Changes in joint kinetics during learning the longswing on high bar

Biomechanics helps us understand the association between technique changes and performance improvement during learning. The aim of this research was to investigate joint kinetic characteristics of technique during learning of the longswing on the high bar. Twelve male, novice participants took part in the learning study. During swing attempts in 8 weekly testing sessions, kinematic data were collected. Inverse dynamics analysis was performed from known zero forces at the toes to quantify joint moments and power at the hips and shoulders. Key biomechanical constraints that limited performance outcome were identified based on changes in joint kinetics during learning. These constraints were the ability to perform a large shoulder power and to overcome passive kinetics acting during the downswing. Constraints to action at the level of joint kinetics differentially challenge learners and therefore could underpin more individual, specific learning interventions. Functional phases, defined by maximum hyperextension to flexion of the hips and maximum flexion to extension of the shoulders, did not describe the key joint kinetics of the hip and shoulder for novices. The functional phases may serve however to identify novices that were unable to overcome the passive kinetic constraint.     

Biomechanical energetic analysis of technique during learning the longswing on the high bar

Biomechanical energetic analysis of technique can be performed to identify limits or constraints to performance outcome at the level of joint work, and to assess the mechanical efficiency of techniques. The aim of this study was to investigate the biomechanical energetic processes during learning the longswing on the high bar. Twelve male, novice participants took part in a training study. Kinematic and kinetics data were collected during swing attempts in eight weekly testing sessions. Inverse dynamics analysis was performed from known zero forces at the toes. Joint work, total energy, and bar energy were calculated. Biomechanical constraints to action, that is, limits to novice performance, were identified as “total work” and “shoulder work”. The most biomechanically efficient technique was associated with an onset of the hip functional phase and joint work that occurred between 10–45° before the bottom of the swing. The learning of gross motor skills is realised through the establishment of a set of techniques with task specific biomechanical constraints. Knowledge of the biomechanical constraints to action associated with more effective and efficient techniques will be useful for both assessing learning and establishing effective learning interventions.     

Race-Specific High School Course Intensity and Student’s Post-secondary Education Attainment

Post-secondary educational attainment is an increasingly important prerequisite to many valued outcomes. This paper examines the association of racially-specific high school course of study with student’s postsecondary educational attainment using ELS 2002–2012 and a comprehensive measure of course intensity derived from students’ patterns of course-taking. Results support a partial presence of racially-specific association of high school course of study. We also find that only Asian-American and American Indian/Alaskan Native students in the middle course intensity and Asian-American students in high course intensity ranges are more likely to obtain at least a 4-year college degree than same-race students in the low course intensity group. However, the same pattern is not evident for White, African-American, multi-racial, and Hispanic students, indicating that they do not experience the same benefit from academically rigorous courses of study. Also, educational expectations do not mediate the relationships among race, course of study, and postsecondary educational trajectory differently for students of different racial groups, i.e., they do not play a larger role in mediating the relationship between course of study and postsecondary educational trajectory for White students.