The Outcome Effect of Shoe Lift for Individuals With Low Back Pain and Pronated Foot Due to Anatomical Leg Length Discrepancy

People with anatomical leg length discrepancy (LLD) commonly presented excessive subtalar pronation of the long leg compared to their short leg in order to equalize leg length. Although such compensation may decrease the stress in the pelvis and/or low back region, the pronated foot may lead to excessive stress loading onto the ankle or foot, resulting in musculoskeletal injuries. Clinically, the pronated foot has been effectively controlled using functional orthoses with proper posting by adjusting the subtalar joint in the neutral position. But for people with compensatory pronated foot resulted from anatomical LLD, to control excessive pronation of the long leg would exaggerate their asymmetry in leg length. Instead, the pronated foot can be controlled simply by adjusting the length of the short leg. However, there is limited evidence of such intervention in previous literature. The purpose of this research project is going to determine the effect of leg length adjustment on pronation control in people with anatomical LLD. According to this purpose, 5 study objectives will be developed: 1) to examine the validity and reliability of LLD measurement using a hand-held laser distance meter, 2) to compare the foot types before and after leg length adjustment, 3) to compare the kinetic variables before and after leg length adjustment during quiet stance, 4) to compare the kinetic variables before and after leg length adjustment during level walking, and 5) to compare symptoms and functional levels related to low back pain (LBP) before and after leg length adjustment. The present research project will be designed as a convenience sampling, prospective, quasi-experimental, and pretest/posttest design. There will be 2 parts in this research: 1) validity and reliability test of laser measure for leg length and 2) foot morphology and kinetic analysis before and after leg length adjustment. For the first part of this research, 10 male adults and 20 adults will be recruited