Plantar Biomechanic Characteristics After High-Intensity Exercise in Young Runners With High-Arched Feet.

Objective: This study aimed to evaluate the plantar biomechanics in high-arched (HA) young runners after they performed a high-intensity (HI) ergometer exercise. Methods: Eighteen collegiate runners with HA feet (age = 19.9 ± 0.6 years, height = 179.4 ± 3.5 cm, weight = 69.3 ± 4.9 kg, arch height index [AHI] = 0.43 ± 0.04) were tested. The participants performed a 5-min HI ergometer exercise. Besides measuring heart rate (HR), blood pressure (BP), and ratings of perceived exertion (RPE), the plantar biomechanic features were assessed before and after exercise. Results: Postexercise, the participants exhibited a fatigue index (FI) of 87.6% ± 7.9%. The mean HR (HR_mean) corresponded to 81.1% ± 5.4% of maximum HR (HR_max). Notably, there was a significant drop (p < 0.001) in systolic BP (SBP) and diastolic BP (DBP) at the 10-min postexercise. The average RPE index was 17.3 ± 1.3. Specifically, the contact area of the hallux (T1) significantly increased (p < 0.05), while the contact area of toes 2-5 (T2-5) and the 5th metatarsal (M5) significantly decreased (p < 0.05). Plantar pressure significantly increased in T1 (p < 0.05), but significantly decreased in M5 and T2-5 (p < 0.05). The force-time integral (FTI) in the forefoot and vertical ground reaction force (VGRF) during heel fully struck and forefoot push off elevated, while the foot progression angle (FPA) significantly increased (p < 0.01). Conclusions: Our findings indicate that HI ergometer exercise has significant impacts on the biomechanic features of HA young runners. Specifically, we observed modifications in plantar area and pressure, FTI, and VGRF, especially in the medial arch and combined with outward rotation of the feet. These results can offer insights to inform future investigations on gait training interventions aimed at reducing the risk of lower extremity injuries in HA young runners.