Determine if individualized mechanical load replacement and supplementation during bed rest can serve as a countermeasure to losses in BMD, to changes in bone quality, and to muscle atrophy during 12 weeks of bed rest.  

1)  Construct an exercise device that integrates aerobic, neurovestibular and resistive training in a compact design to fit the requirements for installation in a planetary base or landing module.

2) Conduct an exercise training study to demonstrate that cardiovascular and resistive exercise on the combined exercise device could improve measures of muscle strength and endurance in the 1-g environment.

3) Integrate the balance training component to the combined countermeasure device and develop an exercise regimen of aerobic exercise, neurovestibular training and resistive exercises aimed at reducing fall risk and proximal femoral bone loss by loading the hip and leg.

4) Conduct an experiment at the UTMB Flight Analog Research Unit where human test subjects (n=30, 15 Males, 15 females), with age, height and BMI representative of the astronaut corps, are randomized into intervention (integrated countermeasure regimen) and control (no exercise) groups in the spaceflight analog.  The aim of the experiment is to validate the ability of the combined exercise device to significantly reduce the risk for fall and subsequent injury by maintaining pre-bed rest physiological status. 

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.

1. Exercise countermeasures are currently only partially protective. Nutritional supplements may improve exercise countermeasures effectiveness. Studies will be solicited to test novel nutritional supplements to improve exercise effectiveness in a bed rest flight analog. This will directly address the gaps to minimize exercise time and hardware that is required.

1)   Develop an evidence-based approach to maintain physiological function while simultaneously decreasing total exercise time and volume by development of a novel exercise prescription for use on ISS.  The exercise regimen will use higher intensity resistance exercises and interval aerobic exercise according to the Intramural and extramural experts convened for two workshops held in 2008: the NASA Muscle Workshop in June 2008 and the NASA International Space Station Exercise Prescription Workshop in October 2008.  

2) Include an increase in the intensity and a reduction in the volume of resistance exercises, include very short, but high intensity interval-type aerobic exercises, and start the exercise countermeasures as early as possible in the flight, preferably in the first week. 

1) Complete hardware specification and development, prototype fabrication and facility (NASA Glenn Research Center)  readiness (including fabrication of support hardware to meet scientific endpoints). 

2) Demonstrate the feasibility and validity of the approach in 1g, in 1/6g in the eZLS, and in the 1/6g lunar bed rest analog while typical lunar activities are being performed based upon NASA's Functional Task Test protocol. 

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.

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