Validity of the Blast Athletic Performance Monitor for Assessing Vertical Jump Height in Female Volleyball Players

Introduction: Wearable activity monitors have been developed for jump height assessment, but the Blast Athletic Performance monitor has not yet been validated, and it remains unclear if the Blast can track changes across a sports season. Methods: Collegiate women’s volleyball players (n = 20) wore the Blast monitor (waistband) while performing standing vertical jumps (SVJs) and one-step vertical jumps (OSJs) weekly during and after a 9-week season. Jump heights from the Blast were compared to a Vertec (criterion). Results: Correlations of Blast and Vertec were moderately high (r = 0.67–0.69), but the Blast underestimated SVJ and OSJ (9.2–10.0 cm), with mean absolute percent errors 19.8–21.0%. A + 23% correction factor reduced errors to 10.5–11.3%. The Blast did not detect small decreases (2–4 cm) in criterion-measured jump height in the postseason. Conclusion: The Blast underestimated jump height and had limited ability to detect changes of up to 5.0 cm following a volleyball season. A relative correction lowered, but did not eliminate, measurement error.     

The communication of laboratory investigations by university entrants

The purpose of the study reported here was to analyse the ways in which unversity entrant science students carry out and communicate experimental activities and to identify a model to explain characteristic communication practices. The study was prompted by a need to inform the development of an introductory laboratory course. The students studied shared an educational background characterised by a lack of experience with laboratory work and scientific writing. Seven groups of three students were studied. The investigative strategies of these groups were observed. Laboratory reports were used to identify the ways in which students communicated these strategies. Data are presented that show a discrepancy between the strategies used and those reported. The results suggest that: (i) students' perceptions of the purpose of a laboratory task influence their decisions on what to report; (ii) understandings of laboratory procedures greatly influence their decision on what to report and on how much detail to include in a report and; (iii) knowledge of discourse rules contributes to effective reporting. It is concluded that students' communication of an investigation results from the differential operation of various perceptual filters that determine both the procedural and discourse elements of their reports. It is recommended that the communication of science should be taught explicitly and alongside the procedures and concepts of science. © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 839–853, 2000     

Ratings of severity of life events by ninth-grade students

Special education, basic, and honors students rated the severity of stress for each of the life events on the Source of Stress Inventory (Chandler, 1981). There was a significant positive relationship between the Chandler rankings and the rankings made by the 60 ninth-grade students. Special education students reported they had experienced more of the events than had honors students, and the special education students reported more intense stress for the experienced events. Life experiences considered more stressful by students when compared to the stress values assigned by the Chandler rankings (teachers and mental health workers) include poor grades in school, loss of job by parent, mother beginning to work, birth of brother or sister, increased arguments with brothers and sisters vision problem requiring glasses.     

Purchasing power parity and cultural convergence: evidence from the global video games market

A shared activity or pursuit can have the effect of bringing about cultural convergence in the form of patterns of behaviour and consumption. This idea is supported by the Axelrod (1997) thesis, which suggests that cultures are more likely to interact and subsequently converge if they have shared traits: one of these being the use of technology. This paper seeks to apply such a cultural perspective to the body of published literature on deviations from the law of one price. Adopting a similar methodology to the popular ‘Big Mac’ index, disparity between official market exchange rate and the real rate of exchange between two currencies is measured using local prices of video game consoles. The results of the study suggest that, while a degree of pricing and cultural convergence across broad geographic areas is observed, many major global currencies are trading at levels that are quite significantly different to that which is suggested by purchasing power parity (PPP) theory.