring variables are sensitive to changes in fitness and fatigue. However, no single monitoring variable could discriminate performance change. As such the use of a multidimensional system that may be able to better account for variations in fitness and fatigue should be considered.

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Kelsie M. Full, Eileen Johnson, Michelle Takemoto, Sheri J. Hartman, Jacqueline Kerr, Loki Natarajan, Ruth E. Patterson and Dorothy D. Sears

effects on these biomarkers. Intraplate and interplate coefficients of variance, respectively, were 3.5% and 6.5% for insulin, 2.1% and 3.2% for glucose, and 8.4% and 18.0% for CRP, measured at UC San Diego as reported previously. Serum estradiol, testosterone, and SHBG were measured at the Reproductive

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Roland van den Tillaar

—Average velocity (± SD ) and coefficient of variance (%) per shooting technique and target height. *A significant difference in velocity between the two heights with this shooting technique on a p  < .05 level. **A significant higher velocity with the other shooting techniques on a p  < .05 level. ***A

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Peter Francis, Kay Gray and Nic Perrem

inability to correct for gravity, and stabilization techniques used. 16 Furthermore, peak torque from a voluntary muscle contraction can be measured within a coefficient of variance of 5%. 17 Many studies have assessed hip abductor strength using handheld dynamometers, 12 , 18 – 20 but comparatively few

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Yoav Gimmon, Hisham Rashad, Ilan Kurz, Meir Plotnik, Raziel Riemer, Ronen Debi, Amir Shapiro and Itshak Melzer

investigate gait changes is studying gait behavior in older adults aged 80 years and older who live independently in the community and have not yet fallen. Thus, we aimed to explore the differences in GA, PCI, and stride time coefficient of variance (CV) of gait in old-old (OO) subjects (i.e., >85) and to