Effects of different resistance loads during resisted sprint running on internal stresses of the ankle joint: a finite element analysis

This study examined how three resistance loads (10%, 20%, and 30% of body weight) affect ankle bone stress during sprint running. Thirty elite male sprinters performed trials, and kinematic, kinetic, and finite‑element analyses were conducted. With increasing load, peak dorsiflexion angle and moments rose, while peak inversion angle fell. The 30% load produced the highest stress in the tibia, talus, and second/third metatarsals, with concentration in the metatarsal shafts. The 20% load generally yielded lower stress than both 10% and 30% conditions. Overall, the 30% load increased local bone stress, whereas the 10% load caused smaller changes. In this sample, the 20% load provided a meaningful training stimulus while maintaining relatively stable bone stress, suggesting it may offer a better balance between training demand and bone loading.