The relationships between exercise intensity, heart rate, and blood pressure during an incremental isometric exercise test

Currently, it is not possible to prescribe isometric exercise at an intensity that corresponds to given heart rates or systolic blood pressures. This might be useful in optimizing the effects of isometric exercise training. Therefore, the aim of this study was to explore the relationships between isometric exercise intensity and both heart rate and systolic blood pressure during repeated incremental isometric exercise tests. Fifteen participants performed seated isometric double-leg knee extension, during which maximum voluntary contraction (MVC) was assessed, using an isokinetic dynamometer. From this, a corresponding peak electromyographic activity (EMG(peak)) was determined. Subsequently, participants performed two incremental isometric exercise tests (at least 48 h apart) at 10, 15, 20, 25, and 30% EMG(peak), during which steady-state heart rate and systolic blood pressure were recorded. In all participants, there were linear relationships between %EMG(peak) and heart rate (r at least 0.91; P < 0.05) and between %EMG(peak) and systolic blood pressure (r at least 0.92; P < 0.05). Also, when repeated tests were compared, there were no differences in the slopes (P > 0.50) or elevations (P > 0.10) for either of the relationships. Therefore, these linear relationships could be used to identify isometric exercise training intensities that correspond to precise heart rates or systolic blood pressures. Training performed in this way might provide greater insight into the underlying mechanisms for the cardiovascular adaptations that are known to occur as a result.     

Partial swing golf shots: scaled from full swing or independent technique?

Abstract

During practice and competition, golfers are required to use submaximal effort to hit the ball a given distance, i.e., perform a partial shot. While the full golf swing has undergone extensive research, little has addressed partial shots and the biomechanical modifications golfers employ. This study investigates the biomechanical changes between full and partial swings, and determines if the partial swing is a scaled version of the full swing. Using a repeated measures design, 13 male golfers completed a minimum of 10 swings in the full and partial swing conditions, whilst club, ball, kinematic, and kinetic parameters were recorded. Large and statistically significant reductions in body motion (centre of pressure ellipse: 33.0%, p = 0.004, d = 2.26), combined with moderate reductions in lateral shift (25.5%, p = 0.004, d = 0.33) and smaller reductions in trunk rotation (arm to vertical at top of backswing: 14.1%, p = 0.002, d = 2.58) indicate golfers favour larger reductions in proximal measures, combined with diminished reductions as variables moved distally. Furthermore, the partial swing was not found to be a scaled version of the full swing implying a new approach to coaching practices might be considered.     

Analysis of cognitive abilities for learning disabled children

The study investigated WISC-R subtest pattern scores of 58 learning disabled children (42 boys and 16 girls) ranging in age from 6 years to 15 years, 10 months. The variation in subtest scores was analyzed by a 1 X 10 analysis of variance with repeated measures on the single factor. Differences between individual subtest means were analyzed by the Newman-Keuls test for simple effects. The evidence indicates that the low subtest scores on Arithmetic, Coding and Information were characteristic of this group. The study did not support the verbal-Performance discrepancies as useful in the diagnosis of learning disabilities.     

Friendship Quality as a Predictor of Young Children's Early School Adjustment

The purpose of this study was to develop a method for assessing young children's perceptions of classroom friendships and to determine whether these perceptions were associated with their adjustment during the transition to grade school. Subscales tapping 5 friendship processes (e.g., validation, aid, disclosure of negative affect, exclusivity, conflict) were extracted from a 24-item friendship interview that was individually administered to 82 kindergarten children ( M age = 5.61) who possessed a reciprocated and stable "best" friend in their classroom. Children's reports of the investigated friendship processes were found to be reliable, and processes such as perceived validation and conflict predicted children's satisfaction with their friendships, and the stability of these relationships. Perceived conflict in friendships was associated with multiple forms of school maladjustment for boys, including higher levels of school loneliness and avoidance and lower levels of school liking and engagement. For both boys and girls, validation and aid forecasted gains in perceived support from classmates, and aid also predicted improvements in children's school attitudes. Perceived exclusivity in friendships was associated with lower levels of achievement. These findings, and others reported in this article, are consistent with the hypothesis that the relational features of children's classroom friendships yield psychological benefits or costs (e.g., provisions) that, in turn, affect their development and adjustment.