Studying slips ,trips falls and footwear

[Gerrard Farrell]

Firstly a simple idea .

Might a long single decked bus with the seating removed (except the for drivers seat ) make the ideal gait laboratory ? If you wanted to study gait on a horizontal plane then park the bus, complete with all the necessary recording equipment on flat ground .If you want to study gait on an inclined surface then park the bus on a suitable hill . Such a set up might be of great benefit to the evaluation of prosthetic lower limbs since the user could be studied walking up hill ,down hill and whist turning and transitioning from one to the other . Walking across an inclined plane could also be studied by parking the bus across a suitably inclined section of road .

So what could we use our gait bus/ lab for that can't already be looked at on a treadmill with incline and decline features ? Well as mentioned above walking across the slope of an incline with a prosthetic limb might be a difficult skill to master and this cant readily be studied on a treadmill .

However one of the biggest advantages of the suggested system is unlike a treadmill the nature of the underfoot surface in the bus/lab can be changed to really anything you want . By its very nature a treadmill will have a broad moving rubber belt which provides a non slip walking surface . However, pavements are rarely made of rubber and they can often be wet and slippery . These type of slippery conditions could be replicated on the bus/lab floor and any incline to be introduced would simply involve maneuvering the bus on an on campus hill or an incline perhaps built for the purpose .
Add a refrigeration aspect to the bus/lab and movement on an icy surface could be looked at in detail . For example the efficacy of non slip footwear could be thoroughly examined .

If a variable walkway longer than a bus was required then a 53 foot long refrigeration trailer with variable temperature settings might be kitted out to provide such a lab whilst still allowing , hill generated , gradient changes . This might allow for a wider range of experimentation .


A perhaps useful but more complex idea might be the following .

With regard to balance perturbation studies in general, it is my understanding that most perturbation delivery systems simulate slips with the functional base of support (FBOS) of a subject being unexpectedly moved out from beneath the centre of gravity (COG) .

However , it is also my understanding that more falls are caused by trips and improper weight shifting than by slips . With this in mind a University specializing in slips trips and falls might benefit from a system designed to allow the COG to be unexpectedly propelled beyond the FBOS . On a one off basis, such a system may involve the following -

Create a circular chassis of about 4-5 m in diameter . The chassis would be supported by 5-6 wheels designed to allow the vehicle to move a bit like shopping trolley , that is able to rotate about a central axis whilst progressing in any horizontal direction .
A body would be built up on the chassis to give a sturdy enclosed space with a roof capable of supporting any necessary safety harness .
The vehicle would be powered by electric motors and would have a top speed of say 3-4 miles per hour . It would have no confounding suspension and an excellent breaking system .
The vehicle would be controlled from an outside vantage point by someone other than the test subject .
A circular or oval road would be required for the vehicle to move around and this would need to be at least 400m-500 long .
A pre existing athletics track would be a possibility .
In practice the vehicle is set moving at 1- 2 mph around the track as it also slowly rotates about its own centre point in a predetermined fashion .
The test subject ,standing in the centre of the vehicle and wearing a safety harness ,would be unaware of whether he/she was traveling facing forwards ,backwards or anywhere in between .
At some point the controller would stop the vehicle causing the COG of the subject to move beyond the FBOS and cameras inside the vehicle would record subject response .
Simulated incorrect weight shifting whilst getting in and out of a chair might also be studied in the vehicle described . ( The chair might need to be secured to the vehicle floor .)
All safety concerns would of course be addressed during a risk assessment stage .


Any thoughts ?
Gerry
Gerard Farrell
Glasgow

[Gerrard Farrell]

Re: Studying slips ,trips falls and footwear

Further to the above posts might it be possible to deliver balance perturbation training to older adults on a large scale ,prevent them from becoming injured by falls and thus reduce prolonged periods of morbidity ?
With that in mind the following ,or a version of it ,might be of some use .
With regard to balance perturbation training the effects of which have been shown to last for a considerable period of time I wonder if the bus idea might be extended .
Some balance training/testing systems include a platform on which a subject stands which is then moved at random to produce balance disturbance and subsequent recovery . All such systems also have safety harnesses to prevent the participants actually falling since safety is a key issue in such training which should only be delivered by qualified individuals .
But why not the following .Instead of delivering training to one individual at a time why not 8-10 and why not bring the testing/training lab to the people to be trained . This is were the bus comes in .
The bus /lab would need to be capable of transitioning from a road going vehicle to a balance training lab possibly along the following lines .
1 Take one bus and remove all seating apart from the drivers seat and two fold away “team member ” seats.
2 Create 8-10 spaced balance stations complete with overhead safety harnesses.
3 Equip bus with a very low gear so that small movements of the bus of say 6 inches can be easily delivered .
4 Have an on off suspension system -on for transit to site -off for training on site .
5 This would be a bit trickier but fit bus with a wheel base that behaves as that of a normal bus during transit but which can be manipulated a bit like the wheel base of a shopping trolley when on site so that perturbations may be delivered in any horizontal direction .(My understanding is that perturbations which move the FBOS forwards, causing a sensation of falling backwards , are the most effective at improving balance in the type of system proposed )
6 Fit bus/balance lab with a computer to control balance training program.

That’s about it . A “Balance Team” might consist of 3 individuals who would travel in the bus /lab to a given destination . The bus would transition into a balance lab by first parking in an appropriately sectioned off area ,switching off the suspension and securing the people to be tested /trained into the safety harnesses at the balance stations . The bus movement program (about 6 inches in any direction) would then be engaged with members of the balance team keeping a close eye on the participants .The trained team would also have the ability to pause the program at any point with safety being paramount .
Research already exists into the levels of balance disruption individuals are comfortable with and so care would be exercised not to exceed these levels.
Obviously 2 team members (one team member would be located outside the bus to ensure the safety of anyone approaching the sectioned off area) cannot accurately record the balance recovery actions of 8 individuals at once so this aspect would be recorded by individual cameras programmed to start recording 2 secs before the planned perturbations and for 5 secs afterwards thus providing a shortened film for later analysis .
You would not attempt any of the above without first ensuring it was completely safe both for those in the bus /lab and for those who might be passing by but if all were tested and passed then, as far fetched as the idea at first seems, perhaps it may have some value .

With regard to the above and the significant retention of the ability of younger and older adults to resist loss of balance after a single session of perturbations I thought the following reference might be of interest –

Learning to resist gait-slip falls: long-term retention in community-dwelling older adults

http://www.ncbi.nlm.nih.gov/pubmed/22341989

by T Bhatt – 2012 – Cited by 17 – Related articles
Arch Phys Med Rehabil. 2012 Apr;93(4):557-64. doi: 10.1016/j.apmr.2011.10.027. Epub 2012 Feb 18.

Kind regards
Gerry
Gerrard Farrell
Wilton Street
Glasgow