Pronation or foot movement - What is important

Area of Science:

• Biomechanics
• Sports Science
• Orthopedics

Background:

• Foot pronation is critical for injury risk and footwear development, but non-invasive dynamic quantification remains challenging.
• Existing methods use surrogate measures with inconsistent results due to high variability.
• This study addresses the need to identify dominant factors in pronation measurement.

Purpose of the Study:

• To determine relationships between commonly used pronation variables.
• To reduce the complex dataset of pronation measures to its dominant factors.
• To improve the understanding of foot movement properties for clinical and manufacturing applications.

Main Methods:

• A cross-sectional study involving 40 barefoot participants.
• Data collection included manual assessment, motion capture, ground reaction forces, and plantar pressure during various standing, walking, and running tasks.
• Sixty-one pronation measures were analyzed using Spearman Correlations and Principal Component Analysis (PCA).

Main Results:

• Two distinct groups of correlated pronation variables emerged.
• One group (4.2%) correlated with the longitudinal arch angle (LAA).
• Another group (10.2%) correlated with the Achilles tendon angle (β), with the remaining 85.6% showing no significant correlation.

Conclusions:

• The longitudinal arch angle (LAA) represents midfoot movement, while the Achilles tendon angle (β) quantifies rearfoot eversion.
• These two dominant variables, LAA-pronation and β-pronation, vary independently and cannot simultaneously quantify pronation.
• Separate assessment of LAA and β is essential for accurately representing foot movement, informing clinical screening and footwear design.