Firstly, a pressure scan is just a snapshot in time (or an average of a number of snapshots) of the forces that are being applied perpendicular to the foot through the stance phase from initial contact to toe off. They will show us the pressure that is acting upon the surface of the foot (force over area). It will enable us to investigate the:
- Peak Pressures (specific area with the highest pressure)
- Pressure Time Integral (pressure applied throughout a period of time)
- COP Pathway and Deviation
- COP Velocity
For out interpretation, the system will present its findings to us in the form of pressure profiles/maps (in pretty colours in 2d or 3d animated or still) and or force time graphs.
Pressure scanning in isolation is not the answer to all your boimechanical needs. The system cannot tell you what is wrong with your client, nor is it able to create an insole for you.
It is a useful tool that will help in your overall assessment and diagnosis of your client, it will also give you some help with your treatment plan and insole/orthotic design.
It should be used in conjunction with hands on and dynamic video/functional testing.
So how to use?
- Choose what you want to assess (peak pressure, P/T integral, COP direction or velocity etc).
- Choose how you wish to view (Pressure map of force/time graph. Using study areas in force time graph view can give you detila of what is happening in deifferent areas of the foot at specific times).
- Choose what you want to change (pressure distribution, COP, velocity) Rarely can you change all the variables all at once but choose what you want dependant of what the client is presenting with.
- Use different:
- Material densities to influence timing (soft to slow down, firm to speed up).
- Material densities to influence force (firm for more force, soft for a little less).
- Posts, think phasically when do you need the posts to function to assist reducing stress on structures. (Think Tibialis Posterior for a good example – when does it work eccentrically and concentrically?).
- Use posts to guide COP.
- Test and retest, see if your interventions have the effects you were intending, ask subjectively have they improved your clients comfort or reduced pain perception? Sometimes only time will tell if the intervention is going to work (regardless of any improvements in kinematics (video eyeballing) or kinetics (pressure scan data). Tell the client to wear them for a few weeks then review and adjust as necessary.