The Influence of the 'Trier Social Stress Test' on Free Throw Performance in Basketball: An Interdisciplinary Study.

The aim of the present study was to explore the relationship between stress and sport performance in a controlled setting. The experimental protocol used to induce stress in a basketball free throw was the Trier Social Stress Test (TSST) and its control condition (Placebo-TSST). Participants (n = 19), novice basketball players but trained sportspersons, were exposed to two counterbalanced conditions in a crossover design.

A scale-based approach to interdisciplinary research and expertise in sports.

After more than 20 years since the introduction of ecological and dynamical approaches in sports research, their promising opportunity for interdisciplinary research has not been fulfilled yet. The complexity of the research process and the theoretical and empirical difficulties associated with an integrated ecological-dynamical approach have been the major factors hindering the generalisation of interdisciplinary projects in sports sciences. To facilitate this generalisation, we integrate the major concepts from the ecological and dynamical approaches to study behaviour as a multi-scale process.

The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation.

The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization modes (in-phase, anti-phase, and intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization mode in contrast to the less stable anti-phase and intermediate mode.

Eye-hand coordination asymmetries in manual aiming.

The authors investigated whether movement-planning and feedback-processing abilities associated with the 2 hand-hemisphere systems mediate illusion-induced biases in manual aiming and saccadic eye movements. Although participants' (N = 23) eye movements were biased in the direction expected on the basis of a typical Müller-Lyer configuration, hand movements were unaffected. Most interesting, both left- and right-handers' eye fixation onset and time to hand peak velocity were earlier when they aimed with the left hand than they were when they aimed with the right hand, regardless of the availability of vision for online movement control.

Synchronising horizontal arm movement with transparent motion.

The relationship between perception and motor performance was studied in a situation that required perceptual processing of a complex motion stimulus in which a target signal had to be segmented, selected, and tracked. Participants were asked to move their arm in synchrony with one surface of a transparent motion display in which two surfaces moved horizontally back-and-forth over each other. The quality of tracking performance was measured as a function of bottom-up and top-down perceptual cues and their interplay.

The type of visual information mediates eye and hand movement bias when aiming to a Müller-Lyer illusion.

Aiming bias typically influences perception but action towards the illusory stimulus is often unaffected. Recent studies, however, have shown that the type of information available is a predictor for the expression of action bias. In the present cyclical aiming experiment, the type of information (retinal and extra-retinal) was manipulated in order to investigate the differential contributions of different cues on both eye and hand movements.

Perceptual-motor adaptations in a synchronization task: the joint effects of frequency and motion coherence manipulations.

Two experiments were conducted to examine the human ability to adapt to a perturbation in a synchronization task. Five experimental signal conditions were tested using random-dot kinematograms, representing four conditions with different coherence levels (100%, 50%, 30% and 10%) and one target-alone condition. Within one trial, increasing or decreasing the frequency of the sinusoidally moving signal dots abruptly in the midst of each trial provoked a perturbation.

The effect of changed visual feedback on intention tremor in multiple sclerosis.

In patients with multiple sclerosis (MS), intention tremor amplitude is enhanced during the visually guided compared to the memory guided motor tasks. In the present study, the effect of visual feedback on intention tremor was investigated during visually guided wrist step-tracking tasks. Specifically, visual feedback of the hand was provided either instantly or averaged over different time windows.

The influence of motion coherence manipulations on the synchronization level of a perception-action task.

The present experiment was conducted to examine the integration of the motion coherence paradigm in a synchronization task. Random-dot kinematograms were used to generate a pattern of oscillating dots representing four different coherence levels (10%, 30%, 50% and 100%) and one target-alone condition. The participants had to synchronize their arm with the coherently moving dots according to two different synchronization modes (in-phase and anti-phase).

Is the learning of goal-directed displacement effector-independent?

The present experiment was designed to investigate whether the learning of goal-directed locomotion is effector independent. To answer this question a bilateral transfer of learning paradigm was used. We wanted to find out whether learning can be transferred from a trained effector system to an untrained one.

Exercise programs for older men: mode and intensity to induce the highest possible health-related benefits.

Background: Although health-related benefits of fitness training in older men are well established, it is not clear yet which mode and intensity of a exercise program is most effective. This study addresses whether the combination of endurance (ED) and resistance training in older men have supplementary health-related benefits in addition to profits attained through endurance training alone. Additionally, effects of moderate- and low-intensity resistance training are compared.

The effects of enhanced visual feedback on human synchronization.

The execution of actions not only reposes on the spatial and temporal organization of the movements as such but also on their appropriate imbedding into the environmental spatio-temporal constraints. Actually, performance outcome appears to be strongly influenced by the strength of the perception-action coupling. The present experiment wants to examine to what degree this coupling strength affects the spatial and spatio-temporal characteristics of a synchronization task.

The control of sequential aiming movements: the influence of practice and manual asymmetries on the one-target advantage.

The present experiment was conducted to explore the effect of practice on the one-target advantage in manual aiming, as well as asymmetries in intermanual transfer of training. Reaction and movement times for the first movement were longer in the 2-target than in the 1-target task, regardless of the amount of practice, hand preference and practice hand. When two movements were required, peak velocity was lower and, proportionally, more time was spent after peak velocity.

The learning of goal-directed locomotion: a perception-action perspective.

This study was designed to better understand the process underlying the learning of goal-directed locomotion. Subjects walked on a treadmill in a virtual reality setting and were asked to cross pairs of oscillating doors. The subjects behaviour was examined at the beginning of the learning process (pretest), after 350 trials (intermediate test), and after 700 trials (posttest).

When visuo-motor incongruence aids motor performance: the effect of perceiving motion structures during transformed visual feedback on bimanual coordination.

Two experiments are reported in which bimanual coordination tasks were performed under correct and transformed visual feedback conditions. Participants were to generate cyclical line-drawing patterns, with varying degrees of coordinative stability, while perceiving correct or transformed visual information of the trajectories on a screen. Visuo-motor transformations that dissociated the perceived movement direction from the actually generated direction, were applied to one or both limbs, resulting in varying degrees of perceptual grouping power.

The visual control of ball interception during human locomotion.

According to the required velocity model, on-line modulations of movement acceleration are performed on the basis of an optically specified difference between required and current behavior. Can this model account for observed displacement regulations in an interceptive task requiring locomotive displacements? In the present study, a virtual reality set-up was coupled to a treadmill. Subjects walking on the treadmill were required to intercept a virtual ball approaching at eye-level by adjusting their velocity, if necessary.

Temporal information for spatially constrained locomotion.

How is locomotion adapted to spatial environmental constraints? The control of this everyday behavior is claimed to be based on information that specifies either spatial or temporal properties of the actor-environment system. Although studies on open-loop locomotor pointing (i.e.

Perception--action coupling model for human locomotor pointing.

How do humans achieve the precise positioning of the feet during walking, for example, to reach the first step of a stairway? We addressed this question at the visuomotor integration level. Based on the optical specification of the required adaptation, a dynamical system model of the visuomotor control of human locomotor pointing was devised for the positioning of a foot on a visible target on the floor during walking. Visuomotor integration consists of directly linking optical information to a motor command that specifically modulates step length in accordance with the ongoing dynamics of locomotor pattern generation.

The effect of aging on the synchronization of human arm movements to external events.

The aim of this study was to analyze the synchronization of cyclical arm movements to an external event and to determine age-related differences when the coupling strength between perception and action is manipulated. A group of young and a group of older subjects had to track a moving light travelling horizontally while manipulating a lever in the same direction (in-phase) or in the opposite direction (anti-phase). The results showed a performance decrease for both age groups in the anti-phase condition as compared to the in-phase condition, yet this decrease was more pronounced for the older persons.

Control of human locomotion under various task constraints.

The goal of this study was to identify the control mechanism used for locomotion pointing regulation under different external temporal constraints. Subjects ( n=8) had to walk on a treadmill through a number of virtual hallways and cross a pair of gliding doors that opened and closed at a constant preset frequency (0.5 Hz or 1 Hz).

The utilization of visual information in the control of reciprocal aiming movements.

Two experiments examined on-line processing during the execution of reciprocal aiming movements. In Experiment 1, participants used a stylus to make movements between two targets of equal size. Three vision conditions were used: full vision, vision during flight and vision only on contact with the target.

The one-target advantage: a test of the movement integration hypothesis.

Two experiments were conducted to compare the temporal structure of single aiming movements to two-component movements involving either a reversal in direction or an extension. For reversal movements, there was no cost associated with the movement time for the first segment of the movement. However, regardless of movement direction, initiation instructions, handedness or effector, two-component extension movements were always associated with a longer movement time for the first movement segment.

Spatially constrained locomotion under informational conflict.

This study investigates the informational based that supports intentional adaptation of locomotion to spatial environmental constraints. A virtual reality setup was used to present subjects with targets providing normal as well as abnormal optical expansion during locomotor pointing (i.e.

The study of locomotor pointing in virtual reality: the validation of a test set-up.

The goal of this experiment was to validate an experimental set-up for studying locomotor pointing. The specific and also original element of this set-up was the interactive nature of virtual reality and movement production. This interaction was achieved through the coupling of a treadmill and a Silicon Graphics system.

Vision and laterality: does occlusion disclose a feedback processing advantage for the right hand system?

The main purpose of this study was to examine whether manual asymmetries could be related to the superiority of the left hemisphere/right hand system in processing visual feedback. Subjects were tested when performing single (Experiment 1) and reciprocal (Experiment 2) aiming movements under different vision conditions (full vision, 20 ms on/180 ms off, 10/90, 40/160, 20/80, 60/120, 20/40). Although in both experiments right hand advantages were found, manual asymmetries did not interact with intermittent vision conditions.