Dynamic Measurement Of Force Within The Shoe During Conditions Of Perceived Exertion

Abstract

The intent of this study was to measure vertical ground reaction forces across different levels of perceived exertion. Specifically, this group of researchers wished to study the effects of exertion upon gait cycle force measurements on the foot. It was proposed that gait cycle forces would be differentially displaced as exertion level increased. An FSCAN measurement device (Tekscan, Inc. Boston, MA) was used to assess within shoe force measurements at the shoe foot interface. This device uses ultra-thin (.0007 inch) sensors to measure vertical ground reaction forces. The device retains the ability to collect 960 individual force measurements over the surface of the foot. The sample used for this study were thirteen recreational male joggers. All subjects used the same brand of athletic jogging shoe to control for shoe to shoe differences. Each of the subjects were tested under six different experimental conditions. These conditions induded; a walk, a jog down a hallway, walk at 3 mph on a treadmill and three levels of perceived exertion (mild, moderate and hard running) as assessed by the Borg scale (RPE). Data analysis included the assessment of force values over three regions of the foot. These regions being: the fore foot, mid foot and the heel or calcaneus. Further, gait cycle timing and frequency were evaluated. Results indicated that the treadmill walking condition (3 mph) elicited the lowest force values of almost all the conditions. The moderate to hard running conditions indicated a change in the gait cycle force mechanics. The forefoot region of the foot under these conditions displayed an inordinate amount of force in comparison to the other conditions. In summary, these findings provide for debate in two areas. First, consideration of these data may lead to some design changes for shoes that are involved in competitive or serious training and or performance. Secondly, the use of treadmill protocols as a treatment for overuse injuries or to lessen the impact of vertical ground reaction forces may be in order.