Three different lifting strategies for controlling the motion patterns of the external load

Area of Science:

• Biomechanics
• Human Movement Science
• Ergonomics

Background:

• Human body coordination during lifting is complex and challenging to manage.
• External load motion control strategies may influence body coordination and spinal joint forces.

Purpose of the Study:

• To investigate if optimizing external load motion patterns can control body coordination and reduce lumbosacral joint compressive forces.
• To synthesize three unique dynamic motion patterns using distinct objective functions.
• To establish the relationship between spinal loading and external load motion control during lifting.

Main Methods:

• A simulation-based optimization approach generated three distinct external load motion patterns.
• Objective functions included maximizing motion smoothness, minimizing center of gravity changes, and minimizing joint moment-to-strength ratios.
• Eight subjects performed lifts using each motion pattern, with lumbosacral joint compressive forces measured.

Main Results:

• Subjects utilizing the motion pattern prioritizing external load smoothness exhibited statistically significant lower compressive force peaks.
• The study successfully indexed and synthesized three biomechanically distinct motion patterns.
• A clear association was found between spinal loading and the control of external load motion patterns.

Conclusions:

• Optimizing external load motion patterns, particularly by maximizing smoothness, can effectively reduce compressive forces on the lumbosacral joint during lifting.
• This research provides a method for controlling spinal loading through external load manipulation.
• The findings have implications for designing safer lifting strategies and ergonomic interventions.