Fluidity as a Measure of Movement Quality.

Area of Science:

• Biomechanics
• Human-System Interaction
• Wearable Technology

Background:

• Quantifying whole-body movement quality unobtrusively is challenging due to complexity.
• Existing spaceflight research often focuses on single-limb or joint kinematics, leaving a gap in functional whole-body assessment.
• Assessing movement quality is vital for understanding spaceflight adaptation and risks in exploration scenarios.

Purpose of the Study:

• To introduce and validate 'fluidity' as a quantifiable metric for whole-body movement quality.
• To develop and test a low-power, wireless, on-body sensor system for unobtrusive kinematic monitoring.
• To demonstrate the utility of fluidity measurement in operational settings, including microgravity environments.

Main Methods:

• Adapted and mathematically refined the definition of biomechanical 'fluidity'.
• Developed a wearable, low-power, wireless sensor system for kinematic data acquisition.
• Validated the fluidity measurement technique in laboratory settings and during parabolic flights.

Main Results:

• Demonstrated discriminatory validity of the fluidity metric across different gravity levels.
• Showcased the ability of fluidity to distinguish between nominal and degraded movement patterns.
• Confirmed the feasibility of unobtrusive, wireless measurement of movement quality in operational environments.

Conclusions:

• Fluidity offers a robust and practical metric for assessing whole-body movement quality.
• The developed sensor system enables unobtrusive, real-time monitoring of human movement.
• This approach has broad applications beyond spaceflight, including exercise physiology, rehabilitation, and human-robotics.