July 2012

Bracing affects plantar pressures and inversion, but not most performance tests

In the moment: Ankle

By Jordana Bieze Foster

Research presented in June at the annual meeting of the National Athletic Trainers Association shed more light on the biomechanical effects of ankle braces that can help reduce the risk of inversion injury.

Investigators from the University of Toledo analyzed plantar pressures in 10 individuals with chronic ankle instability (CAI) and 10 healthy individuals while jump-landing with and without a lace-up ankle brace. Plantar pressures tended to be distributed more medially in the CAI group than the control group, but in both groups midfoot and rearfoot pressures were shifted laterally with brace wear.

“We’re interpreting this shift to mean the foot is in a more neutral position, away from an injurious position,” said Phillip Gribble, PhD, ATC, director of the university’s Athletic Training Research Laboratory, who presented the findings.

Brace type and ankle flexion angle may influence inversion-eversion restriction, according to research from the University of South Alabama in Mobile. In 22 healthy female collegiate athletes, a soft-shell brace and a rigid brace allowed significantly less inversion-eversion range of motion than a lace-up brace across three ankle flexion angles. All braces more effectively controlled inversion-eversion motion when the ankle was positioned in 10° of dorsiflexion compared to neutral or 15° of plantar flexion.

“Studies that do not include dorsiflexion and plantar flexion effects leave us with a limited and incomplete view of the function of that brace,” said John Kovaleski, PhD, ATC, a professor of exercise science at the University of South Alabama, who presented the findings at the NATA meeting.

Researchers from the University of Virginia in Charlottes­ville found that inversion control did not differ significantly among three brace types in 11 young adults with a history of ankle sprains (mean, 3.4 sprains). They compared a lace-up brace, a semirigid brace, and a device featuring an ankle cuff attached directly to the lateral aspect of the shoe; all significantly restricted inversion relative to an unbraced condition.

Brace type also did not have any influence on athletic performance. All three braces decreased star excursion balance test scores compared to no brace, but there was no difference between brace designs. Bracing had no significant effect on scores for the Southeast Missouri agility test, maximum vertical jump, or single leg triple hop test.

“Subjects felt like all three braces negatively affected performance, but in actuality they didn’t affect vertical jump, agility, or triple hop,” said Jenna McDonald, MEd, ATC, an assistant athletic trainer at Nichols College in Dudley, MA, and former graduate student at the University of Virginia, who presented the findings at the NATA meeting.

Sources:
Rix J, Yniguez SL, Armstrong CA, et al. Effects of chronic ankle instability and ankle bracing on plantar pressure distribution during jump-landing. Pre­sented at the 63rd annual meeting of the National Athletic Trainers Asso­ciation, St. Louis, MO, June 2012.

Kovaleski JE, Gurchiek LR, Heitman RJ, et al. Influence of ankle flexion angle on brace support of the ankle complex. Presented at the 63rd annual meeting of the National Ath­letic Trainers Association, St. Louis, MO, June 2012.

McDonald J, Chinn L, Donovan L, et al. Effect of three ankle braces on range of motion and functional performance in subjects with a history of ankle sprains. Presented at the 63rd annual meeting of the National Ath­letic Trainers Association, St. Louis, MO, June 2012.

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