Restriction of motion during simulated inversion on a tilting platform in 10 different akle braces

Eils E, Demming C, Kollmeier G, Thorwesten L, Völker K, Rosenbaum D

Abstract in digital collection (conference)

Abstract

Ankle bracing is a common practice among individuals with chronic ankle instability to prevent recurrent injuries. In sports, the main goal of braces is to ensure stability without influencing performance. A variety of products that consist of rigid or flexible materials is commercially available and may lead to confusion of consumers. A comparative evaluation of the stabilizing effect of several ankle braces should be helpful for the selection of the most appropriate brace. Therefore, the aim of the present study was to compare the stabilizing effect of ten different ankle braces under sudden inversion conditions on a tilting platform. 25 subjects with chronic ankle instability participated in the project (22.7±2.7 years, 70.6±12.4 kg and 177±8.6cm). A trap door with a tilting angle of 30° in the frontal plane was used to simulate lateral ankle sprains. A customized goniometer was used to measure the hindfoot inversion angle inside the shoe. Ten different commercially available ankle braces and the condition without brace (native) were used in all subjects (one rigid reference model (3-Caligamed), five semi rigid (1-Aircast, 2-Malleoloc, 5-Air Gel, 7-Air Brace, 9-LigacastAnatomic) and 4 soft (4-Kalassy, 6-Kalassy-S, 8-Fibulo-Tape, 10-Dynastab)). The testing order of the ten braces was randomized and one shoe model was used for all subjects. Ten repeated trials per brace were recorded and for each trial inversion angles were derived and averaged. Inversion was subdivided into two phases:end of tilting phase (free fall) and maximum inversion phase (weight bearing). A repeated measures Anovawith the alpha-level set to 5% and the Scheffe test for post-hoc comparisons were used for statistical analysis. The inversion angle for native, free fall condition was on average 28°±5°. All braces reduced this angle significantly and values between 12° (#1) and 23° (#8) were reached. Maximum inversion angles of 39°±6°were found for native condition and all braces led to a significant restriction of motion to 20°-33°. Focussing on the categories of braces, significant differences could be found for braces that consist of separate plastic parts on either side of the ankle (# 1, 5, 7, 9) and all other models. Differences between inversion angles at the end of free fall and bearing bodyweight (maximum inversion angle) are in the range of 7° to 11°. In general, semi-rigid braces that contain rigid parts on the medial and lateral ankle (#1,5,7,9) appear to restrict inversion movements more effectively than all other braces. Although all ankle braces significantly reduce sudden inversion, the stabilizing effect of some soft braces may not be sufficient in terms of injury prevention. When focussing on free fall and maximum angles, only differences of 4° could be found between all braces.This finding suggests, that the major function of braces is the restriction of motion in the free fall phase and does not act like a force bypass in the weight bearing situation [1, 2]. This seems to be independent of the category of the braces (semi rigid or soft). For prophylactic use in sports it was shown that the tested braces had no significant influence on performance in a short agility course [3]. From that point of view, some semirigid models (#1, 5, 7, 9) might be recommended as an optimal solution for preventing injuries in sports. On the other hand, it has to be considered, that the special design makes it difficult to wear regular shoes with these braces. In addition, some sports like soccer restrict the use of these models because of using some additional equipment like shin guards.

Details zur Publikation

Publisher: Mester J, King G, Strüder H, Tsolakidis E, osterburg A
Book title: Perspektives an Profiles
Release year: 2001
Publishing company: Sport und Buch Strauss GmbH
ISBN: 3-89001-235-3
Language in which the publication is written: English
Event: Cologne, Germany
Link to the full text: http://www.ecss.de/ASP/EDSS/C06/06-0343.pdf