Preventing knee problems: What the expert advises bikers for healthy knees

The joints of the knees are among the most important in the human body. After all, they bear a large part of our weight when we walk upright on two legs and are regularly exposed to great stress, especially during sport. The knee joints play a particularly crucial role in mountain biking. Without them, there would be no pedalling movement and the healthy leg system, to which the knees belong, is also irreplaceable when absorbing impacts. As a biker, it is therefore no mistake to know as much as possible about your knees. What is really good for the knee joints and what is not?

Cycling is good for your knees

Everyone has heard this statement before. In principle, it is true, but as is so often the case with medical advice, it is not so easy to generalise. Viewed in isolation, the circular movement of the knee is actually good for its health. Cycling sets the fluid in the knee in motion. Pedalling pumps synovial fluid through the knee, which is particularly important for the cartilage inside.

Healthy cartilage tissue does not have blood vessels running through it, but must be supplied with nutrients by the synovial fluid. So if you pedal regularly, you ensure that your knee is nourished and therefore healthy. If the joint moves evenly on a fixed circular path, the knee is less stressed by twisting movements than with other movements. However, a knee is not just made up of cartilage, but is a highly complex "component" of the body. And not all cycling is the same. It makes a huge difference to the knees whether they are moved evenly on an ergometer or rumbling through the terrain on a mountain bike.

After a fall left me with a shattered tibial plateau and no functioning anterior cruciate ligament, I am at high risk of further knee problems. Over the years, doctors and therapists have given me very different advice. It seems that everyone says something different about mountain biking as a knee patient. The stresses involved in biking are quite complex. Finding a real expert is not that easy. - Jan Timmermann, BIKE editor

Cycling is actually considered a "low-impact sport". In other forms of movement, such as jogging, the knee has to absorb high loads. Particularly in sports such as football or tennis, braking movements or quick changes of direction place a high load on the joint at certain points. When pedalling on a bike, on the other hand, the force is built up much more evenly, which is much easier on the joints. However, mountain biking is not just about pedalling and steering. Even if force impacts on the fully extended knee should not occur on an MTB, the "impacts" are often anything but "low".

One of the biggest difficulties is assessing the load on the knee. How problematic are hill sprints, marathons, jumps and drops really? Should I even ride a hardtail through root fields if I care about my joints? I'm young and don't like to be restricted. So knowledge about mountain biking with knee problems is particularly important. - Jan Timmermann, BIKE editor

>> We have interviewed an expert on the subject of mountain biking with knee osteoarthritis.

Interview: What the expert advises for knee problems

Lorenz Westner has been coaching numerous top athletes at the FFB Puch sports school for many years - including mountain bikers. He has been working with Danny MacAskill for twenty years, Emil Johansson trained with him for months, he developed a training system with Fabio Wibmer and Tarek Rasouli, Erik Fedko, Steffi Marth, Loris Vergier and many more are also among "Lenz's" athletes. We interviewed the expert on the subject of knee problems and injuries when mountain biking.

BIKE: "Cycling is good for your knees" - you often hear this statement. Is this also true for mountain biking?

LORENZ WESTNER: Runners, for example, have to support up to 2.5 times their body weight with every step. In contrast, sports in which the body weight is supported are less strenuous. Generally speaking, the statement is true. The movement itself is also very healthy for the knee joint when mountain biking. Of course, there is an increased risk of trauma when biking. Statistically speaking, however, this is significantly lower than in football or handball.

Which knee injuries are typical for mountain bikers?

Injuries caused by falls are speed-dependent and can include complex bone fractures, for example. Another problem when falling on the knee is the weight. Since the spread of e-MTBs, the increase in tibial plateau fractures (fracture of the tibial plateau, editor's note) has been striking. These are relatively severe for the knee joint because they are often associated with injury to ligaments and capsules. With a heavier bike, the forces are naturally higher. If you factor in the generally higher speed of e-bikes, the load increases exponentially.

Can the knee be damaged when mountain biking even without a fall?

The leg is never fully extended when cycling. This can lead to muscular imbalances. Especially when these imbalances develop and the leg axis is not optimal, as is the case with knock knees or bow legs, the likelihood of incorrectly loading the knee increases. Due to the lack of knee extension, the outer thigh is activated more than the inner thigh. The higher muscle tension on one side can cause the kneecap to shift outwards, for example. Bikers notice this when riding with clipless pedals, for example, due to pain on the outside of the knee joint.

Does this mean that bikers can get knee problems even with a perfectly adjusted bike?

Yes, the activity of cycling itself can also lead to problems, as you are travelling in a seated position. Nowadays, there are more and more people who also sit a lot in everyday life. This can exacerbate the problem.

What can mountain bikers do to prevent these problems?

The muscles in the leg should all be trained, and in a balanced way. Of course, there is an adaptation to the type of sport. However, if the differences become too great, consequences will occur. The five pillars of fitness are endurance, strength, flexibility, coordination and speed. If I want to win races, I usually need the endurance component a lot. Nevertheless, I have to train all facets if I want to take preventive action. Most cyclists don't like to stretch. Mobility is often neglected, as is strength training. You get the necessary coordination from cycling itself, although it also helps to set other stimuli. Speed results from the combination of coordination and strength.

A common tip is: "Low cadence and heavy loads are bad for the knee, high cadence and light loads are good for the knee." Is that true?

You can certainly say that. If you can increase your cadence by an average of just five revolutions per minute, you will take a lot of strain off your knees. However, it's not that simple. It requires sport-specific technique training, such as targeted cadence training, one-legged riding and exercises for the so-called "round kick". This is often neglected. There are methods, such as desmodromic training, which are extremely gentle on the joints but are less well known. Even if the knee is already damaged, it is possible to set more energetic training goals.

Which muscles should I train and how should I train them to preventively prepare my knee for mountain biking?

To counteract the one-sidedness of cycling, mainly the inner part of the quadriceps should be strengthened, while the outer and rear parts in particular should be stretched repeatedly. However, stretching alone is not always effective enough. It is better to combine flexibility exercises with fascia and strength training.

What role can orthopaedic aids, such as orthoses, play in the prevention of knee problems?

A healthy knee does not need this. In principle, however, orthoses can be a good aid to protect unstable or restricted knees from harmful rotations or displacements in the joint. They support a functional distribution of force in the knee joint. However, people react differently to such aids. Orthoses should therefore be fitted to the body by a specialist so that they do not constrict or chafe.

So is it worth investing in good material?

After an injury, the insurance company often only pays for a cheap off-the-peg orthosis. Of course, this can also be suitable. But if it doesn't, I am responsible for spending money myself to get equipment that is optimised for me. There are great products out there. They cost money, but they also help me for many years. If you already have knee problems, it may be of secondary importance to you how expensive your rear derailleur is and you would rather invest the money, to have the material adapted to his problems. If I want to cycle four times a week, it makes a lot of sense to spend money, to have my sports equipment ergonomically adjusted for me by an expert before any knee problems occur. Unfortunately, not everyone is prepared to do this. There is still a lot of potential for greater awareness in the cycling community.

How do I recognise that I lack stability in my knee?

When mountain biking, a lack of stability can be noticeable during extreme riding manoeuvres, such as over a root carpet or in bends where the knee is pushed inwards or outwards. If there is a misalignment in the joint, for example, this gives the impression of a lack of strength or reaction speed. If the ligaments are not stable, this can result in a strange feeling, as if the knee is being pulled apart. This rarely occurs when biking, most likely when jumping over an obstacle. When walking, those affected can often have the feeling that the knee is unstable or powerless for fractions of a second.

With previous damage to the joint, should I work on the stability of my knee through strength endurance or should I prepare it for possible falls with high loads to prevent further injury?

I'm not a fan of simulating high loads in training for people with damaged joints. If the cruciate ligament is missing, for example, you have to be doubly careful. In this case, the leg should only be trained hard under safe conditions - for example, squats or leg presses under professional supervision. Higher loads can also be realised there. Reaction speed, strength and coordination can be trained well under controlled conditions on a gyro or wobble board. If you do a lot of mountain biking, you will always be exposed to high loads, for example when jumping. With a clean technique, the conditions there are also relatively safe. However, jumps and trails can be very different. It is better to prepare your leg for mountain biking by doing stabilisation exercises to strengthen it.

What role does knee mobility play for athletes after an injury?

In principle, the aim of the rehabilitation process should be to regain as much mobility as possible. This is not always easy with a serious injury such as a tibial plateau fracture. This is no longer a bumped mudguard, but a severe impairment of the static situation and joint mechanics in the knee. Anyone with an injury should definitely try to maintain the joint's range of motion for as long as possible. For example, an extension deficit of five degrees should not be allowed to gradually increase to ten or even 15 degrees. The body then reacts with compensatory movements in the hip or pelvis and movement sequences are no longer executed in a functionally correct manner, which then indicates problems in other parts of the body.

What can I do as a mountain biker if my mobility is restricted?

In the event of a significant restriction of movement following an injury or after the insertion of a knee prosthesis aids for shortening the cranks are extremely good. With cranks like these, however, we are no longer talking about optimising performance, but about adapting the ergonomics to the health problem. The injured joint is the weakest link in the chain of movement. In this case, the saddle may have to be pushed back a little in order to achieve a reasonably smooth pedalling movement with a less acute knee angle in the upper part of the pedalling movement. In this way, you can prevent the disruption of the injured joint from affecting the ankle, hip or spine. Oval chainrings can also be very helpful in such cases to reduce peak loads in the knee joint when pedalling.