A Prospective Comparison Of Running Biomechanics Between Runners With Plantar Fasciitis And Non-injured Controls

Weekly running distance has been shown to play an important role as a risk factor for plantar fasciitis (PF). Previous retrospective or cross-sectional studies have identified several potential biomechanical risk factors for PF such as kinematic and kinetic parameters. However, there is still a lack of prospective studies regarding biomechanical risk factors for PF in runners. PURPOSE: The aim of this study was to prospectively compare running biomechanics between those with PF (suffered during one-year follow up) and pair-matched non-injured runners. METHODS: Fourteen runners with plantar fasciitis (6 females/8 males; age = 39.1 ± 10.6 years; running distance = 35.5 ± 11.7 km/week; BMI = 22.4 ± 2.6; height = 177.3 ± 9.1 cm, mass = 70.9 ± 11.8 kg) were matched in pairs in terms of age, running distance, height, and mass with non-injured controls. All runners had to meet the criteria of regular running at least 20 km/week. Participants were recorded using a 3-D motion capture system during over-ground running at their preferred training speed. Paired t-test or non-parametric the Wilcoxon signed-ranks test were performed to reveal possible differences in biomechanical variables. Effect size was assessed by Cohen´s d. RESULTS: Surprisingly, no statistically significant differences were found in all tested biomechanical variables (P > 0.05; Table 1). For example, vertical average loading rate appeared to be marginally non-significant, but practical significance (biological relevance) of the differences was still small (P = 0.091; ES = 0.40). CONCLUSION: It appears that running biomechanical variables may not play a significant role in the risk of plantar fasciitis in a population of runners who regularly run more than 20 km/week. Further research should focus on multi-segment foot biomechanics and coordination. Table 1 - Comparison of running biomechanics parameters Variables Runners with PF Pair-matched Controls Mean SD Mean SD P ES (d) Vertical average loading rate (BW/s) 54.7 15.1 48.9 14.2 0.091 0.40 Vertical instantaneous loading rate (BW/s) 77.7 25.3 71.6 22.6 0.402 0.25 Footstrike index (%) 16.0 19.3 15.6 16.8 0.730 NA Sagittal ankle angle at footstrike (°) 70.9 9.4 72.5 9.0 0.604 -0.17 Maximal dorsiflexion during stance (°) 86.4 3.8 86.1 3.9 0.975 NA Sagittal ankle range of motion (°) 15.5 9.4 13.6 9.2 0.594 NA Sagittal knee angle at footstrike (°) 13.1 5.9 11.5 3.9 0.468 0.32 Maximal knee flexion during stance (°) 40.9 5.1 40.8 5.5 0.953 0.02 Sagittal knee range of motion (°) 27.9 4.9 29.3 3.8 0.209 -0.32 Pelvis velocity (m/s) 3.11 0.40 3.00 0.42 0.381 0.27 Step frequency (steps/min) 163.0 8.0 159.4 9.9 0.351 0.40 Stride length (m) 2.30 0.26 2.25 0.35 0.670 0.16 European Union and Ministry of Education, Youth and Sports of the Czech Republic, grant number CZ.02.1.01/0.0/0.0/16_019/0000798 Program 4 Healthy Aging in Industrial Environment, European Union under the LERCO project number CZ.10.03.01/00/22_003/0000003 via the Operational Program Just Transition