Kinetic Risk Factor of
Running-Related Injuries in Female Recreational Runners.
Napier C, MacLean CL, Maurer J, Taunton, JE, Hunt, MA. Scand J Med Sci
Sports. 2018 May.
Text Freely Available
Take Home Message:
A female recreational runner with greater peak braking force is more likely to
get an injury during a 15-week half-marathon training program.

Authors of a recent systematic review showed that gait retraining can address abnormal biomechanics
that may increase the risk of running-related injuries. However, it is unclear
if these proposed biomechanical risk factors are present before an injury and
if they predict who will get an injury. Thus, the purpose of this study was to determine
if several biomechanical factors are associated with the onset of running-related
injuries among female recreational runners. The authors assessed 74 female
novice recreational runners (history of < 2 half marathons) who then
completed a 15-week half-marathon training program. Researchers collected
kinematic and kinetic data while participants ran on a treadmill at a
self-selected moderate intensity pace. The two primary kinetic variables of
interest were average vertical loading rate and peak braking force (PBF), which is the
force in the opposite direction of running. The authors used these variables to
separate runners into three levels: Low, Medium, or High. Hours of running
exposure were collected from beginning of training until a participant was
injured, lost to follow-up, or finished the program. Any lower extremity or low
back overuse injury due to training and resulting in 3 missed training days
counted as an injury. Twenty-two participants (34%) sustained a running-related
injury after an average of 17 hours of running.  Another 33 runners remained uninjured after an
average training time of 43 hours (10 runners dropped out due to unrelated circumstances).
Overall, PBF was the only kinetic variable that predicted a running-related
injury. Specifically, runners with the highest PBF were 5 times more likely to
sustain an injury than those with medium PBF, and 8 times more likely than
those runners with the lowest PBF.

This study is interesting
because the authors assessed biomechanical factors that may predict any
running-related injury. In contrast, previous researchers studying
biomechanical variables concentrated on one injury diagnosis (e.g., tibial
stress fractures or patellofemoral pain). Finding a common risk factor across
injury types is important for clinicians and researchers when performing a
baseline assessment since there is no way to predict which injury, if any, will
develop during training. While biomechanical abnormalities may influence risk
of running-related injuries among novice runners, they are difficult to assess
in most clinical settings. However, these studies are vital for future research
to explore interventions that can target PBF and in turn reduce the risk of running-related
injuries. A noteworthy secondary analysis revealed foot strike pattern (e.g.,
heel strike vs midfoot strike) did not differ between runners who did or did
not develop an injury. Furthermore, they found no relationship between PBF and
foot strike pattern. This may suggest foot strike pattern does not influence running-related
injury risk as much as previously assumed. Interestingly, these results differ
from previous studies that found lower BPF among injured runners compared with
healthy runners. This should prompt clinicians and researchers to be cautious
when assuming that differences between healthy and injured athletes may help us
identify risk factors. We saw this in a recent post on a prospective study of runners that found many of the
long-established factors believed to contribute to running-related injuries
(e.g., arch height, Q-angle) failed to predict new injuries. We need to
remember that interventions aimed to prevent injuries should be based on
prospective findings, whereas our rehabilitative programs should focus on
abnormalities found during an injury assessment.
Questions for Discussion:
If you perform a biomechanical assessment on runners, what are you looking for?
Do you incorporate gait retaining into your rehabilitation programs for injured
runners with a biomechanical abnormality?
Written by: Danielle M. Torp
Reviewed by: Jeffrey
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