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1.
Aerosp Med Hum Perform ; 92(2): 106-112, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33468291

RESUMO

BACKGROUND: Limited research exists into extraterrestrial CPR, despite the drive for interplanetary travel. This study investigated whether the terrestrial CPR method can provide quality external chest compressions (ECCs) in line with the 2015 UK resuscitation guidelines during ground-based hypogravity simulation. It also explored whether gender, weight, and fatigue influence CPR quality.METHODS: There were 21 subjects who performed continuous ECCs for 5 min during ground-based hypogravity simulations of Mars (0.38 G) and the Moon (0.16 G), with Earths gravity (1 G) as the control. Subjects were unloaded using a body suspension device (BSD). ECC depth and rate, heart rate (HR), ventilation (VE), oxygen uptake (Vo2), and Borg scores were measured.RESULTS: ECC depth was lower in 0.38 G (42.9 9 mm) and 0.16 G (40.8 9 mm) compared to 1 G and did not meet current resuscitation guidelines. ECC rate was adequate in all gravity conditions. There were no differences in ECC depth and rate when comparing gender or weight. ECC depth trend showed a decrease by min 5 in 0.38 G and by min 2 in 0.16 G. Increases in HR, VE, and Vo2 were observed from CPR min 1 to min 5.DISCUSSION: The terrestrial method of CPR provides a consistent ECC rate but does not provide adequate ECC depths in simulated hypogravities. The results suggest that a mixed-gender space crew of varying bodyweights may not influence ECC quality. Extraterrestrial-specific CPR guidelines are warranted. With a move to increasing ECC rate, permitting lower ECC depths and substituting rescuers after 1 min in lunar gravity and 4 min in Martian gravity is recommended.Sriharan S, Kay G, Lee JCY, Pollock RD, Russomano T. Cardiopulmonary resuscitation in hypogravity simulation. Aerosp Med Hum Perform. 2021; 92(2):106112.


Assuntos
Reanimação Cardiopulmonar/métodos , Meio Ambiente Extraterreno , Hipogravidade , Adulto , Feminino , Humanos , Masculino , Treinamento por Simulação
2.
Medicine (Baltimore) ; 99(14): e19586, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32243378

RESUMO

To investigate the effects of body weight support (BWS) and gait velocity on cardiovascular responses during walking on an antigravity treadmill early after unilateral and bilateral total knee arthroplasty (TKA).This study was a cross-sectional study design. Fifty patients (7 males and 43 females; average age, 72.0 ±â€Š5.1 years) at 4 weeks after unilateral (n = 25) and bilateral (n = 25) primary TKA were enrolled in the study. Subjects walked on an antigravity treadmill at speeds of 2.5 km/hour and 3.5 km/hour with 3 levels (50%, 25%, and 0%) of BWS. Cardiovascular responses were monitored by measuring oxygen consumption (VO2), heart rate (HR), systolic and diastolic blood pressure (SBP/DBP), the respiratory exchange ratio (RER), and rate pressure product (RPP). Borg rating of perceived exertion (RPE) and a visual analog scale (VAS) of knee pain were recorded immediately after each trial.There were no significant differences in cardiovascular responses between the unilateral and bilateral TKA groups. In the repeated measures Analysis of Variance, VO2 levels, HR, RPP, RPE, RER, and VAS were significantly increased in proportion to 3 levels (50%, 25%, and 0%) of BWS for unilateral and bilateral TKA groups, respectively. Meanwhile, SBP and DBP were unaffected by differences in BWS. At 3.5 km/hour, VO2, RPE, and RER values were statistically greater than those at 2.5 km/hour under the same BWS conditions.We found that the reduction in the metabolic demand of activity, coupled with positive pressure on the lower extremities, reduced VO2 and HR values as BWS increased.Cardiovascular responses vary according to BWS and gait velocity during antigravity treadmill walking. BWS rather than gait velocity had the greatest effect on cardiovascular responses and knee pain.


Assuntos
Artroplastia do Joelho/reabilitação , Peso Corporal , Sistema Cardiovascular/fisiopatologia , Aparelhos Ortopédicos , Osteoartrite do Joelho/fisiopatologia , Velocidade de Caminhada , Idoso , Pressão Sanguínea , Estudos Transversais , Teste de Esforço , Feminino , Frequência Cardíaca , Humanos , Hipogravidade , Masculino , Osteoartrite do Joelho/cirurgia , Período Pós-Operatório
4.
Sci Rep ; 9(1): 10490, 2019 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-31324854

RESUMO

The control of bipedal stance and the capacity to regain postural equilibrium after its deterioration in variable gravities are crucial prerequisites for manned space missions. With an emphasize on natural orthograde posture, computational techniques synthesize muscle activation patterns of high complexity to a simple synergy organization. We used nonnegative matrix factorization to identify muscle synergies during postural recovery responses in human and to examine the functional significance of such synergies for hyper-gravity (1.75 g) and hypo-gravity (0.25 g). Electromyographic data were recorded from leg, trunk and arm muscles of five human exposed to five modes of anterior and posterior support surface translations during parabolic flights including transitional g-levels of 0.25, 1 and 1.75 g. Results showed that in 1 g four synergies accounted for 99% of the automatic postural response across all muscles and perturbation directions. Each synergy in 1 g was correlated to the corresponding one in 0.25 and 1.75 g. This study therefore emphasizes the similarity of the synergy organization of postural recovery responses in Earth, hypo- and hyper-gravity conditions, indicating that the muscle synergies and segmental strategies acquired under terrestrial habits are robust and persistent across variable and acute changes in gravity levels.


Assuntos
Hipergravidade , Hipogravidade , Equilíbrio Postural , Adulto , Aeronaves , Eletromiografia , Feminino , Humanos , Hipergravidade/efeitos adversos , Hipogravidade/efeitos adversos , Masculino , Músculo Esquelético/fisiologia , Equilíbrio Postural/fisiologia , Postura/fisiologia
5.
Sci Rep ; 9(1): 9397, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31253821

RESUMO

Microgravity exposure is associated with loss of muscle mass and strength. The E3 ubiquitin ligase MuRF1 plays an integral role in degrading the contractile apparatus of skeletal muscle; MuRF1 null (KO) mice have shown protection in ground-based models of muscle atrophy. In contrast, MuRF1 KO mice subjected to 21 days of microgravity on the International Space Station (ISS) were not protected from muscle atrophy. In a time course experiment microgravity-induced muscle loss on the ISS showed MuRF1 gene expression was not upregulated. A comparison of the soleus transcriptome profiles between spaceflight and a publicly available data set for hindlimb suspension, a claimed surrogate model of microgravity, showed only marginal commonalities between the models. These findings demonstrate spaceflight induced atrophy is unique, and that understanding of effects of space requires study situated beyond the Earth's mesosphere.


Assuntos
Hipogravidade , Proteínas Musculares/deficiência , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular/etiologia , Atrofia Muscular/metabolismo , Voo Espacial , Proteínas com Motivo Tripartido/deficiência , Ubiquitina-Proteína Ligases/deficiência , Animais , Suscetibilidade a Doenças , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Elevação dos Membros Posteriores , Camundongos , Camundongos Knockout , Atrofia Muscular/patologia , Tamanho do Órgão
6.
Bull Exp Biol Med ; 167(2): 284-286, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31236875

RESUMO

We studied the effects of hypogravity modeled by water immersion on cognitive functions and physiological parameters of monkeys. Cognitive capacities of monkeys were evaluated using computer-controlled joystick task with food reward in case of target hit. Water immersion (3 days for 3 h) affected in cognitive functions, body temperature, and blood parameters. The intensity of changes depended on the type of monkey behavior. In animals with non-aggressive behavior, the number of target hits did not decrease after water immersion, and even slightly increased. On the contrary, aggressive monkeys showed poorer test performance. Body temperature after each cycle of water immersion was decreased slightly in non-aggressive monkeys, while in aggressive animals, the changes were significant. At the same time, changes in the erythrocyte count, hemoglobin concentration, and hematocrit were significant in non-aggressive monkeys. Our results are in line with previous data performed on BION biosatellites and correspond to changes of physiological parameters in astronauts during space flights.


Assuntos
Agressão/fisiologia , Temperatura Corporal/fisiologia , Cognição/fisiologia , Hipogravidade , Imersão , Modelos Biológicos , Animais , Análise Química do Sangue , Hematócrito , Macaca mulatta , Masculino , Voo Espacial , Água
7.
PLoS One ; 14(2): e0211263, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30759113

RESUMO

Moon and Mars are considered to be future targets for human space explorations. The gravity level on the Moon and Mars amount to 16% and 38%, respectively, of Earth's gravity. Mechanical loading during the anticipated habitual activities in these hypogravity environments will most likely not be sufficient to maintain physiological integrity of astronauts unless additional exercise countermeasures are performed. Current microgravity exercise countermeasures appear to attenuate but not prevent 'space deconditioning'. However, plyometric exercises (hopping and whole body vibration) have shown promise in recent analogue bed rest studies and may be options for space exploration missions where resources will be limited compared to the ISS. This paper therefore tests the hypothesis that plyometric hop exercise in hypogravity can generate sufficient mechanical stimuli to prevent musculoskeletal deconditioning. It has been suggested that hypogravity-induced reductions in peak ground reaction force (peak vertical GRF) can be offset by increases in hopping height. Therefore, this study investigated the effects of simulated hypogravity (0.16G, 0.27G, 0.38G, and 0.7G) upon sub-maximal plyometric hopping on the Verticalised Treadmill Facility, simulating different hypogravity levels. Results show that peak vertical GRF are negatively related to simulated gravity level, but positively to hopping height. Contact times decreased with increasing gravity level but were not influenced through hopping height. In contrast, flight time increased with decreasing gravity levels and increasing hopping height (P < 0.001). The present data suggest that the anticipated hypogravity-related reductions of musculoskeletal forces during normal walking can be compensated by performing hops and therefore support the idea of plyometric hopping as a robust and resourceful exercise countermeasure in hypogravity. As maximal hop height was constrained on the VTF further research is needed to determine whether similar relationships are evident during maximal hops and other forms of jumping.


Assuntos
Exercício Pliométrico/métodos , Corrida/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Hipogravidade , Masculino , Voo Espacial , Simulação de Ambiente Espacial
8.
Life Sci Space Res (Amst) ; 20: 12-19, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30797429

RESUMO

BACKGROUND: Ionizing radiation and hypogravity can cause central nervous system (CNS) dysfunctions. This is a key limiting factor for deep space missions. Up until now, the mechanisms through which they affect the neural tissue are not completely understood. OBJECTIVES: We studied how the combination of hypogravity (antiorthostatic suspension model, AS) and ionizing radiations (γ-quanta and 1H+ together, R) affects the CNS. METHODS: We applied separately and in combination AS and R to determine the influence of these factors on behavior and metabolism of monoamines in Wistar rat's brain. RESULTS: We found out that R has a slight effect on both the behavior and metabolism of monoamines. However, when applied in combination with AS the former was able to reduce the negative effects of the latter. The combined effect of ionizing radiation and hypogravity led to the recovery of locomotor activity, orientation and exploratory behavior, and long-term context memory impaired under the impact of hypogravity only. These changes came together with an increase in the serotonin and dopamine turnover in all of the brain structures that were studied. CONCLUSIONS: We received the first evidence of interferential interaction between the effects of ionizing radiation and hypogravity factors with regard to a behavior and monoamine turnover in the brain. Further studies with heavy nuclei at relevant doses (<0.5 Gy) are needed.


Assuntos
Comportamento Animal/efeitos da radiação , Monoaminas Biogênicas/metabolismo , Encéfalo/metabolismo , Hipogravidade , Modelos Biológicos , Radiação Ionizante , Animais , Encéfalo/efeitos da radiação , Masculino , Ratos , Ratos Wistar
9.
PLoS One ; 14(1): e0209079, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30601851

RESUMO

The lacuno-canalicular network (LCN) hosting the osteocytes in bone tissue represents a biological signature of the mechanotransduction activity in response to external biomechanical loading. Using third-harmonic generation (THG) microscopy with sub-micrometer resolution, we investigate the impact of microgravity on the 3D LCN structure in mice following space flight. A specific analytical procedure to extract the LCN characteristics from THG images is described for ex vivo studies of bone sections. The analysis conducted in different anatomical quadrants of femoral cortical bone didn't reveal any statistical differences between the control, habitat control and flight groups, suggesting that the LCN connectivity is not affected by one month space flight. However, significant variations are systematically observed within each sample. We show that our current lack of understanding of the extent of the LCN heterogeneity at the organ level hinders the interpretation of such investigations based on a limited number of samples and we discuss the implications for future biomedical studies.


Assuntos
Hipogravidade , Microscopia Confocal/métodos , Animais , Ecossistema , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Ausência de Peso
11.
J Neurophysiol ; 120(6): 3110-3121, 2018 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-30332330

RESUMO

Overestimation of roll tilt in hypergravity ("G-excess" illusion) has been demonstrated, but corresponding sustained hypogravic conditions are impossible to create in ground laboratories. In this article we describe the first systematic experimental evidence that in a hypogravity analog, humans underestimate roll tilt. We studied perception of self-roll tilt in nine subjects, who were supine while spun on a centrifuge to create a hypogravity analog. By varying the centrifuge rotation rate, we modulated the centripetal acceleration (GC) at the subject's head location (0.5 or 1 GC) along the body axis. We measured orientation perception using a subjective visual vertical task in which subjects aligned an illuminated bar with their perceived centripetal acceleration direction during tilts (±11.5-28.5°). As hypothesized, based on the reduced utricular otolith shearing, subjects initially underestimated roll tilts in the 0.5 GC condition compared with the 1 GC condition (mean perceptual gain change = -0.27, P = 0.01). When visual feedback was given after each trial in 0.5 GC, subjects' perceptual gain increased in approximately exponential fashion over time (time constant = 16 tilts or 13 min), and after 45 min, the perceptual gain was not significantly different from the 1 GC baseline (mean gain difference between 1 GC initial and 0.5 GC final = 0.16, P = 0.3). Thus humans modified their interpretation of sensory cues to more correctly report orientation during this hypogravity analog. Quantifying the acute orientation perceptual learning in such an altered gravity environment may have implications for human space exploration on the moon or Mars. NEW & NOTEWORTHY Humans systematically overestimate roll tilt in hypergravity. However, human perception of orientation in hypogravity has not been quantified across a range of tilt angles. Using a centrifuge to create a hypogravity centripetal acceleration environment, we found initial underestimation of roll tilt. Providing static visual feedback, perceptual learning reduced underestimation during the hypogravity analog. These altered gravity orientation perceptual errors and adaptation may have implications for astronauts.


Assuntos
Hipogravidade , Orientação Espacial , Postura , Adulto , Imagem Corporal , Retroalimentação Sensorial , Feminino , Humanos , Aprendizagem , Masculino , Vestíbulo do Labirinto/fisiologia
12.
Life Sci Space Res (Amst) ; 18: 72-79, 2018 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-30100150

RESUMO

INTRODUCTION: 2015 UK resuscitation guidelines aim for 50-60 mm depth when giving external chest compressions (ECCs). This is achievable in hypogravity if the rescuer flexes and extends their arms during CPR, or using a new method trialed; the 'Mackaill-Russomano' (MR CPR) method. METHODS: 10 participants performed 3 sets of 30 ECCs in accordance with 2015 guidelines. A control was used at 1Gz, with eight further conditions using Mars and Moon simulations, with and without braces in the terrestrial position and using the MR CPR method. The MR CPR method involved straddling the mannequin, using its legs for stabilization. A body suspension device, with counterweights, simulated hypogravity environments. ECC depth, rate, angle of arm flexion and heart rate (HR) were measured. RESULTS: Participants completed all conditions, and ECC rate was achieved throughout. Mean (±â€¯SD) ECC depth using the MR CPR method at 0.38Gz was 54.1 ±â€¯0.55 mm with braces; 50.5 ±â€¯1.7 mm without. ECCs were below 50 mm at 0.17Gz using the MR CPR method (47.5 ±â€¯1.47 mm with braces; 47.4 ±â€¯0.87 mm without). In the terrestrial position, ECCs were more effective without braces (49.4 ±â€¯0.26 mm at 0.38Gz; 43.9 ±â€¯0.87 mm at 0.17Gz) than with braces (48.5 ±â€¯0.28 mm at 0.38Gz; 42.4 ±â€¯0.3 mm at 0.17Gz). Flexion increased from approximately 2° - 8° with and without braces respectively. HR did not change significantly from control. DISCUSSION: 2015 guidelines were achieved using the MR CPR method at 0.38Gz, with no significant difference with and without braces. Participants were closer to achieving the required ECC depth in the terrestrial position without braces. ECC depth was not achieved at 0.17Gz, due to a greater reduction in effective body weight.


Assuntos
Medicina Aeroespacial , Reanimação Cardiopulmonar/métodos , Massagem Cardíaca/métodos , Hipogravidade , Simulação de Ausência de Peso , Adulto , Feminino , Frequência Cardíaca , Humanos , Masculino , Pressão , Voo Espacial , Adulto Jovem
13.
Astrobiology ; 18(9): 1093-1100, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30067083

RESUMO

Including plants in bioregenerative life-support systems enables simultaneous food production and water and air recycling, while closing cycles for water, oxygen, nitrogen, and carbon. To understand and predict higher plant behavior for a wide range of environmental conditions, including reduced gravity levels, a mechanistic physical model is being developed. The emphasis is set on the influence of gravity levels and forced convection on higher plant leaf gas exchanges, which are altered by reduction of free convection in lower gravity environments, such as microgravity or martian and lunar gravities. This study highlights the significance of understanding leaf boundary layer limitations and ultimately will lead to complete mechanistic modeling of mass and energy balances on plant growth in reduced gravity environments.


Assuntos
Meio Ambiente Extraterreno , Hipogravidade , Modelos Teóricos , Desenvolvimento Vegetal , Aceleração , Biomassa , Dióxido de Carbono/metabolismo , Simulação por Computador , Convecção , Oxigênio/metabolismo , Transpiração Vegetal/fisiologia
15.
J Orthop Res ; 36(3): 921-929, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-28762588

RESUMO

The use of shock wave therapy (SWT) and low-intensity pulsed ultrasound (LIPUS) as countermeasures to the inhibited fracture healing experienced during mechanical unloading was investigated by administering treatment to the fracture sites of mature, female, Rambouillet Columbian ewes exposed to partial mechanical unloading or full gravitational loading. The amount of fracture healing experienced by the treatment groups was compared to controls in which identical surgical and testing protocols were administered except for SWT or LIPUS treatment. All groups were euthanized after a 28-day healing period. In vivo mechanical measurements demonstrated no significant alteration in fixation plate strains between treatments within either partial unloading group. Similarly, DXA BMD and 4-point bending stiffness were not significantly altered following either treatment. µCT analyses demonstrated lower callus bone volume for treated animals (SWT and LIPUS, p < 0.01) in the full gravity group but not between reduced loading groups. Callus osteoblast numbers as well as mineralized surface and bone formation rate were significantly elevated to the level of the full gravity groups in the reduced loading groups following both SWT and LIPUS. Although no increase in 4-week mechanical strength was observed, it is possible that an increase in the overall rate of fracture healing (i.e., callus strength) may be experienced at longer time points under partial loading conditions given the increase in osteoblast numbers and bone formation parameters following SWT and LIPUS. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:921-929, 2018.


Assuntos
Tratamento por Ondas de Choque Extracorpóreas , Consolidação da Fratura/efeitos da radiação , Elevação dos Membros Posteriores , Animais , Feminino , Hipogravidade/efeitos adversos , Ovinos , Microtomografia por Raio-X
16.
J Exp Biol ; 221(Pt 3)2018 02 13.
Artigo em Inglês | MEDLINE | ID: mdl-29217625

RESUMO

In gravity below Earth-normal, a person should be able to take higher leaps in running. We asked 10 subjects to run on a treadmill in five levels of simulated reduced gravity and optically tracked centre-of-mass kinematics. Subjects consistently reduced ballistic height compared with running in normal gravity. We explain this trend by considering the vertical take-off velocity (defined as maximum vertical velocity). Energetically optimal gaits should balance the energetic costs of ground-contact collisions (favouring lower take-off velocity), and step frequency penalties such as leg swing work (favouring higher take-off velocity, but less so in reduced gravity). Measured vertical take-off velocity scaled with the square root of gravitational acceleration, following energetic optimality predictions and explaining why ballistic height decreases in lower gravity. The success of work-based costs in predicting this behaviour challenges the notion that gait adaptation in reduced gravity results from an unloading of the stance phase. Only the relationship between take-off velocity and swing cost changes in reduced gravity; the energetic cost of the down-to-up transition for a given vertical take-off velocity does not change with gravity. Because lower gravity allows an elongated swing phase for a given take-off velocity, the motor control system can relax the vertical momentum change in the stance phase, thus reducing ballistic height, without great energetic penalty to leg swing work. Although it may seem counterintuitive, using less 'bouncy' gaits in reduced gravity is a strategy to reduce energetic costs, to which humans seem extremely sensitive.


Assuntos
Aceleração , Marcha , Hipogravidade , Corrida , Adaptação Fisiológica , Fenômenos Biomecânicos , Humanos
17.
Neuroreport ; 29(4): 247-251, 2018 03 07.
Artigo em Inglês | MEDLINE | ID: mdl-29112678

RESUMO

We explored the effect of gravity on the accuracy for estimating durations of 3.5, 7, and 14 s. Experiments were performed on board an Airbus A310 during parabolic flights eliciting repeated exposures to short periods of 0, 1, and 1.8 g. Two methods for obtaining duration estimates were used, reproduction and production of duration, in two conditions: a control counting condition and a concurrent reading condition. Simple reaction times were also measured to assess attention. The results showed that the temporal accuracies during the reproduction task in the concurrent reading condition were significantly underestimated in 0 g compared with 1 g. Reaction times were also longer in 0 g. However, there was no difference in duration estimates in the production tasks. These results suggest that the temporal underestimation in 0 g is caused by decreased selective attention and impaired retrieval of information in episodic memory.


Assuntos
Hipergravidade , Hipogravidade , Percepção do Tempo , Adulto , Atenção , Feminino , Humanos , Masculino , Memória Episódica , Rememoração Mental , Pessoa de Meia-Idade , Tempo de Reação , Leitura , Simulação de Ausência de Peso , Adulto Jovem
18.
Aerosp Med Hum Perform ; 88(9): 841-849, 2017 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-28818143

RESUMO

INTRODUCTION: Creation of the cosmonaut in-flight physical training process is currently based on the leading role of support afferents in the development of hypogravity changes in the motor system. We assume that the strength of support afferents is related to the magnitude of the ground reaction forces (GRF). For this purpose it was necessary to compare the GRF magnitude on the Russian BD-2 treadmill for different locomotion types (walking and running), modes (active and passive), and subjects. METHODS: Relative GRF values were analyzed while subjects performed walking and running during active and passive modes of treadmill belt movement under 1 G (N = 6) and 0 G (N = 4) conditions. RESULTS: For different BD-2 modes and both types of locomotion, maximum GRF values varied in both 0 G and 1 G. Considerable individual variations were also found in the locomotion strategies, as well as in maximum GRF values. In 0 G, the smallest GRF values were observed for walking in active mode, and the largest during running in passive mode. In 1 G, GRF values were higher during running than while walking, but the difference between active and passive modes was not observed; we assume this was due to the uniqueness of the GRF profile. DISCUSSION: The maximum GRF recorded during walking and running in active and passive modes depended on the individual pattern of locomotion. The maximum GRF values that we recorded on BD-2 were close to values found by other researchers. The observations from this study could guide individualized countermeasures prescriptions for microgravity.Fomina E, Savinkina A. Locomotion strategy and magnitude of ground reaction forces during treadmill training on ISS. Aerosp Med Hum Perform. 2017; 88(9):841-849.


Assuntos
Hipogravidade , Locomoção/fisiologia , Educação Física e Treinamento , Adulto , Medicina Aeroespacial , Fenômenos Biomecânicos , Humanos , Masculino , Federação Russa , Simulação de Ambiente Espacial , Suporte de Carga
19.
Aerosp Med Hum Perform ; 88(8): 730-736, 2017 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-28720182

RESUMO

BACKGROUND: Treadmills have been employed as both a form of exercise and a countermeasure to prevent changes in the musculoskeletal system on almost all NASA missions and many Russian missions since the early Space Shuttle flights. It is possible that treadmills may also be part of exercise programs on future Mars missions and that they may be a component of exercise facilities in lunar or Martian habitats. METHODS: In order to determine if the ambient gravity on these destinations will provide osteogenic effects while performing exercise on a treadmill, ground reactions forces (GRFs) were measured on eight subjects (six women and two men) running at 6 mph during parabolic flight in Martian and lunar gravity conditions. RESULTS: On average, stride length increased as gravity decreased. The first and second peaks of the GRFs decreased by 0.156 and 0.196 bodyweights, respectively, per 1/10 g change in ambient gravity. DISCUSSION: Based on comparisons with previously measured GRF during loaded treadmill running on the International Space Station, we conclude that unloaded treadmill running under lunar and Martian conditions during exploration missions is not likely to be an osteo-protective exercise.Cavanagh P, Rice A, Glauberman M, Sudduth A, Cherones A, Davis S, Lewis M, Hanson A, Wilt G. Ground reaction forces during reduced gravity running in parabolic flight. Aerosp Med Hum Perform. 2017; 88(8):730-736.


Assuntos
Hipogravidade , Corrida/fisiologia , Simulação de Ambiente Espacial , Medicina Aeroespacial , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Marte , Lua , Suporte de Carga
20.
Aerosp Med Hum Perform ; 88(7): 682-687, 2017 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-28641686

RESUMO

BACKGROUND: Increased gravito-inertial acceleration, or hypergravity, such as produced in a centrifuge or in an aircraft coordinated turn, causes humans to systematically overestimate their roll tilt in the dark. This is known as the "G-excess" illusion. We have previously modified a mathematical observer model of dynamic orientation perception to replicate these illusory tilt perceptions. This modified model also made a novel, previously untested, prediction that humans would underestimate acute roll tilt in reduced gravitational environments (hypogravity). CASE REPORT: In the current study, we used aircraft parabolic flight to test this prediction in a single subject. Roll tilt perception was reported using a subjective visual vertical task in which the subject aligned an illuminated line, presented in a head mounted display, with their perceived direction of down. The same subject made reports during hypogravity parabolas (0.165 G and 0.38 G, corresponding to lunar and Martian gravity, respectively), hypergravity maneuvers (1.6 G during a pull out maneuver and 1.2 G during a coordinated turn), and 1-G control conditions (both on the ground and in straight and level flight). As hypothesized, the subject significantly underestimated roll tilt in the hypogravity environments by approximately 40% compared to 1-G reports while overestimating roll tilt in the hypergravity environments. DISCUSSION: The amount of underestimation observed was quantitatively consistent with that predicted a priori by the modified observer model. We propose the term "G-shortage" illusion for the underestimation of roll tilt in hypogravity. This illusion may have implications for aircraft pilots and astronauts.Clark TK, Young LR. A case study of human roll tilt perception in hypogravity. Aerosp Med Hum Perform. 2017; 88(7):682-687.


Assuntos
Hipogravidade , Orientação , Propriocepção , Simulação de Ambiente Espacial , Vestíbulo do Labirinto/fisiopatologia , Adulto , Voluntários Saudáveis , Humanos , Masculino
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