Stress fractures most commonly occur in the lower extremities, but also
occur in non-weight-bearing bones, including the ribs, upper extremities,
and the pelvis. The most common sites are the tibia, metatarsals, and fibula.
A recent study demonstrated a high incidence of tarsal navicular stress
fractures, which may be the most common site in certain groups such as
sprinters and hurdlers. Sports associated with specific stress fractures
include rowing and golf (ribs), baseball pitching (humerus), and gymnastics
Recent studies have shown that the incidence of stress fractures
in athletes is higher than previously thought. The most frequent sport
associated with stress fractures is running. One prospective study of 95
track and field athletes showed an annual incidence of approximately 20
percent. (Bennell, K. The incidence and distribution of stress fractures
in competitive track and field athletes: a twelve-month prospective study.
American Journal of Sports Medicine. 1996; 24:211-217.)
The mainstay traditional
treatment for stress fractures is rest. The theory behind this is that
the bone is breaking down faster than it can be built up (because of the
running), therefore rest is needed. A better approach is to view stress
fractures as a connective tissue deficiency of the bone and to determine
why that exact area is weakened.
Women reportedly have a higher rate of
stress fractures than men. (Bennell, K. A prospective study of risk factors
for stress injury in female athletes (abstract). In Medicine and science
in sports and exercise: American College of Sports Medicine Annual Meeting
Supplement. 1995; 27:S196.) It has been found that many female runners
who sustain stress fractures have a significantly later age of menarche
(onset of menstruation), less menses per year, lower bone mineral density
at the spine, and less lower-rib lean mass.
In addition, female distance
runners are known to have a high incidence of eating disorders, which itself
may lead to amenorrhea or nutritional deficiencies. In one prospective
study, females with lower bone density, history of menstrual disturbance,
less lean mass in the lower limbs, a discrepancy in leg length, and who
consume a very low fat diet were at a significant risk for stress fractures.
No significant risk factors were identified in men; however, there was
a strong trend toward low bone density, signifying that stress fractures
are a connective tissue deficiency problem in both men and women since
the mineral content of the bone was decreased. It is generally accepted,
even in traditional medicine circles, that low mineral content in bone
is often due to a deficiency in anabolic hormone production. (Lloyd, T.
Women athletes with menstrual irregularity have increased musculoskeletal
injuries. Med. Sci. Sports Exerc. 1986; 18:374-379. * Bennell, K. Risk
factors for stress fractures in track and field athletes: a twelve-month
prospective study. American Journal of Sports Medicine. 1996;24:810-818.)