Subtalar Pronation Does Not Influence Impact Forces or Rate of Loading During a Single-Leg Landing.

Area of Science:

• Biomechanics
• Sports Medicine
• Orthopedics

Background:

• Static subtalar pronation, assessed via weight-bearing navicular drop (ND), is a common measure of foot posture.
• Understanding its influence on landing mechanics is crucial for injury prevention and performance optimization.

Purpose of the Study:

• To investigate the impact of static subtalar pronation on ground impact forces and loading rates during a single-leg landing task.
• To determine the relationship between navicular drop measurements and key biomechanical variables during landing.

Main Methods:

• Forty-eight healthy volunteers were categorized into three groups based on navicular drop: supinators (<5 mm), neutral (5-10 mm), and pronators (>10 mm).
• Subjects performed single-leg landings from a 0.3-m height onto a force platform, with simultaneous electrogoniometry measuring knee range of motion.
• Peak vertical force, rate of loading, and knee-flexion excursion were analyzed.

Main Results:

• No significant differences in peak vertical force or rate of loading were observed among the supinator, neutral, and pronator groups.
• Knee-flexion excursion, a measure of shock absorption, was similar across all foot posture groups.
• Secondary analyses revealed negative correlations between peak force/rate of loading and knee excursion.

Conclusions:

• Static foot alignment, as indicated by navicular drop, appears to have minimal influence on impact force absorption during a single-leg drop landing.
• Knee flexion is a more significant factor in dissipating landing forces.
• Further research is needed to explore the role of dynamic lower extremity alignment in force dissipation during functional activities.