Knock-knees/bow legs

Knock-knees/bow legs are not merely a cosmetic problem in adults. The main consequence is increased strain on the knee joint.

Over the long term, all severe leg malpositions – knock-knees or bow legs – lead to premature wear of the joint cartilage, so that osteoarthritis of the knee joint/gonarthrosis can be expected to develop.

With the kybun shoe/kybun mat, you can strengthen your stabilising foot and knee musculature and integrate leg axis training into your everyday life without requiring any extra time.


In medicine, angling refers to a deviation of a limb from the normal position (neutral 0 position).

  • A varus position is when the angle of bones or joints towards the centre of the body (=medial) is less than normal (on the knee joint with bow legs (genu varum) for example, less than approximately 186°) (formed by the axes of the thigh and lower leg).
  • A valgus position is when the angle of bones or joints towards the centre of the body is larger than normal (on the knee joint with knock-knees (genu valgum) for example, greater than approximately 186°).

Here you look at the angling of the limb that is further away from the body (= distal). When describing a varus/valgus position in the knee, this is the angling of the lower leg.


Knock-knees are rarely congenital. When knock-knees are congenital, connective tissue weakness is the main cause. A malformation of the bones themselves can be congenital as well.
Knock-knees can be corrected during infancy by applying splints at night or with a plaster cast.
As a rule, knock-knees are a consequence of a kinked flatfoot. The malposition of the feet leads to angling of the legs relative to the knee. The lower leg is guided at an angle to the knee, not unlike a lever, and impairs normal growth.
Rickets is when bone formation is impaired by a lack of vitamin D. The bone does not harden properly and is unable to support the body weight. This can result in knock-knees or bow legs.
Poliomyelitis can cause knock-knees as well.

Bowlegs are entirely normal in newborns and infants and disappear on their own.
Acquired problems may be due totrauma or other factors. Underlying diseases such as obesity (excessive strain), rickets, hormone disturbances, tumours or inflammation can cause bow legs.
Some types of sports make the development of bow legs more likely. These are mainly sports that require a greater use of abductor muscles in the outer thighs than in the inner thighs, making the outer thighs more developed over time. Football is the best known example of this.

Long-term consequences

Pain is one of the symptoms associated with bow legs. This is usually caused by osteoarthritis and irregular wear of the knee joint. Where there is a bow leg on one side only, the spine may become warped because the body tries to compensate.
With bow legs, there is a greater load on the medial femoral condyle (condylus medialis femoris). This puts more strain on the inner meniscus, resulting in gonarthrosis directed towards the middle.

In the worst-case scenario, knock-knees can later lead to knee and hip problems.
Knock-knees can also lead to osteoarthritis of the knee joint (gonarthrosis). With knock-knees, there is a greater load on the lateral femoral condyle. This puts more strain on the outer meniscus, resulting in lateral gonarthrosis.

Conventional therapy

Therapy is based on the causes and may range from treating the underlying disease to an operation.
Foot malpositions are addressed with special heel correction insoles and calisthenics (physiotherapy).
Depending on the severity of the illness, an operation may ultimately be necessary.

The kybun principle of operation – being proactive

The kybun shoe and kybun mat train the core joint stabilising musculature, beginning at the feet. Since you stand directly on soft, elastic material, the foot is able to move freely. This trains the deep foot musculature and improves foot mobility.
The core foot musculature is often severely weakened in case of foot problems. As a result, the foot is no longer stabilised properly. This can lead to pain and even more severe malpositions over time. A stronger foot does not twist as much in everyday life and can balance itself on uneven ground.
With better foot stability, a more correct axial load is placed on the entire leg, and the load/excessive strain on the higher joints (e.g. the knee joints) is reduced. As a result, existing joint pain may be reduced or even go away entirely. Knock-knees and bow legs can be stabilised or even reduced through leg axis training in the kybun shoe or on the kybun mat.

The more often the foot musculature is trained, the faster the foot and knee position improves and pain is reduced.

Initial reactions

Specific initial reactions with leg axis malpositions (knock-knees/bow legs)

With existing foot weaknesses such as kinked flatfoot, standing upright on the soft, elastic kybun material is a challenge for the feet in the beginning. You may become tired and experience lateral/medial rolling of the ankle joint after a short period of use. If you try to actively correct this, you can strengthen your stabilising foot musculature and therefore counteract the foot and knee malpositions.
For further tips, please read more under ‘Application tips’.

For general information about initial reactions, click here: Initial reactions

kybun exercises

For information about the special kybun shoe exercises or the basic kybun mat exercises , please click here: kybun exercises

The following adaptations to the standard implementation of interval walking are important with a leg axis malposition :

  1. Focus on slow exercises which are completed with more control
  2. Slow exercise version: walking backwards (stability is provided by the transverse arch in the forefoot)

Application tips

For active stabilisation training of the foot, we advise wearing the kybun shoe without orthopaedic insoles. The foot musculature needs several months of regular training before it is strong enough to walk several hours in the kybun shoe. Until then, you can wear normal shoes with orthopaedic insoles for relief. After years of using insoles, wearing the kybun shoe all the time may be too much for the feet in the beginning (in the first weeks/months).
Insoles provide passive support for the feet but do not improve the foot situation over the long term in any way. We recommend against constantly wearing orthopaedic insoles. It is best to listen to your body, since it tells you what is good for it and when it needs a break.

Pay attention to putting an even load on the sole in the kybun shoe and ensure that the foot stands upright on the sole. This gives you a favourable leg axis and also prevents the feet and knees from ‘rolling in’ as much.

If you get very tired, feel pain or are no longer able to prevent lateral/medial rolling of the ankle joint, it is time to take a short kybun break.

Avoid making your steps too long; this makes it easier to maintain a good foot position in the kybun shoe. This reduces rolling to the inside.

Some people feel too unstable in the kybun shoe. In this case, we advise you to try various kybun shoe models; some models with a higher cut provide more stability. We also recommend that these customers try a kybun shoe model with a lower rebound effect. It is a bit wider in the midfoot area, therefore making you feel more stable while walking (ask for advice in a kybun specialised shop).

If you still feel too unsafe walking in the kybun shoe, we advise using the kybun mat. The kybun mat is available in three different thicknesses. This allows you to choose the thickness that is most comfortable for you (the thicker, the more unstable, the more intensive the training).
You can also hold on to a fixed object if you need additional support when using the kybun mat. If you have further questions, please contact your local kybun dealer who will be happy to advise you in person.

Avis/Témoignages des clients

This is my first time getting out in my kyBoot shoes. I’ve already done a two-and-a-half-hour hike. I feel like I’m walking on moss. It’s fantastic. I have knock knees and haven’t had any problems without insoles. I’m absolutely delighted.

Media reports/studies

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