Quantifying Quadriceps Forces during Running Performed with and without Infrapatellar Straps.

Running-related knee injuries are associated with high and repetitive quadriceps contractions. Infrapatellar straps are commonly recommended for the prevention and management of those injuries. The effects of infrapatellar straps have been investigated in terms of quadriceps activations. However, these indexes cannot accurately characterize the quadriceps forces, which directly contribute to knee injuries. This study aimed to quantify quadriceps forces during running performed with and without infrapatellar straps based on OpenSim. Experimental data from 18 healthy participants were recorded using a 10-camera motion capture system and two force plates when they performed running at self-selected speeds with and without infrapatellar straps. OpenSim was used to estimate muscle forces, muscle activity, joint kinematics, and joint kinetics. The use of infrapatellar straps significantly reduced peak quadriceps forces (p < 0.001), accumulated forces of quadriceps (p < 0.001), and peak knee extension moments (p < 0.001). Among the four distinct muscles of the quadriceps, the vastus lateralis contributed the most to the reduction in quadriceps muscle forces. Strapping did not result in a significant change in rectus femoris forces (p > 0.05). The use of infrapatellar straps results in lower vastus muscle forces, and thus could be helpful in managing and preventing running-related knee injuries. However, infrapatellar straps may have little effect in people with an excessively forceful rectus femoris.