Video Analysis

The laboratory has a video system which allows sagittal and coronal views of the patient to be recorded simultaneously. The data is recorded on to the computer and can then be viewed frame by frame and in slow motion.

By having a video recording of a patient moving it is possible to look at the movement again and again and so perform a better analysis than by simply eyeballing. It is also possible to slow down the movement for further analysis.

The video provides a permanent record of what the persons movement was like at that point in time and this can be used if further video is collected after an intervention, a period of time or if it is felt there has been a change.

Video Vector

The laboratory has a video vector system which allows sagittal and coronal views of the patient to be recorded simultaneously with the Ground Reaction Force superimposed onto the image. This system utilises the force plate embedded in the floor of the laboratory and the digital video cameras. When a person steps on the ground they apply a force to the ground and the ground applies an equal and opposite force back. Using the Video Vector system it is possible to look at where the ground reaction force is in relation to the ankle, knee and hip joint. This data is then analysed to make an assessment of where the ground reaction force is acting and if this is appropriate. It is not possible to perform video vector analysis if someone is walking with the aid of a rollator or walking frame. The video vector analysis gives the video which enables the movement to be analysed again and again but also adds extra information in the form of the ground reaction force. This technique is particularly useful when looking at people who are wearing splints as it is possible to tune the splints to give a better movement of the ground reaction force through gait. Pedobaragraph The laboratory has a pedobarograph system which enables information to be collected about the pressures on the plantar (bottom) surface of the foot. As well as indicating where there are high pressure areas it is also shows the progression of the centre of pressure. This can be very useful as it can indicate whether a person is spending a large amount of time on one area of the foot and also whether how the centre of pressure is moving could be contributing to their problems. The system enables us to analyse the data in a number of different ways and from this it is possible to make recommendations about possible interventions. High pressure areas on the foot are identified conventionally when an area of hard skin or an ulcer occurs. Using the pedobarograph it is possible to identify high pressure areas before any physical sign is shown. Also the information collected from the pedobarograph is dynamic and so gives an indication of what is occurring as a person walks rather than just a static picture. The information about the progression of the centre of pressure is also useful as it can be that skin damage is caused by a lower pressure acting at a point for a longer time or moving backwards and forwards over a point. Computerised Gait Analysis The Gait and Movement Laboratory has a state of the art  3D Gait Analysis system (BTS MILAN. Eight infra red cameras are used to record the position of small reflective balls which are attached to a patients legs. The accompanying software then reconstructs the markers and, following processing, the result is a 3D image of the patient moving. At the same time as the 3D image is produced a series of graphs showing movement of the pelvis, hips, knees and ankles in three planes is produced. This information is called kinematic data. There is also a force plate in the Gait Analysis Laboratory which is used to collect information about the moments and powers acting at the hips, knees and ankles. This information is collected at the same time as the kinematic data and is called kinetic data. We can also collect information about muscle activity. This is called electromyography and in order to collect this data we apply electrodes to the surface of the skin over specific muscles and connect these to a pack which transfers the information to the computer. We apply these electrodes at the same time as the reflective markers and the data collected is synchronised with the kinematic and kinetic data. Movement is very complex and what we see with our eyes may not always be exactly what is going on. The benefit of 3D Gait Analysis is it is an extra tool in analysing this complex movement. The data gives information about the pelvis, hips, knees and ankles in three planes along with the moments and powers which gives a large amount of data compared with that we can get with our eyes or video. return to top       home