Eccentric loading and range of knee joint motion effects on performance enhancement in vertical jumping

The aim of the study was to determine the effects of variations in eccentric loading and knee joint range of motion on performance enhancement associated with the stretch-shortening cycle in vertical jumping. Seventeen male elite volleyball players performed three variations of the vertical jump which served as the research model: the squat jump (SJ), countermovement jump (CMJ) and drop jump from a height of 30 cm (DJ30). Knee joint angle (70 degrees and 90 degrees of flexion) at the commencement of the propulsive phase for each jump type was experimentally controlled, with the trunk kept as erect as possible. Force and motion data were recorded for each performance and used to compute a range of kinematic and kinetic variables, including hip, knee and ankle angles, angular velocities, work done, net joint moments and a number of temporal variables. The average of 12 trials for each participant was used in a series of repeated measures ANOVA's (jump xk nee, alpha=.05). From both knee joint angles, an increase in eccentric loading resulted in a significant increase in jump height (DJ30>CMJ>SJ; p<.05). These enhancements were significantly greater (p<.05) for 70 degrees in comparison to 90 degrees of knee flexion. From 70 degrees of knee flexion, these enhancements were due to significant increases in work done at all three joints; while from 90 degrees of knee flexion, only the hip and ankle joints appeared to contribute (p<.05). The amount of enhancement associated with employing the SSC in jumping is dependent upon the interaction of the magnitude of eccentric loading and the range of motion used.     

The Dynamic Relationships of Work Affect and Job Satisfaction with Perceptions of Fit

This study assessed the longitudinal relationship between perceived fit (i.e., person–organization fit, person–job fit) and affect‐based variables (i.e., job satisfaction, negative affect, positive affect) using momentary (i.e., within‐person level) and stable (i.e., between‐person level) assessments of both sets of variables. In doing so, we tested 3 theoretical models of the perceived fit and work affect relationship (i.e., fit preceding affect; affect preceding fit; reciprocal fit–affect relations) to determine (a) the antecedents and consequences of fit perceptions, (b) whether fit perceptions exhibit meaningful within‐person variability, and (c) if direct fit perceptions are simply the result of affect/job satisfaction at work or can influence such work experiences. In addition, we examined whether the relationships between affect/job satisfaction and fit perceptions were homologous (i.e., similar) across the 2 levels of analysis (i.e., within‐person and between‐person). Results indicated that fit primarily preceded affect and job satisfaction at both levels of analysis, though some specific relationships exhibited reciprocal causality and others supported affect as an antecedent of fit perceptions. Our findings paint a complex picture of the causal relationship between perceived fit and work affect.     

Reactions to tokenism: The role of individual characteristics in shaping responses to token decisions

When only a handful of members from a disadvantaged group occupy positions of power, they are considered tokens. Previous research suggests that observers tend to consider tokenism as an egalitarian practice. Given its ambiguous nature, we hypothesized that reactions to tokenism would be shaped by individuals' sensitivity to inequality. In Study 1, we showed that women (vs. men) and individuals low (vs. high) on social dominance orientation differentiated more between a token and an egalitarian decision in the context of gender‐related practices. Similar findings were observed in Study 2, which involved gender and feminist identification as independent variables. Additional support, particularly for the role of social dominance orientation, was found in Study 3, which involved an ethnic token. Together, results demonstrate the role of individuals' chronic sensitivity to inequality in shaping their reactions to token practices. Theoretical and practical implications regarding the effect of tokenism on individuals' evaluations and responses to inequality are discussed. Copyright © 2016 John Wiley & Sons, Ltd.     

Links among the Self,Stress, and Psychological Distress during Emerging Adulthood: Comparing Three Theoretical Models

The authors tested three theoretical models linking self, stress, and psychopathological distress in emerging adulthood. The vulnerability model posits that self-concept pathology leads to distress. The scarring model postulates that distress and stress lead to self-concept pathology. The stress generation model stipulates that distress and self-concept pathology lead to the experience of episodic and chronic life stress. Change in ruminative brooding was examined as a potential mechanism in all models. One-hundred and seventy Israeli freshmen (M_[age]?=?23.19, 68% females) were followed up three times over the duration of one year. Distress and six dimensions of the self (self-criticism, self-concept inadequacy, hated sense of self, self-esteem, generalized self-efficacy, and self-concept clarity) were assessed repeatedly. Acute and chronic stresses were measured at Time 2 using the University of California, Los Angeles (UCLA) Stress Interview. Distress prospectively predicted self-concept pathology pertaining to all of the dimensions, except self-concept clarity, which was adversely affected by chronic stress. Change in ruminative brooding mediated scarring for self-criticism, a hated self, and self-concept clarity. Low self-esteem emerged as a powerful chronic stress generator. Self-concept clarity was as the only dimension leading to change in distress. In emerging adulthood, psychological distress and—to a lesser extent—chronic stress might “scar” the self.