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BikeDynamics - Bike Fitting Specialists

Aches and Pains

Many cyclists will put up with a degree of discomfort on their bikes because it can be considerably outweighed by the enjoyment of riding. When this discomfort becomes pain, performance and endurance can be compromised and the enjoyment spoilt. When considering the implications of bike fit to cycling comfort, it is important to consider if the pain only manifests itself whilst riding or is present at other times. If you have lower back pain whilst standing, walking etc. then it is unlikely that you will achieve a pain free position on the bike and you should seek help from a qualified Medical Professional. If the pain only occurs when on the bike, there is a strong chance that the issue will be resolved with a correct bike fitting. Of all the BikeDynamics customers looking to improve their comfort; knee pain followed closely by lower back pain are the most frequent ailments. Numb or painful hands, aching neck and shoulders, foot pain and saddle sores being the other usual culprits. Below is a brief summary of the most common reasons for these problems, with more details on knee and back pain on subsequent pages.


Knee Pain - Front of Knee - Saddle too low.

If complaining of knee pain, most customers will experience it on the anterior (front) surface, either above or just below the kneecap. For some, this may be just due to overuse after time off their bikes and will respond to rest, easier efforts and applied ice. If the condition does not improve, the most likely cause is patella or quadriceps tendonitis due to the saddle being set too low.

Knee joint forces

Patella Tendonitis - Knee Joint Shear forces

A low saddle height will mean that the knee angle is too tight at the top of the stroke. When the cranks are approximately vertical, the quads become the dominant muscle group, effectively pushing the foot over the top. The quads attach onto the tibial tuberosity via a shared tendon that encloses the patella (kneecap). When the quads contract, forces are applied in the direction shown, giving a resultant force pulling the patella against the femur. The shear forces acting at this interface will be dependent upon the efforts being expended and the angle between femur and tibia. As these forces increase, so does the likelihood of tendonitis and harmful stresses in the cartilage behind the kneecap.The BikeDynamics recommendation for the minimum knee angle shown here is to be above 70°. See here for more knee pain symptoms and countermeasures.

Knee Pain




Lower Back Pain

Lower back pain whilst cycling can be either very simple or very difficult to resolve. The simple solution is to raise the handlebars, which will reduce any hyperextension of the lower back and reduce stresses in the inter-vertebral discs. In many cases, lifting the bars just a few mm and improved back flexibility through spending more time in the saddle can be all that is required. Many people continue to suffer lower back pain so other aspects of their position become relevant. Of these, the circumstances that create a posterior tilt of the pelvis are the most frequent cause of back pain amongst BikeDynamics customers.

Lower back pain

Lower Back Pain and Pelvic Tilt

This image shows two cyclists, with the one on the right in a far lower, more aggressive position. One might imagine that of the two, he might suffer more back pain. But this was not the case, with the cyclist on the left suffering debilitating pain, very quickly into a ride. The clue is in the angle of the pelvis. The rider on the left has a noticeable hinge point in his lower back as his pelvis is reluctant to lean forwards and the lower lumbar vertebrae appear to be immobile. The rider on the right meanwhile has a smooth transition from pelvis to lumbar region and along the whole spine. In the left hand case, the saddle was too low and the rider had a very stiff right hip joint. The excessive upwards movement of the knee and lack of mobility in the hip combined to push the pelvis back.

Back Pain


Foot Pain

Foot pain

Foot Pain - Outside edge

One of the most common foot discomforts experienced by BikeDynamics customers is along the outside edge, usually after two or three hours of cycling. Occasionally this is due to poor cleat position holding the feet 'toed in', but the more usual reasons are either a strong fore-foot varus or that the load paths from knees to feet are offset, as shown here. In some cases, with particularly large people, this will be because the hips are spaced wider than the pedal spacing. Usually though, hip joint inflexibility will encourage an outboard knee trajectory. The simple solution here is widen the pedal stance, either with a washer between crank and pedal, or cranks with a wider Q factor. If the cyclist has a strong fore-foot varus, using a wedge or shim can also help spread loads over the whole foot.

Hand Numbness and Pain

Shifter Position

Hand Numbness and Pain

Cyclist’s or Handlebar Palsy is very common and can best be described as a tingling or numbness of the hand along the ulnar nerve. The nerve is compressed in the heel of the hand and is usually first felt in the little or ring finger. Cyclists can also suffer from Carpal Tunnel syndrome, where the median nerve is compressed in the wrist, manifesting as discomfort in the thumb, index and middle fingers. The first consideration when trying to resolve hand pain is to make sure there is not too much weight on the hands, which would be the case if the saddle is too far forwards. The detail of the shifter position and the width of the bars are also very important. Older style brake hoods or upturned shifters can create pressure points at the front and back of the palm as shown top left. By ensuring a smooth transition from bars to shifters (bottom left), loads are spread over the entire width of the palm, reducing pressure on the ulnar nerve. The median nerve is compressed when the wrists are cocked, so they should be kept as straight as possible. Bars that are too wide will encourage a bent wrist, as will shifters that are too high or rotated too far around the bar bends. Thicker handlebar tape with gel inserts can help and mitts are essential. Be careful with some gloves though as the pads placed to cushion the ulnar nerve can sometimes be counterproductive.

Neck and Shoulder Pain

Excessive reach

Neck and Shoulder Pain

Neck and shoulder pain is often due to the reach to the bars being too long. To reach the controls, the elbows may need to be locked and the shoulders rolled forwards. The locked elbows will then become far more efficient at transmitting road vibration into the upper body. The long reach will also imply an aggressive torso angle, straining the neck to be able to see forwards. Attempts to reduce the stretch by moving the saddle forwards can be counterproductive as more weight is then placed on the hands and arms. Raising the bars can help the neck but the best solution is to reduce the stretch with a shorter stem, narrower bars or compact bars with a shorter reach. Ideally the bars will be placed to allow your elbows to be slightly bent with relaxed neck and shoulders.

Saddle Soreness and Numbness

Offset on saddle

Saddle Soreness - Hip Rocking

The most frequent cause of saddle soreness is a saddle that is set too high. As saddle height is increased, hamstring flexibility will eventually limit how far the knee can extend, which means either the heel will need to come up or the hip will need to come down. Ankle flexibility will also have its limits so the hip will need to drop as the foot goes through the bottom of the stroke. The effect of the hips rocking on each pedal stroke is to slide the crotch from side to side over the top of the saddle. A leg length difference can exacerbate this as the cyclist may subconsciously lean the hip of the shorter leg forwards and down. Some people, as shown left, will sit very asymmetrically even though their leg lengths are identical. Choice of saddle can be very personal, making it very difficult to make recommendations. Ideally the cyclist’s weight will be on their sit bones rather than the crotch so the width of the saddle can be an important consideration. The crotch is not designed to be weight bearing so excessive pressure can cause numbness and a frequent desire to urinate. In this case, tipping the nose of the saddle down slightly, or choosing one with a hole in it can be an effective solution.

 

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An excellent summary of Bike Fitting related discomfort and injury.

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The latest scientific knowledge in a range of subjects from Biomechanics to Nutrition.

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'The' text book on conditioning, road cycling biomechanics, nutrition, hydration and trauma.

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Page Last Updated : 5th December 2014 All Rights Reserved. BikeDynamics - Bike Fitting Specialists