The Effects of Prophylactic Ankle Bracing on Dynamic Reach Distance and Obstacle Course Performance in Military Cadets

MILITARY MEDICINE, 177, 5:567, 2012 The Effects of Prophylactic Ankle Bracing on Dynamic Reach Distance and Obstacle Course Performance in Military Cadets Thomas Newman, MEd, ATC*; MAJ Theodore Croy, SP USA†; Joseph Hart, PhD, ATC‡; Susan Saliba, PhD, PT, ATC, FNATA‡ ABSTRACT Ankle braces can protect the ankle joint from ligament sprains and fractures during high-risk military activities such as physical training and parachuting. Although braces are recommended for injury prevention purposes, the impact of braces on physical performance is unknown. This study evaluated lace-up ankle braces, worn inside the boots, across three conditions: no brace, unilateral brace, and bilateral brace on the dependent variables of dynamic lower extremity reach and obstacle course performance. Thirty-seven military cadets were tested over 3 days. Ankle bracing had a small effect upon anterior and composite lower extremity reach distances. Bracing had no effect upon obstacle course performance times. Inside-the-boot ankle bracing restricts lower extremity reaching and mildly impacts mobility, however, no restrictions were observed with running, climbing, jumping, or negotiating obstacles. Lace-up ankle braces can be used in conjunction with combat boots to protect the ankle during high-risk activities without having an impact upon tactical movements. INTRODUCTION In sports and the military, lateral ankle sprains are among the most common musculoskeletal injuries.1,2 There are an estimated 25,000 lateral ankle sprains a day in the United States.3 In the military, lateral ankle injuries account for approximately 25 million limited duty days annually according to the Department of Defense.4 Knapik et al5 shows that ankle sprains are the second leading cause of limited duty days with an average of 16.7 days lost per ankle sprain injury. The mechanism creating the majority of lateral ankle injuries is inversion combined with plantar flexion. Prophylactic taping and bracing are two methods used for lateral ankle support and injury prevention. Taping is used to help stabilize the ankle joint by restricting the plantar flexion and inversion motions. However, it has been shown that the integrity of tape can degrade rapidly within the first 20 minutes after application.6–8 Olmsted et al3 showed that taping cost 3.05 times more than did prophylactic bracing one individual throughout a season. Bracing was both a cost- and time-effective intervention aimed at protecting an ankle during practice and sports and has become more common for lateral ankle sprain injuries because of its resilience and cost.3,6 –8 Prophylactic bracing, however, could cause a detrimental effect on performance by restricting joint motion, adding weight, and slowing down the individual during activity.9,10 The effects of bracing on functional performance are mixed, whereas the preventative injury aspect is generally accepted.10 Bennell et al11 found that postural stability was *University Orthopedics Center, 101 Regent Court, State College, PA 16801. †U.S. Army-Baylor University Doctoral Program in Physical Therapy, Academy of Health Sciences, 3151 Scott Road, Suite 2307, Fort Sam Houston, TX 78234. ‡Department of Human Services/Kinesiology, University of Virginia, 210 Emmet Street South, Charlottesville, VA 22904. decreased as a result of wearing various types of ankle braces. In a meta-analysis by Cordova et al,10 lace-up braces restricted dorsiflexion by almost 20 and plantar flexion by 12 compared to a control group. Range of motion is very important in functional performance, and although this restricted joint movement may protect the joint, it also could lead to a decrease in a functional performance. Cordova et al12 later found that the use of several different types of lace-up ankle and semirigid ankle braces did not affect agility or speed, but resulted in a 5% deficit in vertical jump heights compared to the control group. Additionally, most studies of ankle bracing have been conducted with the participants wearing athletic shoes, however, soldiers require additional ankle support that works in conjunction with a combat boot, and the performance effects of this brace-combat boot system are unknown. There have been many studies showing the increased rate of ankle sprains within the U.S. military.2,4,13,14 Military cadets and recruits participating in basic training programs have an increased rate of injury because of the physical training requirements during these programs.2,13 Cadets and recruits in training are required to run, march, and negotiate obstacles while wearing combat boots and are at risk of suffering ankle injuries during these activities; a fact that drives up costs and delays training progress. In response, the U.S. Army Center for Health Promotion and Preventive Medicine (USACHPPM) has issued a recommendation that prophylactic ankle bracing should be used during high-risk activities such as sports and physical training.4 It was proposed that the use of prophylactic ankle bracing would reduce the incidence rate of lateral ankle injuries, especially in soldiers with a history of lateral ankle sprain. It is important to identify if any detrimental effects of this recommendation may exist in order to further evaluate the performance cost and feasibility of administering the recommended prevention regimen. Furthermore, the ankle brace may not fit properly inside a military boot and the combination may present additional restriction in movement. MILITARY MEDICINE, Vol. 177, May 2012 567 Effect of Ankle Brace on Lower Extremity Reach and Obstacle Course Performance The purpose of this study was to determine if the use of an ankle brace inside a military combat boot would have an effect on dynamic lower extremity reach distances and functional performance. Our hypothesis was that ankle bracing would have small effects on dynamic reach compared to the control condition and little to no detrimental effects on obstacle course performance. METHODS This study utilized a crossover design. Dynamic reach distance was tested using the Star Excursion Balance Test (SEBT) under three conditions: control, unilateral brace, and bilateral brace in a randomized order. Functional performance was tested by the time required to negotiate a military obstacle course under the same three conditions. All participants performed all three levels of the test condition and data collection occurred on three separate days with only one brace condition tested per day. It was predetermined that participants would place the ankle brace on the ankle of the dominant limb during the unilateral brace condition. The dominant limb was described as the one that would be used to kick a ball. Participants All volunteers were currently enrolled as cadets at a statesponsored military institution and signed an informed consent after the purpose and procedures of the study were explained. Male cadets were included if they were free from low (...truncated)