Kinematics, ground reaction force, and muscle balance produced by backward running

This study was conducted at the University of Kentucky Biodynamics Laboratory in Lexington, KY and was partially supported by a grant from the Kentucky Chapter of the American Physical Therapy Association. Backward running (BR) is employed for conditioning and for rehabilitation in sports, orthopaedics, and neurology. Our purposes were to compare kinematics and training effects of BR to forward running (FR). Ten runners (6 males, 4 females, ages 20-34 years) were assigned to a backward running (BRG) or control (FRG) group. Subject isokinetic muscular torque production (IMTP) and biomechanics during FR and BR at 3.58 m/sec were studied at the beginning and after 8 weeks of training. Stance time was significantly shorter during BR. The peak vertical component of the ground reaction force (Fz) and Fz impulse were significantly less during BR. After training, knee extensor IMTP of the BRG increased significantly at 75 and 120 degrees /sec. We concluded that BR produced lower Fz stress than FR and improved knee extensor torque at low speeds. Backward running may be clinically useful for reducing stress to injured joints and for increasing knee extensor strength. J Orthop Sports Phys Ther 1989;11(2):56-63.