Vertical jump height is frequently used by coaches, health care professionals, and strength and conditioning professionals to objectively measure function. The purpose of this study is to determine the concurrent validity of the jump and reach method (Vertec) and the contact mat method (Just Jump) in assessing vertical jump height when compared with the criterion reference 3-camera motion analysis system. Thirty-nine college students, 25 females and 14 males between the ages of 18 and 25 (mean age 20.65 years), were instructed to perform the countermovement jump. Reflective markers were placed at the base of the individual's sacrum for the 3-camera motion analysis system to measure vertical jump height. The subject was then instructed to stand on the Just Jump mat beneath the Vertec and perform the jump. Measurements were recorded from each of the 3 systems simultaneously for each jump. The Pearson r statistic between the video and the jump and reach (Vertec) was 0.906. The Pearson r between the video and contact mat (Just Jump) was 0.967. Both correlations were significant at the 0.01 level. Analysis of variance showed a significant difference among the 3 means F(2,235) = 5.51, p < 0.05. The post hoc analysis showed a significant difference between the criterion reference (M = 0.4369 m) and the Vertec (M = 0.3937 m, p = 0.005) but not between the criterion reference and the Just Jump system (M = 0.4420 m, p = 0.972). The Just Jump method of measuring vertical jump height is a valid measure when compared with the 3-camera system. The Vertec was found to have a high correlation with the criterion reference, but the mean differed significantly. This study indicates that a higher degree of confidence is warranted when comparing Just Jump results with a 3-camera system study.

Three studies investigated the relationship between anxiety, social desirability, and an interpretative bias favoring threat in nonclinical subjects. Interpretative bias was assessed with Mathews, Richards, and Eysenck's (1989)

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Previous neuroimaging studies of scenarios such as the prisoner's dilemma and ultimatum game show how brain systems which evolved to process rewarding and aversive stimuli are activated differentially during adherence to and breaches of norms. One theory of how shared social norms evolve is that they arise from mutually rewarding conventions which, through repeated execution, acquire a normative value that sustains social cohesion even when individual self-interest is not served. The authors report an fMRI study of a 2-player coordination game in which players must coordinate on an arbitrary convention (a left or right button press) to obtain monetary rewards. Once this convention has been established, one of the participants is incentivized to deviate from the equilibrium with the offer of extra reward. During the period prior to decisions to violate the convention, activity was observed in regions associated with reward processing, such as the midbrain, caudate, and orbitofrontal cortex. Activations in advance of decisions to continue coordinating included the amygdala and anterior insulainferior frontal gyrus. The data are discussed in the light of theories which propose the existence of multiple interacting value-based decision-making systems in the human brain.

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