We were approached by our client after their original supplier let them down – more than 18 months into the project! We stepped in, developing the hardware and an innovative control system with a simple wizard-based approach to setup and operation. The whole development was completed in less than 6 months, and our client had only one complaint – they no longer needed to include a two week training course with each machine, as two days was now more than enough.
The machine can be used for Isokinetic, and Isotonic exercises. There is also a facility for CPM.
Isokinetic exercise is where the body’s movements are constrained to a fixed speed. The idea is that the patient tries to move faster and therefore can apply different torques at different joint positions. An isokinetics machine can be used by physiotherapists to diagnose and monitor a range of joint and muscle injuries.One simple use is to determine the difference between real joint injury and fabricated injuries. Insurance companies sometimes look for Physio assesments for injuries before paying out large sums. On a real injury the amount of torque that can be applied is usually directly linked to the amount of pain in the joint. On a real injury this is always at the same point. For a fabricated injury the joint position varies greatly. By plotting torque against joint position for multiple repetitions of an exercise the fabricated injury is usually very clear.
Isotonic exercise is where the torque is kept constant and the subject is asked to move as quickly as possible. This sort of exercise can simulate weight training environments for example and can be used to build up stamina.
CPM, or continuous passive motion, is generally where the joint is assisted in its movement. Typically there is little or no subject input, in that the machine does all the movement. However this aspect of the machine is good for extending joint movement ranges, and is often used to rehabilitate subjects after critical joint operations.
The control system was developed in conjunction with research physiotherapists based in Leeds University. It was specifically designed to guide clinicians through the setup process step by step in a straight forward manner – giving pictures of the tools and set up options as they went along so that results across machines and clinicians were consistent for any given subject. This was a first for the market, where different machines or clinicians would regularly get different results.
The biggest problem on this project was the torque gauge – which was so sensitive it picked up mechanical ringing in the metal framework of the machine. We developed a targetted filter that could remove this ‘noise’ while still leaving the real picture for the clinician. All of this had to be done in realtime as the torque graphs were displayed on the PC screen as the subject carried out the exercise pattern. Ground breaking work also ensured that the machine’s gauges were correctly calibrated so that a 10Kg weight weighed in correctly at every angle at which it was measured. At the time of development, no other Isokinetics machine on the market could make this claim while the ‘arm’ was moving.