Concurrent Exercise on a Gravity-Independent Device during Simulated Microgravity

Cotter, Joshua A.; Yu, Allen R.; Haddad, Fadia; Kreitenberg, Arthur; Baker, Michael; Tesch, Per A.; Baldwin, Kenneth M.; Caiozzo, Vincent J.; Adams, Gregory R.

doi:10.1249/mss.0000000000000483

Cited by 23 publications

(22 citation statements)

References 46 publications

(58 reference statements)

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“…For example, pathways related to mitochondria, energy metabolism, and structural components were downregulated, and those involved in the ubiquitin system upregulated, which is consistent with findings in skeletal muscle after short‐ 10‐15,17 and moderately long periods of unloading 18,19 . Similarly, we found a transcriptomic profile indicating slow‐to‐fast fiber transition, a common event in unloading studies 6,43‐46 . Thus, MYH1 and MYH8, myosin isoforms much more abundant in fast‐twitch fibers, 47 were highly upregulated after bed rest.…”

Section: Discussionsupporting

confidence: 88%

Three months of bed rest induce a residual transcriptomic signature resilient to resistance exercise countermeasures

et al. 2020

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This study explored the muscle genome‐wide response to long‐term unloading (84‐day bed rest) in 21 men. We hypothesized that a part of the bed rest‐induced gene expression signature would be resilient to a concurrent flywheel resistance exercise (RE) countermeasure. Using DNA microarray technology analyzing 35 345 gene‐level probe‐sets, we identified 335 annotated probe‐sets that were downregulated, and 315 that were upregulated after bed rest (P < .01). Besides a predictable differential expression of genes and pathways related to mitochondria (downregulation; false‐discovery rates (FDR) <1E‐04), ubiquitin system (upregulation; FDR = 3E‐02), and skeletal muscle energy metabolism and structure (downregulation; FDR ≤ 3E‐03), 84‐day bed rest also altered circadian rhythm regulation (upregulation; FDR = 3E‐02). While most of the bed rest‐induced changes were counteracted by RE, 209 transcripts were resilient to the exercise countermeasure. Genes upregulated after bed rest were particularly resistant to training (P < .001 vs downregulated, non‐reversed genes). Specifically, “Translation Factors,” “Proteasome Degradation,” “Cell Cycle,” and “Nucleotide Metabolism” pathways were not normalized by RE. This study provides an unbiased high‐throughput transcriptomic signature of one of the longest unloading periods in humans to date. Classical disuse‐related changes in structural and metabolic genes/pathways were identified, together with a novel upregulation of circadian rhythm transcripts. In the context of previous bed rest campaigns, the latter seemed to be related to the duration of unloading, suggesting the transcriptomic machinery continues to adapt throughout extended disuse periods. Despite that the RE training offset most of the bed rest‐induced muscle‐phenotypic and transcriptomic alterations, we contend that the human skeletal muscle also displays a residual transcriptomic signature of unloading that is resistant to an established exercise countermeasure.

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Section: Discussionsupporting

confidence: 88%

Three months of bed rest induce a residual transcriptomic signature resilient to resistance exercise countermeasures

et al. 2020

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“…Unloading causes [18] muscle atrophy, (2) a slow-to fast-fiber type shift, Thus, the data and biopsies we utilized for this study are anonymous.…”

Section: Purpose and Hypothesismentioning

confidence: 99%

“…However, these interventions are time consuming and require equipment that takes up space. Because of this, concurrent exercise training interventions (CE; combining endurance and strength exercises) are being considered as an alternative exercise regimen for helping to prevent a shift of MHC type I to type IIx in antigravity muscles, prevent atrophy, and maintain strength [17][18][19], However, the role of myonuclear domain (MND) on this fiber shift and muscle atrophy remains unclear.…”

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confidence: 99%

Effects Of Concurrent Exercise During Simulated Microgravity On Soleus Muscle Fiber Myonuclear Content

Zapanta

Cotter

Galpin

et al. 2018

Medicine &Amp; Science in Sports &Amp; Exercise

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Exercise countermeasures currently administered on the International Space Station are time-consuming and use large/expensive equipment. It has been established that aerobic exercise can maintain oxidative capacity of muscle fibers, while resistance exercise can help preserve muscle mass in Astronauts and individuals in bed rest. Recently, concurrent exercise (CE) training, combining both modes, has been implemented to save time and yield similar benefits. Cotter et al. (2015) determined that CE is effective at mitigating deconditioning during simulated microgravity (unilateral lower limb suspension, ULLS) but there were differences in fiber-type responses (i.e., fast-twitch vs slow-twitch). This thesis provides additional analyses of muscle samples used in Cotter et al. (2015), investigating soleus muscle (mostly slow-twitch) myonuclei (which help to maintain cell size and function). Modulations in fiber size and myonuclear domain (MND; the area each myonuclei controls) may provide mechanisms for preventing unloading decrements. Our aim was to determine 1) if simulated microgravity affects soleus muscle fiber size and MND size and 2) if CE training mitigates these changes. Previously, 19 subjects were separated into two groups, 10-day ULLS and 10day ULLS + CE. Muscle biopsies were taken pre-and post-intervention, which were isolated into individual fibers (muscle cells), stained for myonuclei, imaged, and analyzed EFFECTS OF CONCURRENT EXERCISE DURING SIMULATED MICROGRAVITY ON SOLEUS MUSCLE FIBER MYONUCLEAR CONTENT for fiber size and MND size. 2x2 ANOVAs determined potential differences in fiber size and MND size between groups, before and after ULLS. Neither group showed significant differences in fiber size or MND size after 10 days of ULLS. These findings suggest that, while 10 days of ULLS may cause a decline in muscle function (as seen in Cotter et al., 2015), it may not be long enough to significantly affect soleus muscle fiber size or MND size. However, inter-individual responses varied from subject to subject, suggesting that some people may be responders (or non-responders) to ULLS and ULLS+CE. This suggests a need for additional analyses among individual participant to help develop "personalized" exercise countermeasures for those undergoing significant periods of unloading (e.g., people in bed rest or Astronauts).

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“…8 Impendence training is primarily achieved through penguin suit, interim resistive exercise device (IRED), advanced resistive exercise device, and so on. 9,10 The astronauts of the International Space Station (ISS) spend 5 h weekly running or cycling, and 3 to 6 days weekly in medium strength impedance training. 11 These pieces of training are of evident effects on resistance to muscle atrophy, decreased strength, and bone loss.…”

Section: Introductionmentioning

confidence: 99%

Passive force control of multimodal astronaut training robot

Zou

Qin

Wang

et al. 2019

International Journal of Advanced Robotic Systems

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For the purpose of solving the problem of astronaut training in weightlessness environment, this article proposes a multimodal astronaut training robot to enable astronauts to perform running, bench press and deep squat training in the weightless environment, so as to help them mitigate the adverse effects brought by the space adaptation syndrome. Taking the modularized wire driving unit as the research object, the dynamic model of the passive force servo system was established; and the passive force control strategy was designed. The experimental results show that the system is of good stability, high steady-state accuracy, and excellent dynamic quality after correction. When the given signal frequency is 10 Hz, the system phase lag is about 9 , and the loading error is about 5%. The passive force servo control strategy can effectively reduce the surplus force. When the speed disturbance frequency of carrying unit is within 3 Hz, the elimination rate of the surplus force can reach 90%.

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Concurrent Exercise on a Gravity-Independent Device during Simulated Microgravity

Cited by 23 publications

References 46 publications

Three months of bed rest induce a residual transcriptomic signature resilient to resistance exercise countermeasures

Three months of bed rest induce a residual transcriptomic signature resilient to resistance exercise countermeasures

Effects Of Concurrent Exercise During Simulated Microgravity On Soleus Muscle Fiber Myonuclear Content

Passive force control of multimodal astronaut training robot

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