Impact of a universal school-based violence prevention program on violent delinquency: distinctive benefits for youth with maltreatment histories

Objective

Child maltreatment constitutes a strong risk factor for violent delinquency in adolescence, with cumulative experiences of maltreatment creating increasingly greater risk. Our previous work demonstrated that a universal school-based violence prevention program could provide a protective impact for youth at risk for violent delinquency due to child maltreatment history. In this study we conducted a follow-up to determine if participation in a school-based violence prevention program in grade 9 continued to provide a buffering effect on engaging in acts of violent delinquency for maltreated youth, 2 years post-intervention.

Methods

Secondary analyses were conducted using data from a cluster randomized controlled trial of a comprehensive school-based violence prevention program. Students (N = 1,722; 52.8% female) from 20 schools participated in 21 75-min lessons in grade 9 health classes. Individual data (i.e., gender, child maltreatment experiences, and violent delinquency in grade 9) and school-level data (i.e., student perception of safety averaged across students in each school) were entered in a multilevel model to predict violent delinquency at the end of grade 11.

Results

Individual- and school-level factors predicting violent delinquency in grade 11 replicated previous findings from grade 9: being male, experiencing child maltreatment, being violent in grade 9, and attending a school with a lower perceived sense of safety among the entire student body increased violent delinquency. The cross-level interaction of individual maltreatment history and school-level intervention was also replicated: in non-intervention schools, youth with more maltreatment in their background were increasingly likely to engage in violent delinquency. The strength of this relationship was significantly attenuated in intervention schools.

Conclusions

Follow-up findings are consistent with the buffering effect of the prevention program previously found post-intervention for the subsample of youth with maltreatment histories.

Practice implications

A relative inexpensive school-based violence prevention program that has been shown to reduce dating violence among the whole student body also creates a protective effect for maltreated youth with respect to lowering their likelihood of engaging in violent delinquency.     

Social-emotional effects of early childhood education programs in Tulsa

This article assesses the effects of Tulsa, Oklahoma's early childhood education programs on social-emotional outcomes, examining teacher ratings of children's behavior from the Adjustment Scales for Preschool Intervention and a measure of attentiveness using fixed effects regressions with propensity score matching. The sample includes 2,832 kindergarten students in 2006, of whom 1,318 participated in the Tulsa Public Schools (TPS) pre-K program and 363 participated in the CAP of Tulsa County Head Start program the previous year. Program participation was associated with lower timidity and higher attentiveness for TPS pre-K alumni and a marginally significant reduction in timidity for Head Start alumni. Results were similar for the free lunch-eligible subsample. We conclude that high-quality, school-based preschool programs can enhance social-emotional development.     

A study of technical signs in science: implications for lexical database development

Both classroom instruction and lexical database development stand to benefit from applied research on sign language, which takes into consideration American Sign Language rules, pedagogical issues, and teacher characteristics. In this study of technical science signs, teachers' experience with signing and, especially, knowledge of content, were found to be essential for the identification of signs appropriate for instruction. The results of this study also indicate a need for a systematic approach to examine both sign selection and its impact on learning by deaf students. Recommendations are made for the development of lexical databases and areas of research for optimizing the use of sign language in instruction.     

Aversive parenting in China: associations with child physical and relational aggression

This study assessed the combined and differential contributions of Chinese mothers and fathers (in terms of spouse-reported physically coercive and psychologically controlling parenting) to the development of peer-reported physical and relational aggression in their preschool-age children (mean age of 5 years). Results of the two-group (boys and girls) latent sum and difference structural equation model showed that combined parenting effects were slightly more prevalent than differential effects in predicting aggression. Furthermore, physical coercion was predictive of aggression in boys whereas psychological control was primarily associated with aggression in girls. Findings extend our understanding of relational aggression and the meaning of aversive parenting, particularly within the Chinese cultural context.     

Peak muscle activation, joint kinematics, and kinetics during elliptical and stepping movement pattern on a Precor Adaptive Motion Trainer

Kinematic, kinetic, and electromyography data were collected from the biceps femoris, rectus femoris (RF), gluteus maximus, and erector spinae (ES) during a step and elliptical exercise at a standardized workload with no hand use. Findings depicted 95% greater ankle plantar flexion (p = .01), 29% more knee extension (p = .003), 101% higher peak knee flexor moments (p < .001) 54% greater hip extensor moments (p < .001), 268% greater anterior joint reaction force (p = .009), 37% more RF activation (p < .001), and 200 % more ES activation (p <. 001) for the elliptical motion. Sixteen percent more hip flexion (p < .001), 42% higher knee extensor moments (p < .001), and 54% greater hip flexor moments (p = .041) occurred during the step motion. Biomechanical differences between motions should be considered when planning an exercise regimen.     

Fast bowling arm actions and the illegal delivery law in men's high performance cricket matches

This study investigated the bowling arm kinematics of 21 elite fast bowlers (mean +/- SD; age = 27.8 +/- 3.9 years) while performing in test, tour and one day international matches. Thirty-one of the 34 deliveries analysed exhibited straightening at the elbow joint (straightening min = 3 degrees, max = 22 degrees, mean +/- SD = 9 +/- 5 degrees), which by strict definition in the 2000 laws of cricket made them illegal. Five deliveries from three bowlers exhibited hyperextension of the bowling elbow (19 +/- 5 degrees). When assessed against an arbitrary threshold of 15 degrees for elbow straightening, ball speeds for deliveries above this threshold (39.5 +/- 2.0 m/s) were significantly faster (effect size = 1.4; p = 0.006) than deliveries below it (37.1 +/- 1.4 m/s). When grouped by delivery length, the bouncers and short deliveries recorded more elbow straightening (12 +/- 6.6 degrees) than the good length deliveries (9 +/- 4.4 degrees) and the full deliveries (8 +/- 5.7 degrees), although these were not statistically significant differences. The results of this study support the implementation of a tolerance threshold for assessing the legality of fast bowling actions. Further research is recommended into in-match kinematic modelling, laboratory based assessments of illegal bowling actions, perceptual aspects of bowling actions and remedial methods to reduce elbow straightening in bowling actions.     

Practicing a maximal performance task: a cooperative strategy for muscle activity

The effect of practice on predicting elbow flexion movement time was studied. Participants (N = 18) performed 400 elbow flexion trials to a target in the horizontal plane. The trials were distributed equally over four sessions. The goal was to decrease the movement time (MT) for the same degree of accuracy. The electromyographic (EMG) activity of the biceps and triceps brachii was monitored with standard Beckman Ag/AgCl surface electrodes. The EMG measures formed two variable sets within one prediction equation. One variable set was composed of the onset of muscle activity relative to the start of movement (motor time) and the duration of muscle activity. The other variable set consisted of the mean amplitude value of the entire burst and of the first 30 ms (Q30) of activity. As the maximal speed of limb movement increased, the duration of muscle activity (motor time and EMG duration) decreased, and the magnitude of muscle activity (MAV and Q30) increased. Most of the change in the duration of muscle activity occurred in Session 1, while the magnitude of muscle activity continued to increase until Session 3. Multiple regression analysis revealed a cooperative strategy between the magnitude and duration of muscle activity. Early in learning, participants adjusted the magnitude of muscle activity to increase limb movement speed. As practice continued, alterations in the duration of muscle activity became more important, while the magnitude changes were less involved. Late in learning, both dimensions of muscle activity were used to decrease MT. We suggest that the interplay between the magnitude and duration of muscle activity may be due to: (a) cognitive factors related to the division of attention in a motor skill, (b) an increase in the frequency of motor unit firing that affects both dimensions of muscle activity, or (c) some combination of (a) and (b).