Advanced Resistive Exercise Device (ARED) - 11.22.16
The Advanced Resistive Exercise Device (ARED) uses adjustable resistance piston-driven vacuum cylinders along with a flywheel system to simulate free-weight exercises in normal gravity. Studies have found that without exercises like those possible on the ARED, astronauts could lose up to 15% of their muscle volume, which could be difficult or even impossible to regain back on Earth. ARED's primary goal is to maintain muscle strength and mass in astronauts during long periods in space. Science Results for Everyone Exercising in space poses unique challenges, but without exercise, astronauts can lose up to 15 percent of their muscle mass, some of it permanently. The Advanced Resistive Exercise Device (ARED) investigation uses a piston and flywheel system to simulate free-weight exercises in normal gravity to work all the major muscle groups through squats, dead lifts, and calf raises. ARED users see results similar to those from free-weight training, suggesting that it could be an effective countermeasure against loss of conditioning during spaceflight. While ARED's primary goal is to maintain muscle strength and mass, resistive exercise also helps astronauts increase endurance for physically demanding tasks such as space walks. Facility Details
Ryan Lien, Johnson Space Center, Houston, TX, United States
Developer(s) Information Pending
Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)
Human Exploration and Operations Mission Directorate (HEOMD)
ISS Expedition Duration
October 2008 - September 2013
The predecessor to ARED, iRED began ISS operations during Expedition 2.
- The Advanced Resistive Exercise Device (ARED) functions to maintain crew health in space. Crewmembers exercise daily on ARED to maintain their preflight muscle and bone strength and endurance. EVA, IVA, re-entry, and emergency egress activities necessitate the crewmembers' continued strength and endurance. The newest resistive exercise device is the Advanced Resistive Exercise Device, or ARED. It was taken to the International Space Station on space shuttle mission STS-126 in November 2008.
- The ARED has the capability to exercise all major muscle groups while focusing on the primary resistive exercise: squats, dead lifts, and calf raises.
- The ARED accommodates all crewmembers, from the 5th percentile Japanese female to the 95th percentile American male.
- The ARED provides a load of up to 600 pounds and has a touch screen that makes it easier for crewmembers to follow a personalized exercise plan. Resistive exercise is a countermeasure. This kind of exercise prevents the major muscle groups from weakening and lessens bone loss. Resistive exercise helps astronauts maintain strength and endurance.
Exercise Platform Subassembly mounts to the ARED structural frame and provides the surface from which to perform exercises. The platform houses two force plates, which act as the reaction surface for all exercises. Four load cells are installed under each force plate to measure the reactive loads. At this test level, the eight load cells and associated wiring harnesses have been installed.
Cylinder / Flywheel Assembly provides the resistive forces for all exercises. The vacuum canisters provide the primary force while the flywheels are used to simulate the inertial component of the exercise as would be experienced on the ground. These are mechanical assemblies only. No sensors or cabling are installed.
Main Arm Assembly includes the wishbone arm and the lift bar components. Load cells have been installed in the lift bar struts and the associated cables have been attached.
Arm Base Assembly includes the load adjustment mechanism, interfaces for the Cylinder / Flywheel Assembly, Main Arm Assembly, Cable Pulley Assembly, and the Frame / Platform Assembly. Two load cells, one rotational sensor, and associated cables are installed. The two load cells measure the reactive loads during cable-based exercises.
Belt / Pulley Assembly provides the capability to perform cable-based exercises. It interfaces the exercise rope to the Arm Base Assembly to provide load for the exercises. This is a mechanical assembly only. No sensors or wiring are installed.
Exercise Bench Assembly is an accessory that mounts to the platform and provides a surface for performing shoulder presses, bench presses, and other seated or lying exercises. It is folded up and stowed when not in use.
Heel Block Assembly is an accessory that mounts to the platform and allows the capability for performing heel-raise exercises. It is removed and stowed when not in use.
The ARED will operate in the following modes:
Resistance is provided by the movement of pistons within the vacuum of the cylinders. The piston rods are attached to an arm base assembly, which acts as a lever arm when the main arm assembly is moved.
In addition, ARED is fitted with a second resistance mechanism. This mechanism is a flywheel assembly that rotates as the arm base assembly is moved. This function provides an inertial load which, when moved, mimics the inertial load of a free-weight.
Resistive load can be changed by turning a load adjustment handle that will move the attachment point of the piston rods, thereby changing the length of the lever arm. The lever is able to provide loads ranging from 0 to 600+ pounds. ARED can be configured to provide exercises using the lift bar or the exercise cable. Using the cable, the loads are limited to a maximum of 150 pounds.
A major feature of ARED is the instrumentation system. This system includes triaxial force sensors located in the exercise platform that are able to record force in three dimensions. In addition, load sensors in the main lift arm and the arm base assembly measure unidirectional forces. The arm base assembly also has rotational sensors that record the range of motion of the arm.
In flight, force data will be sent to the ARED Instrumentation Box (AIB) and recorded using the ARED tablet personal computer (PC). This computer will have a user interface that allows exercise prescriptions to be sent from the Mission Control Center (MCC) at JSC to the ARED tablet PC. The exercise prescription will be automatically loaded into an individual crewmember profile. The profile will be accessed during exercise sessions. During exercise, the load and number of repetitions will be simultaneously recorded and displayed on the tablet PC. On ISS, the recorded data will be automatically downloaded to an on-station server, and then down-linked to the MCC.
- Displays the individual crew member prescription, history, and progress
- Allow crew to select any exercise from their prescription or choose other exercises
- Password protected for crew privacy
- Creates and stores near real-time exercise data files
- Communicates with the OCA at an OS (Windows) system-level basis as defined by the ARED ARED requires 100 watts of continuous and 200 watts peak maximum power. The Load Range is 10-600 lbs on Bar and 5-150 lbs on Cable; stroke Range – 0-30 inches on bar and 0-52 inches on cable. Lift bar must accommodate hand spacing up to 51 inches; platform must accommodate foot spacing up to 47 inches. Able to deliver constant load within 10% over entire stroke and load range; eccentric load must be at least 90% concentric load for load 50-600 lbs; eccentric load must be at least 80% concentric load for load 10-50 lbs. Integration of ARED is into Node 1 at the radial port. ARED performance capabilities are as followed: simulate inertial component of exercise force, meet static and dynamic envelope constraints, meet microgravity requirements, measure exercise forces (22 data points), meet anthropometric requirements, track exercise progress and provide exercise data to the crew and to the ground via the OPS LAN. The ARED facility on-orbit mass not to exceed 700 lbs, and on-orbit spares mass not to exceed 150 lbs. Currently planned maintenance of ARED includes periodic replacement of electrical cables at flex joints, brake cables and exercise cable, as well as an annual calibration and inspections. To the extent possible, maintenance activities will utilize existing standard ISS tools. Orbital replacement units (ORUs), access covers, caps, and structural parts that will be removed for on-orbit maintenance shall be designed with restraining and handling devices for temporary stowage by the crew in a microgravity environment. With humans currently occupying the International Space Station (ISS) for six months and space exploration missions of one to three years on the horizon, preservation of crewmember health and fitness is a major objective of the international space community. Exercise has been the primary utility used by the space agencies in an effort to protect cardio-vascular, bone, and skeletal muscle health while in space for extended stays. ^ back to top
- The design of ARED provides the user with the ability to perform resistive exercise on board the International Space Station (ISS). The ARED employs vacuum cylinders to provide a constant resistance, while flywheel assemblies provide a variable resistance. The variable resistance supplied by the flywheel assemblies is designed to mimic the inertial forces generated when lifting free weights on Earth.
- The ARED is required to have an on-orbit service life of at least 15 years, with a total cycle life of 11.23 million cycles. Eighty percent of the cycles will be bar exercises performed using the lift bar assembly, and twenty percent of the cycles will be cable exercises performed using the cable assembly.
Decadal Survey Recommendations
Information Pending^ back to top
The Advanced Resistive Exercise Device (ARED) was designed to address the limitations of the Interim Exercise Device (iRED) and serve as the next generation of in-flight resistance exercise hardware on the ISS. A study compared the musculoskeletal adaptations to 16 wk of resistance exercise training with the ARED to training with free weights (FW) in healthy, untrained, ambulatory men and women. It was proposed that 16 wk of training with the ARED or with FW would result in significant increases in muscle strength, muscle volume, lean tissue mass, vertical jump (VJ) height, and bone mineral density (BMD), and that FW would increase muscle strength, muscle volume, lean tissue mass, and BMD to a greater extent than ARED because of the differences in inertial characteristics of the ARED flywheels and FW. In ambulatory subjects, ARED training resulted in increases similar to those with FW training for all of the variables measured, the only exceptions being a greater rate of increase in squat (SQ) strength from midtraining to posttraining and a greater rate of increase in VJ height in the FW group. These device-dependent differences might relate to the inability of the ARED flywheels to mimic inertial characteristics of FW throughout the full range of resistances, or they could relate to differences in the biomechanics of exercise between the two devices. Given these findings, and considering the effectiveness of FW training at mitigating bed rest–induced deconditioning, we expect that ARED training will be a more effective countermeasure than iRED training against musculoskeletal deconditioning during spaceflight (Loehr et al., 2010).Results Publications
English KL, Lee SM, Loehr JA, Ploutz-Snyder RJ, Ploutz-Snyder LL. Isokinetic strength changes following long-duration spaceflight on the ISS. Aerospace Medicine and Human Performance. 2015 December 1; 86(12): 68-77. DOI: 10.3357/AMHP.EC09.2015.
Loehr JA, Lee SM, English KL, Sibonga JD, Smith SM, Spiering BA, Hagan RD. Musculoskeletal adaptations to training with the advanced resistive exercise device. Medicine and Science in Sports and Exercise. 2011; 43(1): 146-156. DOI: 10.1249/MSS.0b013e3181e4f161. PMID: 20473227.
Ground Based Results Publications
Fregly CD, Kim BT, De Witt JK, Fregly BJ. Dynamic simulation of muscle loading during ARED squat exercise on the International Space Station. ASME 2013 Summer Bioengineering Conference, Sunriver, Oregon; 2013 June 26 V01AT20A031.
Fregly BJ, Fregly CD, Kim BT. Computational simulation of muscle loading during ARED squat exercise on the International Space Station. Journal of Biomechanical Engineering. 2015 October 16; epub. DOI: 10.1115/1.4031795. PMID: 26473475.
Moore C, Svetlik R, Williams A. Designing for reliability and robustness in International Space Station exercise countermeasures systems. 2017 IEEE Aerospace Conference, Big Sky, MT ; 2017 March 4-11 17 pp.
Nagaraja MP, Jo H. The role of mechanical stimulation in recovery of bone loss—high versus low magnitude and frequency of force. Life. 2014 April 2; 4(2): 117-130. DOI: 10.3390/life4020117.
Moore C, Svetlik R, Williams A. Practical applications of cables and ropes in the ISS countermeasures system. 2017 IEEE Aerospace Conference, Big Sky, MT ; 2017 March 4-11 21 pp.
Fregly CD, Kim BT, Li Z, De Witt JK, Fregly BJ. Estimated muscle loads during squat exercise in microgravity conditions. ASME 2012 Summer Bioengineering Conference, Farjardo, Puerto Rico, USA; 2012 June 20-23 367-368.
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