Wobbly Knees..? Help is at Hand

We’re often ask by clients interested in our bike fitting services if we use “wedges”. Firstly, for the uninitiated here’s a brief introduction into the world of cleat and forefoot wedging…

The majority of people (whether they ride bikes or not) suffer (that’s not really the correct word as for the majority of those same people it’ll never cause them a problem) from a condition called “forefoot varus tilt”. Sounds scary, but all that it means is that when the foot is in an unloaded relaxed, neutral position the forefoot will tilt more away from the centre line of the body (varus) than the heal. This tilt is often blamed for poor knee tracking in cases where the knee inwardly rotates towards the centre line of the bike during the power phase of the pedal stroke. In my experience as a fitter, poor knee trace is often associated with poor muscle function rather than any particular problem in the foot. In this article I’ll present some simple strength work each cyclist can do to improve their knee stability and hence performance on the bike

The knee is just one of the links in what is essentially a mechanism consisting of three levers, the femur (in the thigh), tibia and fibular (in the lower leg) and the many bones that go to make up the foot. The muscles of the body have two tasks to perform when the rider is in motion.

Task 1. Production of power

For the last few years, power has been a buzz word in cycling, and for good reason. Power is just another way of saying how fast we’re converting energy from one form to another. In the case of cycling we’re converting chemical energy stored in our muscles, liver and bloodstream into kinetic energy as we move the bike and ourselves forwards. How fast we convert the energy (our power) determines how fast we can make the bike go. If you were a physics spod at school (something that I’ll happily admit to), you’ll remember that…

Power = Force x Distance/Time

or in English…

Power is a combination of how hard you push the pedals, how far you push them and how quickly you do it. To increase power (and so go faster) we need to push harder, or push further (put the bike in a bigger gear), or pedal faster.
From this, we can see that a primary task of our muscles when riding is to produce high forces. We all knew that anyway of course.

Task 2. Joint stabilisation

A second important, but often overlooked function of the  muscles is the stabilisation of the joints. The muscles of the glutes, quads and calfs are required to provide large forces to turn the pedals and move the bike forwards. These forces act across the joints of the hip, knee and ankle. The body’s muscles must work to stabilise each of the joints to efficiently transmit the key power producing forces whilst pedalling. Only forces that act in the same vertical plane as the cranks act to turn the pedals. It’s the responsibility of the stabilising muscles to keep the powerful forces of the leg acting through the vertical plane of the cranks. Without stable joints, precious power will be lost. When we’re in the business of making bikes and cyclists work efficiently together, that is of course bad news.

A Common Problem with Common Causes – Internal rotation of the knee under load

Sounds terminal!? Again, not as scary as it sounds. All we mean by this is a movement pattern whereby the knee joint rotates and often tracks inwards as the joint is loaded and the knee is extended through the pedal stroke. As we’ve discussed previously, anything that means that vertical forces in the knee aren’t efficiently transmitted to the pedals is bad news, so we’re looking to control and minimse these types of movements on the bike.

The most common causes of this movement pattern are flat feet or collapsing arches often (but not always) combined with poor coordination and conditioning of the abductor muscles found in the lateral (outside) of the glutes. If you’re a triathlete who suffers constantly from soreness and tightness in the sides of your hips, then the chances are you’re suffering in this way. The muscles up in your bum are responsible for controlling (stabilising) the rotation and lateral (side to side) motion of the thigh, knee, shins and on down the chain into the foot. Folk with poor foot structure will find it harder to maintain good knee stability and will often find their abductor muscles get fatigued and sore after hard riding or running (or even just standing around for an extended period of time).

A key to solving the problem is a fix at the start of the kinetic chain. Strengthening and learning to effectively use the abductor muscles will help stabilise the knee joint and make you a better rider. Riders with flat feet or who pronate severley can also be helped by the introduction of a supportive insole in the shoe. The insole won’t instantly solve the problem, but will assist in making life easier for those already overworked (or that should be underconditioned and uneducated) abductor muscles.

Bike Science stock SOLE Thinsport Custom Footbeds specifically for this purpose.

This is not to say that wedges are not a help in some cases, but for the majority of riders we see, simply supporting the arch of the foot and improving the function of the muscles responsible for stabilisation of the knee will show large improvements.

So to get your knees on the right track, here are a set of simple exercises you can use to help gain control and strength and improve knee function whilst riding. The aim of our exercises is not only to gain strength, but to learn a new movement pattern. The more times we can perform the movement well, the faster we’ll get better at it as the pattern becomes ingrained, so concentrate on good form whilst performing any of the exercises.

Exercise 1- The “Clam”

You’ll have seen this exercise on that Pilates DVD that’s gathering dust at the back of the cupboard at home. It’s a very simple and very effective method of learning to use and strengthen the glutes.

Here’s how it’s done…

Lie on your side with your torso, hips and pelvis as close to vertical as you can. Bend both legs up to ninety degrees at the knees with the thighs about 45 degrees from the torso. Now, keeping your pelvis in line with the spine, keep your feeting touching together and raise the top most knee away from the body. If you’re doing this right, you’ll feel the side of your glutes and hips working almost immediately. Do around 10 reps on the first side, then repeat on the other side. Start with a small number of sets, say two sets of ten reps on each side. Gradually build the number of reps and sets.

Exercise 3 – Straight leg raises

A pretty simple one. Lie on your side as in exercise 2, but this time keep your body, and legs in a long straight line. Keeping your pelvis and torso vertical, raise the top most leg whilst concentrating on keeping it straight and long. If you find this exercise a bit too easy, add a stretchy “Theraband” between the feet to stretch whilst performing the movement and add some additional resistance. A “Theraband” can also be used to add resistance to the clam excercise if needed.

Exercises 4 – The Hip Hitch

I personally find this simple exercise to be extremely effective in educating the glutes to fire and assist with the stability of my knees. I’ve known clients react almost immediately (within a few sessions) with improvements in knee pain from performing this exercise…

Stand on a step with one leg straight, but without the knee locked. Now slide the unsupported foot down the surface of the step by rotating the pelvis and dropping the hip on that side. Try not too change the bend in the supporting knee by more than a few degrees (this isn’t a single leg squat) and avoid twisting the pelvis as the foot slides downwards. Now slide the foot back up the surface of the step to level the pelvis. Repeat in sets of 10 reps to start with. Gradually build the number of reps and number of sets over a period of weeks.

Exercise 5 – Practise on the bike

Learn to be observant about how you move whilst riding the bike. The turbo trainer is a great place to pratice this. Occasionally perform a quick visual checkup of how your knees are moving. We often experience clients who once made aware of a movement pattern can pretty much fix it themselves by concentrating on a simple vertical movement of the knee. The 3D motion tracking ability of the Retul measurement system we use is a very powerful educational tool in this respect. Once a rider has seen how he/she moves it becomes much easier to self correct a movement pattern.

Other flexibility and strength work…

Cycling is in general a great way of exercising without the high impact of other sports such as running. Having said that, that’s not an open invitation not to stretch, strengthen and condition your body to the often high demands of riding a bike. A good riding postion along with a regular strength and conditioning routine will help keep you on the road. See the Bike Science YouTube Channel for some more suggested exercises.

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