Does the Achilles Tendon Influence Foot Strike Patterns During an Exhaustive Run?

Area of Science:

• Biomechanics
• Sports Science
• Human Movement Analysis

Background:

• Foot strike pattern (FP) can change during prolonged running, potentially affecting performance and injury risk.
• The role of Achilles tendon (AT) properties in maintaining a consistent FP during exhaustive efforts is not fully understood.
• Nonrearfoot runners may exhibit different adaptations compared to rearfoot strikers.

Purpose of the Study:

• To investigate the relationship between Achilles tendon (AT) length, AT moment arm length, and foot strike pattern (FP) change during an exhaustive run (EXR).
• To determine if training volume influences the association between AT properties and FP consistency in nonrearfoot runners.
• To identify predictors of FP stability during fatiguing running conditions.

Main Methods:

• Twenty-eight nonrearfoot runners (highly and moderately trained) underwent biomechanical analysis during an exhaustive run (EXR) and magnetic resonance imaging (MRI) for AT measurements.
• FP was assessed at the beginning and end of the EXR, with changes calculated.
• Correlational and multiple regression analyses were used to examine associations between FP change, AT dimensions, and training variables.

Main Results:

• Achilles tendon (AT) length significantly correlated with foot strike angle change (r = -.265, P = .049).
• AT moment arm length significantly correlated with strike index change during EXR (r = -.536, P = .003).
• AT length, graded exercise test duration, and training group were significant predictors of foot strike angle change.

Conclusions:

• A longer AT and AT moment arm may be associated with maintaining a consistent foot strike pattern during exhaustive running in nonrearfoot runners.
• Higher training volume appears to support FP stability during fatiguing conditions.
• These findings suggest that AT morphology and training load are important factors for FP consistency in nonrearfoot runners.