Testing Measurement Invariance Across Groups in Longitudinal Data: Multigroup Second-Order Latent Growth Model

In latent growth modeling, measurement invariance across groups has received little attention. Considering that a group difference is commonly of interest in social science, a Monte Carlo study explored the performance of multigroup second-order latent growth modeling (MSLGM) in testing measurement invariance. True positive and false positive rates in detecting noninvariance across groups in addition to bias estimates of major MSLGM parameters were investigated. Simulation results support the suitability of MSLGM for measurement invariance testing when either forward or iterative likelihood ratio procedure is applied.     

Theory-building and theory-confirming observation in science and science education

A paper by Norris presents scientific observation as a highly inferential activity in which human senses have become secondary to instrumentation. Norris takes examples from elementary and secondary curricula to support his position. This paper examines Norris's contentions from two perspectives, that of cognitive psychology and that of the philosophy of science. It is argued here that Norris has discussed only one aspect of observation, theory-confirming observation. Another, pretheoretic or theory-building observation, is more closely related to the curriculum activities he criticized. From a cognitive psychology perspective the theory-confirming observation is of use to the expert, but for novices the absence of domain-specific knowledge and of sophisticated problem-solving processes may render theory-building observation more meaningful for instruction.     

Prediction of attributional consequences in an actual achievement setting

One hundred ninety-six undergraduates who received feedback on a midterm examination participated in this study. A random subgroup formed a cross-validation sample. Through the use of regression analysis, it was found that both objective and subjective performance ratings did not predict subjects' expectancy ratings but did substantially predict their ratings of pride/shame. Inclusion of attributions enhanced prediction of expectancy but not pride/shame ratings of subjects. On the basis of the findings from this study, a partial reformulation of Weiner's attributional model was proposed. In addition, numerous methodological concerns associated with attributional research were examined.     

Being-Together: Thinking through Technologically Mediated Sociality and Community

Our sociality is increasingly enacted through technology. This essay argues that the relationship between the technological mediation of social relations and the ways in which these practices are understood conceptually needs to be critiqued, rethought, and extended. Current approaches tend to accentuate the individual to the detriment of the social and often to understand technology instrumentally. Jean-Luc Nancy's notion of being singular plural and his understanding of the relations between singular beings and of ecotechnics are discussed briefly to illustrate an alternate direction for considering ways of being-together in Western techno-society.     

Changes in tibiofemoral contact forces during running in response to in-field gait retraining

We evaluated the efficacy of an in-field gait retraining programme using mobile biofeedback to reduce cumulative and peak tibiofemoral loads during running. Thirty runners were randomised to either a retraining group or control group. Retrainers were asked to increase their step rate by 7.5% over preferred in response to real-time feedback provided by a wrist mounted running computer for 8 routine in-field runs. An inverse dynamics driven musculoskeletal model estimated total and medial tibiofemoral joint compartment contact forces. Peak and impulse per step total tibiofemoral contact forces were immediately reduced by 7.6% and 10.6%, respectively (P < 0.001). Similarly, medial tibiofemoral compartment peak and impulse per step tibiofemoral contact forces were reduced by 8.2% and 10.6%, respectively (P < 0.001). Interestingly, no changes were found in knee adduction moment measures. Post gait retraining, reductions in medial tibiofemoral compartment peak and impulse per step tibiofemoral contact force were still present (P < 0.01). At the 1-month post-retraining follow-up, these reductions remained (P < 0.05). With these per stance reductions in tibiofemoral contact forces in mind, cumulative tibiofemoral contact forces did not change due to the estimated increase in number of steps to run 1 km.     

Effect of attending to a ball during a side-cut maneuver on lower extremity biomechanics in male and female athletes

Many sports associated with anterior cruciate ligament (ACL) injury require athletes attend to a ball during participation. We investigated effects of attending to a ball on lower extremity mechanics during a side-cut maneuver and if these effects are consistent for males and females. Sagittal and frontal plane hip and knee kinematics and joint moments were measured during side-cut maneuvers in 19 male and 19 female National Collegiate Athletic Association division III basketball players. Participants also experienced two side-cut conditions that required attention to a ball. Our results did not indicate that the effect of attention varies with gender. However, during side-cut conditions while attending to a ball, internal knee adductor moment was 20% greater (p = 0.03) and peak knee flexion angle was 4 degrees larger (p < 0.01). Females demonstrated 5 degrees less hip flexion (p = 0.046), 12 degrees less knee flexion (p < 0.01), and 4 degrees more knee abduction (p = 0.026) at initial contact during all side-cut conditions than males. Attention to a ball may affect lower extremity mechanics relevant to ACL injury. The validity of laboratory studies of lower extremity mechanics for sports that include attention to a ball may be increased if participants are required to attend to a ball during the task.