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In-shoe pressure systems alter gait

Discussion in 'Biomechanics, Sports and Foot orthoses' started by NewsBot, Jul 14, 2008.

  1. NewsBot

    NewsBot The Admin that posts the news.


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    Wearing the F-Scan mobile in-shoe pressure measurement system alters gait characteristics during running
    Pui W. Konga, Hendrik De Heerb
    Gait & Posture; Published online 14 July 2008.
  2. Bruce Williams

    Bruce Williams Well-Known Member

    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.

    Thanks for the post Craig.
  3. 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.

    Nice study- long overdue.
  4. Bruce Williams

    Bruce Williams Well-Known Member


    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.

  5. Bruce if properly designed subjects should have been randomized to test conditions to account for this too, so its still irrelevant.
  6. Adrian Misseri

    Adrian Misseri Active Member

    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.
  7. Mart

    Mart Well-Known Member


    As aid to compensating for this;

    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?



    ABSTRACT. Zhu H, Wertsch JJ, Harris GF, Alba HM.
    Walking cadence effect on plantar pressures. Arch Phys Med
    Rehabil 1995;76:1000-5.
    Objective: Prior studies have examined the effect of cadence
    on ground reaction forces by use of a force plate. Force plate
    studies generally analyze isolated steps and do not provide insight
    into ongoing step-to-step variations or in-shoe plantar
    pressures. The objective of this study was to evaluate the effect
    of walking cadences on in-shoe plantar pressures over extended
    periods of continuous walking.
    Design: Nonrandomized control trial.
    Setting: Laboratory.
    Patients or Other Participants: Volunteer sample of 8 ablebodied
    Interventions: In-shoe plantar pressures were studied during
    four minutes of continuous walking at controlled cadences of
    70, 80, 90, 100, 110, and 120steps/rain. For each cadence more
    than 200 steps were analyzed for each of the 8 subjects.
    Main Outcome Measures: Pressure-time integrals, foot-tofloor
    contact durations, and peak pressures at all 14 locations
    were processed for each step. Changes were calculated compared
    to values at 70steps/rain.
    Results: With increasing cadence, mean pressure-time integrals
    continuously decreased (45% at 120steps/min); mean footto-
    floor contact durations continuously decreased (64% at
    120steps/rain); and mean peak pressures increased (119% at
    Conclusions: Our results show that as walking cadence increases,
    pressure-time integrals and foot-to-floor contact durations
    decrease, and peak plantar pressures increase. This is clinically
    relevant to all kinetic gait studies because our results
    suggest that normal values should be established for each cadence.
    © 1995 by the American Congress of Rehabilitation Medicine
    and the American Academy of Physical Medicine and Rehabilitation
    T HE MEASUREMENT of plantar pressures is useful when
  8. It's probably the boxes, but friction co-efficient of the insole could be contributory also.
  9. 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.
  10. Mart

    Mart Well-Known Member

    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?



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