Grant: Master's Award: Canada Graduate Scholarships

Low-back pain is a global epidemic that costs billions of dollars in lost wages and medical costs. The use of insoles has been shown to alter injury mechanism pathways as back motion and muscle activation are affected by the alignment and behaviour of the hip, knee, ankle and foot joints. Neuromuscular training insoles use disruptive technology to change how the feet respond to interactions with the ground. If such an insole can improve the foot’s ability to sense orientation and improve the stability of the foot during gait, then they may be able to improve the performance of the joints above the foot. The purpose of this study is to quantify the impact of the foot (with and without insoles) on the neuromuscular, 3-D motion, and loading responses of the low back during key tasks. This project will contribute to our fundamental understanding of spine neuromechanics and is supported by the NSERC Discovery Grant that my supervisor, Dr. Drake, current holds (2012-2017). Twenty male and 20 female healthy participants will be asked to wear arch -strengthening orthotics for eight weeks, with in-lab tests performed at the onset and after the eight weeks. Participants in the study will be asked to wear the provided insoles in regular daily activities and then come into the lab for measurements at the beginning and end of the program. During each in-lab session, participants will complete one 15-minute treadmill walking trial (at their normal gait speed), balance challenges, a 30 minute standing task, and lifting tasks while barefoot, shod, and shod with insoles. Each of these tasks will be preceded and followed by ten gait analysis walks on a pressure sensing mats and force measuring plates. Muscle activity (EMG), 3-D motion, force and acceleration measurements will be taken throughout all the trials mentioned above. A seven camera Vicon (MX, Vicon Systems Ltd., Oxford, UK) motion capture system will be used to measure full-body 3-D motion from 75 reflective markers over the legs and trunk. The gait parameters quantified include step lengths, centre of pressure, pressure distribution and pattern. The Vicon markers will be utilized to measure the angles at the ankle, knee, hip, pelvis, lower back and trunk. The 3-D motion, EMG, and force measures will be input into an EMG-driven inverse dynamic model to estimate spine loading at the lower lumbar level. Using surface EMG, muscle activation of 12 key muscles, bilaterally, will be quantified in the trunk and legs. EMG peaks, averages, ranges, on/off-set timing, and co-contraction indices will be quantified. The accelerometers will be attached to the participants at the level of the ankle, tibial plateau, and on the lower back (L3 level); ground impact shockwaves will be measured as they transmit superiorly through the body. With the use of these insoles, I expect to see improvements in the general efficiency of the feet, legs, and trunk in responding to forces imposed during gait and other activities. A decreased shockwave propagation to the low back area is also expected, which will manifest in altered EMG profiles of the trunk and leg . I also expect to see less pronation of the foot due to improved arches which should result in less pelvic tilt. These in turn would decrease the overall level of muscle activity, improved muscular coordination, and so reduce both compressive and shear loading at lower back region with the insoles. This research investigating the underlying biomechanics of a neuromuscular training insole will give the opportunity to gain insight into the neural control and resulting mechanics of the spine to common exposures.