Tibial Strains During Prolonged Downhill Running: A Finite Element Analysis

Area of Science:

• Biomechanics
• Musculoskeletal research
• Sports science

Background:

• Neuromuscular fatigue is a potential factor influencing bone strain in the lower extremities.
• Understanding bone strain responses during fatiguing activities is crucial for injury prevention and performance optimization.

Purpose of the Study:

• To investigate changes in finite element (FE) predicted tibial strains during a fatiguing downhill running protocol.
• To assess the relationship between neuromuscular fatigue, joint loading, and bone strain in the tibia.

Main Methods:

• Twelve physically active males performed a 30-minute downhill running protocol on an instrumented treadmill.
• Motion capture and static optimization estimated lower extremity joint and muscle forces.
• FE models of the tibia-fibula complex, derived from CT scans, predicted peak strain and strained volume.

Main Results:

• Peak ankle joint contact forces shifted, decreasing axially (8.1%) and increasing anteroposteriorly (7.7%) with fatigue.
• Despite changes in joint forces, FE estimations of peak tibial strain and strained volume remained unaffected (p > 0.190).

Conclusions:

• Neuromuscular fatigue can alter lower extremity joint loading patterns during running.
• Tibial strains may not be directly or intuitively influenced by fatigue-induced changes in ankle joint contact forces due to complex biomechanical relationships.