Explore the vast range of titles available.

The aim of the study was to identify changes in the mechanism of postural control among ballroom dancers between standing solo and standing with a partner during specific standard dance positions. Specifically, the study attempted to determine whether the male partner plays a stabilising role in the dance couple. A total of seven competitive dance couples participated in the study. The experimental procedure comprised four dance positions characteristic of international standard dances: standard, starting, chasse and contra check. The dance positions were staged twice – while standing solo and while standing with a partner. The assumption of the assessed position was preceded by a dance phase after which the participants were instructed to freeze on a force plate and hold the position for 30 s. To examine whether subjects standing solo or with partners had greater rambling (RM) or trembling (TR) components in their dance postural profile, the ratios of RM to the center of foot pressure (COP) and TR to COP were computed for velocity. No significant differences were observed in the velocity of COP between standing solo and standing with a partner (p > 0.05). However, during the standard and starting positions, female and male dancers standing solo were characterised by higher values of the velocity of RM/COP ratio and lower values of the velocity of TR/COP ratio than those standing with a partner (p < 0.05). According to the theory behind the RM and TR decomposition, an increase in TR components could indicate a higher reliance on spinal reflexes, which would suggest greater automaticity.

Background Motor challenges are highly prevalent within autism, and increased postural sway has been consistently demonstrated in autistic youth. However, the extent to which sway anomalies extend into adulthood remains understudied. This study aimed to investigate whether increased postural sway is altered in autistic adults compared to neurotypical controls using established sway metrics including sway area and path, as well as rambling-trembling decomposition—an approach that differentiates the postural sway signal into central and peripheral nervous system components. Methods 49 adults with autism spectrum conditions (ASC) and 94 neurotypical controls (NC) participated in a postural sway task on a force platform with manipulations of visual input and stance width. Traditional geometric methods (sway area and path), the spatial characteristics of the body’s adjustment to maintain balance, were measured. As resulting sway measures often covary, multiple factor analysis (MFA) was applied to reduce the measures into distinct, non-redundant dimensions that simplified the data. Group comparisons were completed across these different levels of analysis. Results We observed increased sway path and medio-lateral trembling in ASC compared to NC ( p  < 0.05). Significant group by vision interactions revealed that ASC sway increases were more apparent in eyes-open conditions for sway area and rambling and trembling in the anterior-posterior plane ( p  < 0.01), possibly suggesting differential sensory reweighting of visual input by ASC, or difficulties with multisensory integration. MFA revealed two key dimensions. A fast frequency dimension, linked to peripheral processes, explained most of the overall variance (62.9%) and captured more variance in the ASC group than in NC. A slower frequency dimension, linked to central processes, explained 8.0% of the variance. Limitations Order of sway conditions was consistent among all participants, so it is possible that participant fatigue influenced later sway conditions. Conclusions Building upon previous research finding increased postural sway in autism, we found that combining multiple approaches collectively suggest the critical role of peripheral contributions and visual input in postural sway in autism. Fast-frequency processes that are peripherally-driven may be of particular importance in sway in autistic adults, and should be prioritized in future research to better understand balance performance in autism.

We explored one of the unusual predictions of the concept of back-coupling within the theoretical scheme of the control of posture and movement with setting referent coordinates for the effectors. This concept implies slow drifts of referent coordinates toward actual coordinates leading to unintentional drift in performance. During standing, such slow drifts may lead to a protective step or even a fall and, therefore, corrections are expected leading to body sway at frequencies under 0.1 Hz. Young healthy subjects stood on the force platform quietly for 60 s under two single-task conditions, with eyes open and closed, and two double-task conditions, matching an irrelevant muscle activation signal to a target (MATCH) and performing a subtraction task. The latter was performed with eyes open and closed. The rambling-trembling decomposition was applied to the displacements of the center of pressure in the anterior–posterior direction. Spectral analysis was used to quantify power within typical ranges for Tr and Rm, as well as for a slow Rm component (under 0.1 Hz) addressed as Drift. Closing eyes led to a significant increase in Rm and Tr, but no effects on Drift. Drift increased significantly in the MATCH task with no changes in Rm and a drop in Tr. No effects of the subtraction task were seen on Drift. Overall, our findings suggest that unintentional slow drift of referent body orientation towards the actual body orientation leads to Drift, a specific example of back-coupling reflected in postural sway. This observation can be also seen as an example of physiological minimization of activity of motoneurons. Natural visual feedback is used to avoid the COP drift and/or correct it quickly and effectively; this ability is compromised when vision is used for an unrelated task.

One of the primary contributors to falls in older adults is somatosensory degeneration. A method of center-of-pressure (COP) analysis, rambling-trembling (RM-TR) decomposition, has the potential to significantly improve balance deficit detection. However, its ability to capture sensation-driven changes to postural sway is not well understood. Therefore, the objective of this study is to quantify the effects of progressive simulated somatosensory deficit on COP, RM and TR time series. Fifty-one healthy adults (aged 22.10 ± 1.88 years) completed three 60-s double-limb, quiet standing trials with eyes closed for each randomly-ordered foam thickness condition (no foam, 1/8″, 1/4″, 1/2″, and 1″). Foot-floor kinetic data was collected at 100 Hz using two 6-axis force plates and a 16-bit A/D acquisition system. The data were filtered with a 2nd-order 10 Hz low-pass Butterworth filter and used to calculate COP, RM and TR time series. Range, root-mean-square (RMS), and sample entropy (SampEn) were calculated for each time series. Repeated measures analyses of variance, with α = 0.05, were conducted to compare foam condition for each measure (range, RMS, and SampEn). Results showed range and RMS increased with foam thickness; thicker foams (F3–F4) produced larger increases than thinner foams (F1–F2), with more prominent effects in the AP than ML direction. SampEn decreased as foam thickness increased, but not for all comparisons or measures. TR consistently showed the greatest SampEn values compared with COP and RM. Our findings suggest that RM-TR decomposition can isolate distinct biomechanical contributions to postural sway, each influenced independently by somatosensation. Future work should continue to explore the utility of RM-TR decomposition, particularly in aging populations, to advance our understanding of sensory contributions to postural control and assess its viability as a clinical assessment tool.

Background and Objectives: Some respiratory viruses demonstrate neurotropic capacities. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has recently taken over the globe, causing coronavirus disease 2019 (COVID-19). The aim of the study was to evaluate the impact of COVID-19 on postural control in subjects who have recently recovered from the infection. Materials and Methods: Thirty-three convalescents who underwent COVID-19 within the preceding 2–4 weeks, and 35 healthy controls were enrolled. The ground reaction forces were registered with the use of a force platform during quiet standing. The analysis of the resultant center of foot pressure (COP) decomposed into rambling (RAMB) and trembling (TREMB) and sample entropy was conducted. Results: Range of TREMB was significantly increased in subjects who experienced anosmia/hyposmia during COVID-19 when the measurement was performed with closed eyes (p = 0.03). In addition, subjects who reported dyspnea during COVID-19 demonstrated significant increase of length and velocity of COP (p < 0.001), RAMB (p < 0.001), and TREMB (p < 0.001), indicating substantial changes in postural control. Conclusions: Subjects who had experienced olfactory dysfunction or respiratory distress during COVID-19 demonstrate symptoms of balance deficits after COVID-19 recovery, and the analysis using rambling-trembling decomposition method might point at less efficient peripheral control. Monitoring for neurological sequelae of COVID-19 should be considered.

Background Due to the high postural control demands of sport ju-jitsu, it is likely that long-term sport ju-jitsu training may induce sport-specific adaptations in postural control, especially in positions directly related to combat. The aim of the study was to assess the differences in postural control between elite sport ju-jitsu athletes and untrained controls in non-ecological and ecological conditions and to investigate the relative contribution of spinal and supraspinal mechanisms to postural control in expert athletes. Methods The study was conducted on eleven male elite ju-jitsu athletes and ten non-athletes. The data was collected with the use of a force plate under two conditions: quiet standing and ju-jitsu combat stance. Apart from the standard analysis of the spatial–temporal parameters of center of foot pressure, non-linear measures were used, namely rambling-trembling and sample entropy. The non-parametric Mann–Whitney U test was used to compare both groups. Results The main findings of the study showed that in quiet standing, elite ju-jitsu athletes and non-athletes had comparable postural control in both the anterior–posterior and mediolateral planes. In contrast, in the combat stance, elite athletes had lower values of postural sway and rambling component (range and rms) and higher values of sample entropy in comparison to the non-athletes ( p  < 0.05). No differences were found in the trembling component of sway between groups in the combat stance ( p  < 0.05). Conclusions Smaller postural sway and its rambling component in sport ju-jitsu athletes may indicate the more precise control of center of foot pressure and improved ability in estimating its position. The sample entropy results confirmed that the displacement of center of foot pressure for sport ju-jitsu athletes was more irregular, which demonstrates greater automatization in postural control. The results also confirm the importance of ecological validity in investigating postural adaptations associated with sports expertise.

We explored the how non-athletes, athletes doing mountain sports, and athletes doing sports other than mountain sports use five informational cues (relatedness, autonomy, competence, risk-taking, and weather conditions) for judging the degree of arousal and the degree of satisfaction experienced during mountain rambling. Participants gave their judgment of arousal and satisfaction in 32 scenarios constructed from the orthogonal combination of these information cues. All three groups integrated the informational cues in the same way. The impact of relatedness and the impact risk-taking varied according to the judgment condition.

Dynamic balance is associated with fall risk. The aim of this study is to explore the effects of galvanic vestibular stimulation with very low intensity direct current (dcGVS) on dynamic balance. We used a rocker force platform for assessing the dynamic balance performance. Center-of-pressure (COP) coordinates were acquired and decomposed to rambling (RA) and trembling (TR). We measured sway parameters, including length, average speed, and average range, affected by dcGVS at 0.01 mA with eyes open (EO) and eyes closed (EC). We assessed 33 young healthy subjects and found that all sway parameters were shorter in the EO condition, indicating a better dynamic balance performance. dcGVS significantly improved the dynamic balance performance both in EO and EC conditions. All the sway parameters in COP in EO were significantly shorter than those in EC, indicating a better dynamic balance performance in EO. In EO, RA had greater improvement rates than TR. In EC, only average speed had a greater improvement rate in RA, whereas length and average range had greater improvement rates in TR. These results indicate a different modulation model between EO and EC. These findings indicate that very low intensity dcGVS improved the sway parameters of dynamic balance in young healthy subjects. Moreover, our results suggest different dynamic balance control models between having EO and EC. The mechanisms of these phenomena caused by very low intensity dcGVS require further investigation.

Abstract The Youth Hostels Association (YHA) was founded to provide cheap accommodation for rural holidays. It catered to both walkers and cyclists. However, many perceived the organization as one that favored walkers and considered walking to be a superior form of travel. This perception is examined through the study of four areas; the dispositions and statements of leading figures, the literature of the YHA, the press response to its formation, and the policy interventions of the YHA. Despite this, the YHA had close institutional links with cycling organizations and many cyclists among its members. This article traces the YHA’s relationship with walkers and cyclists and, despite occasional tensions, shows that the two groups could be accommodated within the organization.

The study investigates effects of emotional pictures and words on Center of Pressure (CoP) whole-body reactions, based on theories of emotional valence and arousal, approach–avoidance theory, freezing in humans, and stimulus type (pictures vs. words). For freezing, the study differentiated between rambling and trembling components of the CoP reaction. We hypothesized that negative versus positive emotional valence caused stronger CoP avoidance, for both emotional pictures and words. In addition, freezing was hypothesized to be evident in the CoP trembling component caused by high emotional arousal. Forty-five students enrolled in a teacher program completed a bipedal assessment on a force plate while watching positive versus negative and high- versus low-arousal pictures and words that had been selected from stimulus lists in a pretest. Participants rated the valence and arousal of all stimuli in a questionnaire, the results of which indicated a relationship between negative valence and high arousal. The force plate data confirm the hypotheses. First, negative stimuli elicited significant avoidance CoP shifts, independent of their arousal, as indicated by t tests. This effect was found for both emotional pictures and words. CoP for positive stimuli did not differ from zero. Second, indicating freezing, the CoP trembling component was increased by high arousal, independent of valence. Freezing was only found for emotional pictures. The study discusses both the CoP avoidance effect with respect to valence and stimulus type, and the value of the trembling analysis for freezing. It closes with an analysis of the methodological limitations and with recommendations for future studies.