Validity and reliability of a linear positional transducer across commonly practised resistance training exercises

This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three-dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R² values of >0.85 for all variables excluding deadlift mean velocity (R² = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance.     

Predicting student self-concept,anxiety, and responsibility from self-evaluation and self-praise

Nineteen elementary teachers were observed for the frequency with which they modeled self-praise for their students and taught their students to praise and evaluate themselves. Measures of student self-concept, anxiety, and achievement responsibility were taken at the end of the year. It was found that teacher modeling of self-praise correlated negatively with boys' selfconcept and positively with girls'. Teacher encouragement of students to praise other students correlated positively with boys' anxiety and negatively with girls'. Teacher modeling of self-praise and teacher encouragement of students to praise other students were the best predictors of self-concept.