The Treadmill Kinematics experiment is the first rigorous investigation to quantify the biomechanics of treadmill exercise conditions during long duration space flight on the ISS. Exercise prescriptions are developed under the assumption that walking and running in microgravity have the same training effects as during normal gravity. However, if locomotion kinematics and kinetics differ between microgravity and normal gravity, understanding these mechanisms allows the development of appropriate exercise prescriptions to increase exercise benefits to crew health and well-being.Principal Investigator(s)
Johnson Space Center, Human Research Program, Houston, TX, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)ISS Expedition Duration:
March 2011 - March 2013
27/28,29/30,31/32,33/34Previous ISS Missions
Treadmill Kinematics began operations during ISS Expedition 27.
The purpose of the Treadmill Kinematics experiment is to collect quantitative data from which to assess current exercise prescriptions for participating crewmembers on the International Space Station (ISS). Detailed biomechanical analyses of locomotion will determine if biomechanics differ between normal and microgravity environments and how combinations of subject loading system loads and exercise speed influence joint loading during in-flight treadmill exercise. Biomechanical analyses aid in understanding potential differences in gait motion and allow for model-based determination of joint and muscle forces during exercise. The data are used to characterize differences in specific bone and muscle loading during locomotion in the two gravitational conditions. By understanding these mechanisms, appropriate exercise prescriptions are developed that address deficiencies.
The overriding objective of the Treadmill Kinematics experiment is to determine the most beneficial treadmill exercise conditions that can be used to maintain or improve crewmember health during long-duration space flight. Exercise prescriptions are developed under the assumption that walking and running in microgravity have the same training effects as during normal gravity. These assumptions are based on the belief that there are little differences in locomotion biomechanics between normal and microgravity. Furthermore, treadmill locomotion in microgravity occurs on a vibration-isolated (VIS) treadmill, which may increase the potential for training differences. If locomotion kinematics and kinetics effects differ between microgravity and normal gravity, long-term training effects also differ. Understanding these mechanisms allows the enhanced development of appropriate exercise prescriptions.
Treadmill Kinematics aims to quantify joint kinematics during treadmill locomotion on the ISS, and to compare those to treadmill locomotion on Earth. The goal is to measure joint kinematics during treadmill exercise using motion capture data collection. Exercise prescriptions are developed under the assumption that walking and running in microgravity have the same training effects as during normal gravity. However, if locomotion kinematics differ between microgravity and normal gravity, it is reasonable to hypothesize that training effects also differ. Furthermore, treadmill locomotion in microgravity occurs on a vibration-isolated treadmill, which increases the potential for training differences. Similarities and differences in joint kinematics during treadmill locomotion between normal gravity and microgravity on the ISS are quantified.
Treadmill Kinematics aims to develop a computer model that assesses locomotion speed and external loading condition influences upon joint torque. The overall goal of the advanced exercise prescription being provided to the crewmembers is to increase loading at the joints in order to provide a greater stimulus for bone and muscle health. The computer modeling approach requires inputs of anthropometric measurements, motion kinematics, and external forces applied to the body. External forces applied to the body will be measured with instrumentation built into the treadmill. A subject-specific computer model will be developed and provides joint kinetic approximations. These approximations are used to assess the effectiveness of the exercise prescription and allow for an iterative approach in exercise prescription modification based on evidence. Furthermore, these data provide better understanding of how exercise speed and external load affects the forces experienced by the joints and muscles. Providing subject loading information for exercise prescriptions increases the effectiveness of the exercise prescription.
One of the goals is to assess typical exercise sessions while being minimally intrusive to the crewmember. In addition, since external load (EL) magnitude affects locomotion kinematics and kinetics, collecting data at all speed and EL combinations typically used during in-flight exercise sessions during a single test session is not possible. Therefore, for each data collection session, the subject performs their nominal exercise prescription for that day. Coordination occurs between the investigators to schedule exercise prescriptions that result in the greatest benefit for the investigation by including multiple speeds, EL magnitudes, and variation between sessions. Investigators ensure that at least one trial at 3, 5, and 7 miles per hour (mph) is performed and collected during each data collection session to increase common comparison conditions within and between subjects.
The results from this experiment enable a detailed analysis of locomotion and allow objective assessment of exercise efficacy for crewmembers on the ISS. Results of this analysis are used to determine the treadmill conditions that are most beneficial for maintaining health during space flight.Earth Applications
Data gathered from the Treadmill Kinematics investigation may help scientists understand the biomechanical analyses of locomotion which can be used on Earth to provide researchers with a better understanding of how exercise speed and external load affects the forces experienced by the joints and muscles.
The Treadmill Kinematics experiment requires a subject count of 6 subjects. In-flight data collection will begin at approximately FD15 (after the crewmember has had an opportunity to acclimate to the ISS and has settled into a normal exercise routine) and at approximately 30 day intervals thereafter to monitor progress and assess exercise effectiveness throughout the crewmember’s mission. A total of six sessions per subject is planned. Video and T2 data, including speed, heart rate, load cell, and accelerometer measures, are down-linked after each session.Operational Protocols
Each in-flight data collection session includes videotaping of nominal exercise sessions on the T2. Tape markers, placed at various locations on the body, allow a detailed biomechanical analysis of locomotion. In-flight data collection begins at approximately FD15 (after the crewmember acclimates to the ISS and settles into a normal exercise routine) and at approximately 30 day intervals thereafter to monitor progress and assess exercise effectiveness throughout the crewmember’s mission. A total of six sessions per subject is planned. Video and T2 data including speed, heart rate, load cell, and accelerometer measures, are also be down-linked after each session. Investigators will look at the microgravity biomechanical locomotion data to determine if there are specific speed-load combinations that maximize lower body joint torque. In addition, investigators will compare microgravity kinematics and kinetics to normal gravity baseline values to assess the influence of gravity upon locomotion exercise.
Schaffner G, De Witt JK, Bentley JR, Kozlovskaya I, Hagan RD, Yarmanova E. Effect of subject loading device load levels on gait. NASA Technical Report TP-2005-213169; 2005.