NOTE: End date changed to 5/15/2013 per JSC and PI (Ed., 7/11/2011)

There have been no rigorous evaluations of locomotion biomechanics during exercise in microgravity on the ISS. The installation of the Second-Generation Treadmill (T2) on the ISS will allow the measurement of ground reaction forces (GRF) during exercise. Quantification of these forces is vital to understanding the musculoskeletal benefits of treadmill exercise. GRF data used in combination of joint motion data obtained from video can be used to quantify the joint torques that occur during exercise, which will give critical information regarding exercise efficacy. It is probable that variables such as speed, external load (EL) applied to the waist-shoulder harness, and vibration-isolation affect locomotive biomechanics, which could influence exercise prescription efficacy. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine what combination of subject load and speed optimizes joint loading during in-flight treadmill exercise.

Up to 8 crewmembers will be assessed during nominal exercise sessions on the T2 during long duration ISS mission. Data will be collected from up to 6 sessions per crew member, spaced approximately 30 days apart. Video data will be collected using a standard high-definition video camera, and GRF data will be collected directly from the T2. Data will be downlinked from ISS for post processing. Video will be digitized and joint position throughout exercise will be determined using a two-dimensional direct linear transformation analysis. Position data will be used to determine joint kinematics, and position data will be used with GRF data in an inverse dynamic analysis to determine joint torques. Prior to flight, video and GRF data will be collected in the lab for use in comparisons between gravitational levels.

The data will be used to determine if locomotive biomechanics differ between microgravity and normal gravity. The data will also be used to determine how differences in speed, EL, and the interaction of speed and EL affect locomotive biomechanics. Obtaining these data will help to determine if specific speed and EL conditions exist that maximize joint torques, and thus increase exercise efficacy.

The purpose of this investigation was to examine the biomechanics of running on the second generation treadmill on the International Space Station as it is used during normal exercise. Kinematic and ground reaction force data were collected in the lab prior to flight and throughout the missions of seven subjects. In-flight data were collected during up to six exercise sessions for each subject spaced throughout their mission. Hip, knee, and ankle sagittal motion trajectories, gait temporal kinematics, and ground reaction force parameters were compared between exercise sessions in 1G and 0G. The effects of speed and bungee load on ground reaction force parameters were also examined. We found that joint motion trajectories and gait temporal kinematics remained relatively consistent between 0G and 1G at a given speed. Ground reaction force parameters, however, were significantly decreased in 0G, but did increase with increased speed and bungee load. Furthermore, the relationship between peak ground reaction forces and speed and bungee load were subject-dependent, suggesting that individual variations exist in adaptation strategies to the microgravity environment. Our data suggest that subject-specific relationships can be developed that allow practitioners to prescribe exercise that may more effectively recreate 1G-like ground reaction forces, and that subjects performing exercise at higher speeds obtain ground reaction forces similar to exercising at lower speeds on Earth.

Take Home Message for Exercise: Crewmembers have similar running motions in 0G as they do in 1G, but develop lower ground reaction forces. Running faster will increase the ground reaction forces and increase exercise benefits.

Take Home Message for Motor Control: Running motion does not change in the absence of gravity, but force generation is scaled to approximately the same relative level as in 1G. Control mechanisms that depend on gravity must be secondary to those that are gravity-independent.

NOTE: End date changed to 5/15/2013 per JSC and PI (Ed., 7/11/2011)

There have been no rigorous evaluations of locomotion biomechanics during exercise in microgravity on the ISS. The installation of the Second-Generation Treadmill (T2) on the ISS will allow the measurement of ground reaction forces (GRF) during exercise. Quantification of these forces is vital to understanding the musculoskeletal benefits of treadmill exercise. GRF data used in combination of joint motion data obtained from video can be used to quantify the joint torques that occur during exercise, which will give critical information regarding exercise efficacy. It is probable that variables such as speed, external load (EL) applied to the waist-shoulder harness, and vibration-isolation affect locomotive biomechanics, which could influence exercise prescription efficacy. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine what combination of subject load and speed optimizes joint loading during in-flight treadmill exercise.

Up to 8 crewmembers will be assessed during nominal exercise sessions on the T2 during long duration ISS mission. Data will be collected from up to 6 sessions per crew member, space approximately 30 days apart. Video data will be collected using a standard high-definition video camera, and GRF data will be collected directly from the T2. Data will be downlinked from ISS for post processing. Video will be digitized and joint position throughout exercise will be determined using a two-dimensional direct linear transformation analysis. Position data will be used to determine joint kinematics, and position data will be used with GRF data in an inverse dynamic analysis to determine joint torques. Prior to flight, video and GRF data will be collected in the lab for use in comparisons between gravitational levels.

The data will be used to determine if locomotive biomechanics differ between microgravity and normal gravity. The data will also be used to determine how differences in speed, EL, and the interaction of speed and EL affect locomotive biomechanics. Obtaining these data will help to determine if specific speed and EL conditions exist that maximize joint torques, and thus increase exercise efficacy.

Video and ground reaction force data from all completed sessions have been delivered to the PI and verified for accuracy. To date, all analyses that have been completed have been preliminary. Original analysis software is under development and is currently being tested and validated.

To date, there have been no major issues regarding data collection. All crew have completed their data collection sessions successfully. There have been a few trials that have been repeated due to hardware malfunction or downlink issues. In general, all data collected have been successfully downlinked.

NOTE: End date changed to 5/15/2013 per JSC and PI (Ed., 7/11/2011)

There have been no rigorous evaluations of locomotion biomechanics during exercise in microgravity on the ISS. The installation of the Second-Generation Treadmill (T2) on the ISS will allow the measurement of ground reaction forces (GRF) during exercise. Quantification of these forces is vital to understanding the musculoskeletal benefits of treadmill exercise. GRF data used in combination of joint motion data obtained from video can be used to quantify the joint torques that occur during exercise, which will give critical information regarding exercise efficacy. It is probable that variables such as speed, external load (EL) applied to the waist-shoulder harness, and vibration-isolation affect locomotive biomechanics, which could influence exercise prescription efficacy. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine what combination of subject load and speed optimizes joint loading during in-flight treadmill exercise.

Up to 6 crewmembers will be assessed during nominal exercise sessions on the T2 during long duration ISS mission. Data will be collected from up to 6 sessions per crew member, space approximately 30 days apart. Video data will be collected using a standard high-definition video camera, and GRF data will be collected directly from the T2. Data will be downlinked from ISS for post processing. Video will be digitized and joint position throughout exercise will be determined using a two-dimensional direct linear transformation analysis. Position data will be used to determine joint kinematics, and position data will be used with GRF data in an inverse dynamic analysis to determine joint torques. Prior to flight, video and GRF data will be collected in the lab for use in comparisons between gravitational levels.

The data will be used to determine if locomotive biomechanics differ between microgravity and normal gravity. The data will also be used to determine how differences in speed, EL, and the interaction of speed and EL affect locomotive biomechanics. Obtaining these data will help to determine if specific speed and EL conditions exist that maximize joint torques, and thus increase exercise efficacy.

Motion capture data are collected by a 12 camera motion capture system at 250 Hz, and ground reaction force data are collected by dual force plates built into the treadmill at 1000 Hz. Data are collected simultaneously by a single workstation. To date, none of the processing of the BDC data has been completed for any crewmembers.

Three crewmembers have completed inflight data collection sessions. One crewmember has completed three of six total sessions, and two crewmembers have completed one of six sessions. Inflight data collection includes standard hi-definition videography and ground reaction force recording. Ground reaction force data are collected by the treadmill as part of standard exercise data collection. The first two sessions for each crewmember are monitored in real time at the TeleScience Center at JSC Mission Control. After each session, video and treadmill data are downlinked and collected by the PI. To date, inflight video has been examined for integrity, but has not been processed.

NOTE: End date changed to 5/15/2013 per JSC and PI (Ed., 7/11/2011)

There have been no rigorous evaluations of locomotion biomechanics during exercise in microgravity on the ISS. The installation of the Second-Generation Treadmill (T2) on the ISS will allow the measurement of ground reaction forces (GRF) during exercise. Quantification of these forces is vital to understanding the musculoskeletal benefits of treadmill exercise. GRF data used in combination of joint motion data obtained from video can be used to quantify the joint torques that occur during exercise, which will give critical information regarding exercise efficacy. It is probable that variables such as speed, external load (EL) applied to the waist-shoulder harness, and vibration-isolation affect locomotive biomechanics, which could influence exercise prescription efficacy. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine what combination of subject load and speed optimizes joint loading during in-flight treadmill exercise.

Up to 6 crewmembers will be assessed during nominal exercise sessions on the T2 during long duration ISS mission. Data will be collected from up to 6 sessions per crew member, space approximately 30 days apart. Video data will be collected using a standard high-definition video camera, and GRF data will be collected directly from the T2. Data will be downlinked from ISS for post processing. Video will be digitized and joint position throughout exercise will be determined using a two-dimensional direct linear transformation analysis. Position data will be used to determine joint kinematics, and position data will be used with GRF data in an inverse dynamic analysis to determine joint torques. Prior to flight, video and GRF data will be collected in the lab for use in comparisons between gravitational levels.

The data will be used to determine if locomotive biomechanics differ between microgravity and normal gravity. The data will also be used to determine how differences in speed, EL, and the interaction of speed and EL affect locomotive biomechanics. Obtaining these data will help to determine if specific speed and EL conditions exist that maximize joint torques, and thus increase exercise efficacy.

The ARED was installed on the ISS in early 2009 with the intent of increasing the resistance exercise capabilities during in-flight exercise. The device is capable of providing up to 600 lbs of resistance, incorporates a vacuum cylinder and flywheel resistance system to provide constant and inertial resistance, and allows for the performance of many typical exercises, including the deadlift and parallel squat. Resistance exercise has been performed by astronauts during spaceflght to protect against health losses that occur during microgravity exposure. Despite exercise performance, crewmembers regularly return from missions with bone, muscle, and cardiovascular losses. The proposed iRATs exercise prescription has been developed with the intent of optimizing exercise effectiveness by increasing intensity and volume.

Resistance exercises that load the axial skeleton, such as the parallel squat and deadlift, have been proposed to be critical components of a program designed to maximize the stimuli for bone remodeling. However, there is little evidence regarding the efficacy of specific exercises at providing the joint loads necessary for maintenance of bone. For example, within NASA there is disagreement whether squats performed with heavy loads using a decreased range of motion are superior to the same exercise performed with lighter loads over an increased range of motion. In addition, exercise biomechanics can be altered by modifying variables such as stance width, grip width, range of motion, cadence, and joint orientation. An optimal exercise form may exist that maximizes joint forces, which in turn allows for the specific targeting of the most vulnerable bone sites.

Computer simulation performed in concert with measured data can be used to approximate the loads experienced throughout the musculoskeletal system. The LifeMod System (LifeModeler, Inc., San Clemente, CA) is a dynamics-based software platform that computes the muscle and bone forces that occur during a specific motion. The modeling system can determine the forces that cause a motion (inverse dynamic analysis), and predict motion given a set of muscle forces (forward dynamic analysis). Inverse and forward dynamic simulations are beneficial for analyzing specific movement patterns and for predicting how changes in motion can affect exercise kinetics and related physiological benefits.

A comprehensive understanding of the kinematics and kinetics of resistance exercise performance in microgravity is necessary to optimize exercise prescriptions by including the exercise variations that have the greatest potential health benefits. However, to date, there have been no biomechanical investigations of resistance exercise performance on the ISS or of ARED exercise in microgravity. Collecting biomechanical data during actual exercise sessions on the ISS is expensive and complex, but is required for program optimization. We are proposing a systematic evaluation that increases the probability of success while minimizing impacts on crew time. Our intent is to be the first group to perform biomechanical exercise analysis during long-term ISS missions. Our goal is to provide timely, relevant, and necessary feedback that can be used to increase the health benefits of the in-flight exercise program.

[Ed. note: project added to Task Book in February 2010 when information received from JSC]