How it Works
Most knee braces manage the problem. This one works on it.
A conventional knee brace or compression sleeve does one job: it holds the joint steady and takes load off it. That's genuinely useful, especially in the days after an injury. But it's passive. Wear it for six months and the muscles around your knee are no stronger than when you started — and weak muscles around a knee are part of why the knee hurts.
Pflexx does the supporting part too. The difference is what happens while you're wearing it.
The mechanism
Pflexx is a seamless-knitted compression sleeve with spring elements fitted into the fabric on the inner and outer sides of the knee.
The springs are made from a memory-retentive high-performance polymer. They resist movement of the joint in both directions — as your knee bends and as it straightens. That resistance has to be worked against, and the muscles that do the work are the quadriceps, hamstrings and calves.
The practical effect is that ordinary movement becomes light resistance training. Walking to the shops, going up stairs, standing up from a chair — each of those becomes a small rep. You're not adding an exercise session to your day; you're getting the work from the movement you were already doing.
Because the spring returns to shape, it also gives back a little assistance as you straighten up. Support on the way down, resistance on the way up.
Three resistance levels, included
Every Pflexx comes with all three spring sets. They're interchangeable — take one out, put another in — so you can start light and build up as you get stronger, without buying anything else.
3.5kg — white. The starting point. Suited to early-stage recovery, arthritic and osteoarthritic knees, and gentle rebuilding where the priority is moving comfortably rather than loading the joint.
5.0kg — yellow. General use. Everyday wear, general fitness, and light sport.
7.5kg — black. The heaviest. For structured training, gym work, and sports performance.
Most people start on the white springs regardless of how fit they are. The resistance accumulates over a full day of walking in a way that isn't obvious in the first ten minutes, and building up gradually is more comfortable than starting heavy.
The sleeve
The springs do the strengthening; the sleeve does the supporting.
It's knitted as a tube, which gives even compression around the joint rather than the pressure points you get from a strapped brace. Compression helps stabilise the knee, encourages blood flow, and limits overstretching of the muscle without restricting your range of movement.
The yarn is a performance fibre designed to regulate temperature and move perspiration away from the skin, so the sleeve stays wearable under clothes for a full day rather than becoming damp and uncomfortable after an hour.
What the testing showed
The Pflexx mechanism was tested at various stages at the University of Newcastle upon Tyne. Testing measured muscle activation adjacent to the knee joint while wearing the exerciser, and recorded increases during both walking and running — substantially larger during running, where the joint moves faster and through a greater range, and the springs are therefore worked harder.
That result is the basis of the whole design: it's the evidence that the spring elements are doing measurable work rather than simply sitting in the fabric.
Who it's designed for
Pflexx suits people who want to get stronger, not just get through the day:
Managing arthritis, general wear, or long-term knee pain.
Recovering from a sports injury and rebuilding towards full training.
Preparing for knee surgery, where going in stronger tends to help.
Rebuilding after surgery, under a physio's guidance.
Staying active, walking, gardening, a day on your feet, without the knee deciding otherwise.
If you have a diagnosed injury or you're post-surgery, check with your physiotherapist or surgeon before starting, and start on the lightest springs.
Getting started
Wear it for an hour or two on the first day and build up from there. The resistance is light but it's constant, and the muscles doing the work may be ones that haven't been worked properly in a while.
Once wearing it all day feels easy, move up a spring level.
Not sure which size? The fit guide is on the product page — you'll need a thigh and a calf measurement.