Physical exercise is important for people living under extreme environmental conditions to stay healthy. Particularly in space, exercise can partially counteract the loss of muscle mass and muscle strength caused by microgravity. Monitoring the adaptation of the musculoskeletal system to assess muscle quality and devise individual training programmes is highly desirable but is restricted by practical, technical and time constraints on board the International Space Station (ISS). This study aimed to test the feasibility of using myometric measurements to monitor the mechanical properties of skeletal muscles and tendons in weightlessness during parabolic flights.The mechanical properties (frequency, decrement, stiffness relaxation time and creep) of the m. gastrocnemius, m. erector spinae and Achilles tendon were assessed using the hand-held MyotonPRO device in 11 healthy participants (aged 47 +/-9 years) in normal gravity as well as in microgravity during two parabolic flight campaigns. Results showed significant (p < .05-.001) changes in all mechanical properties of both muscles and the Achilles tendon, indicating a more relaxed tissue state in microgravity. Recordings from a phantom rubber material with the device in a test rig confirmed that the device itself was not affected by gravity, as changes between gravity conditions that were too small (<1%) to explain the changes observed in the tissues.It is concluded that myometric measurements are a feasible, easy to use and non-invasive approach to monitor muscle health in extreme conditions that prohibit many other methods.Real-time assessment of the quality of a muscle being exposed to the negative effect of microgravity and also the positive effects of muscular training could be achieved using Myoton technology.

IntroductionMental impairments, including deterioration of mood and cognitive performance, are known to occur during isolation and space missions, but have been insufficiently investigated. Appropriate countermeasures are required, such as exercise, which is known to prevent mood disorders for prolonged space and isolation missions. Based on the interaction of brain activity, mood and cognitive performance, this study aims to investigate the effect of long-term isolation and confinement and the long-term effect of exercise on these parameters.MethodsEight male volunteers were isolated and confined for about eight month during the winter period at the Antarctic Concordia Station. Every six weeks electroencephalographic measurements were recorded under rest conditions, and cognitive tests and a mood questionnaire were executed. Based individual training logs, subjects were afterwards separated into an active (> 2500 arbitrary training units/interval) or inactive (< 2500 arbitrary training units/interval) group.ResultsA long-term effect of exercise was observed for brain activity and mood. Regularly active people showed a decreased brain activity (alpha and beta) in the course of isolation, and steady mood. Inactive people instead first increased and than remained at high brain activity accompanied with a deterioration of mood. No effect of exercise and isolation was found for cognitive performance.ConclusionThe findings point out the positive effect of regularly performed voluntary exercise, supporting subjective mental well-being of long-term isolated people. The choice to be regularly active seems to support mental health, which is not only of interest for future isolation and space missions.

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Purpose Aging is associated with impaired cerebral blood flow (CBF) and increased risk of cerebrovascular disease. Acute increases in CBF during exercise may initiate improvements in cerebrovascular health, but the CBF response is diminished during continuous exercise in older adults. The effect of interval exercise for promoting increases in CBF in young and old adults is unknown. Methods We compared middle cerebral artery blood velocity (MCAv), end-tidal CO2 (PETCO2) and blood pressure (mean arterial pressure [MAP]) during intensity- and work-matched bouts of continuous (10-min 60%W max, followed by 10-min rest) and interval cycling (10 × 1-min 60%W max, separated by 1-min rest) in 11 young (25 ± 3 yr) and 10 old (69 ± 3 yr) men. Results Middle cerebral artery velocity was higher during continuous compared with interval exercise in the young (P < 0.001), but not in the old. This trend was also seen for changes in PETCO2. Although absolute MAP was higher in the old, the relative rise (%∆) in MAP was similar between age groups and was greater during continuous exercise than interval. When we assessed the total accumulated change in MCAv (area under curve: exercise + recovery), it was higher with interval compared with continuous exercise in both groups (P = 0.018). Conclusion These findings suggest that interval exercise may be an effective alternative for promoting acute increases in CBF velocity, particularly in those older adults who may have difficulty sustaining continuous exercise.

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The effect of sleep deprivation on psychophysical performance and well-being is comprehensively investigated. Research investigating the effect of improved sleep is rare. Just as little exists about attempts to support athletic mental state and performance by improving sleep quality. This study aims to investigate whether sleep quality of top athletes can be improved by auditory brainwave entrainment and whether this leads to enhancements of post-sleep psychophysical states. In a pilot study, 15 young elite soccer players were stimulated for eight weeks during sleep with binaural beats around 2-8 Hz. Once a week after wake-up, participants completed three different questionnaires: a sleep diary, an adjective list for psychophysical and motivational state, and a self-assessment questionnaire for sleep and awakening quality. Fifteen sport students executed the same protocol sleeping on the same pillow, but without stimulation. Subjective ratings of sleep and awakening quality, sleepiness and motivational state were significantly improved only in the intervention group, but did not impact their perceived physical state. In summary, eight weeks of auditory stimulation with binaural beats improved perceived sleep quality and the post-sleep state of athletes, whereas the effect on physical level is assumed to occur in a time-delayed fashion. It seems to be worthwhile - to further elaborate long-time effects and consequences on physical and mental performance.

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