Rectus femoris muscle strain manifests as follows, conscious painful symptoms in the anterior thigh with local masses, examination reveals local swelling, subcutaneous bruising, local pressure pain, and depressions or abnormal masses can be palpated at the injury site. The knee extension resistance test and heel and hip test are obvious painful, and knee extension and hip flexion are obviously limited. The rectus femoris is a long and thick fusiform bipinnate muscle, starting from a short and strong bifurcation tendon, with the straight head starting from the anterior inferior iliac spine and the reflex head starting from the upper acetabulum, covering the lateral part of the iliofemoral ligament, which intersects with the straight head at a right or obtuse angle. A rectus femoris strain can be caused when the force of resistance to knee extension at the rectus femoris muscle exceeds the force that the rectus femoris muscle can withstand. Treatment of rectus femoris strain includes intermittent local ice packs for 30 minutes each time, 4-6 times a day; 24 hours after injury, phototherapy, hydrotherapy, heat therapy, and low-frequency interferential electrotherapy can be done 1-2 times a day, 15 days as a course of treatment.