Mechanical inputs related to perception of lower extremity impact loading severity

Area of Science:

• Biomechanics
• Human Locomotion
• Sports Science

Background:

• Human response to repetitive impact is crucial for understanding injury risk.
• Perception of impact severity is a key factor in locomotor adaptation.
• Limited research exists on the specific mechanical variables influencing impact perception.

Purpose of the Study:

• To investigate the relationship between mechanical impact loading variables and perceived impact severity.
• To identify key biomechanical factors that determine how humans sense impact severity.
• To utilize a psychophysical test procedure to quantify impact perception.

Main Methods:

• A human pendulum apparatus was used to simulate running-like impacts.
• Nineteen subjects received over 100 impacts under nine varied conditions (velocity and interface material).
• Impacts were measured on a force platform to collect biomechanical data.

Main Results:

• Subjective ratings of impact severity strongly correlated with measured biomechanical variables.
• Rate of loading (FRA) and peak shank acceleration showed near-perfect correlation (0.99) with perceived severity.
• FRA alone explained 64% of the variability in perceptual ratings when individual data were analyzed.

Conclusions:

• Impact perception is significantly associated with measurable mechanical input variables.
• Common midsole materials in athletic footwear do not eliminate the perception of impact severity.
• Understanding these relationships can inform the design of footwear and training protocols to manage impact loads.