• AIM 1: Use the XSENS ForceShoe™ as a means to measure static loads on ARED.

• AIM 2: Collect on-orbit data during ARED exercise sessions to aid in the ongoing evaluation of the XSENS ForceShoe™ to support HRP sponsored research.

• Sub Aim 2a: Determine if the XSENS ForceShoe™ is suitable for intermittent or regular use during ARED exercise.

1. Develop a mobile testbed to accurately simulate partial gravity.
2. Determine subject performance and the physiological responses to lunar  activities.
3. Create a series of standardized tests that can be used to determine crewmember readiness for these exploration tasks.

Pressurized space suits impose high joint torques on the wearer, reducing mobility for upper and lower body motions.  Because of the highly altered mobility capabilities and metabolic cost of movement when wearing a space suit, it is necessary for suits to be worn during many aspects of astronaut training and land-based research.  Using actual space suits outside of underwater neutral buoyancy environments is problematic due to the expense, bulk, weight, and difficulty in donning/doffing.  The goal of this project is to demonstrate a novel method for simulating space suit joint torques, which are non-linear and vary with angular position.  This novel method will allow for development of a full space suit simulator for land-based applications, which mimics the joint torques and resulting reduced mobility to a high level of fidelity, while offering characteristics of lighter weight, lower profile, and portability. 

Aurora Flight Sciences, together with the MIT Man-Vehicle Laboratory, are developing a wearable space suit simulator that imitates the mechanical properties of the current EVA space suit (the Extravehicular Mobility Unit, or EMU) and can be used in microgravity or partial gravity EVA experimentation and training.  The space suit simulator will include the following features:

• Quantifiable joint torque stiffness, which can be tuned to provide the capability for simulating current and future space suit designs
• Lightweight, novel joint design to reduce the bulkiness of the suit simulator, and allow it to be donned and doffed within the time required to set up other simulation activities (approximately 15 minutes) in a vertical or horizontal orientation
• Adjustable sizing for subjects of different heights and weights
• Comfortable fit and performance for partial gravity simulation exercises of up to four hours

This space suit simulator is appropriate for the requirements of future microgravity and planetary EVA experimentation, training, and simulation. 

Integration/Unique Aspects: TBD

1. Quantify joint kinematics during treadmill locomotion on the ISS, and to compare those to treadmill locomotion on Earth.
2. Develop a computer model that will assess locomotion speed and external loading condition influences upon joint torque.
3. Determine the combination of subject load and speed that optimize joint loading during in-flight treadmill exercise in order model kinematics differences in different gravitational environments as well as to better inform exercise prescription.

Integration/Unique Aspects: The installation of T2 with its capacity to measure ground reaction forces offers for the first time the available data collection capability to perform inflight biomechanical analyses of treadmill exercise on ISS.

Crewmembers perform resistance exercise on the Advanced Resistive Exercise Device (ARED). There have been no biomechanical analyses of ARED exercise during inflight operations. Ground- and flight-based biomechanical analyses of ARED resistance exercise will be performed in order improve kinematic modeling of differences between various gravitational conditions as well as identify the types of exercises in flight that will have the best loading profiles.

The specific aims of this study are to: 

1. Using motion capture and ground reaction force data,  quantify the joint loading that occurs during resistance exercise using the ARED.
2. Use ground data along with data from a subsequent flight experiment that is planned to understand kinematic differences between ground and flight to help quantify the physiological costs of exploration tasks in variable gravitational environments.
3. Identify which ARED exercise provides the best loading profiles.

Extended space flight as well as existence on the Moon and Mars will require exercise equipment and training protocols designed to maintain physical fitness and general health. Studies will investigate protocols designed to maintain both cardiovascular and musculoskeletal fitness using a gravity independent multi-mode exercise device (M-MED), which has been identified by NASA as potential flight hardware. M-MED can provide either high resistance strength- or low resistance endurance-mode exercises.  Followup studies on exersize protocol may include bed rest studies and evaluation on ISS.

The specific aims of this study are to:

1. Determine effectiveness of the M-MED on measures of muscle strength and aerobic capacity under normal weight bearing conditions.
2. Determine effectiveness of the M-MED on measures of muscle strength and aerobic capacity during skeletal muscle unloading.

This proposal aims to validate in an analog setting a small compact exercise device for the

protection of cardiovascular, muscle, and bone health. This study leverages both currently funded

NSRBRI and NASA work to bring together for the first time, a promising new exercise device and

exercise prescription thus placing this study at a high countermeasure readiness level (moving

from 6-7). More specifically, the NSBRI funded M-MED device uses a flywheel to provide loading for

either high force-low repetition resistance exercise or low force-high repetition, endurance exercise

(rowing). Recent data support M-MED training effectiveness in both ambulatory subjects and over

10 days of muscle unloading using unilateral lower limb suspension model. Accordingly, a new

NASA funded exercise prescription study integrating resistance and aerobic training (iRAT) has

been effective in the preservation of muscle and cardiovascular function over 14 days of bedrest,

but requires the use of 5 different exercise machines. This proposal will combine the M-MED

exercise device and the iRAT exercise prescription into a 70 day bedrest study. Outcome

measurements related to cardiovascular, muscle and bone health will be obtained and integrated to

assess countermeasure effectiveness.

Integration/Unique Aspects: Task to start 10/1/2012.

Identify in-flight exercise loading factors that are associated with maintenance of skeletal muscle strength and bone mineral density.

Hypothesis 1:   We hypothesize that subjects who accumulate the highest magnitude Ground Reaction Forces as normalized to body weight, sustained on a week by week basis, through T2 and ARED exercise will have protected Bone Mineral Density at the hip better than others in the sample group, and that those who accumulate high magnitudes of loads in high numbers early in the increment will have demonstrated better bone health outcomes compared to others in the sample group. 

Hypothesis 2:  We hypothesize that subjects who accumulate greater loading and exercise volume relative to their body weight, sustained on a week by week basis, through T2 and ARED exercise will experience the least change in muscle strength and may experience increased muscle strength as measured by isokinetic and isometric muscular strength testing pre and post flight.

Treadmill use in microgravity requires the use of a harness and a system to provide a subject load to keep the crewmember in contact with the treadmill belt.  A common complaint from returning ISS crew members is that the current harness is uncomfortable.  The pain and chafing that occurs with the use of the current harness contributes to sub-optimal subject loading (approximately 65% of body weight).  A new harness design will be tested to determine if it is more comfortable than the current harness and will allow for greater loading which is expected to result in better maintenance of muscle mass and bone density of the lower extremities

The specific aims of this study are to:

1. Determine if the new harness is more comfortable than the current ISS harness.
2. Determine the loading characteristics (waist versus shoulders) for each of these harnesses.

Long duration space flight is associated with loss of muscle mass and strength and loss of bone mass. To date exercise countermeasures have not been fully effective. Current evidence suggests that the combination of testosterone, amino acids, and exercise will optimize the effectiveness of the existing exercise and nutritional countermeasures. This intervention may improve exercise effectiveness or allow for a reduced volume of required exercise.

The specific aims of this study are to:

1. Determine the effect of monthly cycled testosterone replacement in conjunction with resistance exercise on muscle mass, muscle strength, bone mass and markers of bone metabolism in men aged 35-55.
2. Determine the effect of daily leucine supplementation in conjunction with resistance exercise on muscle mass, muscle strength, bone mass and markers of bone metabolism in women aged 35-55.

Integration/Unique Aspects: This study is one of several potential pharmaceutical or nutritional countermeasures that if promising could be selected for flight validation (see Flight validation studies of pharmaceutical or nutritional supplements).

1. Monitor exercise activities.
2. Detect markers placed on the body and other image features.
3. Recover 3D kinematic body pose.
   

1. Characterize the hip joint contact forces that result during ARED-like exercise through computer simulation.
2. Examine how the use of gravity replacement loads affect hip joint forces in microgravity and partial gravity environments.
3. Perform a sensitivity analysis to examine and optimize the contributions of muscle forces to joint forces.

Extended space flight as well as existence on the Moon and Mars will require exercise equipment and training protocols designed to maintain physical fitness and general health. Studies will investigate protocols designed to maintain both cardiovascular and musculoskeletal fitness using a gravity independent multi-mode exercise device (M-MED), which has been identified by NASA as potential flight hardware. M-MED can provide either high resistance strength- or low resistance endurance-mode exercises.  Followup studies on exersize protocol may include bed rest studies and evaluation on ISS.

The specific aims of this study are to:

1. Determine effectiveness of the M-MED on measures of muscle strength and aerobic capacity under normal weight bearing conditions.
2. Determine effectiveness of the M-MED on measures of muscle strength and aerobic capacity during skeletal muscle unloading.

This proposal aims to validate in an analog setting a small compact exercise device for the

protection of cardiovascular, muscle, and bone health. This study leverages both currently funded

NSRBRI and NASA work to bring together for the first time, a promising new exercise device and

exercise prescription thus placing this study at a high countermeasure readiness level (moving

from 6-7). More specifically, the NSBRI funded M-MED device uses a flywheel to provide loading for

either high force-low repetition resistance exercise or low force-high repetition, endurance exercise

(rowing). Recent data support M-MED training effectiveness in both ambulatory subjects and over

10 days of muscle unloading using unilateral lower limb suspension model. Accordingly, a new

NASA funded exercise prescription study integrating resistance and aerobic training (iRAT) has

been effective in the preservation of muscle and cardiovascular function over 14 days of bedrest,

but requires the use of 5 different exercise machines. This proposal will combine the M-MED

exercise device and the iRAT exercise prescription into a 70 day bedrest study. Outcome

measurements related to cardiovascular, muscle and bone health will be obtained and integrated to

assess countermeasure effectiveness.

Integration/Unique Aspects: Task to start 10/1/2012.

Treadmill use in microgravity requires the use of a harness and a system to provide a subject load to keep the crewmember in contact with the treadmill belt.  A common complaint from returning ISS crew members is that the current harness is uncomfortable.  The pain and chafing that occurs with the use of the current harness contributes to sub-optimal subject loading (approximately 65% of body weight).  A new harness design will be tested to determine if it is more comfortable than the current harness and will allow for greater loading which is expected to result in better maintenance of muscle mass and bone density of the lower extremities

The specific aims of this study are to:

1. Determine if the new harness is more comfortable than the current ISS harness.
2. Determine the loading characteristics (waist versus shoulders) for each of these harnesses.

Long duration space flight is associated with loss of muscle mass and strength and loss of bone mass. To date exercise countermeasures have not been fully effective. Current evidence suggests that the combination of testosterone, amino acids, and exercise will optimize the effectiveness of the existing exercise and nutritional countermeasures. This intervention may improve exercise effectiveness or allow for a reduced volume of required exercise.

The specific aims of this study are to:

1. Determine the effect of monthly cycled testosterone replacement in conjunction with resistance exercise on muscle mass, muscle strength, bone mass and markers of bone metabolism in men aged 35-55.
2. Determine the effect of daily leucine supplementation in conjunction with resistance exercise on muscle mass, muscle strength, bone mass and markers of bone metabolism in women aged 35-55.

Integration/Unique Aspects: This study is one of several potential pharmaceutical or nutritional countermeasures that if promising could be selected for flight validation (see Flight validation studies of pharmaceutical or nutritional supplements).

1. To determine the time course, composition, and source of increased oxidant activity in unloaded muscle.
2. To evaluate selected antioxidants as countermeasures for weakness in unloaded muscle.
3. To test NAC as a countermeasure for handgrip fatigue in humans.
   

1. Develop protocol to study astronaut volunteers before flight and on multiple occasions during flight using the MARES device to provide loading to the feet and legs as well as device that can apply pressure to the soles of the feet. The effects on muscle activation and performance associated with foot pressure alone or foot pressure plus lower limb loading will be investigated.

Integration/Unique Aspects: This entry reflects only definition phase of the grant

Introduction

Exposure to the microgravity conditions of spaceflight causes astronauts to experience alterations in multiple physiological systems. These physiological changes include sensorimotor disturbances, cardiovascular deconditioning, and loss of muscle mass and strength. These changes might affect the ability of crewmembers to perform critical mission tasks immediately after landing on a planetary surface. To date, changes in functional performance have not been systematically studied or correlated with physiological changes. To understand how changes in physiological function affect functional performance, an interdisciplinary pre- and postflight testing regimen (Functional Task Test [FTT]) has been developed that systematically evaluates both astronaut postflight functional performance and related physiological changes. The overall objective of the FTT is to identify the key underlying physiological factors that contribute to performance of functional tests that are representative of critical mission tasks.  Flight, bed rest, and factors of influence ground analogs (e.g weight suit, muscle strength; galvonic stimulation, sensorimotor control) will be used to address specific aims.

Specific Aims

1) Determine the effects of short and long-duration spaceflight on functional performance.

2) Compare the rate of recovery in functional performance between short and long-duration spaceflight.

3) Determine how postflight changes in sensorimotor, cardiovascular and muscle physiology impact functional performance.

Aim 1- Identify changes in brain structure, function, and network integrity as a function of 60 days head down tilt bed rest and characterize their time course:  We will acquire brain structural and functional images at two time points pre, two time points during, and three time points post bed rest in 15 individuals and 15 age- and gender-matched controls.  We hypothesize that bed rest participants will exhibit changes from pre to post the intervention that are significantly greater than those seen in control participants across the same time period.  Scans conducted during and following bed rest will characterize the time course of changes and recovery. 

Aim 2- Specify relationships between structural and functional brain changes and performance and characterize their time course:  We will administer a broad ranging battery of sensory, motor, and cognitive assessments at the time points described for Aim 1.  We hypothesize that bed rest participants will exhibit pre- to post-intervention decrements in sensorimotor performance as we have shown in our past work, which will correlate with the neural changes identified under Aim 1.  Additionally, for some measures and time points, we expect that there will be no performance effects despite alterations in brain structure and function due to compensatory brain processes that will be identifiable with neuroimaging approaches.

This task also informs VIIP1 gap and the HCI and BMed Risks.