Why does stability matter in cycling performance? Should we all spend a bit more time on one leg in 2019?
Learn how you can test your balance and stability yourself at home and begin some simple work to improve your riding!

As more of us are beginning to train with ever more sophisticated power meters, giving us more information than ever to understand our performance, it is important to understand what exactly goes into generating the forces we are measuring and analysing. Why do you feel like one leg is ‘smoother’ or ‘works better’ than the other one? Why does your power meter always show a 47%:53% split in power production left vs right? Why can’t your knees stay in a straight line when you push down on the pedal?

As cyclists we often obsess about and aim for symmetry. Symmetry of pedalling technique, joint angles during bike fit and power output. Before continuing it is important to realise that in many ways human beings are not symmetrical and that perfect symmetry in everything we do on the bike may A. not be possible and B. may not always improve performance and reduce injury risk.

There are many reasons why an individual may not present in the same way on both sides of the body. Environmental factors include; the type of work we do, how long we spend doing certain activities where one side is used more than the other and sporting background. Intrinsic factors can include; neurological dominance, biomechanics, injury history, and whilst rare, skeletal asymmetry.

It is commonly accepted however that significant asymmetry in movement patterns can lead to increased joint and tissue loading and therefore increase the risk of injury. It is therefore still a valid goal in training to reduce any discrepancy in physical conditioning between the two sides of the body in order to perform optimally and this could be especially important in endurance cycling.

So, where does balance come into all this?

Without boring you all to death here it is important to cover some basic anatomy. The skeletal system is a collection of bones with a goal of protecting vital organs and which come together at joints to provide articulation for movement. There are different types of joint. Some, like the knee, are hinge like joints which allow only 2 main movements, flexion and extension (opening and closing). Other joints allow movement in multiple directions like the ball and socket of the hip joint.

The muscular system can be viewed as an an interwoven network of large power producing muscles with smaller stabilising muscles alongside. The larger power producing muscles generate the force, the smaller stabilising muscles work to make sure the force is delivered in the right direction. In cycling the gluteals and the quadriceps should be contributing the majority of force in the drive phase of the pedal stroke (12-6 on a clock face) to extend the hip and knee in the saggital plane. However if the stabilising muscles of the hip, ankle and foot aren’t doing their job then it can be difficult to control the movement in the required direction and movement can occur that does not help to push the pedal down. In this case more energy can be used than necessary and lower forces are transferred to the pedal to push the bike forward therefore reducing efficiency and impacting performance.

In many ways the mechanism of pushing the pedal down is similar to the action of standing up from a chair on one leg. Both movements require a combination of hip and knee extension from a position of flexion. In pedalling as we push on one pedal the opposite leg should be switched off before then switching the extensor mechanisms on again around 12 o’clock to engage its drive phase. So effectively pedalling is also a single leg activity. This is repeated quickly around 80-90rpm. (I must stress here that for the purpose of this blog post this is a rather simplified view of pedalling dynamics during steady state cycling and that there are clearly some caveats with situations that require both ‘push and pull’ under different loads or terrain. For more information on pedalling dynamics please see work of Dr Jeff Broker and Prof. Jim Martin and many others who are experts in this field.)

If we break down the components of the push phase of the pedal stroke from a physical conditioning point of view it can be said that in order to produce force there must be:

• Adequate strength and endurance of the hip extensors (glutes) and knee extensors (quads) to create movement
• Adequate strength and endurance of the ankle plantar flexors (calfs) to hold the foot and ankle in a static position to transfer the forces from above to the pedal
• Effective activation and endurance of stabilising muscles of hip/pelvis and foot/ankle
• The co-ordination and control to put all of the above into action at the same time