Load Carriage During Walking Increases Dynamic Stiffness at Distal Lower Limb Joints

Area of Science:

• Biomechanics
• Human Movement Science
• Orthopedics

Background:

• Walking requires adaptable movement patterns, especially when carrying external loads.
• Understanding lower limb joint responses to load is crucial for analyzing gait adaptations.
• Dynamic joint stiffness is a key parameter reflecting joint behavior during locomotion.

Purpose of the Study:

• To investigate how dynamic joint stiffness of the lower limb changes with added walking load.
• To determine the specific contributions of the ankle, knee, and hip joints to load adaptation.

Main Methods:

• Thirteen participants walked in unloaded and loaded (30% body mass) conditions.
• Dynamic stiffness was calculated using the moment-angle relationship during the power absorption phase.
• Analysis focused on sagittal plane motion of the ankle, knee, and hip.

Main Results:

• Ankle and knee dynamic stiffness significantly increased during loaded walking compared to unloaded.
• No significant change in hip dynamic stiffness was observed with added load.
• The magnitude of stiffness increase differed between joints, with ankle and knee showing greater changes than the hip.

Conclusions:

• The ankle and knee joints play a critical role in adapting to increased walking loads.
• Non-uniform increases in dynamic joint stiffness indicate specialized roles for different lower limb joints under load.
• Findings provide insight into the biomechanical strategies employed during loaded locomotion.