Athletic background is related to superior trunk proprioceptive ability,postural control,and neuromuscular responses to sudden perturbations

Trunk motor control is essential for athletic performance, and inadequate trunk motor control has been linked to an increased risk of developing low back and lower limb injury in athletes. Research is limited in comparing relationships between trunk neuromuscular control, postural control, and trunk proprioception in athletes from different sporting backgrounds. To test for these relationships, collegiate level long distance runners and golfers, along with non-athletic controls were recruited. Trunk postural control was investigated using a seated balance task. Neuromuscular control in response to sudden trunk loading perturbations was measured using electromyography and kinematics. Proprioceptive ability was examined using active trunk repositioning tasks. Both athlete groups demonstrated greater trunk postural control (less centre of pressure movement) during the seated task compared to controls. Athletes further demonstrated faster trunk muscle activation onsets, higher muscle activation amplitudes, and less lumbar spine angular displacement in response to sudden trunk loading perturbations when compared to controls. Golfers demonstrated less absolute error and variable error in trunk repositioning tasks compared to both runners and controls, suggestive of greater proprioceptive ability. This suggests an interactive relationship between neuromuscular control, postural control, and proprioception in athletes, and that differences exist between athletes of various training backgrounds.     

时间定价与主观时间流逝速度感对利他行为的影响

采用筛选图片时间任务作为被试利他意愿的指标,考察在两种主观时间流逝速度（时间飞逝和时间缓慢）条件下,被试（时间定价组和非时间定价组）对利他行为的影响。结果发现,非时间定价组在时间飞逝和缓慢条件下利他行为差异不显著,但是时间定价组在时间飞逝条件下比在时间缓慢条件下利他行为时间明显较短。结果表明,时间定价组在时间飞逝条件下充分显现时间的价值,减少利他时间,而在时间缓慢条件下,在可接受的时间成本范围内,被试表现出较为乐于助人,证实了主观时间流逝速度会对个体利他行为产生影响。     

The influence of attentional focus on the development of skill representation in a complex action

ObjectivesRecent research has indicated that performers' mental representation of a motor skill changes over the course of learning. In the present study, we sought to ascertain whether the type of instructions (instructions that emphasize either an internal or external focus of attention) influences the development of skill representation during motor learning.DesignParticipants without golf experience were recruited to practice a golf putting task over the course of three training days. Participants were randomly assigned to either an internal focus (focus on the swing of the arms; n = 10) or external focus (focus on the speed of the ball roll; n = 10) learning group. Changes in putting performance and mental representation structure were assessed over the course of learning, as well as during a follow-up retention test two days after practice.MethodsMental representation structure was measured employing the structural dimensional analysis of mental representations (SDA-M), which provided psychometric data on the structure of the mental representation in long-term memory. Additionally, the change in putting accuracy and consistency was recorded over the course of learning.ResultsFindings indicated that the external focus group performed with greater accuracy and consistency during training, and revealed a larger degree of development in their mental representation of the putting task.ConclusionsOverall, our findings suggest that facilitating the link between an action and its effect by means of an external focus is crucial for motor performance as well as the development of skill representation.     

Self-control over combined video feedback and modeling facilitates motor learning

Allowing learners to control the video presentation of knowledge of performance (KP) or an expert model during practice has been shown to facilitate motor learning (Aiken, Fairbrother, & Post, 2012; Wulf, Raupach, & Pfeiffer, 2005). Split-screen replay features now allow for the simultaneous presentation of these modes of instructional support. It is uncertain, however, if such a combination incorporated into a self-control protocol would yield similar benefits seen in earlier self-control studies. Therefore, the purpose of the present study was to examine the effects of self-controlled split-screen replay on the learning of a golf chip shot. Participants completed 60 practice trials, three administrations of the Intrinsic Motivation Inventory, and a questionnaire on day one. Retention and transfer tests and a final motivation inventory were completed on day two. Results revealed significantly higher form and accuracy scores for the self-control group during transfer. The self-control group also had significantly higher scores on the perceived competence subscale, reported requesting feedback mostly after perceived poor trials, and recalled a greater number of critical task features compared to the yoked group. The findings for the performance measures were consistent with previous self-control research.     

Motor abundance and control structure in the golf swing

Variability and control structure are under-represented areas of golf swing research. This study investigated the use of the abundant degrees of freedom in the golf swing of high and intermediate skilled golfers using uncontrolled manifold (UCM) analysis. The variance parallel to (V_UCM) and orthogonal to (V_Orth) the UCM with respect to the orientation and location of the clubhead were calculated. The higher skilled golfers had proportionally higher values of V_UCM than lower skilled players for all measured outcome variables. Motor synergy was found in the control of the orientation of the clubhead and the combined outcome variables but not for clubhead location. Clubhead location variance zeroed-in on impact as has been previously shown, whereas clubhead orientation variance increased near impact. Both skill levels increased their control over the clubhead location leading up to impact, with more control exerted over the clubhead orientation in the early downswing. The results suggest that to achieve higher skill levels in golf may not lie simply in optimal technique, but may lie more in developing control over the abundant degrees of freedom in the body.     

Different task success criteria affect expectancies of success but do not improve golf putting performance

This study examined how providing different criteria for success affected perceived expectations of success, performance, and learning in a golf-putting task. Twenty-nine physical education students were divided into three experimental groups: (a) a large-circle (LC) group that practiced 10 blocks of five putts, each with a 40 cm diameter circle around the target; (b) a small circle (SC) group that practiced with a 10 cm diameter circle around the target; and (c) a control (C) group that practiced with a 25 cm diameter circle around the target. Forty-eight hours after practice, the participants performed a retention test and a transfer test with a 25 cm diameter circle. The transfer test included putting from a greater distance and from a different angle. Throughout the study, we asked the participants to tell us what they think their chances are to land 1, 2, 3, 4, and 5 balls out of 5 possible balls in each block. There were four main findings: (a) the SC group had lower expectancies of success compared with the LC and C groups in acquisition; (b) there were no group differences in performance or learning among groups; (c) golf club kinematic parameters worsened in the transfer test; and (d) the LC group reduced their expectancies of success from the retention to the transfer test, but the expectancies of the SC and C groups remained the same. We conclude that changes in success criteria affect expectancies of success but do not affect actual putting performance or learning.     

Practice variability promotes an external focus of attention and enhances motor skill learning

Variability in practice has been shown to enhance motor skill learning. Benefits of practice variability have been attributed to motor schema formation (variable versus constant practice), or more effortful information processing (random versus blocked practice). We hypothesized that, among other mechanisms, greater practice variability might promote an external focus of attention on the intended movement effect, while less variability would be more conducive to a less effective internal focus on body movements. In Experiment 1, the learning of a throwing task was enhanced by variable versus constant practice, and variable group participants reported focusing more on the distance to the target (external focus), while constant group participants focused more on their posture (internal focus). In Experiment 2, golf putting was learned more effectively with a random compared with a blocked practice schedule. Furthermore, random group learners reported using a more effective distal external focus (i.e., distance to the target) to a greater extent, whereas blocked group participants used a less effective proximal focus (i.e., putter) more often. While attentional focus was assessed through questionnaires in the first two experiments, learners in Experiment 3 were asked to report their current attentional focus at any time during practice. Again, the learning of a throwing task was more effective after random relative to blocked practice. Also, random practice learners reported using more external focus cues, while in blocked practice participants used more internal focus cues. The findings suggest that the attentional foci induced by different practice schedules might be at least partially responsible for the learning differences.     

Advancing a grounded theory of parental support in competitive girls’ golf

Parental support in youth sport has been associated with positive athlete outcomes, such as sport enjoyment and continued participation. Although research has demonstrated the significant and influential role parents fulfil in the youth sport context, there remains a dearth of theoretical frameworks detailing parental support in youth sport and an absence of empirical research examining parental support across athlete development stages and sports. The present study sought to examine athletes’ perceptions of parental support, with a view to advancing a grounded theory of parental support in youth golf. Fourteen online synchronous focus groups were conducted with an international sample (Australia, Canada, England, Finland, Ireland, New Zealand, Scotland) of 61 girls, in the specialising (n = 27) and investment stages (n = 34) of athlete development. Data were analysed in three phases: open-coding, axial coding, and theoretical integration. The substantive grounded theory is constructed on the core category of ‘Individual Parental Support Preferences’. This core category is underpinned by four sub-categories of parental support which were evident across development stages: instrumental, informational, emotional, and autonomy support, and is influenced by a host of athlete (e.g., athletes’ performance), parent (e.g., parents’ knowledge), and contextual characteristics (e.g., location). Unconditional parental support is an important aspect of emotional support, however the concept of adopting a person-first approach to sport parenting is novel. These results provide a rich and novel insight of parental support in girls’ golf, advancing a grounded theoretical understanding of parental support mechanisms in a youth sport context.