Ankle Joint Biomechanics in Recreational Runners with Resolved and Incident Plantar Fasciitis: A One‐Year Prospective <scp>4HAIE</scp> Cohort Study

The aim of this study was to compare running biomechanics between retrospective and prospective cases of plantar fasciitis, and healthy matched controls. A further analysis from the 4HAIE cohort, the current study included four groups: 10 prospectively newly injured runners with plantar fasciitis during the 1-year follow-up (PPF), 14 retrospectively injured runners with no report of any prospective lower limb injury (RPF; resolved plantar fasciitis), and two groups of 24 matched healthy controls (10 CON1 and 14 CON2; matching criteria: sex, age, weakly running distance, BMI, height, mass, and body fat). All participants completed eight overground running trials, during which three-dimensional kinematic and kinetic data were collected. Key variables included vertical component of ground reaction force (VGRF) and ankle joint angle waveforms. Statistical parametric mapping using paired and independent t-tests was performed to identify differences between groups. In addition, baseline MRI of plantar fascia and inflammatory markers were evaluated as control variables. The most notable findings were observed in the frontal plane: the PPF group showed significantly greater ankle eversion compared to CON1 (between 10%-100% stance, p < 0.001) and RPF (0%-100% stance, p < 0.001). In addition, both PPF and RPF displayed greater VGRF than their controls (25%-50% stance, p < 0.001). These findings offer new insights into plantar fasciitis-related running biomechanics. Prevention and management may benefit from altered technique and motion-control/stability footwear or insoles, particularly in runners with a history of plantar fasciitis and in uninjured runners exhibiting elevated ankle eversion and increased VGRF near peak eversion.