You may have noticed whilst watching the pros on television their knees moving in and out during the pedal stroke. Some cyclists will drift inwards to such a degree that the inside of their knee and thigh may touch the top tube.
This inward-outward side-to-side movement of the knees (commonly referred to as knee tracking) during cycling doesn't look beautiful, however, does it have any significant detrimental effects on performance or increased risk of injury?
By placing a marker on the middle of the knee-cap and dynamically analysing the cyclist from the front it has been found that 3 common knee tracking patterns exist.
Straight up and down
The knee does not significantly deviate, creating a straight up and down tracking line.
Image: Straight up and down
During the power phase, the knee will move medially towards the top tube, then laterally deviate or move away for the top tube during the up-stroke. Creating a teardrop shape.
In this pattern, the knee will move medially at the beginning of the down-stroke and then laterally (away from the top tube) in the latter half of the down-stroke. The knee will then exhibit a similar pattern during the up-stroke. First moving medially then laterally as it returns to the top of the pedal stroke.
When tracked, this in-out-in-out movement of the knee creates a figure 8 pattern.
Image: Figure 8
It is important to note that all three patterns can occur habitually due to the camber of the shoes, the width between pedals (narrow will cause medial movement) and normal muscle activation (bias on hip internal rotation because of increased hip flexion).
After analysing knee tracking in 21 uninjured pro-cyclists it was found that the average range of medial-lateral movement was 22mm (range 12mm to 41mm) and a range of the three above patterns was displayed evenly amongst the cycling group.
No one pattern produces more power or carries an increased risk of injury, however, the degree to which the knee moves and how well the cyclist can control these movements seems to be key.
This theory is supported by two studies showing that cyclists with a history of knee pain adopt a more medial knee position and have reduced control of knee movement compared to uninjured cyclists (Bailey 2003 and Theobald 2014).
Both studies showed that a degree of knee movement is normal amongst all cyclists (injured and uninjured) however; it was the injured cyclists who displayed greater medial (inward) movement of the knee during the power phase (down-stroke) (Bailey 2003) and overall increased rotation and medial-lateral movement (Theobald 2014).
It is hypothesized that this increased inward movement of the knee increases compressive forces at the knee-cap and ITB potentially leading to an overload of these structures, pain and dysfunction.
Another theory is that the excessive medial-lateral movement of the knee causes early fatigue in hip muscles leading to a greater reliance on the quads to produce power. This has the potential to overload the quads creating excessive loading and strain on the anterior aspect of the knee.
If you are prone to suffering anterior knee pain and feel that excessive knee tracking (especially medially) may be a contributing factor, here are a few things to consider.
Uncontrolled and excessive adduction and internal rotation of the hip/thigh is the major cause of excessive knee movement, therefore, training of the external rotators and abductors is key.
One great exercise is to perform squats with a band around your knees. The band will try to pull your knees inwards so resisting this movement, pushing out against the band and focusing on good knee tracking during your squat will activate the correct muscle around your hip.
Image: Squat with resistance band
Control and reduction in knee tracking during cycling can also be achieved through manipulation of the cyclist’s shoes and pedals. A narrow pedal width or an incorrect camber of the shoe can cause excessive medial loading and cause the knee to drift inward. Having your seat too low may also cause excessive knee movement as the leg attempts to gain more range.
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