The objectives of this pilot study were to analyze the electromyography (EMG) activity of masseter and anterior temporalis muscles during chewing in 2 different posture conditions: natural head posture (NHP) and maximum yet comfortable forward head posture (FHP) in healthy individuals; and to compare EMG activity between subjects based on their NHP during chewing. Methods: Fifteen subjects participated. Sagittal head posture in sitting position was clinically assessed using a plumb line. Participants were classified as having FHP or upright head posture (UP). Surface EMG was used to evaluate superficial masseter and anterior temporalis bilaterally during chewing in NHP and FHP. Three trials with five chewing cycles were recorded. EMG data were normalized using a maximum voluntary contraction. An independent t-test was used to calculate differences between sides. If no differences were found, both sides were analyzed together. To analyze differences between the 2 conditions, a paired t-test was used. Independent t-test was used to calculate difference between subjects with UP and FHP. Results: A significant increase in muscle activity was found for masseter muscle in the FHP condition. No differences were found in muscle activity in natural head position by posture classification. A trend of increased activity was observed for masseter and temporalis muscles during chewing in FHP. Conclusion: Head and neck posture was found to influence masticatory muscle activity during the function of chewing. The results of this study may help clinicians to better understand the association between head and neck posture alterations with masticatory muscles related disorders.

No abstract

This study was conducted with 90 poultry slaughterhouse workers, which perform the function of removing chicken parts from the conveyor belt, and sample was composed of 66 women (33.5 ± 6.5 years) and 24 men (35.7 ± 7.2 years), aiming to analyze the influence of anthropometry in the shoulder joint of these workers. Body discomfort was evaluated by a human body diagram, being applied at the end of the work shift. The anthropometric measurement of shoulder was performed by measuring the height of the acromion process, being compared with the height of the conveyor belt. Analysis of the results was performed by descriptive statistics, mean, standard deviation, percentage and percentiles 5%, 50% and 95%. It was found that the height of the conveyor belt was 1.74 meters, while the average shoulder height of workers was 1.38 meters for percentile 5%, 1.41 meters for percentile 50% and 1.65 meters for percentile 95%. The discomfort regions were shoulder 45%, neck 29%, column 26%, arms 23%, and wrists and hand 20%. The upper limb assessment was performed with percentile 5% through the Rapid Upper Limb Assessment method, resulting in a final score > 7, indicating the need for adjustments of the work organization. It was concluded that the workplace does not meet the workers' anthropometric characteristics, mainly affecting the shoulder joint, and correction ergonomics becomes necessary so that the workers involved in this study can perform their functions with health, comfort and safety.

RESUMO: As modifi cações estruturais podem ser mensuradas a partir da avaliação postural, pois esta possibilita melhor entendimento sobre os desequilíbrios osteomioarticulares do aparelho locomotor. O objetivo do presente trabalho foi caracterizar os desvios posturais de atletas de duas diferentes modalidades praticadas no Centro de Treinamento de Alto Rendimento da Região Norte. Participaram do estudo 15 indivíduos, sendo 6 praticantes da modalidade tênis de mesa (TM) e 9 mulheres praticantes da modalidade ginástica rítmica (GR). Para avaliação da postura foi utilizada uma câmera digital (SONY®, DSC-S600) em 3 posições: vista anterior, vista posterior e perfi l lateral direito, sendo os dados processados no software SAPO. Os valores médios do ângulo Q da GR são maiores que TM, bem como a inclinação anterior torácica da coluna da GR é maior que TM, diferente da assimetria do ombro do grupo TM, que apresentou valores maiores que GR. Situação contrária foi observada para a assimetria de quadril. Desta forma, os atletas estudados não apresentaram valores diferentes dos habituais e o protocolo com a redução dos pontos anatômicos, demonstra boa relação para as variáveis analisadas.Palavras-chave: postura, posturografi a, alto rendimento, desempenho, análise postural.

Sedentary behavior is prevalent in older adults. Older adults often underutilize public parks for exercising because the parks do not support their needs and preferences. Engaging older adults on the redesign of parks may help promote active lifestyles. The objectives of this pilot study were to evaluate (1) the effects of wearing augmented reality (AR) and virtual reality (VR) glasses on balance; (2) the effects of different virtual walls separating the walking trail from the roadway on older adults’ gait, and (3) the preferences of the participants regarding wall design and other features. The participants were ten older adults (68 ± 5 years) who lived within two miles from the park. Balance and gait were assessed using a force plate and an instrumented mat. It was feasible to use AR with older adults in the park to evaluate features for redesign. Motion sickness was not an issue when using AR glasses, but balance was affected when wearing VR goggles. The area of postural sway increased approximately 25% when wearing AR glasses, and it increased by close to 70% when wearing VR goggles compared to no glasses. This difference is clinically relevant; however, we did not have enough power to identify the differences as statistically significant because of the small sample size and large variability. Different walls did not significantly affect the participants’ gait either because they did not alter the way they walked or because the holograms were insufficiently realistic to cause changes. The participants preferred a transparent wall rather than tall or short solid walls to separate the park from the roadway.