Prolonged treadmill walking in healthy participants with and without the use of foot orthoses to support the medial longitudinal arch

In the research setting, instrumented treadmills are often used to study prolonged periods of walking. This thesis examines the effects of in-shoe foot orthoses on walking gait during prolonged periods of treadmill walking. The two types of foot orthoses investigated were: 1) a pedorthist hand-made orthotic with medial longitudinal arch (MLA) support and 2) a proprioceptive feedback-type orthotic designed to stimulate the intrinsic foot muscles of the MLA. The three kinematic variables observed over 60 minutes of intermittent treadmill walking were toe-out angle in the transverse plane, pelvic tilt angle in the sagittal plane, and trunk lean angle in the frontal plane. Kinematic data were collected with a real-time optical motion capture system that consisted of five high resolution digital cameras which tracked the location of the reflective markers placed on the surface of skin. Static and dynamic trials were collected and analyzed to calculate the change in joint angles every 5 minutes of testing. Due to the appearance of three distinct groups for the kinematic variables, each participant was assigned into one of the following groups: Increase Group, No Change Group, or Decrease Group based on the magnitude of the change in joint angles during the 60 minutes of treadmill walking. To be assigned into either the Increase or Decrease Groups, the kinematic variable had to change by at least 1.5˚. In all three conditions, data interpreted within the three subgroups showed statistical significance. In the Control condition, statistical significance was detected in the Increase Group for pelvic tilt angle and the Decrease Group for toe-out angle. In the MLA orthotic condition, statistical significance was detected in the Increase Group for pelvic tilt angle and the Decrease Group for trunk lean angle. In the Proprioceptive orthotic condition, statistical significance was detected in the Increase Group for pelvic tilt angle and the Decrease Group for trunk lean angle. Overall, generic insoles and the two types of foot orthoses have minimal changes on the three kinematic gait variables over 60 minutes of treadmill walking