Humans use minimum cost movements in a whole-body task

Area of Science:

• Biomechanics
• Human Movement Science
• Robotics

Background:

• Human musculoskeletal systems are complex, yet common movements exhibit stereotypical patterns.
• Energetic cost is a significant factor in many human movements like walking and reaching.
• Previous research indicated consistent posture sequences across subjects during whole-body curve tracing.

Purpose of the Study:

• To investigate if humans select movement trajectories that minimize energetic cost.
• To test the hypothesis that movement economy influences the choice of general human movements.
• To explain the observed commonalities in posture sequences during arbitrary whole-body movements.

Main Methods:

• Utilized a forty-eight degree of freedom human dynamic model.
• Computed movement costs for nominal and perturbed tracing trajectories.
• Compared energetic costs between different movement patterns using the dynamic model.

Main Results:

• Perturbed tracings were found to be more energetically expensive than nominal tracings.
• Movement cost analysis supported the hypothesis of minimum cost selection.
• Data infers that original movement traces were chosen based on minimum energy expenditure.

Conclusions:

• Human movement strategies, even for arbitrary tasks, appear to be optimized for energetic economy.
• Minimum cost principles likely underlie the observed consistency in human movement patterns.
• Understanding movement cost is crucial for explaining general human motor control and biomechanics.