Heel pad stiffness in runners with plantar heel pain

Objective. To evaluate significant differences in heel pad stiffness within a cohort of runners with diagnosed plantar heel pain and to explore the cl inical importance of maximum heel pad stiffness values. Design. A cross-sectional design was used to quantify the heel pad stiffnes s of 166 runners with 33 diagnosed with plantar heel pain. Background. Palpation is still widely used to evaluate heel pad stiffness s ubjectively in everyday clinical practice. However, there is limited quanti fiable data pertaining to heel pad stiffness measurements in runners and th ose with heel pain. Methods. A portable hand-held device measured force applied by a metal prob e, and its displacement into the plantar Surface of the heel pad. Non-linea r modelling allowed curve coefficients b(0) and b(1) to be evaluated and wa s described by an exponential function using a non-linear regression equati on. Exploratory analysis was used to describe a single-point approximation for clinical use, Results. An independent t-test demonstrated a statistically significant dif ference between the curve coefficient b(1) (P<0.05). No significant differe nce was found for coefficient b(0) between the plantar heel pain group and the non-plantar heel pain group (p>0.05). Exploratory analysis demonstrated maximum mean stiffness of 3.22 N/mrn for the non-plantar heel pain group a nd 2.87 N/mm, for the plantar heel pain-group, an 11% mean difference. Conclusion. The results suggested that heel pad stiffness may be associated with plantar heel pain subjects.