In the present investigation, all external support devices significantly reduced passive range of motion compared with the cutout shoe/no support device condition and with the normal shoe/no support device condition. Inversion and eversion were restricted more effectively than were plantar flexion and dorsiflexion, with a minor effect on rotation. This is in accordance with results from the literature.1,6,10,17 Eils et al6 compared the 3-dimensional passive support charac- teristics of 10 different ankle braces with a similar device. All tested braces (rigid, semirigid, soft) provided significant limitation of motion compared with the no brace condi- tion. Siegler et al17 tested 4 different braces and reported a similar result for both lace-on and stirrup braces. Alves et al1 as well as Hartsell and Spaulding10 tested the passive support of ankle braces for inversion and eversion in a plant- arflexed position and confirmed the results. Thus, the above reported results are in accordance with the literature.
One result of the present investigation is that the semi- rigid brace showed a higher passive stability for plantar flexion than did the soft brace when worn inside a shoe. This was also reported by Eils et al.6 When focusing on brace application in sports, it has to be considered that a higher amount of plantar flexion is often desirable, whereas it is of disadvantage in the early healing phase of ankle ligaments after an acute injury.
A considerable amount of stability of external support devices is lost when removing the shoe. The significant loss of passive stability of the semirigid brace has direct impli- cations for the recommendation of braces in barefoot sports. Instead of semirigid braces, soft braces can be recommended in barefoot sports because they provide a serious amount of passive stability, minimize the risk of self-injury (contain no rigid parts), and may be worn in contact sports such as judo or karate.
Three different external support devices were used in the present investigation. Although it was shown that tape has the highest initial passive stability (and this stability is only minimally influenced by the shoe), it is not recommended as a first choice because it has been shown previously that the mechanical stability of tape is almost completely lost after 20 minutes of exercise.21 In addition, it is not possible to read- just tape during training sessions or games (in contrast to braces). Furthermore, from an economical and practical point of view, regular tape application is more expensive than is a brace and is more time consuming15; that is, additional man power is necessary to adequately apply tape. That is why we recommend the soft brace for use in barefoot sport activities.
One remaining question is, Why does the stirrup brace significantly lose its stabilizing effect when used under cutout shoe conditions? Without a shoe, the forefoot is able to invert/evert and transfer this movement partly to the rear of the foot. The shoe, however, restricts this motion of the forefoot and adds collateral pressure to the brace.