Alternative conceptions in animal classification: A cross-age study

Employing a cross-age design, this study examined students' alternative conceptions in animal classification at the elementary, secondary, and college levels. Based on a previous study that made use of clinical interviews and a classification task, subjects (N = 468) were administered a multiple-choice/free-response instrument that probed understanding of the concept animal, the vertebrate/invertebrate distinction, and the principal vertebrate classes. Results suggest that students subscribe to a highly restricted view of animals; applying the label almost exclusively to vertebrates, especially to common mammals. When asked to distinguish between vertebrate and invertebrate animals and to classify several species into vertebrate groups, a wide range of alternative conceptions emerged. Cross-age comparisons indicate that many of these alternative views remain intact throughout the school years, while others yield more readily to formal instruction and/or nonschool experiences. Considered within the context of a neoconstructivist view of learning, several suggestions are offered for teaching concepts in animal classification.     

The reliability and validity of the bar-mounted PUSH BandTM 2.0 during bench press with moderate and heavy loads

ABSTRACT

The aim of this study was to assess the reliability and validity of the bar-mounted PUSH Band^TM 2.0 to determine peak and mean velocity during the bench press exercise with a moderate (60% one repetition maximum [1RM]) and heavy (90% 1RM) load. We did this by simultaneously recording peak and mean velocity using the PUSH Band^TM 2.0 and three-dimensional motion capture from participants bench pressing with 60% and 90% 1RM. We used ordinary least products regression to assess within-session reliability and whether the PUSH Band^TM 2.0 could accurately predict motion capture velocity. Results showed that PUSH Band^TM 2.0 and motion capture peak and mean velocity reliability was acceptable with both loads. While there was a tendency for the PUSH Band^TM 2.0 to slightly overestimate peak and mean velocity, there was no fixed bias. However, mean velocity with 60 and 90% 1RM demonstrated proportional bias (differences between predicted and motion capture values increase with magnitude). Therefore, PUSH Band^TM 2.0 peak velocity with 60 and 90% 1RM is valid, but mean velocity is not.