30-70% of cyclists suffer from cervical, dorsal, or lumbar back pain. There is a tendency towards hyperextension of the pelvic/spine angle which resulted in an increase in tensile forces at the sacral promontory. These forces can easily be reduced by appropriate adjustment of the seat angle–that is, by creating an anterior inclining angle. The incidence and magnitude of back pain in cyclists can be reduced by appropriate adjustment of the angle of the saddle. (Salai M. Brosh T. Blankstein A. Oran A. Chechik A. Effect of changing the saddle angle on the incidence of low back pain in recreational bicyclists. British Journal of Sports Medicine. 33(6):398-400, 1999).
It has been found that many of these cyclists suffer from discogenic disease. The number of previous sports-related injuries, was predictive of neck and back pain, and a strong tendency toward neck and back pain was observed for athletes with more total years of participation in sports due to overuse injuries.
The aetiology of this problem in cyclists has not been adequately researched. Bicycle fit, improper equipment, training errors, and individual anatomic factors are important evaluation considerations. By learning how to recognize and treat contributing factors, as well as learning a few simple bike-fitting techniques, physicians can treat and prevent many common problems of this popular activity. The bicycle should be checked for proper fit. It is necessary to relieve the rider’s extended position by using handlebars with less drop, using a stem with a shorter extension, raising the stem, or moving the seat forward. Changing hand positions on the handlebars frequently, riding with the elbows “unlocked,” varying head position, using padded gloves and handlebars, and riding on wider tires all reduce the effects of road shock. (Mellion MB. Neck and back pain in bicycling. Clinics in Sports Medicine. 13(1):137-64, 1994.
Causative factors are thought to be prolonged forward flexion, flexion-relaxation or overactivation of the erector spinae, mechanical creep and generation of high mechanical loads while being in a flexed and rotated position. A pilot study was performed to examine whether differences existed in spinal kinematics and trunk muscle activity in 9 cyclists with and 9 cyclists without non-specific chronic low back pain using electromagnetic tracking system and EMG was recorded bilaterally from selected trunk muscles. Data were collected every five minutes until back pain occurred or general discomfort prevented further cycling. Cyclists in the pain group showed a trend towards increased lower lumbar flexion and rotation with an associated loss of co-contraction of the lower lumbar multifidus. This muscle is known to be a key stabiliser of the lumbar spine. The findings suggest altered motor control and kinematics of the lower lumbar spine are associated with the development of LBP in cyclists. (Burnett AF. Cornelius MW. Dankaerts W. O’sullivan PB. Spinal kinematics and trunk muscle activity in cyclists: a comparison between healthy controls and non-specific chronic low back pain subjects-a pilot investigation. Manual Therapy. 9(4):211-9, 2004).
Inappropriate saddle positions may also be a cause of lower back pain. Partial and complete cutout saddle designs may increase anterior pelvic tilt, and saddles with a complete cutout design may increase trunk flexion angles under select cycling conditions. A saddle with a partial cutout design may be more comfortable than a standard or complete cutout saddle design. (Bressel E. Larson BJ. Bicycle seat designs and their effect on pelvic angle, trunk angle, and comfort. (Medicine & Science in Sports & Exercise. 35(2):327-32, 2003 Feb).
A radiographic study conducted to evaluate dorso-lumbar angular values (angle between the mid-back at T12 and lower back at L3) to define the most physiological sitting position during cycling. Two different pedal unit positions were tested; the first one in a bicycle frame type with pedals in front of the saddle axis and the second one with the pedals behind the saddle axis, in order. The findings showed that the incidence and importance of low back pain in cyclists can be reduced with appropriate pedal unit position; the position with pedals behind the saddle axis permits more physiological spine angles in comparison with the classic one having the pedals in front of the saddle axis; this fact is due to a different pelvic position which coincides with lumbar angles. (Fanucci E. Masala S. Fasoli F. Cammarata R. Squillaci E. Simonetti G. Cineradiographic study of spine during cycling: effects of changing the pedal unit position on the dorso-lumbar spine angle.Radiologia Medica. 104(5-6):472-6, 2002)