Countermeasure Development for Lumbopelvic Deconditioning in Space

Physical inactivity and lumbopelvic deconditioning have been linked to increased incidence of non-specific low back pain (LBP) and spinal injury in those who are exposed to microgravity (e.g. astronauts and individuals on long-duration bed rest) and in the general population. Astronauts have an increased risk of experiencing moderate to severe LBP during microgravity exposure and herniated intervertebral discs within 1 year following spaceflight. Atrophy and reduced motor control of the lumbar multifidus (LM) and transversus abdominis (TrA) muscles resulting from periods of deconditioning are linked to non-specific LBP and spinal injury risk in both post-flight astronauts and general populations. However, voluntary recruitment of these two key muscles is difficult and presents a rehabilitation challenge. This chapter reviews the concept of spinal stability as it relates to microgravity, discusses how existing exercise countermeasures used in space do not successfully maintain lumbopelvic muscle size, and introduces the functional readaptive exercise device (FRED) that shows potential to activate the LM and TrA muscles automatically and in a tonic fashion, which has relevance to rehabilitation of both astronaut and terrestrial populations

The immediate effects of exercise using the Functional Re-adaptive Exercise Device on lumbopelvic kinematics in people with and without low back pain

Background - Dysfunction of the lumbar multifidus (LM) and transversus abdominis (TrA) muscles is associated with low back pain (LBP). The Functional Re-adaptive Exercise Device (FRED) has shown potential as a non-specific LBP intervention by automatically recruiting LM and TrA. Loss or lordosis and altered lumbopelvic positioning has also been linked to LBP and is often trained within LM and TrA interventions. The effect that FRED exercise has on lumbopelvic positioning and lumbar lordosis is unknown. Objectives - To assess the effect of FRED exercise on lumbopelvic kinematics and alignment to establish whether FRED exercise promotes a favourable lumbopelvic posture for training LM and TrA. Design - Within and between-group comparison study. Method - One hundred and thirty participants, 74 experiencing LBP, had lumbopelvic kinematic data measured during over-ground walking and FRED exercise. Magnitude-based inferences were used to compare walking with FRED exercise within participants and between the asymptomatic and LBP groups, to establish the effects of FRED exercise on lumbopelvic kinematics, compared to walking, in each group. Results - FRED exercise promotes an immediate change in anterior pelvic tilt by 8.7° compared to walking in the no-LBP and LBP groups. Sagittal-plane spinal extension increased during FRED exercise at all spinal levels by 0.9° in the no-LBP group, and by 1.2° in the LBP group. Conclusions - FRED exercise promotes a lumbopelvic position more conducive to LM and TrA training than walking in both asymptomatic people and those with LBP

Movement amplitude on the Functional Re-adaptive Exercise Device: deep spinal muscle activity and movement control

Purpose: Lumbar multifidus (LM) and transversus abdominis (TrA) show altered motor control, and LM is atrophied, in people with low-back pain (LBP). The Functional Re-adaptive Exercise Device (FRED) involves cyclical lower-limb movement against minimal resistance in an upright posture. It has been shown to recruit LM and TrA automatically, and may have potential as an intervention for non-specific LBP. However, no studies have yet investigated the effects of changes in FRED movement amplitude on the activity of these muscles. This study aimed to assess the effects of different FRED movement amplitudes on LM and TrA muscle thickness and movement variability, in order to inform an evidence-based exercise prescription. Methods: Lumbar multifidus and TrA thickness of eight healthy male volunteers was examined using ultrasound imaging during FRED exercise, normalised to rest at four different movement amplitudes. Movement variability was also measured. Magnitude-based inferences were used to compare each amplitude. Results: Exercise at all amplitudes recruited LM and TrA more than rest, with thickness increases of approximately 5 mm and 1 mm, respectively. Larger amplitudes also caused increased TrA thickness, LM and TrA muscle thickness variability and movement variability. The data suggest that all amplitudes are useful for recruiting LM and TrA. Conclusions: A progressive training protocol should start in the smallest amplitude, increasing the setting once participants can maintain a consistent movement speed, in order to continue to challenge the motor control system

Use of pedometers as a tool to promote daily physical activity levels in patients with COPD: a systematic review and meta-analysis

The aim of this study was to examine the use of pedometers as a tool to promote daily physical activity levels in patients with COPD.A systematic review meta-analysis of pedometer physical activity promotion in patients with COPD was conducted. Medline/PubMed, Cochrane Library, Web of Science and CINAHL were searched from inception to January 2019. The search strategy included the following keywords: physical activity promotion, pulmonary rehabilitation and daily physical activity. The eligibility criteria for selecting studies were randomised controlled trials reporting pedometer physical activity promotion in patients with COPD.Improvements in steps per day were found with pedometer physical activity promotion either standalone (n=12, mean 0.53 (95% CI 0.29textendash0.77); p=0.00001) or alongside pulmonary rehabilitation (n=7, 0.51 (0.13textendash0.88); p=0.006). A subgroup analysis reported significant differences in the promotion of physical activity based on baseline physical activity levels and the type of instrument used to assess levels of physical activity.Future trials should consider the way in which pedometers are used to promote physical activity to inform clinical practice in the setting of pulmonary rehabilitation.Pedometer based physical activity promotion as a standalone intervention or alongside pulmonary rehabilitation induces meaningful improvements in daily physical activity levels (steps per day) in patients with COPD. http://bit.ly/2LnxM2

Synergistic research synthesis enabling evidence based practice

Introduction Evidence based practice requires showing upon what we are basing medical opinions and guidelines, or recognising when evidence is absent that guidance is “expert opinion” and research is required to fill evidence gaps. Aerospace is one of the final medical fields to begin organising a critical summary, adapted periodically, of evidence underpinning operations, and the Aerospace Medicine Systematic Review Group is a new initiative to fill this gap. This group facilitates high quality, transparent synthesis of evidence, to inform operational medical guidelines in best practice, while simultaneously guiding future research by identifying research gaps. The group has (A) facilitated a second review with the European Space Agency Medical Office to inform human Lunar and Martian mission medical considerations and (B) developed and published, open access, new review methods to aid others to undertake aerospace medicine systematic reviews. Methods (A) Electronic databases were searched from the start of records to April 2016. Studies were assessed with the Cochrane risk of bias tool. Effect size analysis was used to assess the effect of various g loading on human biomechanical and cardiopulmonary systems. (B) A new rating scale to appraise technical principles of studies to simulate partial gravity was implemented. Additional method guides for developing questions, protocol drafting, data extracting, quantifying effects and scoring a bed rest study quality were also developed. Results (A) The review identified 43 studies that found partial gravity appears unable to protect against cardiovascular and biomechanical changes. (B) The group designed and developed a website (www.aerospacemed.rehab/systematic-review-group) to provide free access to methods developed by the group and provide links to wider resources. Discussion The systematic review informed medical considerations for future human exploration missions and demonstrates how systematic synthesis of the evidence base more strongly and better informs medical operations than expert opinion, basic reviews or disordered individual studies. Limitations in the current conduct and reporting of aerospace medicine research are also highlighted. Continuing development of review methods, published as open access guides on the group website and working with review teams globally, will help bring synergy to, and enable high quality summary, of the aerospace medicine evidence base

Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

The European Space Agency has recently announced to progress from low Earth orbit missions on the International Space Station to other mission scenarios such as exploration of the Moon or Mars. Therefore, the Moon is considered to be the next likely target for European human space explorations. Compared to microgravity (µg), only very little is known about the physiological effects of exposure to partial gravity (µg < partial gravity < 1 g). However, previous research studies and experiences made during the Apollo missions comprise a valuable source of information that should be taken into account when planning human space explorations to reduced gravity environments. This systematic review summarizes the different effects of partial gravity (0.1-0.4 g) on the human musculoskeletal, cardiovascular and respiratory systems using data collected during the Apollo missions as well as outcomes from terrestrial models of reduced gravity with either 1 g or microgravity as a control. The evidence-based findings seek to facilitate decision making concerning the best medical and exercise support to maintain astronauts’ health during future missions in partial gravity. The initial search generated 1323 publication hits. Out of these 1323 publications, 43 studies were included into the present analysis and relevant data were extracted. None of the 43 included studies investigated long-term effects. Studies investigating the immediate effects of partial gravity exposure reveal that cardiopulmonary parameters such as heart rate, oxygen consumption, metabolic rate and cost of transport are reduced compared to 1 g, whereas stroke volume seems to increase with decreasing gravity levels. Biomechanical studies reveal that ground reaction forces, mechanical work, stance phase duration, stride frequency, duty factor and preferred walk-to-run transition speed are reduced compared to 1 g. Partial gravity exposure below 0.4 g seems to be insufficient to maintain musculoskeletal and cardiopulmonary properties in the long-term. To compensate for the anticipated lack of mechanical and metabolic stimuli some form of exercise countermeasure appears to be necessary in order to maintain reasonable astronauts’ health, and thus ensure both sufficient work performance and mission safety

Exercise countermeasure preferences of three male astronauts, a preliminary qualitative study

Background: A single flywheel exercise countermeasure has been chosen for use on-board the Orion Multi-Purpose Crew Vehicle for spaceflight missions of up to 30 days. As previous missions have typically involved the use of multiple exercise countermeasures there is a concern that the use of only flywheel may lead to boredom and reduce astronaut adherence to exercise prescriptions, presenting a risk to their health and the operational success of the mission. To determine if this will be a concern, this qualitative work identified astronaut-reported operational considerations for the implementation of an exercise countermeasure device for use during spaceflight, and if current plans for the implementation of a single flywheel exercise countermeasure device may affect astronaut adherence to exercise prescriptions. Methods: The responses of three male astronauts to an open-ended qualitative survey were analysed using thematic analysis. All participants were required to currently be taking part in, or have previously taken part in, human spaceflight. Results: Astronaut preferences for the use of an exercise device during spaceflight were categorised into three broad themes: exercise device ease of access, motivational and behavioural considerations, and operational and technical considerations. The three astronauts considered a single flywheel-based exercise device suitable for use as the sole exercise countermeasure on-board the Orion MPCV, and similar capsular spacecraft, so long as it met several conditions. The device should engage astronauts in a varied exercise prescription. The device should also meet the physiological expectations required of exercise countermeasures for spaceflight deconditioning. The device should be enjoyable to use, and measures should be put in place to reduce boredom (via variety in exercise prescription). The device should be easy to access in terms of both use and setup/takedown. Finally, the device should only be used without other exercise countermeasures for missions of 30 days or less. Conclusion: Individual crewmember preferences should be taken into consideration following crew selection to ensure the greatest adherence to exercise prescriptions. The data reported here should be used to supplement, not entirely inform, the development and use of future exercise countermeasures

Hypogravity reduces trunk admittance and lumbar muscle activation in response to external perturbations

Reduced paraspinal muscle size and flattening of spinal curvatures have been documented after spaceflight. Assessment of trunk adaptations to hypogravity can contribute to develop specific countermeasures. In this study, parabolic flights were used to investigate spinal curvature and muscle responses to hypogravity. Data from five trials at 0.25g, 0.50g and 0.75g were recorded from six participants, positioned in a kneeling-seated position. During the first two trials, participants maintained a normal, upright posture. In the last three trials, small-amplitude perturbations were delivered in the anterior direction at the T10 level. Spinal curvature was estimated using motion capture cameras. Trunk displacement and contact force between the actuator and participant were recorded. Muscle activity responses were collected using intramuscular electromyography (iEMG) of the deep and superficial lumbar multifidus, iliocostalis lumborum, longissimus thoracis, quadratus lumborum, transversus abdominis, obliquus internus and obliquus externus muscles. The root mean square iEMG and the average spinal angles were calculated. Trunk admittance and muscle responses to perturbations were calculated as closed-loop frequency response functions. Compared with 0.75g, 0.25g resulted in: lower activation of the longissimus thoracis (P=0.002); lower responses of the superficial multifidus at low frequencies (P=0.043); lower responses of the superficial multifidus (P=0.029) and iliocostalis lumborum (P=0.043); lower trunk admittance (P=0.037) at intermediate frequencies; and stronger responses of the transversus abdominis at higher frequencies (p=0.032). These findings indicate that exposure to hypogravity reduces trunk admittance, partially compensated by weaker stabilizing contributions of the paraspinal muscles and coinciding with an apparent increase of the deep abdominal muscle activity

Effectiveness of nutritional countermeasures in microgravity and its ground-based analogues to ameliorate musculoskeletal and cardiopulmonary deconditioning – A Systematic Review

A systematic review was performed to evaluate the effectiveness of nutrition as a standalone countermeasure to ameliorate the physiological adaptations of the musculoskeletal and cardiopulmonary systems associated with prolonged exposure to microgravity. A search strategy was developed to find all astronaut or human space flight bed rest simulation studies that compared individual nutritional countermeasures with non-intervention control groups. This systematic review followed the guidelines of the Cochrane Handbook for Systematic Reviews and tools created by the Aerospace Medicine Systematic Review Group for data extraction, quality assessment of studies and effect size. To ensure adequate reporting this systematic review followed the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analyses. A structured search was performed to screen for relevant articles. The initial search yielded 4031 studies of which 10 studies were eligible for final inclusion. Overall, the effect of nutritional countermeasure interventions on the investigated outcomes revealed that only one outcome was in favor of the intervention group, whereas six outcomes were in favor of the control group, and 43 outcomes showed no meaningful effect of nutritional countermeasure interventions at all. The main findings of this study were: (1) the heterogeneity of reported outcomes across studies, (2) the inconsistency of the methodology of the included studies (3) an absence of meaningful effects of standalone nutritional countermeasure interventions on musculoskeletal and cardiovascular outcomes, with a tendency towards detrimental effects on specific muscle outcomes associated with power in the lower extremities. This systematic review highlights the limited amount of studies investigating the effect of nutrition as a standalone countermeasure on operationally relevant outcome parameters. Therefore, based on the data available from the included studies in this systematic review, it cannot be expected that nutrition alone will be effective in maintaining musculoskeletal and cardiopulmonary integrity during space flight and bed rest

Systematic review of the technical and physiological constraints of the Orion Multi-Purpose Crew Vehicle that affect the capability of astronauts to exercise effectively during spaceflight

Background The constraints of the Orion Multi-Purpose Crew Vehicle present challenges to the use of current exercise countermeasures necessary to prevent severe deconditioning of physiological systems during microgravity exposure beyond Low Earth Orbit. The purpose of this qualitative systematic review was to determine the technical constraints of the Orion Multi-Purpose Crew Vehicle which may hinder astronauts’ capabilities to effectively exercise during long distance spaceflight. Methods Databases were searched from the start of their records to December 2018. Included documents were quality assessed with the AMSRG quality scoring tool and Thematic Analysis was used to analyse the included documents to assess technical constraints of the Orion Multi-Purpose Crew Vehicle. Results 19 studies were included in the final review. All identified constraints, other than data transmission limitations, were found to ultimately be a result of the volume and upload mass constraints of the Orion Multi-Purpose Crew Vehicle. There was a lack of detailed studies and lack of consistency in specifying spacecraft in the literature that limit the conclusions of this review. Conclusion Space agencies are advised to ensure that information on relevant spacecraft constraints is readily available to researchers. This information should be made accessible in an official published document as opposed to disparate and grey literature, and include quantitative information rather than qualitative summaries