@article{ZieglerEhrlenspielBrand2009,
  author    = {Ziegler, Matthias and Ehrlenspiel, Felix and Brand, Ralf},
  title     = {Latent state-trait theory : an application in sport psychology},
  issn      = {1469-0292},
  doi       = {10.1016/j.psychsport.2008.12.004},
  year      = {2009},
  abstract  = {Objective: Questionnaires are often applied in sports psychology to measure a person's trait or state. However, the extent to which the questionnaire captures differences because of trait or state influences is often unclear. The latent state-trait (LST) theory offers the opportunity to separate both variance sources. This separation allows estimating specific reliability coefficients. Design: The present paper gives a theoretical introduction to LST and its basic ideas. Using a real data set with N = 156 athletes we exemplify the steps necessary to derive the LST coefficients. All athletes filled out a comprehensive inventory assessing competitive anxiety on two occasions. Method: The data are analysed with structural equation models based on LST principles. Results: The results confirm the questionnaire's trait saturation. Conclusion: Finally, results are discussed in light of practical and theoretical implications.},
  language  = {en}
}
@article{HeissEngbertGroepeletal.2010,
  author    = {Heiss, Christian and Engbert, Kai and Groepel, Peter and Ziegler, Matthias and Brand, Ralf},
  title     = {Self-leadership and volition : distinct and potentially supplemental constructs?},
  issn      = {0033-2941},
  doi       = {10.2466/01.03.07.14.Pr0.107.5.447-462},
  year      = {2010},
  abstract  = {Self-leadership and volition are conceptually similar concepts. Both propose self-influence strategies that aim to improve the motivation and self-direction necessary to perform well. The present study assesses whether self- leadership strategies maintain construct-specific variance when compared with the similar strategies of volition. Results from a questionnaire study (N=320) indicate that self-leadership and volitional strategies are distinguishable and only moderately (r=.33) correlated. Self-leadership, therefore, supplements volition during goal attainment. Findings are discussed in light of the Rubicon model of action phases.},
  language  = {en}
}
@misc{BrandHeckZiegler2014,
  author    = {Brand, Ralf and Heck, Philipp and Ziegler, Matthias},
  title     = {Illegal performance enhancing drugs and doping in sport},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401404},
  pages     = {11},
  year      = {2014},
  abstract  = {Background: Doping attitude is a key variable in predicting athletes' intention to use forbidden performance enhancing drugs. Indirect reaction-time based attitude tests, such as the implicit association test, conceal the ultimate goal of measurement from the participant better than questionnaires. Indirect tests are especially useful when socially sensitive constructs such as attitudes towards doping need to be described. The present study serves the development and validation of a novel picture-based brief implicit association test (BIAT) for testing athletes' attitudes towards doping in sport. It shall provide the basis for a transnationally compatible research instrument able to harmonize anti-doping research efforts. Method: Following a known-group differences validation strategy, the doping attitudes of 43 athletes from bodybuilding (representative for a highly doping prone sport) and handball (as a contrast group) were compared using the picture-based doping-BIAT. The Performance Enhancement Attitude Scale (PEAS) was employed as a corresponding direct measure in order to additionally validate the results. Results: As expected, in the group of bodybuilders, indirectly measured doping attitudes as tested with the picture-based doping-BIAT were significantly less negative (eta(2) = .11). The doping-BIAT and PEAS scores correlated significantly at r = .50 for bodybuilders, and not significantly at r = .36 for handball players. There was a low error rate (7\%) and a satisfactory internal consistency (r(dagger dagger) = .66) for the picture-based doping-BIAT. Conclusions: The picture-based doping-BIAT constitutes a psychometrically tested method, ready to be adopted by the international research community. The test can be administered via the internet. All test material is available "open source". The test might be implemented, for example, as a new effect-measure in the evaluation of prevention programs.},
  language  = {en}
}
@misc{WolffBrandBaumgartenetal.2017,
  author    = {Wolff, Wanja and Brand, Ralf and Baumgarten, Franz and L{\"o}sel, Johanna and Ziegler, Matthias},
  title     = {Modeling students' instrumental (mis-)use of substances to enhance cognitive performance},
  issn      = {1866-8364},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-401441},
  pages     = {11},
  year      = {2017},
  abstract  = {Background: Healthy university students have been shown to use psychoactive substances, expecting them to be functional means for enhancing their cognitive capacity, sometimes over and above an essentially proficient level. This behavior called Neuroenhancement (NE) has not yet been integrated into a behavioral theory that is able to predict performance. Job Demands Resources (JD-R) Theory for example assumes that strain (e.g. burnout) will occur and influence performance when job demands are high and job resources are limited at the same time. The aim of this study is to investigate whether or not university students' self-reported NE can be integrated into JD-R Theory's comprehensive approach to psychological health and performance. Methods: 1,007 students (23.56 ± 3.83 years old, 637 female) participated in an online survey. Lifestyle drug, prescription drug, and illicit substance NE together with the complete set of JD-R variables (demands, burnout, resources, motivation, and performance) were measured. Path models were used in order to test our data's fit to hypothesized main effects and interactions. Results: JD-R Theory could successfully be applied to describe the situation of university students. NE was mainly associated with the JD-R Theory's health impairment process: Lifestyle drug NE (p < .05) as well as prescription drug NE (p < .001) is associated with higher burnout scores, and lifestyle drug NE aggravates the study demands-burnout interaction. In addition, prescription drug NE mitigates the protective influence of resources on burnout and on motivation. Conclusion: According to our results, the uninformed trying of NE (i.e., without medical supervision) might result in strain. Increased strain is related to decreased performance. From a public health perspective, intervention strategies should address these costs of non-supervised NE. With regard to future research we propose to model NE as a means to reach an end (i.e. performance enhancement) rather than a target behavior itself. This is necessary to provide a deeper understanding of the behavioral roots and consequences of the phenomenon.},
  language  = {en}
}