This condition is commonly referred to as cyclists palsy and research has shown that this is usually due to compression of the ulnar nerve as it runs through a narrow space in the wrist known as the channel of guyon . With prolonged loading of the wrist in the extended position on the bars this can compress the ulnar nerve leading to weakness in the small muscles of the hand and sensory changes in the hand and fingers (pins and needles and numbness). The advent of bars that have changed riding positions over recent years and changes to frame lengths have played a part in the frequency of ulnar nerve compression in cyclists.
Median nerve compression also occurs and in long distance events the frequency of participants reporting symptoms has been as high as 36% in some long distance events. This data also suggests that even short rides can injure the nerve(s) and the effects can be cumulative over time. The median nerve supplies the middle two fingers and the ulnar supplies the outer two fingers of the hand as seen in the diagrams below.
What are the risks of nerve compression?
Over a long period of time the nerve can be damaged and this damage is not always able to repaired by the body. If long term compression occurs there can be permanent muscle weakness or sensory deficit.When should the cyclist seek professional help?
If the tingling and numbness is not improving or there is muscle weakness in the hands, EMG studies are a useful guide to the ability of the nerve to conduct electrical signals from the brain to the hand.
Treatment options for nerve compression should always be conservative to start and altering riding position through bar height, angle of bars, hand position during riding, riding with suicide grip (thumbs on the same side of the bars as the fingers) are all useful options to de load the wrist extensor mechanisms.
Gloves that still have good padding are essential and like bike seats must be changed regularly when they are not performing their function appropriately.
Bar tape or bars that are the most appropriate width for the riders wrists. Not everyone has the same size hands and wrist and excessive width (especially for those with small hands and wrists) and narrowness of the bars can increase grip loading and subsequent tensile stress in the wrist and hand.
Shoulder positioning when riding is important as well and compression in riders of the first rib has also been shown to increase nerve compression. The best position for the shoulder girdle is with the arms not locked straight and a small bend in the elbow. The shoulder blades themselves should be kept wide and the chest not allowed to drop toward the bars/hands.
The ulnar nerve stretch is useful for cyclists to perform regularly to improve the nerves mobility. The best stretch is for 10-15 seconds five times. However, there are a series of stretches that can be performed to help relieve nerve issues in this area.
Any persistence of symptoms or worsening of symptoms should require professional consultation with your doctor or sports physiotherapist.