Background & Objective: The purpose of the current study was to investigate the compressive and shear mechanical forces of knee and ankle joints during running via modeling analysis.
Material &Methods: 25 active healthy men (height 176.39±5.93 m, Mass 72.30±8.84 kg, Foot size 43.38±1.05) were asked to run with 3.5-4 m/s velocity in barefoot condition. Lower extremity was modeled via markers, then kinematic and kinetic parameters were recorded with synchronization of the video camera (JVC, 250 Fps) and force plate systems (Kistler, 1000 Hz). Maximum compressive and shear forces of knee and ankle joints were calculated using inverse dynamics. Descriptive analysis and paired T-test were used to evaluate force loading pattern and compare mechanical forces magnitudes respectively (SPSS software, P<0.05).
Result: Compressive and shear forces in knee began to increase after an initial stance and reached to their peak amounts just before midstance. The ankle mechanical forces showed the similar pattern but reached its peak in late stance before toe off. The peak compressive force was significantly greater by 78% in knee joint compared with the ankle. However, ankle joint had greater shear force than the knee (P=0.01, 39%).
Conclusion: The results revealed that the knee joint has a potential for injuries related to compressive tensions. However, an ankle joint, there is a potential for shear damages. In conclusion, protective tools and methods for knee joint including tape and knee straps are suggested for prevention of possible injuries during running.