Independent Influences of Increased Step Length and Step Frequency on Lower-Limb Joint Loading During Fast Walking

Area of Science:

• Biomechanics
• Orthopedics
• Human Movement Analysis

Background:

• Excessive joint loading accelerates orthopedic disease progression.
• Walking speed significantly impacts joint load, making gait modification crucial for prevention.
• Understanding how step length and frequency affect joint loading is vital for developing preventative strategies.

Purpose of the Study:

• To investigate the independent effects of increased step length and step frequency on hip, knee, and ankle joint loading during fast walking.
• To identify gait parameters that minimize joint stress in fast walking conditions.

Main Methods:

• Twelve healthy participants performed preferred (PW), step-length-increased (SL), and step-frequency-increased (SF) fast walking.
• Joint loading was assessed using musculoskeletal modeling of marker trajectories and ground reaction forces.
• Key metrics included peak joint forces, impulses, and per-unit-distance impulses in multiple directions.

Main Results:

• Increased step length (SL) led to higher peak joint forces across hip, knee, and ankle compared to preferred walking (PW).
• Increased step frequency (SF) generally suppressed joint loading increases and showed lower impulse and PUD impulse values than SL and PW.
• SF particularly reduced anteroposterior hip loading and mediolateral knee loading.

Conclusions:

• Increasing step length significantly elevates joint loading during fast walking.
• Increasing step frequency is an effective strategy for attenuating joint loading.
• Modifying step frequency offers a potential method to reduce the risk of orthopedic diseases associated with fast walking.