Targeted exercise may prevent hip fractures

NEW YORK (Reuters Health) – Exercise that targets a weak
region of the hipbone may help prevent fractures, but simple
walking will not, new research indicates.

As people age, the outer “cortical” layer of bone in a
particular region the hipbone or upper femur become thinner,
making the hip more prone to fracture, according to the report
in The Lancet medical journal.

The findings are based on a CT scan analysis of 77 femurs
from people between 20 and 95 years of age who died suddenly of
causes not related to bone disease or fractures.

Substantially thinning of the cortical layer in the neck of
bone that connects the hip “ball” to the rest of the thighbone
was observed with aging, Dr. Jonathan Reeve, from Addenbrooke’s
Hospital in Cambridge, UK, and colleagues found.

After 60 years of age, bone thickness in this zone fell by
6.4 percent per decade, the report indicates.

Regardless of whether the bone-thinning disease
osteoporosis was present or not, thinning in the cortical layer
impaired the femur’s ability to absorb energy, making it more
likely to break, the researchers note.

“Because walking does not sufficiently (condition the upper
femur), the fragile zones in healthy bones may need
strengthening, for example with more well targeted exercise,”
the authors conclude.

They point out that while walking does not put a
significant load the fragile area, other exercises that
basically flex the hip joint do “involve extension of the upper
femur under load.” These include cycling, sculling, gymnastics
and weights.

In a related editorial, Dr. Charles H. Turner, from Indiana
University in Indianapolis, notes that the present report
provides “a compelling argument for more diligent assessment of
the regional patterns of bone loss in the (upper femur) and
point to the need for targeted interventions that strengthen
bone” in this area.

SOURCE: The Lancet, July 9, 2005.