Engineering topics

Guilliams, Mark E.

Publications and source records attributed to Guilliams, Mark E..

8 records

NASA NTRS2011

Load Variation Influences on Joint Work During Squat Exercise in Reduced Gravity

Resistance exercises that load the axial skeleton, such as the parallel squat, are incorporated as a critical component of a space exercise program designed to maximize the stimuli for bone remodeling and muscle loading. Astronauts on the International Space Station perform regular resistance exercise using the Advanced Resistive Exercise Device (ARED). Squat exercises on Earth entail moving a portion of the body weight plus the added bar load, whereas in microgravity the body weight is 0, so all load must be applied via the bar. Crewmembers exercising in microgravity currently add approx.70% of their body weight to the bar load as compensation for the absence of the body weight. This level of body weight replacement (BWR) was determined by crewmember feedback and personal experience without any quantitative data. The purpose of this evaluation was to utilize computational simulation to determine the appropriate level of BWR in microgravity necessary to replicate lower extremity joint work during squat exercise in normal gravity based on joint work. We hypothesized that joint work would be positively related to BWR load.

DeWitt, John K.↗

NASA NTRS2011

Preflight and In-Flight Exercise Conditions for Astronauts on the International Space Station

The physiological demands of spaceflight require astronauts to have certain physical abilities. They must be able to perform routine and off-nominal physical work during flight and upon re-entry into a gravity environment to ensure mission success, such as an Extra Vehicular Activity (EVA) or emergency egress. To prepare the astronauts for their mission, a Wyle Astronaut Strength Conditioning and Rehabilitation specialist (ASCR) works individually with the astronauts to prescribe preflight strength and conditioning programs and in-flight exercise, utilizing Countermeasure Systems (CMS) exercise hardware. PURPOSE: To describe the preflight and in-flight exercise programs for ISS crewmembers. METHODS: Approximately 2 years before a scheduled launch, an ASCR is assigned to each astronaut and physical training (PT) is routinely scheduled. Preflight PT of astronauts consists of carrying out strength, aerobic and general conditioning, employing the principles of periodization. Exercise programs are prescribed to the astronauts to account for their individual fitness levels, planned mission-specific tasks, areas of concern, and travel schedules. Additionally, astronauts receive instruction on how to operate CMS exercise hardware and receive training for microgravity-specific conditions. For example, astronauts are scheduled training sessions for the International Space Station (ISS) treadmill (TVIS) and cycle ergometer (CEVIS), as well as the Advanced Resistive Exercise Device (ARED). In-flight programs are designed to maintain or even improve the astronauts pre-flight levels of fitness, bone health, muscle strength, power and aerobic capacity. In-flight countermeasure sessions are scheduled in 2.5 h blocks, six days a week, which includes 1.5 h for resistive training and 1 h for aerobic exercise. CONCLUSIONS: Crewmembers reported the need for more scheduled time for preflight training. During flight, crewmembers have indicated that the in-flight exercise is sufficient, but would like more reliable and capable hardware.

Guilliams, Mark E.↗

NASA NTRS2011

Post Flight Reconditioning for US Astronauts Returning from the International Space Station

Prior to spaceflight, each astronaut undergoes medical requirement testing to establish a preflight baseline for physiologic functions. Astronauts returning from the International Space Station can experience deficits in all or some of the following areas: aerobic capacity, muscular strength, power, endurance, stamina, bone, balance, agility, coordination, orthostatic tolerances, proprioception, neurovestibular function and flexibility. These losses occur from living in microgravity and are consistent with deficits seen in terrestrial, de-conditioning individuals. Since 2001, the Astronaut Strength, Conditioning and Rehabilitation (ASCR) specialists have administered a reconditioning program, focusing on all deficits, which improves the physical condition of all returning astronauts. In most cases, astronauts have reached or surpassed their preflight physical condition. Purpose: This presentation will describe and explain the postflight reconditioning program for returning astronauts. Methods: The postflight reconditioning program is designed to stress the body systems that affect the following: aerobic capacity, muscular strength, power, endurance, stamina, bone, balance, agility, coordination, orthostatic tolerances, proprioception, neurovestibular function and flexibility. Postflight reconditioning begins on landing day, is scheduled for two hours per day, 7 days a week for 45 days and is tailored to the specific needs of the astronaut. Initially the program focuses on basic ambulation, cardiovascular endurance, strength, balance, flexibility and proprioception. The program advances through 45 days and specific attention is given to each astronaut s overall condition, testing results, medical status, and assigned duties after their mission. Conclusion: Astronauts will experience noticeable deficits in their physical condition after living in microgravity for an extended length of time. After completing postflight reconditioning, it is shown that astronauts have regained, and in most cases improved upon, their preflight baseline condition.

Nieschwitz, Bruce↗

NASA NTRS2010

Reliability of a Test Battery Designed for Quickly and Safely Assessing Diverse Indices of Neuromuscular Function

Spaceflight affects nearly every physiological system. Spaceflight-induced alterations in physiological function translate to decrements in functional performance. Purpose: To develop a test battery for quickly and safely assessing diverse indices of neuromuscular performance. I. Quickly: Battery of tests can be completed in approx.30-40 min. II. Safely: a) No eccentric muscle actions or impact forces. b) Tests present little challenge to postural stability. III. Diverse indices: a) Strength: Excellent reliability (ICC = 0.99) b) Central activation: Very good reliability (ICC = 0.87) c) Power: Excellent reliability (ICC = 0.99) d) Endurance: Total work has excellent reliability (ICC = 0.99) e) Force steadiness: Poor reliability (ICC = 0.20 - 0.60) National

Spiering, Barry A.↗

NASA NTRS2010

Biomechanical Analysis of T2 Exercise

Crewmembers regularly perform treadmill exercise on the ISS. With the implementation of T2 on ISS, there is now the capacity to obtain ground reaction force (GRF) data GRF data combined with video motion data allows biomechanical analyses to occur that generate joint torque estimates from exercise conditions. Knowledge of how speed and load influence joint torque will provide quantitative information on which exercise prescriptions can be based. The objective is to determine the joint kinematics, ground reaction forces, and joint kinetics associated with treadmill exercise on the ISS. This study will: 1) Determine if specific exercise speed and harness load combinations are superior to others in exercise benefit; and 2) Aid in the design of exercise prescriptions that will be most beneficial in maintaining crewmember health.

DeWitt, John K.↗

NASA NTRS2009

Functional Task Test (FTT)

This slide presentation reviews the Functional Task Test (FTT), an interdisciplinary testing regimen that has been developed to evaluate astronaut postflight functional performance and related physiological changes. The objectives of the project are: (1) to develop a set of functional tasks that represent critical mission tasks for the Constellation Program, (2) determine the ability to perform these tasks after space flight, (3) Identify the key physiological factors that contribute to functional decrements and (4) Use this information to develop targeted countermeasures.

Bloomberg, Jacob J.↗

NASA NTRS2004

Heat Production During Countermeasure Exercises Planned for the International Space Station

This investigation's purpose was to determine the amount of heat produced when performing aerobic and resistance exercises planned as part of the exercise countermeasures prescription for the ISS. These data will be used to determine thermal control requirements of the Node 1 and other modules where exercise hardware might reside. To determine heat production during resistive exercise, 6 subjects using the iRED performed 5 resistance exercises which form the core exercises of the current ISS resistive exercise countermeasures. Each exerciser performed a warm-up set at 50% effort, then 3 sets of increasing resistance. We measured oxygen consumption and work during each exercise. Heat loss was calculated as the difference between the gross energy expenditure (minus resting metabolism) and the work performed. To determine heat production during aerobic exercise, 14 subjects performed an interval, cycle exercise protocol and 7 subjects performed a continuous, treadmill protocol. Each 30-min. exercise is similar to exercises planned for ISS. Oxygen consumption monitored continuously during the exercises was used to calculate the gross energy expenditure. For cycle exercise, work performed was calculated based on the ergometer's resistance setting and pedaling frequency. For treadmill, total work was estimated by assuming 25% work efficiency and subtracting the calculated heat production and resting metabolic rate from the gross energy expenditure. This heat production needs to be considered when determining the location of exercise hardware on ISS and designing environmental control systems. These values reflect only the human subject s produced heat; heat produced by the exercise hardware also will contribute to the heat load.

Rapley, Michael G.↗

NASA NTRS1998

Exercise Countermeasures Demonstration Project During the Lunar-Mars Life Support Test Project Phase 2A

This demonstration project assessed the crew members' compliance to a portion of the exercise countermeasures planned for use onboard the International Space Station (ISS) and the outcomes of their performing these countermeasures. Although these countermeasures have been used separately in other projects and investigations, this was the first time they'd been used together for an extended period (60 days) in an investigation of this nature. Crew members exercised every day for six days, alternating every other day between aerobic and resistive exercise, and rested on the seventh day. On the aerobic exercise days, subjects exercised on an electronically braked cycle ergometer using a protocol that has been previously shown to maintain aerobic capacity in subjects exposed to a space flight analogue. On the resistive exercise days, crew members performed five major multijoint resistive exercises in a concentric mode, targeting those muscle groups and bones we believe are most severely affected by space flight. The subjects favorably tolerated both exercise protocols, with a 98% compliance to aerobic exercise prescription and a 91% adherence to the resistive exercise protocol. After 60 days, the crew members improved their peak aerobic capacity by an average 7%, and strength gains were noted in all subjects. These results suggest that these exercise protocols can be performed during ISS, lunar, and Mars missions, although we anticipate more frequent bouts with both protocols for long-duration spaceflight. Future projects should investigate the impact of increased exercise duration and frequency on subject compliance, and the efficacy of such exercise prescriptions.

Lee, Stuart M. C.↗