Monitoring the pressure impact of a runner's footstep on the inner sole of the shoe

The research goals are to learn about the biomechanics of human footsteps and apply the knowledge to the understanding of the subsequent wave energy that is transferred into the ground or track surface. Phase (1) research is focused on learning about the time development of the footstep pressure that a runner’s foot is transferring to the innersole of an athletic shoe, along with accelerometer information. A Tekscan FlexiForce Model A401 force sensor (25.4 mm sensing diameter and 0.208 mm thick) coated with a polyester substrate was chosen due to its versatile force range if biased and placed in an operational amplifier feedback loop. The response time is <5 microseconds. Two force sensors will be placed on the upper side of a removable innersole to measure force near the ball and heel of the foot. Phase (2) is to use a Digi Intl XBee 802.15.4 Development Kit to communicate (using a wireless link) the transducer voltage responses. The transmitting module is strapped to the runner’s ankle. A receiving module receives data streams and connects to a USB computer interface. Phase (3) converts the data streams to measurements of pressure vs. time. Preliminary experiments and a data analysis will be presented.