scholarly journals Muscle synergies for the control of single-limb stance with and without visual information in young individuals

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
L. Labanca ◽  
M. Ghislieri ◽  
M. Knaflitz ◽  
G. Barone ◽  
L. Bragonzoni ◽  
...  
Keyword(s):  
Visual Information ◽  
Balance Control ◽  
Control Strategies ◽  
Age Groups ◽  
Optimal Number ◽  
Muscle Synergies ◽  
Balance Assessment ◽  
Sporting Activities ◽  
Muscle Activations ◽  
Postural Task

Abstract Purpose Single-limb stance is a demanding postural task featuring a high number of daily living and sporting activities. Thus, it is widely used for training and rehabilitation, as well as for balance assessment. Muscle activations around single joints have been previously described, however, it is not known which are the muscle synergies used to control posture and how they change between conditions of normal and lack of visual information. Methods Twenty-two healthy young participants were asked to perform a 30 s single-limb stance task in open-eyes and closed-eyes condition while standing on a force platform with the dominant limb. Muscle synergies were extracted from the electromyographical recordings of 13 muscles of the lower limb, hip, and back. The optimal number of synergies, together with the average recruitment level and balance control strategies were analyzed and compared between the open- and the closed-eyes condition. Results Four major muscle synergies, two ankle-dominant synergies, one knee-dominant synergy, and one hip/back-dominant synergy were found. No differences between open- and closed-eyes conditions were found for the recruitment level, except for the hip/back synergy, which significantly decreased (p = 0.02) in the closed-eyes compared to the open-eyes condition. A significant increase (p = 0.03) of the ankle balance strategy was found in the closed-eyes compared to the open-eyes condition. Conclusion In healthy young individuals, single-limb stance is featured by four major synergies, both in open- and closed-eyes condition. Future studies should investigate muscle synergies in participants with other age groups, as well as pathological conditions.

scholarly journals Effects of Surface Type on Balance Control Strategies in Handstand

2020 ◽  
Vol 27 (4) ◽  
pp. 3-6
Author(s):  
Paweł Arnista ◽  
Michał Biegajło ◽  
Andrzej Mastalerz ◽  
Tomasz Niźnikowski
Keyword(s):  
Balance Control ◽  
Control Strategies ◽  
Balance Assessment ◽  
Training Experience ◽  
Surface Type ◽  
Body Balance ◽  
National Team ◽  
Soft Surface ◽  
Reaction Forces ◽  
Study Participants

Abstract Introduction. A proper manner of maintaining body balance in handstand requires high levels of motor and coordination skills and, first and foremost, specialist training. Therefore, this study sought to determine the effects of surface type on body balance strategies in handstand. Material and Methods. The study included twelve Polish National Team artistic gymnasts with training experience of 16.5 ± 2.12 years. Pedagogical experiment was used as the research method. Body balance assessment of gymnasts was carried out using three tests on different types of the surface. In the first test, the study participants performed handstand on the hard surface. The second one involved executing handstand on canes, whereas the third test consisted in performing handstand on the soft surface. Results. An increase in ground reaction forces (Fx, Fy) was noted in the handstand tests performed on canes (SNS) and on the soft surface (SNA). Conclusions. The analysis revealed that the surface type exerts an influence on the effectiveness of balance control. The findings may constitute the source of knowledge for athletes and coaches about changing conditions of maintaining a stable position when performing handstand during gymnastic training.

scholarly journals An Algorithm for Choosing the Optimal Number of Muscle Synergies during Walking

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3311
Author(s):  
Riccardo Ballarini ◽  
Marco Ghislieri ◽  
Marco Knaflitz ◽  
Valentina Agostini
Keyword(s):  
Motor Task ◽  
Optimal Number ◽  
The Other ◽  
Simulated Dataset ◽  
Muscle Synergies ◽  
Mean Square ◽  
Real Dataset ◽  
Traditional Approaches ◽  
Selection Of ◽  
Semg Signals

In motor control studies, the 90% thresholding of variance accounted for (VAF) is the classical way of selecting the number of muscle synergies expressed during a motor task. However, the adoption of an arbitrary cut-off has evident drawbacks. The aim of this work is to describe and validate an algorithm for choosing the optimal number of muscle synergies (ChoOSyn), which can overcome the limitations of VAF-based methods. The proposed algorithm is built considering the following principles: (1) muscle synergies should be highly consistent during the various motor task epochs (i.e., remaining stable in time), (2) muscle synergies should constitute a base with low intra-level similarity (i.e., to obtain information-rich synergies, avoiding redundancy). The algorithm performances were evaluated against traditional approaches (threshold-VAF at 90% and 95%, elbow-VAF and plateau-VAF), using both a simulated dataset and a real dataset of 20 subjects. The performance evaluation was carried out by analyzing muscle synergies extracted from surface electromyographic (sEMG) signals collected during walking tasks lasting 5 min. On the simulated dataset, ChoOSyn showed comparable performances compared to VAF-based methods, while, in the real dataset, it clearly outperformed the other methods, in terms of the fraction of correct classifications, mean error (ME), and root mean square error (RMSE). The proposed approach may be beneficial to standardize the selection of the number of muscle synergies between different research laboratories, independent of arbitrary thresholds.

scholarly journals Trends of Stomach Cancer in Central Serbia

Medicina ◽  
2021 ◽  
Vol 57 (7) ◽  
pp. 665
Author(s):  
Miodrag M. Stojanovic ◽  
Natasa K. Rancic ◽  
Marija R. Andjelkovic Apostolovic ◽  
Aleksandra M. Ignjatovic ◽  
Mirko V. Ilic
Keyword(s):  
Stomach Cancer ◽  
Preventive Measures ◽  
Age Groups ◽  
Optimal Number ◽  
P Value ◽  
Age Group ◽  
Joinpoint Regression ◽  
Mortality Trends ◽  
Incidence Trend ◽  
Incidence And Mortality

Somach cancer is the third most common cause of cancer-related deaths worldwide. The objective of the paper was to analyze the incidence and mortality trends of stomach cancer in Central Serbia in the period between 1999–2017. Materials and Methods: trends and annual percentage change (APC) of the incidence and mortality rate with corresponding 95% confidence intervals (CI) were calculated by joinpoint regression analyses. The optimal number of Joinpoints was identified using the Monte Carlo permutation method. The trend was considered to be significantly increasing (positive change) or decreasing (negative change) when the p-value was below 0.05 (p < 0.05). Results: the total number of new cases was 16,914 (10,873 males and 6041 females) and the total number of mortality cases was 14,790 (9348 in and 5442 in females). Almost one third (30.8%) of new cases were registered in the 60–69-year age group, and new cases were significantly more frequent in males than in females (30.8% vs. 29.02%, p < 0.001). Joinpoint regression analysis showed a significant decrease of incidence trend in females during the 2000–2015 period with APC of −2.13% (95% CI: −3.8 to −0.5, p < 0.001). An insignificant decrease in incidence trend was in males with APC of −0.72% (95% CI: −2.3 to 0.9, p = 0.30). According to the joinpoint analysis, a significant decrease of mortality trends both in males during 2000–2015 with APC of −2.21% (95% CI: −1.6 to −7.5, p ≤ 0.001 and in females, during the same period, with APC of −1.75% (95% CI: −2.9 to −0.6, p < 0.001) was registered. From 2015 to 2017, a significant increase of mortality was registered with APC of 44.5% (95% CI: from 24.2 to −68.1, p ≤ 0.001) in females and in males with APC of 53.15% (95% CI: 13.5 to −106.6, p ≤ 0.001). Conclusion: a significant decrease of stomach cancer incidence trend in females and insignificant decrease of incidence trend in males were determined in Central Serbia. Based on presented results, the mortality trend decreased significantly both in males and in females during 2000–2015, and from 2015 to 2017 we recorded a significant increase in mortality in both sexes. We found significantly more new cases in women than in men in the age group of 40–49, and the mortality of stomach cancer was significantly more frequent among females compared to males in the age groups 30–39, as well as in the 50–59 age group. There is a need for improving recording and registration of new cases of stomach cancer, especially in females. Urgent primary and secondary preventive measures are needed—introducing stomach cancer screening and early detection of premalignant changes. Urgent primary and secondary preventive measures are needed.

The influence of dynamic visual environments on postural sway in the elderly

1999 ◽  
Vol 9 (3) ◽  
pp. 197-205
Author(s):  
L.L. Borger ◽  
S.L. Whitney ◽  
M.S. Redfern ◽  
J.M. Furman
Keyword(s):  
Visual Information ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Age Groups ◽  
The Elderly ◽  
Visual Scene ◽  
Elderly Subjects ◽  
Mean Velocity ◽  
Healthy Elderly ◽  
Young Subjects

Postural sway during stance has been found to be sensitive to moving visual scenes in young adults, children, and those with vestibular disease. The effect of visual environments on balance in elderly individuals is relatively unknown. The purpose of this study was to compare postural sway responses of healthy elderly to those of young subjects when both groups were exposed to a moving visual scene. Peak to peak, root mean squared, and mean velocity of the center of pressure were analyzed under conditions combining four moving scene amplitudes ( 2 . 5 ∘ , 5 ∘ , 7 . 5 ∘ , 10 ∘ ) and two frequencies of scene movement (0.1 Hz, 0.25 Hz). Each visual condition was tested with a fixed floor and sway referenced platform. Results showed that elderly subjects swayed more than younger subjects when experiencing a moving visual scene under all conditions. The elderly were affected more than the young by sway referencing the platform. The differences between the two age groups were greater at increased amplitudes of scene movement. These results suggest that elderly are more influenced by dynamic visual information for balance than the young, particularly when cues from the ankles are altered.

scholarly journals Hygienic requirements for school buildings’ modern architectural and planning solutions

2021 ◽  
Vol 100 (9) ◽  
pp. 998-1003
Author(s):  
Vladislav R. Kuchma ◽  
Marina I. Stepanova
Keyword(s):  
Age Groups ◽  
Optimal Number ◽  
Educational Process ◽  
Psychological Wellbeing ◽  
School Design ◽  
Physical Factors ◽  
School Buildings ◽  
Digital Learning ◽  
Functional Connections ◽  
Modern School

Introduction. In the last decade, it has become evident that the school is not ready to provide the material and technical capabilities for the modern educational process. The school design strategy is changing, but these innovations are hardly reflected in the research of hygienists. The purpose of the study is to substantiate the hygienic requirements for modern architectural and planning solutions of school buildings. Materials and methods. Expert-analytical research was carried out. The object of the study: documents regulating the sanitary and epidemiological wellbeing of the population, the development of school education infrastructure, documents and publications that reveal the prospects for designing schools. Results. Most functioning school buildings do not meet the requirements for modern school infrastructure. Fewer and fewer students report that they “really like school”, which negatively affects their academic performance and psychological wellbeing. The need for fundamental changes in the construction of school buildings is recorded in the National Educational Initiative “Our New School” (2010). The design decisions of school buildings should take into account the experience of quarantine measures that had to be faced in the context of the spread of the new coronavirus infection (COVID-19). Hygienic requirements for modern architectural and planning solutions for school buildings are: taking into account climatic and geographical conditions; ensuring the psychological wellbeing of children, primarily due to the optimal number of classes and placement of educational premises for different age groups on separate floors, in blocks, buildings; convenient functional connections with the site; the possibility of transforming beliefs, protection from the effects of physical factors and the penetration of pollution from the environment, safe use of digital learning tools, optimal lighting and air-heat regime; sufficient area of educational premises for one student; optimal conditions for physical activity and physical education, regular healthy nutrition, meeting the needs of students in primary health care. Conclusion. Hygienic requirements for the spatial characteristics of school buildings should take into account the new risks to children’s health.

scholarly journals The burden of the current curative expenditure of injury in Dalian, China-A study based on “System of Health Accounts 2011”

2020 ◽  
Author(s):  
Shu Sun ◽  
Liuna Yang ◽  
Xinzhu Hu ◽  
Yalan Zhu ◽  
Boxi Liu ◽  
...  
Keyword(s):  
Foreign Body ◽  
Lower Limb ◽  
Control Strategies ◽  
Age Groups ◽  
The Body ◽  
Age Group ◽  
Curative Care ◽  
Health Accounts ◽  
System Of Health Accounts ◽  
The Cost

Abstract Background Injury is one of the major public health problems, which causes more than 5 million deaths in the world every year. Cases of specific types of injury put a tremendous threat to human health and also add a heavy medical burden on individuals and societies. This study was to calculate and analyze the current curative expenditure (CCE) of injury in Dalian and consequently to provide control strategies for decision-makers. Main text: A total of 565 medical institutions were selected with multistage stratified cluster random sampling, containing 4,375,351 valid samples. Subsequently, the distribution of injury CCE in different dimensions (including age and site of injury) was analyzed under the framework of System of Health Accounts 2011(SHA 2011) using the established database. There were increases from 32.36/100,000 in 2006 to 37.34/100,000 in 2017 and from 46.12/100,000 in 2006 to 54.48/100,000 in 2017 in urban and rural residents respectively. The study found that the CCE of injury in Dalian had reached 1572.73 million RMB, accounting for 7.45% of the total curative care expenditure. In the 15–25 age group, the cost of injury accounts for a larger proportion of CCE than other age groups. Among the injuries in different regions of the body, injuries to the spine, lower limb, head and foreign body entering cost the most. Conclusions Dalian has a relatively serious burden of injury costs. The essential and primary goal is to reduce the cost and increase the benefit of attending to patients with injuries. Specific control strategies should be tilted toward the age group 15–25. Injuries to the spine, lower limb, head and foreign body entering also should be priorities of interventions.

scholarly journals Lower complexity of motor primitives ensures robust control of high-speed human locomotion

2020 ◽  
Author(s):  
Alessandro Santuz ◽  
Antonis Ekizos ◽  
Yoko Kunimasa ◽  
Kota Kijima ◽  
Masaki Ishikawa ◽  
...  
Keyword(s):  
High Speed ◽  
Muscle Activation ◽  
Human Locomotion ◽  
Muscle Synergies ◽  
Activation Patterns ◽  
Motor Primitives ◽  
Muscle Activation Patterns ◽  
Relative Contribution ◽  
Muscle Activations ◽  
Low Dimensional

AbstractWalking and running are mechanically and energetically different locomotion modes. For selecting one or another, speed is a parameter of paramount importance. Yet, both are likely controlled by similar low-dimensional neuronal networks that reflect in patterned muscle activations called muscle synergies. Here, we investigated how humans synergistically activate muscles during locomotion at different submaximal and maximal speeds. We analysed the duration and complexity (or irregularity) over time of motor primitives, the temporal components of muscle synergies. We found that the challenge imposed by controlling high-speed locomotion forces the central nervous system to produce muscle activation patterns that are wider and less complex relative to the duration of the gait cycle. The motor modules, or time-independent coefficients, were redistributed as locomotion speed changed. These outcomes show that robust locomotion control at challenging speeds is achieved by modulating the relative contribution of muscle activations and producing less complex and wider control signals, whereas slow speeds allow for more irregular control.

Implicit postural control strategies in older hemodialysis patients: An objective hallmark feature for clinical balance assessment

2014 ◽  
Vol 40 (4) ◽  
pp. 723-726 ◽  
Author(s):  
Justine Magnard ◽  
Dan Hristea ◽  
Gaëlle Lefrancois ◽  
Angelo Testa ◽  
Anne Paris ◽  
...  
Keyword(s):  
Postural Control ◽  
Control Strategies ◽  
Hemodialysis Patients ◽  
Balance Assessment ◽  
Hallmark Feature

scholarly journals The impact of product presentation on decision-making and purchasing

2019 ◽  
Vol 22 (3) ◽  
pp. 365-380 ◽  
Author(s):  
Rosy Boardman ◽  
Helen McCormick
Keyword(s):  
Decision Making ◽  
Eye Tracking ◽  
Visual Information ◽  
Age Groups ◽  
Target Market ◽  
Consumer Decision Making ◽  
Consumer Decision ◽  
Content Type ◽  
Product Presentation ◽  
The Impact

Purpose This paper aims to investigate how apparel product presentation influences consumer decision-making and whether there are any differences between age groups. Design/methodology/approach A mixed methodology was used including eye-tracking and qualitative in-depth interviews, with a purposive sample of 50 participants between age 20 and 70. Findings A higher number of product presentation features resulted in increased positive visual, cognitive and affective responses as consumers wanted as much visual information as possible to aid decision-making. Images of models attracted the most attention and were the most influential product presentation feature, followed by mannequin images and the zoom function. The 20 s spent much less time viewing and interacting with the product presentation features than middle age groups (30 s-50 s), had minimal fixations on mannequin images and had a much quicker decision-making process than other age groups. Practical implications The research informs retailers which product presentation features are the most effective for their target market to aid consumer decision-making with the aim of reducing returns. Originality/value The paper contributes to the literature by providing more in-depth insights than previous studies into the impact of online product presentation on consumer decision-making by using qualitative research and eye-tracking. The research also explores more product presentation features than previous research and investigates the presentation of apparel products, which are notoriously the most difficult products for consumers to assess online. The research is unique in its exploration of age differences in relation to product presentation features.

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