Anterior cruciate ligament functional brace use in sports.

The routine use of functional knee braces in the anterior cruciate ligament-deficient, injured, or reconstructed knee, lacks biomechanical support. Although subjective reports favoring bracing are plentiful, objective proof of significant control of tibial translation is not. This in vivo study was designed to assess the effect of six popular braces on anterior tibial translation, isokinetic performance, and neuromuscular function in five chronically unstable anterior cruciate ligament-deficient knees. A knee stress test was performed on a specially designed device that allowed free tibial movement while monitoring anterior tibial translation and muscle function in the quadriceps, hamstring, and gastrocnemius muscles. Results show that braces can decrease anterior tibial translation between 28.8% and 39.1% without the stabilizing contractions of the hamstring, quadriceps, and gastrocnemius muscles. With lower extremity muscle activation and bracing, anterior tibial translation was decreased between 69.8% and 84.9%. Some improvement in spinal level muscle reaction times was seen with brace use, especially in the quadriceps muscle. Unfortunately, most braces appear to consistently slow hamstring muscle reaction times at the voluntary level.

Basketball shoe height and the maximal muscular resistance to applied ankle inversion and eversion moments.

To determine if the height of a basketball shoe alters the maximal inversion and eversion moment that can be actively resisted by the ankle in the frontal plane, we tested 20 healthy, young adult men with no recent ankle injuries. Subjects underwent unipedal functional ankle strength testing under weightbearing conditions at 0 degrees, 16 degrees, and 32 degrees of ankle plantar flexion using a specially designed testing apparatus. Testing was performed with the subject wearing either a low- or a three quarter-top basketball shoe. Shoe height did not significantly affect an individual's ability to actively resist an eversion moment at any angle of ankle plantar flexion. However, tests at 0 degrees of ankle plantar flexion demonstrated that the three quarter-top basketball shoe we tested significantly increased the maximal resistance to an inversion moment by 29.4%. At 16 degrees of ankle plantar flexion, inversion resistance was also significantly improved by 20.4%. These results show that athletic shoe height can significantly increase the active resistance to an inversion moment in moderate ankle plantar flexion. The findings apply to a neutral foot position in the frontal plane, an orientation equivalent to the early phase of a potential ankle sprain.