Advanced Resistive Exercise Device (ARED) - 11.14.18

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ISS Science for Everyone

Science Objectives for Everyone
The Advanced Resistive Exercise Device (ARED) uses adjustable resistance piston-driven vacuum cylinders along with a flywheel to system to provide loading for crew members to experience load and maintain muscle strength and mass 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.

The following content was provided by Cody W. Burkhart, and is maintained in a database by the ISS Program Science Office.
Facility Details


Facility Manager(s)
Cody W. Burkhart, JSC, Houston, TX, United States

Facility Representative(s)
Information Pending

Developer(s) Information Pending

Sponsoring Space Agency
National Aeronautics and Space Administration (NASA)

Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)

ISS Expedition Duration
October 2008 - September 2013

Expeditions Assigned

Previous Missions
The predecessor to ARED, iRED began ISS operations during Expedition 2.


  • Onboard
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    Facility Description

    Facility Overview

    • The Advanced Resistive Exercise Device (ARED) functions to maintain crew health in space. Crew members exercise daily on ARED to maintain their preflight muscle and bone strength and endurance. EVA, IVA, re-entry, and emergency egress activities necessitate the crew members' continued strength and endurance. The current 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 and put into service January 2009.
    • The ARED has the capability to exercise all major muscle groups while focusing on the primary resistive exercise:  squats, dead lifts, and heel raises.
    • The ARED accommodates all crew members, from the 5th percentile Japanese female to the 95th percentile American male.
    • The ARED provides a load of up to 600 pounds for bar and 250 pounds for cable exercise and connects to a Space Station Computer (SSC) that makes it easier for crew members to follow a personalized exercise plan. Resistive exercise is a countermeasure, which prevents the major muscle groups from weakening and lessens bone loss. Resistive exercise helps astronauts maintain strength and endurance.
    ARED consists of seven distinct assemblies:
    Exercise Platform Subassembly mounts to the ARED structural frame and provides the surface from which to perform exercises. The platform houses two force plates, with 4 load cells installed under each plate to measure the reactive loads for all exercises.

    Cylinder/Flywheel Assembly generates the loads for all exercises. The vacuum canisters provide the primary force while the flywheels provide the simulated inertial component of the exercise as would be experienced on the ground. These are mechanical assemblies only.

    Main Arm Assembly includes the wishbone arm and the lift bar components. Load cells were installed in the lift bar struts.

    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. These assemblies contain two load cells and, one rotational sensor. The two load cells measure the reactive loads during cable-based exercises.

    Belt/Pulley Assembly provides the capability to perform cable-based exercises. It provides the interfaces between the exercise rope and the Arm Base Assembly via the Cable Arm Ropes to provide load for the exercises. This is a mechanical assembly only.

    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. Situps and other core exercises can be performed using the bench as well. 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 operates 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 250 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 a rotational sensors that record the range of motion of the arm.

    In flight, force data is sent to the ARED Instrumentation Box (AIB) and recorded using the ARED tablet personal computer (PC). This computer has 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 is automatically loaded into an individual crew member profile. The profile is accessed during exercise sessions. During exercise, the load and number of repetitions are simultaneously recorded and displayed on the tablet PC. On ISS, the recorded data is automatically downloaded to an on-station server, and then down-linked to the MCC:
    • Displays the individual crew member prescription, history, and progress
    • Allows crew to select any exercise from their prescription or choose other exercises
    • Provides crew privacy with password protection
    • Creates and stores near real-time exercise data files
    • Communicates with the Orbiter Communications Adapter (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 crew member 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.

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    Facility Operations

    • 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.

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    Decadal Survey Recommendations

    Information Pending

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    Results/More Information

    The Advanced Resistive Exercise Device (ARED) was designed to provide adequate strength training equipment for astronauts assigned to long duration missions on the International Space Station (ISS). The ARED functional capabilities address the load and operational limitations of the Interim Exercise Device (iRED), and has been in serve on ISS since 2009. A ground 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 iRED because of the differences in inertial characteristics of the ARED flywheels and FW. In ambulatory subjects, ARED training resulted in strength, volume, and functional fitness gains 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. In long duration missions of 6 months, astronauts also increased their resistance exercise from 33% to 46% after resistive devices were updated from iRED to ARED. 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.


    Researchers from the European Space Agency (ESA) have published a detailed description of an individualized exercise training program during ESA crewmembers’ time on the ISS and a postflight physical assessment to evaluate their musculoskeletal health. On average, crewmembers have shown increases in cardiovascular and resistance exercise workload towards the end of their mission on the ISS. The physical assessment reported that crewmembers showed deficiencies in muscle strength, power, core muscle endurance, and hip flexibility 6 days after landing. Significant recovery in most areas, except jump performance and flexibility, was observed after 21 days. These studies highlight the importance of investigating musculoskeletal health during and after space flight to help crewmembers maintain their cardiovascular and musculoskeletal health while on the ISS to improve their re-adaptation to life on Earth.


    Results Publications

      Petersen N, Lambrecht G, Scott J, Hirsch N, Stokes M, Mester J.  Postflight reconditioning for European astronauts – A case report of recovery after six months in space. Musculoskeletal Science & Practice. 2017 January; 27 Suppl 1: S23-S31. DOI: 10.1016/j.msksp.2016.12.010. PMID: 28173929.

      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.

      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.

      Petersen N, Jaekel P, Rosenberger A, Weber T, Scott J, Castrucci F, Lambrecht G, Ploutz-Snyder LL, Damann , Kozlovskaya IB, Mester J.  Exercise in space: the European Space Agency approach to in-flight exercise countermeasures for long-duration missions on ISS. Extreme Physiology & Medicine. 2016 August 2; 5: 9. DOI: 10.1186/s13728-016-0050-4. PMID: 27489615.

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    Ground Based Results Publications

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    ISS Patents

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    Related Publications

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    Related Websites

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    NASA Image:  ISS030E148403 - European Space Agency astronaut Andre Kuipers, Expedition 30 flight engineer, exercises in the Tranquility node of the International Space Station, using the Advanced Resistive Exercise Device (ARED).

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    NASA Image:  ISS030E012688 - NASA astronaut Dan Burbank, Expedition 30 commander, exercises using the Advanced Resistive Exercise Device (ARED) in the Tranquility node of the International Space Station.

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    NASA Image:  ISS038E041426 - Japan Aerospace Exploration Agency (JAXA) Koichi Wakata, Expedition 38 Flight Engineer (FE), exercises on the Advanced Resistive Exercise Device (ARED) in Node 3. Photo was taken during Expedition 38.

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    NASA Image:  ISS039E011261 - Expedition 39 flight engineer Steve Swanson exercises on the Advanced Resistive Exercise Device (ARED) in the Tranquility Node 3.

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    NASA Image:  ISS040E006102 - European Space Agency astronaut Alexander Gerst,Expedition 40 flight engineer, gets a workout on the Advanced Resistive Exercise Device (ARED) in Node 3 Tranquility module of the International Space Station.

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    NASA Image:  ISS042E016567 - Flight engineer and European Space Agency (ESA) astronaut Samantha Cristoforetti exercises on the Advanced Resistive Exercise Device (ARED) in the Tranquility Node 3.

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