April 2013

AFOs affect plantar flexion strength in some high-level volleyball players

In the moment: Ankle

By Jordana Bieze Foster

Volleyball players without ankle instability who wear hinged stirrup ankle foot orthoses (AFOs) may experience decreased plantar flexion strength as a result, according to research from Loyola University in Maywood, IL.

In 59 collegiate and professional volleyball players, investigators found that plantar flexion force/weight ratio was significantly lower with AFOs than without—particularly in male players who did not have functional ankle instability (FAI).

The finding suggests not only that AFOs might affect performance, but also that the altered force/weight ratio might affect dynamic stabilization of the foot-ankle complex, said Marc R. Angerame, MD, a former medical student at Loyola University and current orthopedic surgery resident at Carolinas Medical Center in Charlotte, NC. Angerame presented the findings in March at the annual AAOS meeting.

The researchers found that AFO use was associated with significantly lower inversion force/weight ratio in female athletes, regardless of FAI status. However, when both genders were considered together, AFO use did not significantly affect inversion or eversion force/weight ratio.


Pinzur MS, Angerame M, Tonino PM. The impact of ankle bracing on functional ankle instability in elite volleyball athletes. Presented at the Annual Meeting of the American Academy of Orthopaedic Surgeons, Chicago, March 2013.

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