Causes of higher risk of stress fractures in female runners

Date:
August 11, 2020
Source:
Thomas Jefferson University
Summary:
A pair of new studies identify overlooked physiological factors
and lack of knowledge around wellness as contributors to risk of
stress fracture in women who run.



FULL STORY ========================================================================== Running is one of the most popular forms of exercise, enjoyed by a
broad range of age groups and skill levels. More women are running recreationally compared to men; specifically 54% of runners are female
as indicated by a 2018 National Runner Survey. Women, however, are at
least twice as likely as men to develop stress fractures, an injury that impacts around 20% of runners. However, information is still lacking
on how to best prevent and treat stress fractures in women. New pilot
research from Jefferson suggests physiological factors that could be
included in routine screening for stress fracture risk, as well as
changes in training approach to aid in prevention.


==========================================================================
The researchers examined physiological differences that might contribute
to increased risk of stress fractures in a study published in Sports
Health and also surveyed women's perception of risk and behaviors that contribute to stress fractures in a separate study published in Physical Therapy in Sport.

"Most of the literature focuses on elite runners or athletes," says
Therese Johnston, PT, PhD, MBA, Professor in the Department of Physical
Therapy and first author of both studies. "It was important for us to
capture the regular or average female runner in these studies, and the
main goal was to see how we can prevent a first or subsequent fracture."
Both studies surveyed the same group of 40 female recreational runners,
age 18- 65 years. 20 women had a history of running-related stress
fractures, and they were matched according to age and running abilities
with 20 women with no history of stress fractures. The two studies
aimed to assess what contributed to risk of stress fractures, from
the physiological, such as -- bone structure and density, muscle mass,
hormonal status, to ones influenced by training routine, such as training intensity, nutrition, insufficient strengthening, and ignoring pain.

"This mixed methods approach provides a richer context and a more
detailed picture of the practices and risks that contribute to stress
fractures in every-day women runners," says Jeremy Close, MD, Associate Professor in Family and Sports Medicine and one of the lead authors on
the research. "It also tells us how perceived risk informs physiological
risk." For the study focused on physiological factors, the subjects
underwent a comprehensive blood panel that examined levels of hormones
like estradiol and testosterone, vitamins and minerals important for
bone health such as vitamin D and calcium, and bone markers. They also underwent dual energy x-ray absorptiometry (DXA) to test for bone mineral density. The researchers found that while there was no difference in
estradiol hormone levels between the two groups, women who had a stress fracture history reported menstrual changes or irregular periods as a
result of their training, or during peak training times.

The blood panel also examined markers for bone formation and resorption,
and pointed to increased bone turnover in the group of women with stress fractures.

They also found through the DXA testing that women with a history of
stress fractures had lower hip bone mineral density compared to women
with no history of stress fractures, indicating decreased bone strength
that could increase risk of injury.

"DXA for bone density and blood testing for bone markers are not
routinely performed in this population -- they are usually reserved
for post-menopausal women -- so we may be missing important clinical
indicators for stress fractures in these women," says Dr. Johnston. "While
the link between menstrual changes and bone strength is unclear, our
findings also indicate that asking female runners about any menstrual irregularities during heavier training times is important during routine screening." For the study investigating women's self-perception of risk, interviews were conducted with the goals of finding out which factors
women thought were associated with stress fractures or maintaining bone
health while running.

Several themes emerged from these interviews, specifically, compared to
women without stress fractures, women with histories of stress fractures
had increased their training load more quickly. Also, while they knew
of the importance of nutrition and strengthening exercises, women with
a history of stress fracture more often reported not having or making
the time for a balanced diet and proper cross-training to complement
their running regimen.

Finally, women in this group reported pushing through the pain and running despite an injury more often than those without stress fracture. "In
the interviews, it sounded like these women had trouble knowing which
pain was normal, and which pain was abnormal. They also reported not
always receiving appropriate guidance from healthcare providers on how
to progress running safely," says Dr. Johnston.

"It is clear that there needs to be more guidance from healthcare
providers for woman runners on how to prevent stress fractures"
says Dr. Close. "It can be very frustrating for these women who are
on a path to wellness, but are impeded by an injury that can take
several months to heal. If they don't have the proper guidance on how
to return to running safely, they risk a second injury." "We hope
that our findings will encourage more thorough and routine screening
in women runners for bone density and strength," says Dr. Johnston,
"as well as a comprehensive education plan on how to balance running
with cross-training, and how to interpret pain cues from the body, to
help women differentiate between normal aches and pains and indicators
of a serious injury." Dr. Johnston plans to continue this research by
studying women with acute stress fractures as they start running again,
in order to identify factors related to successful or unsuccessful
return to running following a stress fracture. The study will include
Dr. Close as well as Marc Harwood, MD, Service Chief in the Department
of Non-Operative Sports Medicine at Rothman Orthopaedic Institute.


========================================================================== Story Source: Materials provided by Thomas_Jefferson_University. Note:
Content may be edited for style and length.


========================================================================== Journal References:
1. Therese E. Johnston, Colleen Dempsey, Frances Gilman, Ryan
Tomlinson,
Ann-Katrin Jacketti, Jeremy Close. Physiological Factors of
Female Runners With and Without Stress Fracture Histories: A Pilot
Study. Sports Health: A Multidisciplinary Approach, 2020; 12 (4):
334 DOI: 10.1177/ 1941738120919331
2. Therese E. Johnston, Jeremy Close, Phil Jamora, Susan F. Wainwright.

Perceptions of risk for stress fractures: A qualitative study of
female runners with and without stress fracture histories. Physical
Therapy in Sport, 2020; 43: 143 DOI: 10.1016/j.ptsp.2020.02.018 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200811120221.htm

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