In previous studies of attentional focus effects, investigators have measured performance outcome. Here, however, the authors used electromyography (EMG) to determine whether differences between external and internal foci would also be manifested at the neuromuscular level. In 2 experiments, participants (N = 11, Experiment 1; N = 12, Experiment 2) performed biceps curls while focusing on the movements of the curl bar (external focus) or on their arms (internal focus). In Experiment 1, movements were performed faster under external than under internal focus conditions. Also, integrated EMG (iEMG) activity was reduced when performers adopted an external focus. In Experiment 2, movement time was controlled through the use of a metronome, and iEMG activity was again reduced under external focus conditions. Those findings are in line with the constrained action hypothesis (G. Wulf, N. McNevin, & C. H. Shea, 2001), according to which an external focus promotes the use of more automatic control processes.

EMG activity as a function of the performer's focus of attention.

Although a considerable amount of research has established the beneficial effects of social support on health and well-being, relatively little work has focused on identifying those processes by which social support influences various health promoting behaviors. Various lines of research demonstrate converging evidence which suggests that self-efficacy may operate as one possible mediator linking psychosocial influences to positive health functioning associated with regular habitual exercise. The present study examined the relationships among social support, self-efficacy, and the ongoing exercise behavior of sedentary adults. Latent growth modeling techniques were utilized to determine whether self-efficacy served a mediational role in the influence of social support on exercise behaviors. Findings are discussed with reference to the role of cognitive and behavioral mechanisms in the relationship between supportive functions of social networks and improvements in health and well-being associated with regular exercise.

Social support and efficacy cognitions in exercise adherence: A latent growth curve analysis

The main purpose of the present meta-analysis was to examine the criterion-related validity of the 20-m shuttle run test for estimating cardiorespiratory fitness. Relevant studies were searched from twelve electronic databases up to December 2014, as well as from several alternative modes of searching. The Hunter-Schmidt's psychometric meta-analysis approach was conducted to estimate the population criterion-related validity of the 20-m shuttle run test. From 57 studies that were included in the present meta-analysis, a total of 78 correlation values were analyzed. The overall results showed that the performance score of the 20-m shuttle run test had a moderate-to-high criterion-related validity for estimating maximum oxygen uptake (r p = 0.66-0.84), being higher when other variables (e.g. sex, age or body mass) were used (r p = 0.78-0.95). The present meta-analysis also showed that the criterion-related validity of Leger's protocol was statistically higher for adults (r p = 0.94, 0.87-1.00) than for children (r p = 0.78, 0.72-0.85). However, sex and maximum oxygen uptake level do not seem to affect the criterion-related validity values. When an individual's maximum oxygen uptake attained during a laboratory-based test is not feasible, the 20-m shuttle run test seems to be a useful alternative for estimating cardiorespiratory fitness. In adults the performance score only seems to be a strong estimator of cardiorespiratory fitness, in contrast among children the performance score should be combined with other variables. Nevertheless, as in the application of any physical fitness field test, evaluators must be aware that the performance score of the 20-m shuttle run test is simply an estimation and not a direct measure of cardiorespiratory fitness. Key pointsOverall the 20-m shuttle run test has a moderate-to-high mean criterion-related validity for estimating cardiorespiratory fitness.The criterion-related validity of the 20-m shuttle run test is significantly higher for adults than for children. However, when the performance score is combined with other variables, the criterion-related validity value increases considerably among children.Sex and maximum oxygen uptake level of individuals seem not to affect the criterion-related validity of the 20-m shuttle run test.When individuals' maximum oxygen uptake attained during a laboratory-based test is not feasible, the 20-m shuttle run test seems to be a useful alternative for estimating cardiorespiratory fitness.

https://www.jssm.org/hfpdf.php?volume=14&issue=3&page=536

Criterion-Related Validity of the 20-M Shuttle Run Test for Estimating Cardiorespiratory Fitness: A Meta-Analysis

https://libres.uncg.edu/ir/asu/f/Caldwell_Karen_2009_Effect_of_Pilates_training.pdf

Effect of Pilates and taiji quan training on self-efficacy, sleep quality, mood, and physical performance of college students.

Acceleration performance is important for field sport athletes that require a high level of repeat sprint ability. Although acceleration is widely trained for, there is little evidence outlining which kinematic factors delineate between good and poor acceleration. The aim of this study was to investigate the kinematic differences between individuals with fast and slow acceleration. Twenty field sport athletes were tested for sprint ability over the first three steps of a 15m sprint. Subjects were filmed at high speed to determine a range of lower body kinematic measures. For data analysis, subjects were then divided into relatively fast (n = 10) and slow (n = 10) groups based on their horizontal velocity. Groups were then compared across kinematic measures, including stride length and frequency, to determine whether they accounted for observed differences in sprint velocity. The results showed the fast group had significantly lower (~11-13%) left and right foot contact times (p < .05), and an increased stride frequency (~9%), as compared to the slow group. Knee extension was also significantly different between groups (p < .05). There was no difference found in stride length. It was concluded that those subjects who are relatively fast in early acceleration achieve this through reduced ground contact times resulting in an improved stride frequency. Training for improved acceleration should be directed towards using coaching instructions and drills that specifically train such movement adaptations.

/pdf/kinematic-determinants-of-early-acceleration-in-field-sport-2us645l8s6.pdf

Kinematic determinants of early acceleration in field sport athletes.

Science and Medicine of Exercise and Sport. Edited by Warren R. Johnson and E. R. Buskirk. Pp. 486. (Harper and Row: New York and London, 1973.) £10.00.

R. Y. Calne

Papers

Exercise and sport