Cortical reorganization to improve dynamic balance control with error amplification feedback

Background Error amplification (EA), virtually magnify task errors in visual feedback, is a potential neurocognitive approach to facilitate motor performance. With regional activities and inter-regional connectivity of electroencephalography (EEG), this study investigated underlying cortical mechanisms associated with improvement of postural balance using EA. Methods Eighteen healthy young participants maintained postural stability on a stabilometer, guided by two visual feedbacks (error amplification (EA) vs. real error (RE)), while stabilometer plate movement and scalp EEG were recorded. Plate dynamics, including root mean square (RMS), sample entropy (SampEn), and mean frequency (MF) were used to characterize behavioral strategies. Regional cortical activity and inter-regional connectivity of EEG sub-bands were characterized to infer neural control with relative power and phase-lag index (PLI), respectively. Results In contrast to RE, EA magnified the errors in the visual feedback to twice its size during stabilometer stance. The results showed that EA led to smaller RMS of postural fluctuations with greater SampEn and MF than RE did. Compared with RE, EA altered cortical organizations with greater regional powers in the mid-frontal cluster (theta, 4–7 Hz), occipital cluster (alpha, 8–12 Hz), and left temporal cluster (beta, 13–35 Hz). In terms of the phase-lag index of EEG between electrode pairs, EA significantly reduced long-range prefrontal-parietal and prefrontal-occipital connectivity of the alpha/beta bands, and the right tempo-parietal connectivity of the theta/alpha bands. Alternatively, EA augmented the fronto-centro-parietal connectivity of the theta/alpha bands, along with the right temporo-frontal and temporo-parietal connectivity of the beta band. Conclusion EA alters postural strategies to improve stance stability on a stabilometer with visual feedback, attributable to enhanced error processing and attentional release for target localization. This study provides supporting neural correlates for the use of virtual reality with EA during balance training.

Acute Impact of Proprioceptive Exercise on Proprioception and Balance in Athletes

This study aimed to compare the acute effect of a proprioceptive exercise session and a non-specific exercise session on knee position sense, and the static and dynamic balance of athletes. Sixty male athletes (19.4 ± 1.2 years) participated in a within-subjects repeated-measures study. Knee position sense in closed kinetic chain, and static (BESS test) and dynamic balance (Y-balance test) were measured before and after two exercise sessions, consisting of 10 min of non-specific exercise in a cycle-ergometer or proprioceptive exercise with an unstable platform. Overall, both exercise sessions significantly improved knee position sense, BESS score, and YBT composite score, and no differences were detected between proprioceptive and non-specific sessions (knee position sense, −6.9 ± 65.2% vs. −11.5 ± 75.0%, p = 0.680; BESS, −19.3 ± 47.7% vs. −29.03 ± 23.5%, p = 0.121; YBT, 2.6 ± 2.7% vs. 2.2 ± 2.2%, p = 0.305). Twenty athletes did not improve knee position sense after the exercise session (non-responders). When analyzing only the exercise responders, both sessions improved knee position sense, but the improvement was greater after the proprioceptive exercise session (56.4 ± 25.6% vs. 43.8 ± 18.9%, p = 0.023). In conclusion, a single proprioceptive, as well as non-specific, exercise session increased knee position sense and balance. The proprioceptive exercise seems to be more effective in improving joint position sense when considering only athletes who respond to the intervention.

A Model for SynbioticActivity Evaluation: Static and Continuous Co-Culture Fermentation of BifidobacteriumAdolescentis ATCC 15703 and Bacillus Cereus ATCC 9634

In this study, the ability of a probioticstrain (BifidobacteriumadolescentisATCC 15703) to inhibit the growth of the common food contaminantBacilluscereusATCC 9634was studied, both individually and as part of a synbiotic with FOS during batch or continuous fermentation (flow fermentation). The conditions of the flow fermentation corresponded to the parameters of the human large intestine: maintaining a pH of 6.8; anaerobiosis; and a medium flow rate of 0.04 h−1. Bifidobacteria and bacilli were co-cultivated on a prebiotic carbohydrate substrate (10 g/L) and the prebiotic was replaced with glucose (10 g/L).The results of the batch and flow fermentation were compared.The synbiotic efficacy of the probioticBif. adolescentisand the prebiotic FOSagainst the common food contaminantBac. cereuswas shown for all conditions. Fermentation of a pure culture of bifidobacteria with varying prebiotic concentrations (2, 5, 10, 15 and 20 g/L) was carried out to study the state of dynamic balance. It was demonstrated that 48 hours is enough to achieve stable dynamic balance.Prebiotics were co-cultivated with varying carbohydrate concentrations of 5, 10, and 15 g/L.The results showed that increasing the prebiotic concentration increased the duration of the lag-phase and reduced the final number of bacilli. Keywords: probiotics, prebiotics, synbiotics, gastrointestinal tract modeling, antagonism, co-culture fermentation

Association between Inter-Limb Asymmetries in Lower-Limb Functional Performance and Sport Injury: A Systematic Review of Prospective Cohort Studies

Background: Inter-limb asymmetry in lower-limb functional performance has been associated with increased risk of sport injury; however, findings are not always consistent. Purpose: To conduct a systematic review on whether inter-limb asymmetry in lower-limb functional performance can predict sport injury. Methods: Four electronic databases (MEDLINE, EMBASE, Web of Science, and SportDiscus) were systematically searched for prospective cohort studies reporting the association between inter-limb asymmetry in lower-limb functional performance and sport injury. Results: A total of 28 prospective cohort studies were included in the analyses. Collectively, the findings were highly inconsistent, and a clear statement on the association between each asymmetry and sport injury was difficult. Conclusions: Highly inconsistent findings make it difficult to create clear recommendations on the relationship between the inter-limb asymmetry in lower-limb functional performance (power, muscle flexibility, and dynamic balance) and sport injury. The influence of potential factors (selection of tests/parameters, participant characteristics, definition of injury, and ways of calculating asymmetry) should be considered when using previous findings.

Proprioception and neuromuscular control at return to sport after ankle surgery with the modified Broström procedure

The modified Broström procedure (MBP) is an initial treatment for symptomatic chronic ankle instability (CAI) patients. This study aimed to compare the proprioception and neuromuscular control ability of both affected and unaffected ankles at the time of return to sports after MBP for patients with scores of normal controls. 75 individuals (40 who underwent MBP, 35 normal controls) participated. The dynamic balance test scores were significantly higher in the affected ankle of the patients than in the controls (1.5 ± 0.6° vs. 1.1 ± 0.4°, p < 0.003). The time to peak torque for dorsiflexion (60.8 ± 13.9 ms vs. 52.2 ± 17.5 ms, p < 0.022) and eversion (68.9 ± 19.1 ms vs. 59.3 ± 21.1 ms, p < 0.043) was significantly delayed in the affected ankle of the patients than in the controls. The dynamic balance test and time to peak torque in CAI patients remained significantly reduced at the time of return-to-sport after MBP. Clinicians and therapists should be aware of potential deficits in proprioception and neuromuscular control when determining the timing of return to sports after MBP.

The Acoustic Nature of “Storm Nose”, “Supercell” Vortices and Tornadoes

The process of cumulonimbus cloud Cb calvus formation in the middle latitudes of real atmosphere is analyzed in this work. Its transformation from initial lifecycle stage to “maturity” undergoes due to the formation of the waveguide called “aerial acoustic channel” in the troposphere near the level of temperature minimum that is close to 2 km altitude. This “aerial acoustic channel” can be considered as analog of “deep sound channel” that corresponds to the minimal sound speed level. Tropospheric “channel” related to the thermal inversion zone is almost unlimited horizontally. Synchronous generation of two compression waves (ascending one above Cb and descending one inside Cb) is caused by Cb calvus dome ascension. The first one can provoke the aerodynamic draft previously unexplained. The second one results in the growth of its “storm nose” and in the axial and peripheral descending mechanisms in Cb. The penetration of Cb into stratosphere results in the destruction of dynamic balance around Cb top and hence in its unloading in the descending decompression wave. Here the air cools down to the “dew point” in the place of conjugation with parental cloud – due to Snellius law it results in the formation of aerosol “vortex” as condensation front; this “vortex” has calculated value of its generatrix against vertical. Due to D. Snow’s criterion, this vortex forms either “supercell” vortex or tornado vortex.

Presenting a framework for the successful entry of women entrepreneurs into green entrepreneurship

Purpose The concentration of women entrepreneurs on influential events such as the development of green entrepreneurship, which lead to the coordination and dynamic balance between economic and environmental goals, can create a bright future for businesses with sustainable and environmentally friendly architecture. The main purpose of this study is to provide a framework for the successful entry of women entrepreneurs into green entrepreneurship. Design/methodology/approach The present qualitative applied descriptive-analytical study was conducted on a population of women entrepreneurs working in green businesses. This population was obtained by the non-probability chain sampling method and an exploratory interview with the saturation of 12 individuals. Thematic analysis was used to analyze the findings. Findings The results revealed that creating shared value, inclusive social acceptance, multifaceted interactions and green dynamic bedding are effective in the entry of women entrepreneurs into green entrepreneurship in the form of “competitive empowerment” and “multiplied green synergy”. Thus, managers and planners should consider some factors, including shared value, social acceptance, inclusive acceptance, building green culture, knowledge flows, multiple participation, networking dimension, green marketing, competitiveness, creating platforms, green technologies and risk management. Originality/value This research tries to present a framework for the entry of women entrepreneurs into green entrepreneurship area.

Postural control and risk of falling in people who are blind: The effect and durability of perturbation and vestibular exercises

The aim of this study was to compare the effect and durability of perturbation and vestibular exercises on balance and the risk of falling in people with visual impairment (VI). Thirty-six men with VI were divided into three groups, including a control and two experimental (perturbation and vestibular) groups. The experimental groups performed perturbation and vestibular exercises for 4 weeks and three sessions per week. Biodex balance system was used to assess balance and falling risk before and after training interventions. To evaluate the effects within and between groups at three levels of measurement: pre-test, post-test, and durability effect between three groups, repeated measures analysis of variance (ANOVA) and one-way ANOVA were used. Repeated measures ANOVA test showed that both experimental groups showed significant improvements in static balance, dynamic balance, and falling risk. In comparison between the groups, the results showed that in the post-test and durability stages, there was a significant difference between the groups and the perturbation exercise group had a greater effect on the dependent variables. Due to the effectiveness of exercises, it is recommended that people with VI pay attention to balance-based perturbation exercises to strengthen the somatosensory system and vestibular exercises to strengthen the vestibular system.