By Chad Asplund, MD, Charles Webb, DO, and Thad Barkdull, MD
Apr 14, 2005, 07:21
Introduction
Participation in cycling
has steadily increased over the past ten years. Individuals looking for a
low-impact alternative to running and other aerobic activity have found cycling
to meet these needs.In fact, the American Bureau of
Transportation Statistics estimates that more than 49 million Americans ride
bicycles at least monthly, with over 5 million people riding at least 20
days/month. [BTS] As a result, the number of cycling-related injuries has also
risen, with the majority due to overuse.Improper bicycle
fit, technique, or training patterns may either cause or exacerbate these
injuries, and can lead to dysfunction, impaired performance, and
pain.
Neck and back pain are
common in cyclists because of the body’s positioning during riding.
Several studies have demonstrated that neck and back
injuries are the most common overuse injuries evaluated following six to
eight-day distance bicycle tours (Figure 1). [Wilber/Weiss AJSM/Dannenberg]
Wilber, et al. found that 44.2 % of male and 54.9% of female recreational
cyclists presented for medical treatment of neck pain, while approximately 30%
presented with back pain. [Wilber] Weiss also reported that 66.4 % of
recreational cyclists reported neck and shoulder symptoms following an 8-day,
500-mile bicycle tour. [Weiss] The prevalence of such
injuries, especially in recreational riders, suggests that more understanding is
needed by riders and their health care providers to prevent such injuries by
proper education and fit, and treating these injuries when they
occur.A better understanding of the pathologic mechanism of
musculoskeletal overuse injuries, specifically in cyclists, is key in developing
good preventive and treatment strategies for the neck and back injuries they
frequently experience.
Overuse
Injuries
Overuse injuries occur
when a tissue accumulates damage caused by repetitive sub-maximal loading.
Repetitive activity fatigues a specific structure, such as tendon or bone.
Without adequate recovery, micro trauma stimulates an inflammatory response,
causing the release of vasoactive substances, inflammatory cells, and enzymes
that damage local tissue. Over time, this trauma leads to clinical injury.
Continued activity produces degenerative changes that result in weakness, loss
of flexibility, and chronic pain. Thus, in overuse injuries, the problem is
often not acute tissue inflammation (tendonitis), but chronic degeneration, or
tendinosis. [Khan]
Pain in overuse injuries
typically has an insidious onset.However, it may also have
an acute-on-chronic presentation. Overuse injuries most likely occur when an
athlete changes the mode, intensity, or duration of training. Biomechanical
(intrinsic) factors and equipment or training regimen (extrinsic) issues are the
main contributors to overuse injuries.It is the extrinsic
issues that cause most of the overuse injuries in cyclists. [Mellion, Team
Physician]
While problems such as
fractures, dislocations, and ligament ruptures usually only occur after major
trauma, overuse injuries are much more common. Thus, these
factors should be considered when evaluating neck and back pain as well as all
cycling-relatedinjuries—and one must consider bicycle fit,
training distance and intensity, and anatomic factors to determine the exact
mechanism.Often, adjustments in the bicycle or the
individual’s exercise regimen may be all that is necessary to ameliorate their
symptoms and accelerate the healing process.
Bicycle
Anatomy
Bicycles consist of a
frame, handlebars, brakes, wheels, pedals, gears, and other components (figure
2). The key part is the frame, made of metal or metal alloys such as titanium,
aluminum, steel, or carbon. Frames can be thought of as two triangles: the front
triangle consists of the top tube, the seat tube, and the down tube; the chain
stay, seat stay, and seat tube compose the rear triangle. Handling and
maneuverability are affected by the angles within each of these triangles.
Racing bicycles have a more upright geometry, with larger angles for increased
maneuverability. Touring bicycles have a flatter geometry, which much less
pronounced angles for easier handling and comfort.In
contrast, mountain bikes, designed for maneuverability and stability, have a
geometry that provides for a lower center of gravity, resulting in much smaller
angles in the frame.
Frame size is determined
by the seat tube length in centimeters (mountain bicycles in inches), measured
from the center of the bottom bracket to the center of the top tube or from the
top of the bottom bracket to the top of the top tube. The top tube length
affects the reach of the rider and is an important measurement for proper frame
fit. The “virtual top tube” measurement is the top tube plus stem length, which
equals the total reach.While different bicycles are designed
to position the rider differently (touring bikes allow for an upright ride, with
less extension placed on the back, while racing and mountain bikes focus on the
need for a more stream-lined ride—thus the rider is more “laid out” and has to
extend his or neck more.These differences impact what type
of pain the rider experiences.
Neck and Upper Back
Pain
Neck pain can be
exacerbated by several factors to include riding position, technique, and
comorbid conditions.In the cycling position, the neck is
extended and the back flexed for prolonged periods.Riding in
drop handlebars for long periods increases the load on the arms and shoulders as
well as hyperextension of the neck, leading to muscle fatigue and
pain.If the virtual top tube length (top tube plus stem
length) is too long for the rider, or if aero bars are used, hyperextension of
the neck is further increased.Prolonged hyperextension of
the neck and associated muscle strain may lead to trigger points in the muscles
of the neck and upper back.Trigger points are small rubbery
knots that form in muscle and adjacent muscle sheaths (fascia), which send pain
signals to the brain and contribute to a pain-spasm-pain cycle.Trigger points are frequently caused by direct blunt trauma, or by
repetitive microtrauma, as is seen in overuse athletic injuries.Certain techniques common to cyclists may also cause trigger point
pain.Cyclists frequently present with pain in their left
levator scapula caused by frequently looking over their left shoulder for
oncoming traffic.Additionally, comorbidities must be
assessed; in older riders, for example, it is prudent to question about
radicular symptoms because a certain degree of neck pain may be secondary to
arthritis in the cervical spine.
Thoracic outlet syndrome
(TOS) is a less common, but important cause of neck pain.TOS
may present with tingling in the fingers; pain in the neck, shoulder, and arm;
headaches in the back of the head; weakness of the arm and hand; cold or
cyanotic hands.These symptoms may worsen with such
activities as elevating the arm to comb or blow-dry one's hair or drive a
car.TOS is most often produced by hyperextension neck
injuries, typically traumatic, but may also be caused by repetitive over
hyperextension of the neck.
Riders suffering from
neck pain should inspect the fit of their bicycle.One way to
reduce neck hyperextension is by raising the handlebars, or using handlebars
with a shallower drop.Another method is to reduce the
virtual top tube length, by using a shorter stem.Moving the
saddle forward also reduces virtual top tube length, but the rider should be
cautious as improper fore/aft saddle position can lead to knee pain.
Changes to riding
technique can also help with neck pain.A rigid riding
position transmits more shock directly to the neck and shoulders. Riding with
unlocked elbows and changing hand position (i.e. from drops to brake hoods) can
alter neck posture minimizing pain.Although some handlebar
materials provide a softer or stiffer ride, there is currently no evidence that
changing handlebar material affects neck pain.Educating
cyclists to frequently stretch their neck during more leisurely parts of the
ride may reduce the frequency and severity of neck pain.
Other factors
contributing to neck pain are helmet fit and handlebar width. The helmet should
be worn so that it is snug, stable, and level on the head with the front rim
barely visible to the rider’s eye. Improperly fitted helmets
may cause excessive neck extension in order to maintain visibility, resulting in
further neck pain as described above.Handlebars should be
shoulder width apart (measured from acromion to acromion across the anterior
chest) and comfortable.Handlebars that are too wide may
cause excessive trapezius and rhomboid strain leading to muscle spasm and pain.
(Burke)
Back Pain
Back pain is also very
common in cycling.Cycling position leads to prolonged back
flexion, resulting in muscle pain in the unconditioned back.The low back is the primary muscle group generating power and controlling
the movement of the bicycle.If the back is not well
conditioned and flexible, muscle fatigue and strain will occur, leading to
pain.
The virtual top tube
length and the amount of spinal flexion in the rider’s back should be
investigated in cyclists with back pain.If the handlebars
are too low, the flexion (lordosis) of the spine is exaggerated resulting in
increased pressure on the lumbar spine.If the top tube
length is too short, the sacral spine will flex, increasing pressure on the
intervertebral disks.Ensuring that the handlebar height and
top tube length are correct should help minimize back pain (discussed
below).
Pelvic position also
contributes to back pain, as a misaligned pelvis will cause strain to the back
musculature.Tight quadriceps will tend to tilt the pelvis
forward, while tight hamstrings predispose to backward pelvic tilt.The Thomas test measures the degree of flexibility of the hip flexors,
while the popliteal angle can objectively assess hamstring
flexibility.Pushing large gears or extended hill climbing
may fatigue the gluteus and the hamstrings, causing the pelvis to tilt
backwards, aggravating the back musculature, causing pain.Also, the strength of the abdominal muscles is critical to maintaining
stable pelvic positioning.Core muscle group strengthening
and lower extremity stretching will help with proper pelvic positioning and lead
to pedaling efficiency.
Researchers have
reported that low back pain among men and women cyclists occurs at rates of up
to 50% [Salai] and may be related to the cyclist’s position on the
bicycle.To help reduce the incidence of back pain some have
suggested that a forward pelvic tilt is favorable as it decreases lumbar flexion
and tensile stress to the longitudinal ligaments of the lumbar spine. [de Vey]
Although there is evidence to show that anterior pelvic tilt would reduce the
incidence of low back pain, it may increase pressure on the anterior perineum,
and may also contribute to increased hyperextension of the neck and neck pain.
[Bressel]
Abnormal pelvic tilt is
not the only cause of lower back pain in cyclists.The
lumbosacral junction, a point of support from which the power of the legs is
generated and transmitted to the pedals, may also be a source of pain an injury
when there is an improper fit between rider and bicycle. The cyclist’s position
on the bicycle compresses the anterior portion of the intervertebral disk and
opens up the posterior side.This tenses the posterior
ligamentous complex, leading to low back pain.During
load-bearing activity, increased abdominal pressure can protect against this by
increasing spinal stability and reducing discal load. [Nachemson] However,
because of respiratory needs, the cyclist cannot employ this defense mechanism.
Bicycle
Fit
The virtual top-tube
length is the most important fit factor for neck and back pain.Proper reach gives you easier breathing, better neck and lower back
comfort, weight distribution, and bicycle handling.“Ideal
position" varies here more than anywhere else for cyclists, depending on riding
style, flexibility, body proportions, and frame geometry, among
others.Unfortunately, there is no set formula for
sizing the top tube and stem.The top tube length contributes
to the distance from the seat to the handlebars, and therefore should vary with
the rider's size.Both arm length and torso length figure
into the proper distance from seat to handlebars.After the
frame is constructed, the distance from seat to handlebars can be adjusted by
replacing the stem.However, use of a stem shorter than 40mm
or longer than 140mm alters the stability of the bicycle, so it is of some
importance that the top tube length be as close to correct as possible.
One indicator of proper
“reach” comes from glancing down at the front hub while riding in the drop
handlebars; your view of the front hub should be obstructed by the handlebar. In
another fit technique your elbows, bent at 65–70° with your hands in the drops,
should be within an inch or two of your knees at the top of your stroke.
[Lemond]Finally, Bicycling Magazine recommends that while in
a comfortable position with hands on the brake hoods, looking straight ahead,
that a plumb bob dropped from the tip of the nose should intersect the
stem.
As much as possible,
forward lean toward the handlebars should come from the pelvis rotating toward
the handlebar rather than the back bending.Ideally, the back
will be straight, pelvis tilted with no loss of breathing efficiency.
Handlebar
Height
If the handlebars are
too low, excess lordosis of the lumbar spine and increased hyperextension of the
cervical spine occurs, leading to both low back and neck pain.Measure the handlebar height by holding a yardstick on the seat so that
the yardstick extends over the bars noting the difference between the seat and
the bars. Ideally, the handlebars should be even with the seat or between even
and 4 centimeters lower.Extremely fit, flexible cyclists may
have their handlebars up to 5-9 centimeters below the level of the seat
[Lemond/Bicycling].The competitive cyclist will have their
bicycle adjusted to fit how they individually ride.
Stretching and Strength
Training
Because cycling demands
prolonged back flexion and neck extension, ensuring that your neck and back are
flexible is very important.The cycling process demands
repetitive hip and leg flexion anchored by a stable pelvis.Core strength and stability should be sought for all riders.A physical therapist or a sports medicine provider can easily teach
common back and neck stretches and back core-strengthening exercises.
Conclusion
Neck and back pain is a
common complaint among cyclists.By making a few select
adjustments to the bicycle added to a core strengthening and stretching program,
this ailment can be easily remedied.Proper fit should be
ensured; this is accomplished by relieving over extension by using handlebars
with less drop, shorter stem, elevating the stem or adjusting the seat
position.Changing hand position frequently, relaxing the
elbows, and varying head position will decrease the likelihood of developing
neck and back pain.As more people seek low-impact ways to
improve and maintain their cardiovascular fitness, physicians will no doubt see
more patients who have neck and back pain related to bicycling. By learning a
few simple bike-fitting techniques, physicians can treat and prevent many common
problems of this popular activity.
References
US Department of
Transportation: Bureau of Transportation Statistics: Bicycle use among adult US
residents. OmniStats 2002;2(6):1-3
WilberCA, Holland GJ, Madison RE, et al. An
epidemiologic analysis of overuse injuries among recreational cyclists. Int J
Sports Med 1995: 16: 201-6.
Weiss BD. Nontraumatic
injuries in amateur long distance bicyclists. Am J Sports Med 1985; 13(3):
187-192.
Dannenberg AL, Needle S,
Mullady D, et al. Predictors of injury among 1638 riders in a recreational
long-distance bicycle tour: cycle across Maryland. Am J Sports Med 1996; 24(6):
747-753.
Conti-Wyneken AR.
Bicycling injuries. Phys Med Rehab Clin NA 1999; 10(1): 67-76.
MellionMB: Bicycling, in MellionMB (ed): Team Physician's Handbook.
Philadelphia, Hanley & Belfus, 2002, pp
52-70
MellionMB. Neck and back pain in bicycling.
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MellionMB. Common cycling injuries:
management and prevention. Sports Med 1991; 11(1): 52-70.
Burke ER. Proper fit of
the bicycle.Clin Sports Med 1994; 13(1): 1-14.
Sanner WH, O’Halloran
WD. The biomechanics, etiology, and treatment of cycling injuries. J Am Podiatr
Med Assoc 2000; 90(7): 354-376.
Salai, M., T. Brosh, A.
Blankstein, A. Oran, and A. Chechik. Effect of changing the saddle angle on the
incidence of low back pain in recreational bicyclists. Br. J. Sports Med. 33:
398–400, 1999.
de Vey Mestdagh, K.
Personal perspective: in search of an optimum cycling posture. Appl. Ergon.
29:325–334, 1998.
Bressel E, Larson BJ.
Bicycle seat designs and their effect on pelvic angle, trunk angle, and comfort.
MSSE 2003; 35(2): 327-332.
Nachemson AL. The lumbar
spine: an orthopaedic challenge. Spine 1976;1:59.
Khan KM, Cook JL,
Taunton JE, et al. Overuse tendinosis, not tendonitis. Phys Sports Med 2000;
28(5): 31-46.
Lemond G, Gordis K. Greg
Lemond’s Complete Book of Bicycling.New York City, Perigree Books, 1990,
pp 118-145.
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