Speed-Related Energy Flow and Joint Function Change During Human Walking.

Area of Science:

• Biomechanics
• Human locomotion analysis
• Gait dynamics

Background:

• Mechanical energy transfer between body segments occurs via joints during human walking.
• Joint mechanics are coordinated to adapt to changes in walking speed.
• Understanding joint and segment contributions to speed alteration is crucial for gait analysis.

Purpose of the Study:

• To analyze the functional behaviors of major human joints during walking.
• To investigate how joints and segments modify walking speed during different stance phase periods (collision, rebound, preload, push-off).

Main Methods:

• Gait experiments were conducted at three self-selected walking speeds.
• Mechanical works of joints and segments were calculated from collected gait data.
• Net joint work was used to determine joint function indices.

Main Results:

• Primary joint functional behaviors remain consistent across different walking speeds.
• Joint function indices, such as strut functions, may change slightly with speed (e.g., decrease with faster walking).
• The hip and ankle demonstrate increased energy absorption during collision and enhanced propulsion during push-off at higher speeds, while the knee of the stance leg shows no contribution to speed alteration.

Conclusions:

• Human walking speed is modulated through the coordinated actions of the hip and ankle during collision and push-off phases.
• Altering walking speed induces fundamental changes in joint mechanics, particularly in energy management and propulsion.
• The waist functions as a strut, enhancing stability during faster walking impacts.