Perceived distance during golf putting

Errorless Training Benefits Motor Learning and Kinematic Outcomes in Children With Autism Spectrum Disorders

Most children with Autism Spectrum Disorder (ASD) have some form of motor deficits. Additionally, based on executive dysfunction, working memory is often atypical in these children. Errorless learning reduces demands on working memory. In this study, we investigated the effectiveness of errorless training on these children's ability to learn golf putting. Participants (N = 20), aged 9-13 years (M = 10.15, SD = 1.4), were randomly assigned to either: (a) an errorless (ER) training group (n = 10) or (b) an explicit instruction (EI) group (n = 10). The ER group practiced putting from different distances without any instruction, while the EI group practiced putting at a particular distance with instruction. We measured motor performance (e.g., putting accuracy) and kinematic variables (e.g., putter face angle). One-way analyses of variance showed that motor performance significantly improved in both groups, but that the ER group showed significantly better accuracy retention (p < .028) and transfer learning (p < .047) than the instructional group. Kinematic variables were also significantly different between the two groups on the transfer test. These findings supported the benefits of errorless training compared to explicit instruction to teach motor skills to children with ASD.

Movement Modifications Related to Psychological Pressure in a Table Tennis Forehand Task

Although many studies on choking under pressure used closed skills, such as golf putting, we examined the influence of pressure on movement during a dynamic skill by studying participants' kinematic and kinetic changes during a table tennis forehand task under pressure. Thirty novice table tennis players hit forehand shots toward a target for 135 practice trials and then performed 10 no-pressure and 10 pressure trials. We added psychological pressure by instructing participants they could earn monetary rewards for successful performance and by cancelling accumulated scores for a poor performance. We measured racket head and ball movements as kinematic variables and grip force as a kinetic variable. We also measured state anxiety and heart rate as checks on our manipulation of psychological pressure. In the pressure condition, both state anxiety and heart rate increased significantly ( p < .025), though the pressure level was relatively small. Analysis of kinematic measures revealed that back swing and forward swing were reduced in length; speed of forward swing and ball speed decreased significantly ( p < .008) under pressure. Also, under pressure, ball and racket contact point shifted forward significantly ( p < .008) to reduce the distance between impact and target locations, and performance declined as the ball-landing locations shifted leftward ( p < .007). Grip force showed no significant change. We conclude that, under pressure, movement was modified toward reduced displacement and lower speed in an apparent risk-aversive hitting strategy; these modifications resulted in a performance decrement.

Anxiety Influences the Perceptual-Motor Calibration of Visually Guided Braking to Avoid Collisions

We investigated whether anxiety influences perceptual-motor calibration in a braking to avoid a collision task. Participants performed either a discrete braking task (Experiment 1) or a continuous braking task (Experiment 2), with the goal of stopping before colliding with a stop sign. Half of participants performed the braking task after an anxiety induction. We investigated whether anxiety reduced the frequency of crashing and if it influenced the calibration of perception (visual information) and action (brake pressure) dynamically between-trials in Experiment 1 and within-trials in Experiment 2. In the discrete braking task, anxious participants crashed less often and made larger corrective adjustments trial-to-trial after crashing, suggesting that the influence of anxiety on behavior did not occur uniformly, but rather dynamically with anxiety amplifying the reaction to previous crashes. However, when performing continuous braking, anxious participants crashed more often, and their within-trial adjustments of deceleration were less related to visual information compared to controls. Taken together, these findings suggest that the timescale and nature of the task mediates the influence of anxiety on the performance of goal-directed actions.