Biomechanical comparison of 3 ankle braces with and without
free rotation in the sagittal plane.

Alfuth M, Klein D, Koch
R, Rosenbaum D. J of Athl Training.
2014; 49(5): 608-616.

Take Home Message: In both passive and dynamic conditions, hinged
and unhinged ankle braces increased ankle stability compared with no brace.
There was no clinical relevant differences between braces.

Lateral ankle sprains are commonly sustained
during physical activity. Ankle braces are recommended
to reduce the risk of an ankle sprain; however, there are various ankle brace designs. A better
understanding of how well different ankle brace designs limit ankle range of
motion would help clinicians recommend ankle brace models that would best to reduce
the risk of a lateral ankle sprain. Therefore, Alfuth and colleagues completed
a within-subject crossover study to assess the ability of 3 different ankle
braces to limit ankle range of motion during dynamic and passive motion. The
authors recruited 17 healthy participants. All participants were physically
active and had no history of ankle injuries in the past 6 months. The authors
tested the participants while wearing each of the 3 commercially available
ankle braces as well as the control condition for both the dynamic and passive
testing protocol. The order of the ankle braces and control condition was
randomized. One brace had a semi-rigid shell with foam-filled air cells and
crossing straps (AirCast AirGo). The second brace was hinged with polypropylene
shells and crossing straps (DARCO Body Armor Embrace). The third brace was a
neoprene sock with a flexible hinged outer cast, which could be tightened with
a hook-and-loop strap (McDavid Ankle X). During the dynamic testing protocol participants
stood on a hinged platform. The tester then induced an unexpected 30
foot inversion. Inversion movement was
measured with an in-shoe goniometer for all conditions.  During passive testing, participants were
secured into an apparatus which passively moved the ankle in 3 movement planes
(6 directions) at a defined torque (12Nm for dorsiflexion, 9Nm for 5 other
movements). Overall, the 3 brace models reduced ankle inversion compared with the
control condition during dynamic and passive testing. During passive testing,
all of the braces limited plantar flexion (~4 to 17 degrees) and dorsiflexion
(~2 to 4 degrees) compared with no brace. Passive testing revealed the hinged brace
without a neoprene sleeve (Embrace) allowed more ankle motion than either
hinged brace. While the hinged brace with a neoprene sleeve (Ankle X)
restricted ankle inversion the most during the dynamic test it also permitted
more plantar flexion (~10 degrees) than the brace without a hinge (AirGo). While
all 3 braces allowed different amounts of ankle inversion, the authors
acknowledged that the difference between hinged and non-hinged models was not
clinically relevant.

Overall, the current study suggests that ankle
braces significantly reduce ankle dynamic and passive ankle inversion range of
motion. Further, the data suggests that this remains true regardless of whether
or not the ankle brace is a hinged or un-hinged model. The results of the
current study should be of interest to clinicians who recommend ankle braces to
physically active individuals. While this information is useful, clinicians
should be aware that other ankle brace models that were not tested in this
study may respond differently. Participants also had no ankle injury at the
time of testing. It is conceivable that injured athletes’ ankles would respond
differently due to proprioceptive deficits as a result of the injury.
Furthermore, participants were not in a fatigued state when tested. This may
alter the results as muscle fatigue may lead to a delayed response in
compensating for ankle inversion. Despite these limitations, this study
indicates that clinicians could recommend hinged or unhinged ankle braces for
physically active individuals who hope to reduce their risk of an ankle sprain.

for Discussion: Do you recommend ankle braces to your athletes with chronic
ankle instability? If so, do you tend to recommend specific models or ankle
braces with specific features?

Written by: Kyle Harris
Reviewed by: Jeffrey

Related Posts:

Alfuth, M., Klein, D., Koch, R., & Rosenbaum, D. (2014). Biomechanical Comparison of 3 Ankle Braces With and Without Free Rotation in the Sagittal Plane Journal of Athletic Training, 49 (5), 608-616 DOI: 10.4085/1062-6050-49.3.20