The Advanced Resistive Exercise Device (ARED) (Fig.1) is unique countermeasure hardware available to crewmembers aboard the International Space Station (ISS) used for resistance exercise training to protect against bone and muscle loss during long duration space missions. ARED instrumentation system was designed to measure and record exercise load data, but: - Reliably accurate data has not been available due to a defective force platform. - No ARED data has been recorded since mid-2011 due to failures in the instrumentation power system. ARED load data supports on-going HRP funded research, and is available to extramural researchers through LSDA-Repository. Astronaut Strength, Conditioning, and Rehabilitation specialists (ASCRs) use ARED data to track training progress and advance exercise prescriptions. ARED load data is necessary to fulfill medical requirements. HRP directed task intends to reduce to program risk (HRP IRMA Risk 1735), and evaluate the XSENS ForceShoeTM as a means of obtaining ARED load data during exercise sessions. The XSENS ForceShoes"TM" will fly as a hardware demonstration to ISS in May 2014 (39S). Additional portable load monitoring devices (PLMDs) are under evaluation in the ExPC Lab. PLMDs are favored over platform redesign as they support future exploration needs

Caldwell, Erin

Hanson, Andrea

Kreutzberg, Galen

Newby, Nate

Peters, Brian

Ploutz-Snyder, Lori

Sinka, Joe

NASA Technical Reports Server

1 A n d r e a  H a n s o n ,  2 B r i a n  P e t e r s ,  2 E r i n  C a l d w e l l ,  2 N a t e  N e w b y ,  2 J o e  
S i n k a ,  3 G a l e n  K r e u t z b e r g ,  4 L o r i  P l o u t z - S n y d e r .
1 N A S A  J o h n s o n  S p a c e  C e n t e r
2 W y l e  S c i e n c e  T e c h n o l o g y  &  E n g i n e e r i n g  G r o u p
3 N a t i o n a l  S p a c e  B i o m e d i c a l  R e s e a r c h  I n s t i t u t e  S u m m e r  S t u d e n t  
4 U n i v e r s i t i e s  S p a c e  R e s e a r c h  A s s o c i a t i o n
PORTABLE LOAD MEASUREMENT DEVICE 
FOR USE DURING ARED EXERCISE ON ISS
https://ntrs.nasa.gov/search.jsp?R=20140008724 2019-08-29T13:52:11+00:00Z
• The Advanced Resistive Exercise Device (ARED) was installed on ISS in 
2009.
• ARED provides up to 600 lb resistive loads, and accommodates ~40 different 
exercises.
• Reliable and accurate exercise data has not been available since installation.
• Crewmembers fill out spreadsheets and manually record exercise data.
• Manual logs are not historically as accurate as direct measurement.
• XSENS ForceShoes™ are the first COTS portable load monitoring device 
(PLMD) to offer high accuracy (~2%), ground reaction force measurements.
• PLMDs are not as widely used on the ground, but are favorable technology 
option when considering future exploration needs.
XSENS FORCE SHOE
• Each Force Shoe is instrumented with:
• Two six degrees-of-freedom (6-DOF) tri-axial force (Fx,y: ±130 lbforce, Fz: ±260 lbforce), 
and torque (Tx,y,z: ±177 lb-in ) sensors. 
• Two XSENS MTx sensors that measure tri-axial acceleration (± 180 m/s2 ) and inertial 
parameters (± 1200 deg/s)
• Powered by 4 AA-batteries
• Communication via Bluetooth or serial USB cable
• Shoes weigh ~2.5 lb each, and are ~1.5 inches tall
• The better the tools, the better the science
• ARED design requirement states that load measurements must be 
accurate within ± 1%. Center of pressure should be measured within ±
0.5 cm.
— Errors of ±0.5cm and ±1.0cm in CoP calculation result in errors (7% 
and 14%, respectively) in joint torque calculations [McCaw & DeVita, J. 
Biomech, 1995] and is compounded during biomechanical analysis.
• Bone responds positively  to an accumulation of
mechanical input (ground reaction forces). 
— Overestimating GRF could reduce 
training benefits to crewmembers.
— Underestimating GRF could result 
in unnecessary discomfort and physical exertion.
WHY WE NEED ACCURATE MEASUREMENT
• Safety
Rx (lbs) ± 1% 5% 10%
‐ 198 190 180
+ 202 210 220
‐ 297 285 270
+ 303 315 330
‐ 396 380 360
+ 404 420 440
‐ 495 475 450
+ 505 525 550
‐ 594 570 540
+ 606 630 660
200
300
400
500
600
• ARED can deliver up to 600 lb exercise loads.
• Original ARED calibration curves believed to be erroneous  up to ~10% .
• Can lead to inefficient prescriptions when Rx is underestimated for safety. It is 
best to take out the guess work! 
? ?
• Researchers are forced to accept increased risk of erroneous/incomplete exercise 
log data which limits interpretation of results outcomes.
• Risk of promoting a poor countermeasure protocol or not promoting a promising 
one with large uncertainty in the data.
• May prolong research to reach statistical conclusions (higher cost, longer 
schedules).
• Uncertainty in the data limits the ability to close HRP Gaps and mitigate Risks.
• Cannot write effective requirements documents for next gen exercise hardware.
• Cannot send our crews off on long duration exploration missions with any 
confidence that we know how to best protect them.
• Lost opportunity to learn after enormous investment in the ISS, HRP funded 
science, CMS hardware updates.
• Research informs operations.
Exercise
Countermeasures
• Fulfill medical requirements.
• CMS Engineering troubleshoots hardware 
life cycles and anomalies.
• ISS structures group analyze impact to 
station structure.
• Enhance existing hardware, and inform 
future device requirements and design.
• Research: SPRINT, VO2 Max, Treadmill 
Kinematics, ARED Kinematics.
GROUND & PARABOLIC FLIGHT TESTS
Controlled ground evaluation
Parabolic 
Flight
HILT
Functional checkout
Test Stand Load Flight Ground
mean (±SD) spread mean (±SD) spread
Average % of Target (Fz, ±SD)
91.8% (±1.5) 90.4 – 94.4% 102.8% (±0.9) 100.2 – 104.3%
Average % of Target (Fx,y,z, ±SD)
105.0% (±1.8) 102.4 – 107.8% 104.5% (±1.2) 102.6 – 107.7%
N=6 N=51
Bungee Load Flight Day 2 Flight Day 4*
mean (±SD) spread mean (±SD) spread
Average % of Target (Fz, ±SD)
99.3% (±2.8) 94.6 – 101.7% 89.4% (±0.2) 89.2 – 89.6%
Average % of Target (Fx,y,z, ±SD)
103.7% (±1.9) 101.8 – 106.6% 92.8% (±1.3) 91.8 – 94.2%
N=5 N=3
HILT Eval HILT Evaluation
N=25 mean (±SD) spread
Average % of Target (Fx,y,z, ±SD) 101.2% (±0.8) 98.1 – 103.7%
HILT Eval Function Checkout
N=30 mean (±SD) spread
Average % of Target (Wireless) 100.3% (±0.8) 97.7-101.9%
Average % of Target (Wired) 100.6% (±1) 98.2-102.7%
ISS FORCE SHOE ENGINEERING EVALUATION
• Hardware arrived to ISS on 39S (May 2014).
• Wireless receiver will arrive on Orb2 (~July 3rd).
• First data expected by June/July 2014.
• Aims of hardware demonstration:
• 1: Use the ForceShoes™ as a means to measure static loads on ARED. 
• 2: Collect dynamic data during ARED exercise to aid in the ongoing evaluation of the 
XSENS ForceShoe™ to support HRP sponsored research.                          
Static load data will be collected on the T2 under stationary (non-motorized) conditions, to 
compare the ForceShoe™ load measure to that recorded by the T2 load sensors.  
• Inform transition of use for research, and modifications required to next 
generation PLMD for use as a daily operational tool.
FORCE SHOES HARDWARE
• Launched to ISS May 29th!
METHODS & ANALYSIS
• Each static load measure will be made in triplicate.
• Up to 6 load levels with treadmill bungees.
• Up to 20 load increments on ARED.
• High and low bar static load measures.
• Squat, deadlift, bicep curls.
• Data will be analyzed for:
• Repeatability and Accuracy.
• Tri-axial force components. 
• Evaluate range/robustness of Bluetooth communication.
ESTIMATION OF LOAD DISTRIBUTION
RESEARCH TAKES SPACE!
SPACE DEMANDS INNOVATION!
TO THE MOON, MARS & BEYOND!
Habitable Volume: 316 Ft3Habitable Volume: 15,000 Ft3
International Space Station Orion Capsule
PORTABLE LOAD MONITORING DEVICES
XSENS 
ForceShoe™
Nike+ 
Hyperworkout Shoe
Aurora Flight Systems:
Enhanced Dynamic Load Sensors –
Phase II SBIR
JSC Robotics Team: 
X1/X2 Force Shoe
ADVANCED EXERCISE CONCEPTS
Design requirements: small footprint, low power usage, resistance and 
aerobic capabilities in one device…highly effective.
MMED FlywheelNGRED HERO
THANKS!
Contact Info:  
andrea.m.hanson@nasa.gov
Acknowledgments
Exercise Physiology, & Countermeasures Lab
Brian Peters, Wyle
Lori Ploutz-Snyder, USRA
Erin Caldwell, Wyle
Nate Newby, Wyle
Joe Sinka, Wyle
Galen Kreutzberg, NSBRI Summer Student
Linda Loerch, NASA
Noel Skinner, Wyle
Funding
NASA Human Research Program
Barbara Corbin, NASA HRP
David Baumann, NASA HRP
Flight Projects Team
Stephanie Flint, NASA JSC
Anthony Rys, NASA JSC
Steve Huppman, Wyle
ISS Medical Projects
Alonso Fuentes, Lockheed Martin
David Sehrt, Lockheed Martin
Crewmembers
Inc. 40, 41, 42
BACKUP CHARTS
ARED EXERICSES
Traditional Bar Exercises:
Heel Raises
Front Squat
Single leg squat
Squat
Sumo squat
Bench press
Shoulder press
Shrugs
Deadlift
Romanian deadlift
Sumo deadlift
Biceps curl
Bent over row
Tricep extension
Upright row
Traditional Cable Exercises:
Biceps curls
Bent over row
Triceps extension
Upright row
Single arm row
Side bend
Crunches/Situps
Cable deadlift
Cable RDL
Cable sumo deadlift
Cable tripceps extension
Hip adduction
Hip abduction
Hip extension
Hip flexion
Lateral shoulder raise
Rear shoulder raise
Triceps kickback
Wrist curl

HOW DO ACSM/AHA RECOMMENDATIONS 
COMPARE TO ISS EXERCISE?
.
Day 1 Day 2 Day 3 Day 4 Day 5 Day 6 Day 7
ARED 35‐60 min
35‐60 
min
35‐60 
min
35‐60 
min
35‐60 
min
35‐60 
min
T2 30 min 30 min 30 min 30 min
CEVIS 30 min 30 min
 Recommended: 
- 2 days of strength training 
- 150 min of moderate 
aerobic exercise per week
- ~10,000 steps per day 
 Actual:
- 6 days muscle 
strengthening
- ~180 minutes aerobic 
activity
- 5-6K steps per day, 4 days 
a week are acquired
 Intensity is absolutely key 
to success in order to 
reduce exercise time 


Portable Load Measurement Device for Use During ARED Exercise on ISS

Sinka, J.

Kreutzburg, G.

Peters, B.

Caldwell, E.

Ploutz-Snyder, L.

Hanson, A.

A. Hanson1, B. Peters1, E. Caldwell1, J. Sinka1, G. Kreutzburg2, L. Ploutz-Snyder3  
1Wyle Science Technology & Engineering Group, 2National Space Biomedical Research Institute Summer Student, 
3Universities Space Research Association.         Contact: andrea.m.hanson@nasa.gov 
Background 
 
• The Advanced Resistive Exercise  
Device (ARED) (Fig.1) is unique  
countermeasure hardware  
available to crewmembers aboard  
the International Space Station  
(ISS) used for resistance exercise  
training to protect against bone  
and muscle loss during long  
duration space missions. 
• ARED instrumentation system was designed to 
measure and record exercise load data, but:  
- Reliably accurate data has not been available due to a 
defective force platform. 
- No ARED data has been recorded since mid-2011 due 
to failures in the instrumentation power system. 
• ARED load data supports on-going HRP funded 
research, and is available to extramural researchers 
through LSDA-Repository. 
• Astronaut Strength, Conditioning, and Rehabilitation 
specialists (ASCRs) use ARED data to track training 
progress and advance exercise prescriptions. 
• ARED load data is necessary to fulfill medical 
requirements. 
• HRP directed task intends to reduce to program risk 
(HRP IRMA Risk 1735), and evaluate the XSENS 
ForceShoeTM as a means of obtaining ARED load data 
during exercise sessions. 
• The XSENS ForceShoes™ will fly as a hardware 
demonstration to ISS in May 2014 (39S). 
• Additional portable load monitoring devices  
(PLMDs) are under evaluation in the ExPC Lab. 
• PLMDs are favored over platform redesign as they 
support future exploration needs. 
Figure 1: ARED  
Methods 
 
• XSENS ForceShoe™ measure tri-axial force and torque 
data at 50 Hz (Fig. 2). 
• Ground and Parabolic flight (Fig. 3) evaluations were 
performed to test the XSENS ForceShoes™. 
Results 
ISS Force Shoe Demo 
Other PLMDs 
Output (per load cell) Units 
  Fx,y  
(lb-force) 
Fz  
(lb-force) 
Sensing Range ±130 ±260 
Resolution 0.1 0.1 
Single Axis Overload 1146 2248 
Table 1: Summary of XSENS Senor Load 
Monitoring Specifications. 
Figure 3: Parabolic Flight Test of XSENS 
ForceShoe™ 
A: Support console and test stand with static load 
force application device. 
B: Operator hovering over the support console and 
data acquisition system. 
C:Operator standing in the ForceShoes™ wearing the 
harness/bungee system. 
A 
B 
C 
• Subjects (n=4)will perform 1 T2 session (Fig. 4A) and 4 
ARED sessions (Fig. 4B). 
• A number of static load measures will be collected on 
the T2 by adding/subtracting spacers to the bungee 
assembly decrease/increase the pull down load. 
• During ARED sessions static and dynamic activity will be 
performed during squat, deadlift and bicep curl. 
- A series of static loads will be collected in increments of 
25 lb, from 0-500 lb. 
• Transition to operational use will be assessed upon 
completion of the in-flight hardware demo. 
Figure 5: PLMDs under evaluation. 
A) JSC Robotics X1 Force Shoe 
B) Aurora Flight Systems Force Plates (SBIR Phase I completed) 
C) Nike Hyperworkout+ Shoe (SAA) 
*USARIEM/MIT LL instrumented boot not shown here. 
Figure 2: XSENS ForceShoe™ and 
instrumented subject. 
• An X-Y test stand  and  bungee system with in-line load 
cells used to apply and measure an input load to 
compare to ForceShoe™ measurements. 
• Custom LabVIEW software developed to record data. 
• Body weight + 45, 90, and 135 lb measured on a force 
plate and compared to ForceShoe™ load measures. 
 X-Y Test Stand Load Flight Ground 
   mean (±SD) spread  mean (±SD) spread 
Average % of Target 
(Fz, ±SD) 
91.8% (±1.5) 90.4 – 94.4% 102.8% (±0.9) 100.2 – 104.3% 
Average % of Target 
(Fx,y,z, ±SD) 
105.0% (±1.8) 102.4 – 107.8% 104.5% (±1.2) 102.6 – 107.7% 
  N=6   N=51   
Table 2: Results of static load measurements in ForceShoe™ vs X-Y test stand, in flight and ground 
for measurements made from 40-200 lb. 
 Bungee Load Flight Day 2 Flight Day 4* 
   mean (±SD) spread  mean (±SD) spread 
Average % of Target 
(Fz, ±SD) 
99.3% (±2.8) 94.6 – 101.7% 89.4% (±0.2) 89.2 – 89.6% 
Average % of Target 
(Fx,y,z, ±SD) 
103.7% (±1.9) 101.8 – 106.6% 92.8% (±1.3) 91.8 – 94.2% 
  N=5   N=3  
Table 3: Results of static load measurements made while subject was wearing the ForceShoes™ and 
bungee pull down load was applied during standing. 
 HILT Eval HILT Evaluation 
   mean (±SD) spread 
Average % of Target 
(Fx,y,z, ±SD) 
101.2% (±0.8) 98.1 – 103.7% 
  N=25   
Table 4: Results of load measurements made while subject was wearing the ForceShoes™ and standing on 
a force plate. Analysis included BW, three additional weight loads, and set of deadlifts from 5 subjects. 
• Additional PLMDs are under evaluation in the ExPC lab, 
as described in Fig. 5. 
• Goal is to identify a device that will meet both research 
and daily operational needs. 
Figure 4A: Concept of test 
protocol for T2 measurement. 
Figure 4B: Concept of test 
protocol for ARED measurement. 
A B 
• ForceShoes™ demonstrate accuracy and low variability 
(<5%) between measures. 
• Subjects reported acceptable comfort and ease of use. 
• Custom software and ForceShoe™ hardware operate 
well in simulated microgravity environment. 
• Recommended for flight demo aboard ISS to monitor 
ARED exercise loads. 
This research is sponsored by HRP Directed Task MTL 922. 
B 
C 
A 
*ForceShoes™ were zeroed during 2g pull out creating an offset in the data. 
https://ntrs.nasa.gov/search.jsp?R=20140012615 2019-08-31T18:03:47+00:00Z


Portable Load Measurement Device for Use During ARED Exercise on ISS

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