Automated testing of the controlled resistance exercise device (C-red) for spaceflight

Area of Science:

• Spaceflight physiology
• Biomechanics
• Exercise engineering

Background:

• Muscle and bone atrophy are significant concerns during spaceflight unloading.
• Resistance exercise is a key countermeasure.
• The Controlled Resistance Exercise Device (C-RED) uses a unique mechanical advantage, potentially introducing asymmetric loading.

Purpose of the Study:

• To develop an automated system for testing the bilateral symmetry of the C-RED device.
• To evaluate the impact of winching material (cord vs. strap) on loading symmetry.
• To assess the trade-offs between symmetry, strength, and durability for spaceflight applications.

Main Methods:

• An automated testing system was designed to eliminate human bias in evaluating device loading.
• Bilateral symmetry tests were conducted using both cord and strap winching materials.
• Loading characteristics and material properties (strength, wear resistance) were analyzed.

Main Results:

• Both cord and strap materials exhibited some degree of asymmetric loading in the C-RED.
• Cord provided more symmetric loading but had lower strength and was prone to fraying.
• Straps demonstrated superior strength and wear resistance but resulted in slightly less symmetric loading.

Conclusions:

• The C-RED device exhibits inherent asymmetric loading, irrespective of the winching material.
• Straps are recommended for C-RED due to their enhanced strength and durability, outweighing the minor reduction in loading symmetry.
• This research informs the selection of materials for spaceflight exercise equipment to ensure safety and effectiveness.