Sports performance adaptations through occlusal splint: Case reports of triathlon athletes

OBJECTIVE

Occlusal disturbances affect human posture and sports performance. This study aimed to monitor biomechanical adaptations to personalized occlusal splints.

METHODS

Splints were customized based on stabilometry, thermography, sEMG, and kinesiography, and administered to three triathlon athletes. They were evaluated during a 4-month period, using isokinetic indexes, running kinematics and anaerobic outputs.

RESULTS

Individuality emerged as a key factor driving type, quantity, quality, and time trajectories of adaptations. The use of instrumental and clinical tests allowed the detection of static balance and biting function improvements, but not necessarily parallel to sports performance improvements.

CONCLUSION

The authors argue that strength and kinematic imbalances are joint and task-specific and support the use of multi-stage monitoring of the biomechanical effect of mouthpieces. Kinematics of cycling and running may be widely assessed with ecological and inexpensive methods. Strength imbalances need to be continuously monitored due to the high informative value to injury prevention.

The Relationship between Personality and Postural Control in Young Adults—A Pilot Study

Postural control is a term used to describe how the central nervous system regulates sensory information from other systems to produce adequate motor output to maintain a controlled, upright posture. Emotions (fear, anxiety) and thus personality type can affect the strategy of body control. This study aimed to evaluate the impact of personality on postural control. Thirty-three healthy individuals participated in this study. The big-five model was used to examine personality traits. Each participant performed four different standing tasks (one and both legs standing with eyes open (eo) and closed (ec): 2eo, 2ec, 1eo, 1ec). We showed that the dominant personality traits in the study group were extraversion and agreeableness. There were significantly low negative associations between nonlinear parameters and personality traits. A moderate correlation was noted for the 1eo trial between Openness and the Lyapunov exponent. In conclusion, nonlinear measures provide a possible link between personality and postural control. The relationships detected are weak. It shows that factors such as visual control and the size of the support area rather than personality will play a significant role in describing postural control.

Are You “Gazing” at Me? How Others' Gaze Direction and Facial Expression Influence Gaze Perception and Postural Control

In everyday life, interactions between humans are generally modulated by the value attributed to the situation, which partly relies on the partner's behavior. A pleasant or cooperating partner may trigger an approach behavior in the observer, while an unpleasant or threatening partner may trigger an avoidance behavior. In this context, the correct interpretation of other's intentions is crucial to achieve satisfying social interactions. Social cues such as gaze direction and facial expression are both fundamental and interrelated. Typically, whenever gaze direction and facial expression of others communicate the same intention, it enhances both the interlocutor's gaze direction and the perception of facial expressions (i.e., shared signal hypothesis). For instance, an angry face with a direct gaze is perceived as more intense since it represents a threat to the observer. In this study, we propose to examine how the combination of others' gaze direction (direct or deviated) and emotional facial expressions (i.e., happiness, fear, anger, sadness, disgust, and neutrality) influence the observer's gaze perception and postural control. Gaze perception was indexed by the cone of direct gaze (CoDG) referring to the width over which an observer feels someone's gaze is directed at them. A wider CoDG indicates that the observer perceived the face as looking at them over a wider range of gaze directions. Conversely, a narrower CoDG indicates a decrease in the range of gaze directions perceived as direct. Postural control was examined through the center of pressure displacements reflecting postural stability and approach-avoidance tendencies. We also investigated how both gaze perception and postural control may vary according to participants' personality traits and emotional states (e.g., openness, anxiety, etc.). Our results confirmed that gaze perception is influenced by emotional faces: a wider CoDGs was observed with angry and disgusted faces while a narrower CoDG was observed for fearful faces. Furthermore, facial expressions combined with gaze direction influence participants' postural stability but not approach-avoidance behaviors. Results are discussed in the light of the approach-avoidance model, by considering how some personality traits modulate the relation between emotion and posture.

Attention demands of postural control in non-specific chronic low back pain subjects with low and high pain-related anxiety

Impaired postural control in chronic low back pain (CLBP) has been attributed to deficits in sensory and motor functions. However, it is not known if pain-related anxiety affects motor and cognitive function of postural control. The aim of this study was to compare the interactive effects of postural and cognitive function in CLBP patients with high and low pain-related anxiety and healthy subjects. Thirty-eight patients with nonspecific CLBP (19 with low and 19 with high pain-related anxiety levels) and 20 asymptomatic subjects participated. Postural control was assessed by center of pressure (COP) parameters including mean total sway velocity, area, anterior-posterior (A-P), and medial-lateral (Med-Lat) range. Postural task was assessed during four conditions (eyes open with and without ankle vibration-eyes closed with and without ankle vibrations). Participants performed the postural task with or without auditory Stroop task. Average reaction time and error ratio of auditory Stroop test were calculated as measures of the cognitive task performance. Significantly reduced sway area was observed in CLBP patients with high pain-related anxiety and control subjects during the dual-task condition as compared with the single task. In addition, A-P range was significantly reduced in CLBP patients with high pain-related anxiety during dual tasking when eyes were closed with ankle vibration. In addition, only the CLBP subjects with high pain-related anxiety showed significantly longer reaction times by increasing the difficulty of standing postural task. Pain-related anxiety may influence the postural cognitive interactions in CLBP patients. Furthermore, it may be considered as a contributing factor for postural strategies adopted by CLBP patients.

The Influence of Fear of Falling on Orthostatic Postural Control: A Systematic Review

Posture is a complex sensory-motor behavior that can be influenced by the fear of falling (FoF) during environmental changes. The aim of this paper is to investigate the influence of FoF on orthostatic postural control in healthy individuals by a systematic review. Thirteen articles were selected. Some other articles (31 references) were used to contextualize and discuss the topic. Studies in the environment made changes on the environment, in which participants were positioned in high hydraulic platforms at different heights, showed a decrease in the center of pressure in the anteroposterior oscillation where the platform was higher. This change in postural control strategy and the FoF are correlated. It can modulate the activity of the muscle spindle (H-reflex) and probably induce postural freezing phenomenon (anticipated postural anxiety). We can conclude that further studies are needed to understand the physiological echanisms involved in FoF and its relation to changes in postural control strategy.