Effect of chainring ovality on joint power during cycling at different workloads and cadences

Non-circular chainrings theoretically enhance cycling performance by increasing effective chainring diameter and varying crank velocity, but research has failed to consistently reproduce the benefits in cycling trials. The aim of this study was (1) to investigate the effect of different chainring shapes on sagittal knee joint moment and sagittal lower limb joint powers and (2) to investigate whether alterations are affected by cadence and workload. Fourteen elite cyclists cycled in six conditions (70, 90 and 110 rpm, each at 180 and 300 W), for 2 min each, using three chainrings of different ovalities (1.0–1.215). Kinematic data and pedal forces were collected. For most conditions, only the chainring with the highest ovality (1.215) was characterised by smaller sagittal knee joint moments, smaller relative sagittal knee joint power contribution and larger relative sagittal hip joint power contribution, which suggests a change from maximising efficiency to maximising power production. Effect sizes increased with higher cadences, but not with higher workload. This study has application for athletes, clinicians and sports equipment industry as a non-circular chainring can change joint-specific power generation and decrease knee joint moment, but certain ovality seems to be necessary to provoke this effect.     

When does an opportunity become an opportunity? Unpacking classroom practice through the lens of ecological psychology

Drawing on ecological psychology, this paper considers how student engagement is an accomplishment of the classroom system. Specifically, this paper presents an analysis of two teachers and their students who were using a project-based unit in their mathematics classes. The two teachers used identical curricular materials, but had dramatically different personal histories of teaching and different instructional practices. Our goal is to investigate the role of the teacher in supporting student engagement by considering the kinds of opportunities to learn that were presented by the teacher, and the relationship between those opportunities to learn and the ways their students engaged. Pragmatically, this paper contributes to our understanding of how teachers’ framing of activity significantly impacts the ways that students are likely to engage tasks. Theoretically, this paper highlights the interactional nature of learning, with the goal of clarifying why learning is not simply an individual accomplishment.     

Toward Intentional,Reflective, and Assimilative Classroom Practices with Students with FASD

The value of research-informed classroom practices is well recognized and thus this qualitative study was designed to explore, from multiple perspectives, the experiences and influences of classroom practices for students with Fetal Alcohol Spectrum Disorders (FASD). The inductive analysis of 11 focus groups and three interviews involving 60 individuals working closely with this student population—31 teachers, seven administrators, 16 allied professionals, and six caregivers—generated three themes: understanding the whole student, responding within dynamic environments, and optimizing student-centered programming. This study provides an essential step toward better-prepared educators for meeting the learning and developmental needs of students with FASD as well as other complex populations. The implications for developing professional learning opportunities reflective of intentional, reflective, and assimilative classroom practices are discussed.     

Numeration a l'ecole elementaire

This paper presents results of research concerning the construction of the concept of natural integers by children. By testing the same children, whose school history was known with accuracy, at one year in tervals, we have sought to determine:

— How their competence in counting and numeration evolved during this period.

— What the mechanisms of this evolution were.

— What role school learning played.

     

Research Experience as a Component of Science and Mathematics Teacher Preparation

Journal of Science Teacher Education -     

Effects of contextual cues previously paired with footshock or illness on behavior and pain sensitivity in the rat

Rats were used in four experiments to study the effects on behavior and pain sensitivity of exposure to a context previously paired with footshock or injection of the emetic drug lithium chloride (LiCl). Exposure to a context previously paired with footshock or injection of LiCl provoked the species-typical defense response of freezing (Experiments 1A and 1B). Exposure to a context previously paired with footshock additionally produced hypoalgesia when rats were tested using the tailflick test (Experiment 1A). By contrast, exposure to a context previously paired with injection of LiCl produced hyperalgesia when rats were tested using the tailflick test (Experiment 1B). However, exposure to a context previously paired with injection of LiCl did provoke hypoalgesia when rats were tested for pain sensitivity using either the hotplate or formalin tests (Experiment 2), which was mediated by the release of endogenous opioid peptides (Experiment 3). These results are discussed with reference to the processes governing associative regulation of defensive behavior and pain control.     

Representing How Rabbits Quack and Competitors Act: Limits on Preschoolers' Efficient Ability to Track Perspective

This study investigated whether humans have two mind‐reading systems whereby the efficient system, unlike the flexible system, is naturally limited. There were two experiments and the first included adults as well as children (3‐ to 4‐year‐olds; total N = 128). In Experiment 1, all groups efficiently gazed in anticipation of an agent's beliefs about object location but not object identity (an ambiguous figure). In Experiment 2, children showed limits in anticipating a competitive agent's action in terms of his perspective on what is desirable. Flexibility in verbally predicting agents' actions across contexts developed with age. Convergence on signature limits across different ages and methods suggests that indirect anticipations involve minimal mind reading, whereas direct predictions tap a refined understanding of perspective.     

Explicit Vocabulary Instruction in Kindergarten: Case Studies of Students With and Without Language Disorders

Research demonstrates that children can make more significant gains through explicit instruction of vocabulary than implicit instruction (Blachowicz and Fisher in Teaching vocabulary in all classrooms, Allyn & Bacon, Boston, MA, 2010; Dalton and Grisham in Read Teach 64(5):306–317, 2011). Effective explicit instruction often includes high quality conversations with teachers and peers (Towson et al. in J Early Interv 38(4):230–246, 2016; Wasik in Read Teach 63(8):621–633, 2010). Data for this study were collected from a larger study designed to explore students’ use of vocabulary words following explicit instruction with the words during an interactive read-aloud. A deeper microanalysis of student discussion, scaffolded by adults, was conducted. The transcribed student discussions, recorded during peer talk, were analyzed using NVivo 10 (QSR International in NVivo (version 10). NVivo qualitative data analysis software, QSR International, Doncaster, VIC, 2012) software. These case studies describe the vocabulary development of two children with diagnosed speech and language disorders and one child without a speech and language impairment.     

The status of training and performance research in the AECT journals

“HPT has had a significant impact on the instructional design and technology field.” Cynthia Conn is working on her Ph.D. in educational technology at the University of Northern Colorado Jacqueline Gitonga is currently working on her Ph.D. in human resource education at the University of Illinois at Urbana-Champaign. Her research interests are in training and development, instructional design and human performance technology.