I'd certainly like to see how the subjects wore the system as that can be a factor for some.
Also, we know that treadmill running takes some time to get used to even w/o a mobile system in the small of your back.
I have personally experienced the pull of a sensor in a tight cuff that alters my walking gait.
this can be adjusted if teh patient informs us of the problem.
Ultimately, for me at least, this has little impact since I have my subjects walk on a flat floor and not on a treadmill.
I have little doubt that there are some changes in the gait parameters even w/ walking, but I think the benefit of information far out weighs the potential changes that may or may not occur.
The argument of treadmill versus over ground running is irrelevant here since the study was within subjects design of treadmill running with f-scan versus treadmill running without f-scan. The differences observed were due to the f-scan!
I think this is a useful study, common sense would have lead to the conclusion that if you strap something to the bottom of your legs then it will have an influence in kinetics and/ or kinematics anyway. But as Bruce pointed out the benefits may out-weigh the detractions. Lets face it, the very act of observing somebody's gait is likely to alter their gait.
I made no comment re: overground running vs treadmill running.
My comment was on how long the subjects may have had to get used to treadmill running and how that may have affected the study with and without the F-scan involved.
Looking at the actual construct of the F-Scan apparatus, I wonder if such a fine sheet in the shoe would make that big a difference, granted that we often put different thickness and composition insoles in people's shoes. Would it be moreso the box on the back and the straps around the ankles affecting COM and stride length/frequency, not to mention the wires hanging out everywheich way which may phychologically affect the subject as they are (sub)consiously worried about tripping? I also agree with Simon, being that the treadmill is a constant, that shouldn't affect results.
as walking cadence increases, pressure-time integrals and foot-to-floor contact durations
decrease, and peak plantar pressures increase.
Cavanaghs multivariate analysis of segmented
plantar force distribution found correlation
of peak pressures at heel contact to approach velocity which is likely determined by stride length.
I did a quick pubmed search for effects of clothing on kinematics, nothing seems to have been published on this, I wonder if effects of pants vs shorts would reveal similar change in kinematics?
Probably. Here's an experiment: strap some blocks same dimension and weight as the f-scran "blocks" to the bottom of you ankles and repeat the experiment as above. Change the position of the the blocks and see what happens... try this perform the experiment without f-scan, just in a pair of shoes, now add extra weight to each shoe... No such thing as a free lunch.
I j had a look at this paper for methodology and noticed that the conclusion states;
"Although statistical significant differences were found between running conditions in many gait parameters, the magnitude of the differences was very small in comparison to the repeatability of the measured parameters. This suggests that such differences are generally within the normal variability observed during running and therefore are unlikely to have any meaningful influence in practice. Similar findings on the difference in human locomotion between overground and treadmill conditions regarding its statistical and clinical significance have been previously addressed [16].
In summary, this study has shown that running while wearing the F-Scan mobile in-shoe measurement system lead to changes in gait characteristics during running though the differences were too small to have clinical implications. Despite the differences being small, future instrumentation development should minimize the potential influence a measurement device may have on natural movement".
Should we limit our excitement about the kinematic effects given the other sources of error likely and the kind of information we probably are trying to explore (which would see the effects of the apparatus as a constant in the same way as the treadmill does in comparative studies?
cheers
Martin
The St. James Foot Clinic
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