The purpose of this experiment was to evaluate a new treadmill harness design for comfort during exercise, and measure the loads in the harness straps for direct comparison with the current U.S. Treadmill with Vibration and Isolation System (TVIS) Harness. The Station Detailed Test Objective (SDTO) research protocol was aimed at improving comfort, plus increasing consistent loading for crewmembers exercising on the ISS treadmill. The Center for Space Medicine (CSM) Harnesses was instrumented to allow for objective correlation with subjective ratings of comfort. To provide a direct comparison with the ISS treadmill harness, the load distribution, and subject load device, (loading applied to the ISS treadmill harness) was also measured. The ISS treadmill harnesses were instrumented by the crew on-orbit during a one-time set up activity.
The Glenn Harness for treadmill running aboard the ISS was evaluated favorably against the current treadmill harness for crew comfort between November 2009 and November 2010. Four out of five male crewmembers preferred the improved comfort of the Glenn Harness over the current operational Treadmill Harness, The Johnson Space Center (JSC) Crew Office endorsed continued to provide flight Glenn Harness units to the crewmembers as a crew preference item. Since completion of this SDTO, all eligible male crewmembers have requested Glenn Harnesses, and as of February 2012, thirteen units have been provided. However, the two female crewmembers enrolled in the SDTO protocol did not prefer the Glenn Harness, due to stiffness in the shoulder straps in the chest area.
The project team held a crew debrief in March 2011 with these crewmembers, gathered feedback, and subsequently developed three alternative design prototypes to address the issues; (1) a modified strap, (2) a yoke with spreader, and (3) a quick release yoke. They were then tested for comfort by three test subjects running the SDTO protocol in simulated zero-g supine running and by eight female crewmembers on the Treadmill 2 (T2) trainer at JSC. Although the yoke styles presented a promising alternative to the traditional strap design, the modified strap style was preferred overall. The yoke styles were found to be sensitive to the degree of forward lean in upright running and caused some restriction in breathing. The consensus based on these results was to proceed with recommending the modified strap style to be incorporated into the flight inventory for future crews to use. The inventory will have small, medium, large, and extra large sizes available for both male and female crewmembers. A standard sizing template and protocol was also developed, with crew size currently obtained ideally at least 6 months before flight, so the Glenn Harness can be fabricated and certified for flight in time for manifesting and launch.
|Mission||Launch/Start Date||Landing/End Date||Duration|
|Expedition 20||05/27/2009||10/11/2009||137 days|
|Expedition 21||10/11/2009||12/01/2009||51 days|
|Expedition 22||11/30/2009||03/18/2010||109 days|
|Expedition 23||03/18/2010||06/01/2010||75 days|
|Expedition 24||06/01/2010||09/25/2010||117 days|
|Expedition 25||09/24/2010||11/25/2010||31 days|