Search

Physiological deconditioning is a critical problem in space, especially during long-term missions. Resistance exercise, coupled with lower body negative pressure (LBNP), has been shown to be effective in counteracting some of the deconditioning related problems. This paper describes the development of a compact and effective resistance exercise machine that works within an existing environmentally controlled LBNP Box, and is designed to simulate both exercise and sitting, to decrease microgravity-induced deconditioning by simulating physiological and biomechanical features of upright exercise and daily activities. Theoretical calculations are carried out to determine whether kinematics, musculoskeletal loadings, and metabolic rate during supine exercise within the existing LBNP Box are similar to those of an upright posture in Earth gravity (1G). Preliminary results show subjects that use the resistance machine presented in this paper will be able to elicit loads comparable to exercise on Earth, since the ground reaction forces are greater than their body weight (BW). The largest single-leg forces during resistance exercise are 1.16 BW (232 lbs) during supine position when γ, the angle between the horizontal and the ground pivot on the right side of the mechanism, equals 187 degrees and minimal at 0.68 BW (136 lbs) when γ equals 177 degrees. At the lowest setting of the machine, peak resistance of the foot pedal during the outward stroke is 196 lbf. This force, added to the force due to the 50 mmHg of negative differential pressure, gives a total force of 400 lb, which is 2 BW. The results suggest that this machine can be used to collect and establish a database under both terrestrial conditions and microgravity environments, such as the International Space Station (ISS), to enhance medical researchers’ understanding of how LBNP paired with exercise impacts osteoporosis, orthostatic intolerance, and cardiovascular health.

INTRODUCTION: The LBNP box is widely used to study cardiovascular physiology, orthostatic intolerance and responses to exercise. An exercise multiplatform (ENTIRETY) was constructed for use in an LBNP box. The study evaluated physiological responses and perceived exertion (RPE) during 5 min of exercise using ENTIRETY in supine and standing positions. METHODS: Six subjects (28.8±10.9yr, 64.8±11.2kg,163.2±6.9cm) had heart rate (HR), oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER), electromyography of the VL and VM muscles (sEMG), and Borg scale RPE measured at rest and during exercise in both body positions. RESULTS: Increased HR during the 5 min exercise was not affected by body position. However, a decrease in VO2 and VCO2 (29.34±22.79ml/kg/min; 26.30±6.66ml/kg/min) mean measurements for the supine position in comparison to the orthostatic position (14.2±4.45ml/kg/min; 18.40±4.55ml/kg/min) (P

The purpose of this study was to compare the LBNP tolerance between genders. Twenty healthy subjects (8 men, 12 women) were exposed to 10 min of 45mmHg LBNP. Baseline was taken in the sitting and supine positions. Finger blood pressure and heart rate (R) were recorded continuously. Stroke volume (SV), cardiac Output (CO) and total peripheral resistance (TPR) were calculated by a pulse contour method. Baseline cardiovascular variables were similar in all females, independently of the menstrual cycle Phase and they were considered as one group. Seven of 8 men and 7 of 12 women completed the 10 min of LBNP. Non-finishers (n=6) increased heart rate, decreased systolic blood pressure, mean blood pressure, calculated SV and CO in comparison with the Finisher (n=14) group (p

Uma das maiores limita??es encontrados por aviadores ? conhecido como hip?xia, ou seja, a diminui??o de um adequado suprimento de oxig?nio aos tecidos e c?lulas. Embora acidentes por hip?xia sejam raros, podem-se citar acidentes como Payne Stewart, Cipriota Helios Airways e casal Glazer. Tanto a FAA quanto a ANAC exigem somente disciplinas te?ricas de medicina aeroespacial nos cursos de forma??o de pilotos, por?m, um estudo revelou que 90% dos pilotos de linha a?rea concordam que h? uma necessidade de treinamento pr?tico. Com o objetivo de possibilitar e aperfei?oar este tipo de treinamento, o presente projeto desenvolveu um sistema de treinamento de hip?xia em c?mara de hip?xia normob?rica denominado CHN-ERC. O desenvolvimento foi dividido em quatro sistemas denominados: infraestrutura (Infra), sistema de controle (SC), sistema de seguran?a (SS) e sistema de mistura gasosa (SMG). Ao final do projeto, foi desenvolvido uma c?mara contendo as dimens?es de 2.000 X 2.000 X 2.000 mm, pesando aproximadamente 63 Kg e podendo ser utilizado por dois alunos sentados ou um aluno utilizando uma bicicleta ou esteira ergom?trica. A infraestrutura foi desenvolvida com tubos de PVC e revestimento com lona de vinil. Foi desenvolvido um sistema de controle projetado para adquirir sinais de sensores de O2 e CO2, utilizando um ox?metro port?til Teledyne, al?m de processar e controlar o hardware dos demais sistemas. Para o controle, a homogeneiza??o e a exaust?o da mistura gasosa foi desenvolvido o SMG. Este foi projetado para o envio dos gases contidos nos cilindros de O2 medicinal a 100% e N2 medicinal a 100% para a CHN-ERC, al?m de garantir a mistura e a homogeneiza??o desses gases. Para garantir a seguran?a do aluno que ir? fazer o treinamento e do instrutor, foi desenvolvido o SS. Ap?s a conclus?o da CHN-ERC, tornou-se poss?vel o aprimoramento de treinamento de pilotos com c?mara de baixo custo (aproximadamente R$ 23.300,00), al?m de mostrar-se eficiente para a utiliza??o em treinamento para melhoramento no condicionamento f?sico de atletas de alto rendimento e desenvolvimento de HAST (Hypoxia Altitude Simulation Test). One of the biggest challenges find by aviators is known as hypoxia; that is, the decrease in adequate oxygen supply to tissues and cells. Even though accidents due to hypoxia are rare, it?s possible to quote accidents like Payne Stewart, Cipriota Helios Airways, and the Glazer couple. Both FAA and ANAC demand only theoretical disciplines of aerospace medicine in pilot formation courses, however, a study revelad that 90% of airline pilots agree that there is a necessity of practical training. With the goal of enabling and enhancing this kind of training, this present project developed a system of hypoxia training in normobaric hypoxia chamber, called CHN-ERC. The development was divided in four systems called: Infraestructure (INFRA), Control System (SC), Safety System (SS) and Gaseous Mixture System (SMG). At the project?s conclusion, a camera measuring 2000x2000x2000mm was developed, weighting approximately, 63.35Kg that could be used by two seated students or one student in either a ergonomic bike or treadmill. The structure was developed using PVC tubes covered with vinyl surface. A control system design to acquire signals from O2 and CO2 sensors was developed using the Teledyne portable oximeter, which also processed and controlled other?s systems hardware. To control gaseous mixture homogenization and exhaustion, a system to control these parameters was also developed. This was designed to release gas in cylinders of medicinal O2 at 100% and medicinal N2 at 100% to the CHN-ERC, also ensuring mixture and homogenization of these gases. To ensure both instructor and training student safety, a system named SS was developed. After the CNH-ERC conclusion, it became possible to not only improve pilot training with a low cost chamber (aprox. R$ 23.300), but also efficient in high-end physical training improvement for athletes and HAST (hypoxia altitude simulation test) development.