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The importance of the Hip Flexors in correct bike set up

Since I started doing bike fitting (many years ago) there have been three things that consistently come up in fitting sessions:

  1. Saddle is too high
  2. Saddle is too far forward
  3. Tight hip flexors – predominantly on the left side

While the saddle position is a quick one to fix the hip flexor issue is something that cannot be addresses as easily.

The hip flexors play an important role in maintaining a balanced, powerful and pain free position on the bicycle.  An overly tight hip flexor, usually on just one side of the body, often leads to misaligned hips and in turn this negatively impacts the pedalling technique and can lead to a range of pains.

Why do we get tight hip flexors?

Quite simply, it is primarily caused by the way we undertake our ‘everyday’ activities, such as the way we sit in an office chair, on a sofa or even stand up.  Most people favour their dominant side (right side for most of us) and this often results in the left hip flexor becoming tighter than the right side. Think about how you sit down on your work chair or sofa.  Do you tend to lean more to one side or the other?  Do you favour resting your left elbow on the side of the chair or sofa, etc.  In turn this ‘favouring’ of one side leads to an imbalance in our bodies, and for the hips it means they are not correctly aligned.

As we spend far more time doing these activities each day (than we do riding our bike) this results in the misaligned hip position becoming the ‘norm’.  Unfortunately for us, when we jump on our bike it doesn't magically correct the problem, rather we take it with us and that’s where the problems start.

How does a tight hip flexor impact cycling?

First and foremost, having a tight hip flexor usually results in a rider holding that hip higher throughout the entire pedal stroke.   In turn this results in the hips being tilted, with one side higher than the other.  For riders with a tight left hip this means that the right hip is lower and therefore the right leg doesn’t extend as far on the down-stoke as the left one does.   Conversely with the left hip being higher the left leg must extend further than the right one.  This variance in leg extension (between the left and right side) leads to an unbalanced pedalling stroke and a range of other problems. 

When setting up their position on a bicycle most riders self-select their own preferred saddle height based off the perceived extension of their dominant leg.  In the case above this often leads to a raising of the saddle so that the right (dominant) leg is perceived as having the correct extension. However, while the right leg is being taken care of the left leg is now being stretched even more, usually beyond the levels of flexibility for that leg as well as taking it outside a good biomechanical range.  To understand this further lets go back to the initial position.  The right hip is lower and therefore the right leg is under extending.  However at the same time the left hip is higher and therefore the left leg must extend farther to reach the pedal.    Raising the saddle height simply increases the level of reach required on both sides.

In turn this can lead to a rider twisting their hips to compensate (with the tight side twisted forward). This reduces the extension of the leg on the tight side and increases the extension on the dominant side.  Lower back pain is a common results of both of these positions.


Detecting tight hip flexors and misaligned hips

When assessing a rider’s position on the bike these issues can be detected in several ways:

  1. Using a goniometer you can check the knee extension angles for both legs.  If there is a significant variance between the extension of both legs then the hips may be tilted to one side.  A visual inspection of the hips (from the rear) will often confirm this.
  2. When standing (or riding) behind a rider you can check whether the centre seam of their knicks is directly over the centre line of their saddle.  If it’s permanently off to one side then the odds are their hips are twisted.
  3. With a rider on a stationary trainer you can use a plumb bob to check the parity of the knee alignment for both legs.  Simply place your right crank at the foremost position (ie 3 o’clock – or as far forward as it can go with the cranks parallel to the ground) then drop a plumb bob from the front of your knee and note where is falls in relation to the end of the crank.  Then repeat this with the left leg.   If the hips are indeed twisted this should be revealed by one knee being farther forward than the other (as seen by the plumb bob line being different).  [NB: this is similar to the KOPS method for saddle setback however it is for a completely different purpose]

As indicated above, there are a range of common ‘self-managed’ solutions for adjusting the bike fit in these circumstances.  However, invariably the rider is always tweaking their saddle height or puts up with some level of dull ache (or serious pain).     The problem of course is that the saddle height isn't the issue, its the hips.


So what’s the solution?

First and foremost it’s dealing with the flexibility and range of motion of the hip flexors and other muscles that are responsible for maintaining correct hip/pelvis alignment. 

For mild cases, regular stretching is usually the quickest and most reliable solution.  Moderate cases usually require a combination of approaches, with a visit to a masseuse or physiotherapist being added to the mix.

For more serious cases the best approach is to head to a physiotherapist for a musculoskeletal assessment.  This will help identify any and all other problems and the physio can then provide advice on the most appropriate activities to correct the imbalance/alignment issues.  This may range from massage to stretching and strengthening activities.

The final requirement is to correct the saddle height so that it is positioning correctly for both legs.  This can be a bit tricky as while their is still a misalignment of hips one, or both legs may not be extending correctly.  The key is to persist with the remedial activities (stretching etc) and perhaps reduce the volume or intensity of the riding.  Often it means modifying the saddle height in small increments until the correct height is identified over time.


What can you do to prevent this problem from occurring?

The number one thing you can do is to incorporate regular stretching into your weekly training routine. 

Secondly, if you are experiencing lower back pain, knee pain or saddle sores, then you should get your bike set up checked.  This will not only ensure everything is set up correctly but it should also identify whether you have a problem with your hip alignment and then provide suggestions (as above) on a course of action to correct it.

Check out the bike fitting services page for more details on how we can help you get the most out of your bike set up.  We will also shortly have an online bike fitting questionnaire that will help you check for other problems with your bike set up.  Keep an eye on our blog for more details once it’s released.


Jason Mahoney Monday 16 September 2013 at 08:51 am | | Tips

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