From an article in press in JAPMA entitled: ‘A proof in concept study for measuring gait speed, steadiness, and dynamic balance under various footwear conditions outside of the gait lab’ by James Wrobel, Sarah Edgar, Dana Cozzetto, James Maskill, Paul Perterson, and Bijan Najafi
Until recently, objective assessment of gait outside of the constraints and subsequent methodological issues of the gait lab has been elusive. Traditionally, gait is assessed using laboratory-based systems such as optical motion measurement systems and force platform in a gait laboratory. Although these systems are clinically accepted as ‘the gold standard’, there have been several drawbacks. Firstly, the number of consecutive strides that can be measured is limited. This means that inter-cycle variability of gait, involved in balancing the body and walking during varying circumstances, cannot be investigated using the existing systems as it requires a larger number of consecutive strides to be measured. Instrumented treadmills can address this limitation; however, uncertainty remains regarding the extent to which treadmill walking can be used to mimic overground walking. In addition, the narrow path offered by the treadmill as well as small freedom for inter-cycle speed variability may hinder freedom in selection of gait trajectory or speed. Therefore, it may not replicate natural gait behavior of subject during everyday life. Finally, recent studies revealed that subjects may modify their gait pattern when walking outside of a gait laboratory environment. For example, Najafi et al.  by studying the gait pattern of 25 elderly subjects inside and outside of a gait laboratory environment demonstrated that elderly people walk significantly faster outside of a gait lab environment despite an excellent test-retest reliability. These results may indicate that gait parameters assessed inside of a gait laboratory environment may not replicate subject’s gait outdoors in which subjects more frequently use their prescribed footwear.
Advances in the technology of body-worn sensors during the last decade have allowed investigators to use this technology for measuring various aspects of human performance. These areas include studying the spatio-temporal parameters of gait, joint and segment angles (kinematics), monitoring daily physical activity, and evaluating the risk and fear of falling. These studies are based on the use of miniaturized and integrated sensors in combination with lightweight, small measuring devices that can be carried without interfering with normal activity. One of the main advantages of body-worn sensors compared to laboratory-based measuring systems is that they are ambulatory and can be used in free conditions continuously over long periods of time.
Recently four podiatric students at Dr Scholl college of podiatric medicine (Sarah Edgar, Dana Cozzetto, James Maskill, Paul Perterson, Class 2011), examined the effect of custom foot orthoses (CFO) and prefabricated foot orthoses (PFO) on self-selected walking speed, walking speed variability, and dynamic balance in medio-lateral direction outside of a gaitlab and based on using body worn sensor technology. Their results revealed that in the CFO condition, gait speed is improved on average 13.5% over the barefoot condition and 9.8% over the regular shoe condition. The medial-lateral range of motion of center of mass (COM) was reduced 55% compared to shoes alone and PFO. This may suggest a better gait efficiency and lower energy cost with CFO. This tendency remained after normalizing COM by gait speed, suggesting that irrespective of gait speed, CFO improves COM motion in medial-lateral direction compared to other footwear conditions. Gait inter-cycle variability measured by inter-cycle coefficient of variation of gait speed was decreased on average by 26% and 19% compared to barefoot and shoes alone condition respectively. The decrease in gait unsteadiness after usage of CFO may suggest improved proprioception from the increased contact area of CFO v. the barefoot condition
The finding of this innovative study may open new avenues for objective assessment of the impact of prescribed footwear on dynamic balance and spatio-temporal parameters of gait as well as assessing gait adaptation after usage of a custom foot orthoses. This research has been accepted to be published in JAPMA and another multi-centers study was initiated to validate these observations in a lager sample and in patients suffering from various lower extremity complications.
 B. Najafi, J. L. Helbostad, R. Moe-Nilssen, W. Zijlstra, and K. Aminian, “Does walking strategy in older people change as a function of walking distance?” Gait Posture, vol. 29, pp. 261-266, Feb 2009.
 J. Wrobel, S. Edgar, D. Cozzetto, J. Maskill, P. Peterson, and B. Najafi, “A proof in concept study for measuring gait speed, steadiness, and dynamic balance under various footwear conditions outside of the gait lab?” Journal of the American Podiatric Medical Association, 2010 (In Press).