Influence of physical and psychological stress on decision-making performance of soccer referees.

Soccer referees have to make quick and accurate decisions while experiencing physical stress (i.e., fatigue) and psychological stress (i.e., pressure from the crowd). Researchers have examined the influence of physical and psychological stress on skilled referees' decision-making performance separately; however, referees usually experience both types of stress simultaneously. The aim of the study was to investigate the influence of both physical and psychological stress on skilled and less-skilled soccer referees' decision-making performance. To simulate the physical and psychological stress during a game, 25 referees were asked to make foul decisions while running on a treadmill and/or being exposed to auditory stress. Referees were more physically fatigued in the physical and psychologically stressed in the psychological stress condition. However, this only negatively influenced their decision-making performance in the video test during the submaximal physical stress condition, when compared to the resting condition. The results also indicate that the experienced referees learned to cope with fatigue and psychological stress regarding their cognitive processes. The effects seem to be differentially detrimental, depending on the league level of refereeing, but also whether physical and psychological stress are induced separately. The study protocol could help referees train in a simulated learning environment, besides on-field games.

Gaze Behavior of Gymnastics Judges: Where Do Experienced Judges and Gymnasts Look While Judging?

Gymnastics judges and former gymnasts have been shown to be quite accurate in detecting errors and accurately judging performance. PURPOSE: The purpose of the current study was to examine if this superior judging performance is reflected in judges' gaze behavior. METHOD: Thirty-five judges were asked to judge 21 gymnasts who performed a skill on the vault in a video-based test. Classifying 1 sample on 2 different criteria, judging performance and gaze behavior were compared between judges with a higher license level and judges with a lower license level and between judges who were able to perform the skill (specific motor experience [SME]) and those who were not. RESULTS: The results revealed better judging performance among judges with a higher license level compared with judges with a lower license level and more fixations on the gymnast during the whole skill and the landing phase, specifically on the head and arms of the gymnast. Specific motor experience did not result in any differences in judging performance; however, judges with SME showed similar gaze patterns to those of judges with a high license level, with 1 difference in their increased focus on the gymnasts' feet. CONCLUSION: Superior judging performance seems to be reflected in a specific gaze behavior. This gaze behavior appears to partly stem from judges' own sensorimotor experiences for this skill and reflects the gymnasts' perspective onto the skill.

Long-term effects of acoustic reafference training (ART).

In sport visual feedback is often used to enhance performance, mostly neglecting the auditory modality. However, athletes produce natural sounds when they move (acoustic reafferences) which they perceive and use to control their movements. We examined the short- and long-term effects of a training intervention on a complex movement by using acoustic reafferences. Natural step sounds produced during hurdling were recorded and played back to the participants immediately before each trial, with an increase (fast group), decrease (slow group), or no manipulation (control group) in the tempo. All groups increased their hurdling performance regarding overall running time, with the slow group showing the best performance development. After a 10-week retention, the fast and slow group further increased performance, whereas the control group declined. The repeated experience with acoustic information associated with the rhythmic pattern of hurdling may have helped developing a cognitive representation of that movement, especially regarding long-term effects.

Auditory reafferences: the influence of real-time feedback on movement control.

Auditory reafferences are real-time auditory products created by a person's own movements. Whereas the interdependency of action and perception is generally well studied, the auditory feedback channel and the influence of perceptual processes during movement execution remain largely unconsidered. We argue that movements have a rhythmic character that is closely connected to sound, making it possible to manipulate auditory reafferences online to understand their role in motor control. We examined if step sounds, occurring as a by-product of running, have an influence on the performance of a complex movement task. Twenty participants completed a hurdling task in three auditory feedback conditions: a control condition with normal auditory feedback, a white noise condition in which sound was masked, and a delayed auditory feedback condition. Overall time and kinematic data were collected. Results show that delayed auditory feedback led to a significantly slower overall time and changed kinematic parameters. Our findings complement previous investigations in a natural movement situation with non-artificial auditory cues. Our results support the existing theoretical understanding of action-perception coupling and hold potential for applied work, where naturally occurring movement sounds can be implemented in the motor learning processes.

Influence of players' vocalisations on soccer referees' decisions.

The influence of a potentially fouled player's vocalisations on the referee's decisions was investigated. Experienced soccer referees watched video clips of real-match situations that were presented either without sound or with sound where a player's vocalisations were clearly audible and made judgements regarding fouls, direction of play and personal penalties. The results revealed that players' vocalisations had no impact on the foul decisions of the referees. However, once a referee made a foul decision, the player's vocalisations led to an increased number of personal penalties (increase in yellow cards) for the foul-causing player. In addition to crowd noise, a player's vocalisations during a foul are used as a proximal cue in the referee's decision-making process.

The perception of natural and modulated movement sounds.

The motor system is engaged when we perceive movement in the environment, even when we have no sensorimotor experience of that movement. It has been suggested that this ability relies on internal models that comprise specific exteroceptive representations, such as audition and vision. It has been shown that, for human movements, the quality of perception depends on the closeness between the perceived movement and the perceiver's own capability of reproducing it. Thus, if we are able to reproduce a movement, we also have the interoceptive motor memories that enable us to run internal models and perceive the same movements more accurately when merely observed. In a behavioral study we investigated if participants would be able to distinguish between self-produced and other-produced movement sounds from a previously recorded hurdling performance. We also analyzed if participants' discriminative ability would vary as a function of specific sound features, examining rhythmic step structure and amplitude range. The results reveal that participants were able to distinguish between their own and others' movement sounds. However, changing either rhythmic step structure or amplitude range of the sounds did not influence this self-other discrimination. We suggest that identification of one's own movement sounds is holistically achieved as an auditory gestalt.

Gymnastic judges benefit from their own motor experience as gymnasts.

Gymnastic judges have the difficult task of evaluating highly complex skills. My purpose in the current study was to examine evidence that judges use their sensorimotor experiences to enhance their perceptual judgments. In a video test, 58 judges rated 31 gymnasts performing a balance beam skill. I compared decision quality between judges who could perform the skill themselves on the balance beam (specific motor experience = SME) and those who could not. Those with SME showed better performance than those without SME. These data suggest that judges use their personal experiences as information to accurately assess complex gymnastic skills. [corrected].