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Jos J. de Koning and Dionne A. Noordhof

know that it is not that simple. Is the winner really the best athlete? Did the training intervention give a performance benefit, and which performance-determining variable was improved? There is a lot of uncertainty in our day-to-day practice, while the world around us is asking for unambiguous

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Amanda Kastrinos, Rachel Damiani and Debbie Treise

, including high uncertainty and risk of a fatal outcome, a review of the coverage revealed that 86.2% of articles published in the United Kingdom had a neutral tone. Articles relied on scientific information rather than personal stories and sensationalized information ( Hilton & Hunt, 2011 ). Parasocial

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Lisa S. Jutte, Kenneth L. Knight and Blaine C. Long

Objective:

Examine thermocouple model uncertainty (reliability + validity).

Design:

First, a 3 × 3 repeated measures design with independent variables electrothermometers and thermocouple model. Second, a 1 × 3 repeated measures design with independent variable subprobe.

Intervention:

Three electrothermometers, 3 thermocouple models, a multi-sensor probe and a mercury thermometer measured a stable water bath.

Main Outcome Measures:

Temperature and absolute temperature differences between thermocouples and a mercury thermometer.

Results:

Thermocouple uncertainty was greater than manufactures’ claims. For all thermocouple models, validity and reliability were better in the Iso-Themex than the Datalogger, but there were no practical differences between models within an electrothermometers. Validity of multi-sensor probes and thermocouples within a probe were not different but were greater than manufacturers’ claims. Reliability of multiprobes and thermocouples within a probe were within manufacturers claims.

Conclusion:

Thermocouple models vary in reliability and validity. Scientists should test and report the uncertainty of their equipment rather than depending on manufactures’ claims.

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Franklin Camargo-Junior, Marko Ackermann, Jefferson F. Loss and Isabel C.N. Sacco

The aim of this study was to investigate the effect of errors in the location of the center of pressure (5 and 10 mm) on lower limb joint moment uncertainties at different gait velocities (1.0, 1.5, and 2.0 m/s). Our hypotheses were that the absolute joint moment uncertainties would be gradually reduced from distal to proximal joints and from higher to lower velocities. Joint moments of five healthy young adults were calculated by inverse dynamics using the bottom-up approach, depending on which estimate the uncertainty propagated. Results indicated that there is a linear relationship between errors in center of pressure and joint moment uncertainties. The absolute moment peak uncertainties expressed on the anatomic reference frames decreased from distal to proximal joints, confirming our first hypothesis, except for the abduction moments. There was an increase in moment uncertainty (up to 0.04 N m/kg for the 10 mm error in the center of pressure) from the lower to higher gait velocity, confirming our second hypothesis, although, once again, not for hip or knee abduction. Finally, depending on the plane of movement and the joint, relative uncertainties experienced variation (between 5 and 31%), and the knee joint moments were the most affected.

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Daniel J. Larson and Joel Maxcy

The world governing body for cycling proscribed the use of two-way radio communication in road cycling races, with the ban set to become fully effective in 2012. The ban was instituted because radio use was perceived to have altered the cycling competitions by making outcomes more predictable and of less interest to sport’s consumers. This empirical analysis of the policy rationale considers the uncertainty of outcome hypothesis (UOH) as it applies to professional cycling races and creates a novel measure, the likelihood of breakaway success (LBS). The LBS is analyzed in 1436 bicycle races between 1985–2010 to examine potential changes in outcomes associated with the use of two-way radio technology by competitors and team directors. The data suggests that radio technology has had a significant association with event outcome types. The relevance of the findings to intraorganizational communication, management, and hierarchies of sports teams are also discussed.

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William P. Berg and Michael R. Hughes

Muscle activation was measured using EMG in 28 males (n = 28) while participants caught visually identical balls of known and unknown weights (50, 1.32, 2.18, and 2.99 kg) under variable (1–10s) and constant (3s) foreperiods. EMG integrals were computed for three time intervals before the catch (anticipatory), and one after (compensatory). Load uncertainty caused the CNS to use an anticipatory strategy characterized by preparation to catch balls of an unknown weight by utilizing about 92% of the muscle activation used to catch the heaviest possible ball under the known weight condition. The CNS appeared to scale anticipatory muscle activation to afford an opportunity to catch a ball of an unknown weight between .50 and 2.99 kg. The constant 3s foreperiod, which permitted temporal anticipation, did not influence the anticipatory neuromotor strategy adopted by the CNS to cope with load uncertainty. Load uncertainty also altered compensatory neuromotor control in catching.

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Marc Lavoie and Wilbert M. Leonard II

The stacking of blacks in noncentral positions is a time-consistent feature of professional baseball. It is shown that differential batting and slugging averages between positions are also a structural feature. The structure of stacking as well as its evolution are well explained by the uncertainty thesis, that is, the belief that discrimination and differential barriers to entry are linked to the difficulty and lack of objectivity in assessing player performance at a given position. However, because the uncertainty thesis fails to predict the expected performance differentials between black and white players, auxiliary hypotheses have to be entertained. It is concluded that a combination of the uncertainty thesis and the well-known centrality hypothesis may best explain what occurs in baseball.

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Dominic Malcolm

This article addresses clinical practice in sport medicine. Combining notions of medical uncertainty with a figurational sociological emphasis on interdependence, the article illustrates how uncertainty characterizes the medical understanding, clinical treatment, and patient experience of concussion. Faced with uncertainty, the clinician’s desire for recognition and validation through athletes’ dependence on them enables medically based diagnostic and treatment guidelines to be replaced by the understanding and definition of concussion dominant in the sport subculture. Clinicians further invoke strategies that protect their professional status and therefore secure their interdependence with others in the sport club figuration. The study advances our understanding by illuminating the basis on which clinicians and athletes negotiate treatment and the impact of these experiences on clinicians’ actions and beliefs.

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Paul R. Surburg

The effects of uncertainty of occurrence and uncertainty of time—use of catch-trials and preparatory intervals—in simple reaction time (RT) trials were investigated with nonhandicapped and mentally retarded subjects. The results showed that: (a) Catch-trials impaired the performance of this task, (b) catch-trials did not differentiate among groups of subjects, and (c) preparatory intervals differently affected RT latencies of nonhandicapped and mentally retarded subjects. Interpretation of findings suggests that the use of catch-trials induced preparation decrements and that preparation decrements may explain in part the poorer RT performance of retarded subjects.

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Daniel Cury Ribeiro and Jefferson Fagundes Loss

Link segment models are usually used to calculate proximal net reaction forces (PRF), as well as, proximal net moments (PNM). The correlation between electromyographic data and PNM is usually used to verify the model’s results. Nevertheless, this method permits only a qualitative verification of the obtained results. To assess model’s results in a quantitative perspective, another approach is needed. The aim of the current study was to assess the propagation of uncertainty on a link segment model results and identify the main sources of error on the quantification of PRF and PNM. One male performed five repetitions of different upper limb movements. An inverse dynamics approach associate with 3D link segment model was used to quantify PRF and PNM. The results of the model were evaluated by the use of Kleine and McClintock’s equation. The propagation of uncertainty for PRF reached, on average, 0.27 and for PNM, 0.97. The main cause of propagation of uncertainty was associated to the second time derivative calculations. Consequently, it is possible to suggest that the reduction of small distortions of center of mass acceleration will diminish the proximal net moment and proximal reaction force uncertainty values.