Kneehab is an electric muscle stimulation system built into a neoprene sleeve that you wear over your quads. It delivers an electrical stimulus to make your quads contract. There are separate areas for the VMO muscle and the bulk of the quads so that VMO can be made to contract before the bulk of the quads and can be preferentially trained.
Mr Willis-Owen has tried this himself and has been very impressed. It really does help to isolate the VMO muscle and get it contracting on its own. On high settings you can get very powerful contractions going, similar to a heavy gym session. After use it leaves a greater awareness of the muscle making it easier to learn to use the muscle in other activities.
Frustratingly the NHS and most insurers do not fund this however the machines can be purchased directly from the manufacturer or hired on a monthly basis. Mr Willis-Owen has no financial links what-so-ever with the manufacturer and his enthusiasm is purely because he thinks this is a useful device.
Kneehab wont solve the underlying problem of knee pain. If you have pain in your knee you should get it looked at first before embarking on Kneehab. Mr Willis-Owen would be happy to see you, establish what is wrong and whether Kneehab is right for you. Email him to discuss.