Wearing the F-Scan mobile in-shoe pressure measurement system alters gait characteristics during running.

This study investigated the influence of wearing an F-Scan mobile in-shoe pressure measurement system on running characteristics. Six subjects ran on a treadmill at three speeds (3.5 ms(-1), 4.5 ms(-1) and 5.4 ms(-1)) with and without wearing the F-Scan system while kinematic data were collected at 240 Hz using a motion capture system. Six gait cycles were selected for analysis, with touchdown and toe-off visually identified based on foot markers displacement. Spatio-temporal gait parameters including stride frequency, stride length, stride length relative to height, and stance time were determined. A 2x3 ANOVA with repeated measures (alpha=0.05) was performed to identify differences in each gait parameter between running with and without the F-Scan system at different speeds. Wearing the F-Scan system did not affect the stance time but lead to an increase in stride frequency (P<0.05) and a decrease in stride length (P<0.05) and relative stride length (P<0.05). As speed increased, stance time decreased while stride frequency, stride length and relative stride length increased (all P<0.001). These results imply that wearing the F-Scan system alters gait characteristics and therefore data obtained may not represent those in a real life setting, at least in the case of running. One should take into account the potential risk of the movement of interest being altered when interpreting data obtained while subjects were wearing the F-Scan system. Future instrumentation should minimize the potential influence a measurement device may have on natural movement.