Effects of a Semirigid and Softshell Prophylactic Ankle Stabilizer on Selected ~erforma~ce- Tests Among High School Football Players

Transcription

1 Effects of a Semirigid and Softshell Prophylactic Ankle Stabilizer on Selected ~erforma~ce- Tests Among High School Football Players Kevin Macpherson, MEd, ATC ' Michael Sitler, EdD, A TC~ Iris Kimura, PhD, ATC, PT MaryBeth Horodyski, PhD, A TC4 I njuries to the talocrural joint, or ankle, are the most common injuries in sports (16). At the high school level, 45% of basketball injuries, 31% of soccer injuries, and 16% of football injuries involve the ankle joint (5,lg). The vast majority of ankle injuries are sprains, and a disproportionately high number of ankle sprains involve the lateral ligament complex (5). Various injury intervention systems have been used to reduce the incidence of ankle sprains. Adhesive taping has traditionally been used to prevent ankle sprains (13). Adhesive taping, however, has been criticized as it restricts ankle range of motion and loosens with use. Rarick et al (20) determined that tape loses 40% of its supportive strength after 10 minutes of vigorous exercise. Myburgh et al (17) reported that tape offered no significant ankle support after 1 hour of exercise. Bunch et al (3) determined that the mechanical support of tape significantly decreased after 20 minutes of repetitive inversion loading. Ankle taping has also been criticized for its expense. Rovere et al (22) estimated that it cost $400 to tape both ankles of one football player for an entire season at Wake Forest University. Burks et al (4) estimated that it cost $16,000 to tape the No prophylactic ankle stabilizer performance study has been conducted to date using high school football players, ie., players who are at risk of ankle sprains. In addition, the effect that prophylactic ankle stabilizer use has on performance by player position is unknown. The purpose of this study was to determine the effect of a semirigid and sofishell prophylactic ankle stabilizer on performance by football player position in events testing vertical jump, speed, and agility. Twentyfive high school football players participated in the study. All subjects denied any history of ankle injury within I year of the study and previous experience with prophylactic ankle stabilizer use. Subjects completed three tests [vertical jump, m (40-ydj sprint, and m (20-ydj shuttle run] under three different ankle treatments: Aircast SportStimp, Donloy RocketSoc, and nonbraced control. Results of the study indicated that the Aircast SportStirrup and Donloy RocketSoc, when compared with a nonbraced control, had no significant effect on vertical jump, m (40-yd) sprint, and m (20-yd) shuttle run performance. Skill players had faster m (40-yd) sprint times than strength players regardless of ankle treatment. In conclusion, the Aircast SportStimp and Donloy RocketSoc did not facilitate or adversely affect performance involving vertical jump, speed, and agility of high school football players. Key Wonls: ankle, stabilizing prophylactic, athletic performance ' Athletic Trainer, Graduate Athletic Training Program, Department of Physical Education, Temple University, Philadelphia, PA Graduate Coordinator, Department of Physical Education, 125 Pearson Hall, Temple University, Philadelphia, PA ' Graduate Coordinator, Athletic Training, Department of Physical Education, Temple University, Philadelphia, PA Graduate Coordinator, Athletic Training, Department of Exercise and Sport Sciences, University of Florida, Gainesville, F1 ankles of football players for one season at the University of Utah. An alternative to ankle taping is the prophylactic ankle stabilizer. Two general types of prophylactic ankle stabilizers are currently available: semirigid and softshell. The first noncommercial semirigid prophylactic ankle stabilizer was developed in 1974 and was constructed of Orthoplast (Johnson and Johnson, Skill- man, NJ) (24). It was developed as an alternative to plaster casting of ankle sprains (14). In 1980, the first commercially available semirigid prophylactic ankle stabilizer, the Aircast Airstimp (Aircast Inc., Summit, NJ), was marketed (24). Softshell prophylactic ankle stabilizers were first introduced in the early 1980s and were made of a variety of materials, including canvas and neoprene rubber. JOSPT Volume 21 Number 3 March 1995

2 RESEARCH STUDY Authors by PAS Type Semirigid PAS Greene and Hillrnan (7) Bocchinfuso et al (2) Softshell PAS Paris (1 8) Burks et al (4) PASS Tested DonJoy ALP Aircast SportStirrup Active ~nkle Swede-0-Universal McDavid New Cross Swede-0-Universal Kallassy Effect on Vertical lum~ 'Decreased *Decreased *Decreased * Statistically significant. ALP = Ankle Ligament Protector. TABLE 1. Summary of semirigid and softshell prophylactic ankle stabilizer (PAS) effect on vertical jump performance. Prophylactic ankle stabilizers have been tested under a variety of experimental conditions. Biomechanically, they have been reported to significantly limit ankle inversion and eversion range of motion preexercise, during, and postexercise (1,7, 8,10,11,12,13,15). Clinically, prophylactic ankle stabilizers have been shown to be efficacious in reducing the incidence of ankle injuries in the athletic setting (22,23,25). Another important aspect of prophylactic ankle stabilizers is their effect on performance (Tables 1-3). Robinson et al (21) tested a specially designed high-top basketball shoe with plastic stiffeners sewn into the seams. They reported that obstacle course performance was significantly Authors by PAS Type PASS Tested Effect on Running Performance Semirigid PAS Greene and Wight (9) Aircast Airstirrup *Decreased base running DonJoy ALP base running Bocchinfuso et al (2) Aircast Sportstirrup run Active Ankle Training Brace m run Softshell PAS Greene and Wight (9) Swede-0-Universal base running Paris (18) Swede-0-Universal run - McDavid run New Cross 45.7-rn run * Statistically significant. A1 P = Ankle Ligament Protector. TABLE 2. Summary of semirigid and softshell prophylactic ankle stabilizer (PAS) effect on ~nning performance. Authors by PAS Type PASS Tested Effect on Agility Semirigid PAS Bocchinfuso et al (2) Aircast SportSti~ n'"" Active Ankle TI aining Brace 4-point run Softshell PAS Burks et al (4) Swede-0-Univc?MI Paris (1 8) Kallassy Swede-0-Universal McDavid New Cross TABLE 3. Summary of semirigid and sohhell prophylactic ankle stabilizer (PAS) effect on agility performance. I48 slower with use of the modified basketball shoe. Greene and Hillman (7) reported that female collegiate volleyball players' vertical jump was not significantly reduced when wearing the DonJoy Ankle Ligament Protector (ALP) (DonJoy Orthopaedics, Carlsbad, CA). Comparing three different prophylactic ankle stabilizers, Greene and Wight (9) determined that use of the Aircast Airstirrup resulted in a significant reduction in female collegiate softball players' base-running performance, whereas the DonJoy ALP and Swede-0-Universal (Swede-0-Universal, North Branch, MN) ankle brace did not. Burks et a1 (4) reported that varsity collegiate athletes' vertical jump heights decreased but shuttle run performance was not affected when wearing the Kallassy (Sports Supports Prophylactic ankle stabilizers have been shown to be efficacious in reducing the incidence of ankle injuries. Inc., Dallas, TX) and Swede-0-Universa1 prophylactic ankle stabilizers. Paris (18) reported that elite soccer players' performance was not significantly affected in tests of speed, balance, and agility when wearing the McDavid A101 (McDavid Knee Guard Inc., Claredon, IL), New Cross #I20 (New Cross International Limited, Scarborough, Ontario, Canada), or Swede-0-Universal ankle brace. Vertical jump, however, was significantly decreased with use of the New Cross prophylactic ankle stabilizer. Recently, Bocchinfuso et al (2) reported that use of the Active Ankle Training Brace (Active Ankle Systems, Inc., Louisville, KY) and Aircast SportStirrup (Aircast, Inc., Summit, NJ) had Volume 21 Number 3 March 1995 JOSR

3 no affect on vertical jump, 24.38m sprint, shuttle run, or four-point run performance of high school basketball players. Little consensus of agreement exists as to the effect that prophylactic ankle stabilizers have on athletic performance. These differences are attributed to factors that include: type of brace tested, performance tests employed, subject variability, and research design. No prophylactic ankle stabilizer performance study has been conducted to date using high school football players, ie., players who have a relatively high risk of ankle sprains (6). In addition, the effect that prophylactic ankle stabilizers have on performance by player position is unknown. Further research needs to be conducted. METHODS Subjects Twenty-five males who denied prior ankle injuries within the last year and experience with prophylactic ankle stabilizers volunteered to serve as subjects for the study. Sub jects were high school varsity football players (xage = 16 t.99 years, x weight = 80.7 t 12.7 kg, and x height = cm) during the football season. In accordance with the Institutional Review Board of Temple University, appropriate parental and subject informed consent were obtained prior to data collection. Prophylactic Ankle Stabilizers Tested The semirigid and softshell prophylactic ankle stabilizers tested in the present study were the Aircast SportStirmp (Aircast, Inc., Summit, NJ) and DonJoy RocketSoc (DonJoy Orthopaedics, Carlsbad, CA), respectively. The Aircast SportStirrup was chosen because of its popularity in the sports medicine setting; the RocketSoc was chosen because it is JOSF'T Volume 21 Number 3 March 1995 FIGURE 1. Aircast AirStirrup. relatively new to the prophylactic ankle stabilizer market. The Aircast SportStirrup (Figure 1) consists of medial and lateral thermoplastic shells which are lined with inflatable air sacs. The shells are connected to a pliable heel pad via Velcro@ (Velcro USA, Inc., Manchester, NH) attachment. Two pivoting Velcro straps secure the shells to the lower leg. The RocketSoc (Figure 2) is constructed of neoprene rubber. It slides over the ankle and has an opening anterior to the talocrural joint. Covering the mid-foot to approximately cm superior to the medial and lateral malleoli, the brace has three external Velcro straps which are stra- - A - FIGURE 2. Donjoy Orthopaedics RocketSoc. FIGURE 3. The m (20-ydl shuttle run. tegically placed to restrict ankle inversion and eversion. Performance Tests Each subject was required to perform the following performance tests as described: Vertical Jump Standing perpendicular to the test wall and with fingers chalked, each subject crouched and then jumped vertically as far as he could, touching the wall at the height of his jump. The difference between the standing vertical reach and peak jump height was recorded as the vertical jump height. Vertical jump height was recorded to the nearest 1.27 cm m (40yd) Sprint From a standing start, each subject ran forward from the goal line m (40 yd) as fast as he could. Time was recorded to the nearest.o1 second using an electronic Mametta Millisecond Timer (Manietta Apparatus Company, Marrietta, OH) m (20yd) Shuttle Run (Figure 3) From a standing start, each subject ran forward from the start line 4.57 m (5 yd) to his right and touched a second line with his hand and turned. The subject then ran 9.14 m (10 yd) to his left, touched a third line with his hand and turned. The subject then ran 4.57 m (5 yd) to the right, crossing the start/finish line. Time was recorded to the nearest.o1 second using a hand-held stopwatch. Tester Reliability Investigator measurement reliability was established for the three performance tests used in the study. Ten randomly selected subjects

4 RESEARCH STUDY not associated with the study underwent repeat tests in order to obtain an estimate of intratester reliability. Testing was completed 10 days prior to the first data collection session for record. The same protocol procedures (ie., warm-up and test protocol) as used in the experimental phase of the study were used in the reliability assessment. Interclass correlation coefficients (ICC) revealed reliable investigator measurements: vertical jump, ICC (2,l) =.97; m (40-yd) sprint, ICC (2,l) =.88; and m (20-yd) shuttle run, ICC (2.1) = 36. Testing Procedures Testing was performed on 4 separate days with approximately 7 days between test sessions. Test session 1 was used as a pretest to allow subjects to become familiar with the performance test requirements and data collection procedures. During the pretest, subjects performed all tests without any type of ankle support. Experimental condition (Aircast SportStirrup, DonJoy RocketSoc, and nonbraced control) order was randomized over the three test sessions. Performance tests [vertical jump, m (40-yd) sprint, and m (20-yd) shuttle run] were randomized within each test session to minimize the effects of fatigue and learning. Prior to the beginning of testing, subjects completed a group warm-up, which consisted of jogging for 8 minutes, stretching, and a submaximal trial for each of the performance tests. The submaximal warm-up trial was completed in order to familiarize each subject with the test protocol. Subjects were required to complete each test twice, with the best score recorded as the criterion measure. Subjects rested approximately 2 minutes between trials and 10 minutes between performance tests. No verbal encouragement was given during testing. All testing was performed on a grass football field. Each subject provided his own regulation football shoes for all testing and was required to be consistent in the footwear worn across trials and test sessions. Testing was not performed during inclement weather. Subjects were bilaterally braced during prophylactic ankle stabilizer testing..data Analysis The criterion measure for each of the three dependent variables [vertical jump, m (40-yd) sprint, and m (20-yd) shuttle run] was analyzed. The data analyses consisted of three 2 X 3 analyses of variance (ANOVAs) with repeated measures on the independent variable of brace condition (within-subjects factor). Player position (skill vs. strength) was tested as a betweensubjects factor. Skill players (N = 12) consisted of quarterbacks, running backs, wide receivers, and defensive backs. Strength players (N = 13) consisted of offensive lineman, defensive lineman, and linebackers. Data were analyzed using the SPSSPC+ Release 4.0 (SPSS, Chicago, IL) statistical package. All statistical analyses were completed in the null form, and the.05 level of probability was considered significant. RESULTS Vertical Jump Means and standard deviations for the vertical jump are presented in Table 4. The ANOVA showed no significant main or interaction effects in vertical jump for ankle treatment or player position m (40-yd) Sprint Means and standard deviations for the m (40-yd) sprint are presented in Table 5. The ANOVA showed no significant brace main or interaction effects for the m (40-yd) sprint. There was, however, a significant (F(1,23) = 5.36, p =.03) main effect for position. Skill players Player Position Treatmenl SD Skill (N = 12) Aircast Donjoy Control Strength (N = 13) Aircast Donloy Control ANOVA (positionl = F(1,23) = 1.38, p =,252. ANOVA (brace) = F(2,46j = 2.79, p =.072. ANOVA (position by brace) = F(2,46) =.lo, p =.lo. Skill player position = Quarterbacks, running backs, wide receivers, and defensive backs. Strength player position = Offensive and defensive linemen and linebackers. TABLE 4. Means and standard deviations fcm) for vertical jump. (X = ) had faster m (40-yd) sprint times than strength players (X = ) m (20-yd) Shuttle Run Means and standard deviations for the shuttle run are presented in Table 6. The ANOVA showed no significant main or interaction effects for the m (20-yd) shuttle run. DISCUSSION The results of this study indicate that the Aircast SportStirrup and DonJoy RocketSoc had no significant effect on vertical jump, 36.56m (40- yd) sprint, and m (20-yd) shuttle run performance. In general, the findings of this study are consistent ANOVA (position) = F(1,23) = 5.36, p =.03. ANOVA (brace) = F(2,461 =.32, p =.726. ANOVA (position by brace) = F(2,461 =.14, p = 368. Skill player position = Quarterbacks, running backs, wide receivers, and defensive backs. Strength player position = Offensive and defensive linemen and linebackers. TABLE 5. Means and standard deviations (seconds) for m (40-yd) sprint. - Volume 21 Number 3 March 1995 JOSPT

5 RESEARCH STUDY ANOVA (position) = Ff1,23) = 3.41, p =,078. ANOVA (brace) = F(2,46) = 1.55, p =.223. ANOVA (position by brace) = f(2,46) =.89, p =.418. Skill player position = Quarterbacks, running backs, wide receivers, and defensive backs. Strength player position = Offensive and defensive linemen and linebackers. TABLE 6. Means and standard deviations (seconds) for m (20-ydl shuttle run. with the results reported by Burks et al (4), Greene and Hillman (7), Bocchinfuso et al (2), and Paris (18). No research has been conducted to date on the DonJoy RocketSoc, a softshell prophylactic ankle stabilizer. Research conducted on vertical jump and prophylactic ankle stabilizer use has produced varying results. Green and Hillman (7) and Bocchinfuso et a1 (2) reported that the Aircast Sportstirrup, Active Ankle Training Brace, and DonJoy ALP had no significant effect on vertical jump performance. All three of these semirigid prophylactic ankle stabilizers resist ankle joint inversion/eversion but allow ankle plantar flexion and dorsiflexion. By allowing ankle joint movement in the sagittal plane, vertical jump was not impeded. Other authors have reported on softshell prophylactic ankle stabilizer use and vertical jump performance. Paris (18) reported that the New Cross ankle brace significantly decreased vertical jump height, whereas the Swede-O-Universal and McDavid ankle braces did not. Conversely, Burks et al (4) reported that both the Swede-O-Universal and Kallassy ankle braces significantly decreased vertical jump height. Although both prophylactic ankle stabilizers tested by Burks et al were softshell, they significantly limited ankle joint plantar flexion and dorsiflexion. Ostensively, because ankle joint movement was reduced, vertical jump performance was decreased. Results of the present study indicated that the DonJoy RocketSoc had no significant effect on vertical jump. This result may be attributed to the design and materials used in the manufacturing of the RocketSoc. The DonJoy RocketSoc is made of neoprene rubber instead of cloth or canvas like the Swede-O-Universa1 and New Cross ankle braces. In addition, the RocketSoc has an anterior opening to the talocrural joint. Presumably, this opening allows normal ankle joint plantar and dorsiflexion to occur, thereby, not impeding vertical jump performance. The effect of prophylactic ankle stabilizer use on running performance is varied. Bocchinfuso et a1 (2) reported that the Aircast Sport- Stirrup and Active Ankle Training The effect of prophylactic ankle stabilizer use on running performance is varied. Brace had no significant effect on m sprint performance of high school basketball players. Paris (18) reported that the Swede-O-Universal, New Cross, and McDavid ankle braces had no significant effect on elite soccer players' 45.7-m sprint performance. Conversely, Greene and Wight (9) determined that the Aircast Airstirrup significantly reduced base-running times of collegiate softball players, whereas the DonJoy ALP and Swede-O-Universal ankle brace did not. Greene and Wight compared the designs of the two semirigid prophylactic ankle stabilizers tested in their study. They concluded that the bulkiness of the Aircast Airstirrup may have interfered with the subjects' ability to perform efficient cutting and turning maneuvers, thus, de- creasing base-running performance. Interestingly, the Aircast Airstirrup is not designed for use in competition but for ankle joint compression and support following acute injury. Conversely, the Aircast Sportstirrup, tested by Bocchinfuso et al and in the present study, is designed for prophylactic use in competition. Thus, it appears that softshell and functional semirigid prophylactic ankle stabilizers have no detrimental effect on running performance. Very little research has been conducted to date on the effect of pre phylactic ankle stabilizer use on agility. The research that has been conducted has produced consistent results. Burks et a1 (4) reported that two softshell prophylactic ankle stabilizers, the Swede-O-Universal and Kallassy ankle braces, had no significant effect on intercollegiate athletes' shuttle run performances. Bocchinfuso et al (2) reported that two semirigid prophylactic ankle stabilizers, the Aircast Sportstirrup and Active Ankle, had no significant effect on high school basketball players' shuttle run and four-point run perf~rmances. Paris (18) reported that elite soccer players' agility test performance was not significantly affected when wearing the Swede-0-Universal, New Cross, or McDavid ankle braces. The results of this study are in agreement with the findings of Burks et al, Bocchinfuso et al, and Paris: semi-, rigid and softshell prophylactic ankle stabilizers have no significant effect on shuttle run performance. The effect of prophylactic ankle stabilizer use on performance by player position has not previously been assessed. In the present study, subjects were stratified into one of two player position groups: skill or strength. Skill players consisted of quarterbacks, running backs, wide receivers, and defensive backs. Strength players consisted of offensive lineman, defensive linemen, and linebackers. Results indicated that skill players had faster 36.56m (40- yd) sprint times than strength play- JOSFT * Volume 21 * Number 3 * March 1995

6 RESEARCH STUDY -- The use of prophylactic ankle stabilizers did not affect performance in tests of vertical jump, speed, and agility for either skill or strength players ers, regardless of ankle treatment. This difference in running performance was not unexpected and may be attributed to specific performance demands of the two positions. A finding unique to this study, however, was the independent relationship between player position and prophylactic ankle stabilizer use on performance. In other words, the use of prophylactic ankle stabilizers did not affect performance in tests of vertical jump, speed, and agility for either skill or strength players. CONCLUSION The effect of prophylactic ankle stabilizer use on athletic performance has become increasingly important within the sports medicine community. Based on the findings of the present study, semirigid and softshell prophylactic ankle stabilizers have no significant effect on athletic performance by football player position in tests of vertical jump, speed, and agility. JOSPT ACKNOWLEDGMENTS The authors thank Aircast Inc., Summit, NJ, and DonJoy Orthopaedics, Carlsbad, CA, for providing the prophylactic ankle stabilizers used for testing in this study and Linda Murareski for her assistance in preparation of the manuscript. REFERENCES I. Alves J, Alday R, Ketcham D, Lentell G: A comparison of the passive support provided by various ankle braces. 1 Orthop Sports Phys Ther 15: 10-18, Bocchinfuso C, Sitler M, Kimura I: Effects of two semirigid ankle stabilizers on performance involving speed, agility, and vertical power. 1 Sports Rehabil 3~ , Bunch R, Bednarski K, Holland D, Macinanti R: Ankle joint support: A comparison of reusable lace-on braces with taping and wrapping. Phys Sports Med 13: , Burks R, Bean B, Marcus R, Barker H: Analysis of athletic performance with prophylactic ankle devices. Am J Sports Med 19: , Garrick I: The frequency of injury, mechanism of injury, & epidemiology of ankle sprains. Am J Sports Med 5: ?, Garrick I, Requa R: The epidemiology of foot and ankle injuries in sport. Clin Sports Med 7:29-36, Greene T, Hillman S: Comparison of support provided by a semirigid orthosis and adhesive ankle tape before, during and after exercise. J Orthop Sports Phys Ther 18: , Greene T, Roland C: A comparative isokinetic evaluation of a functional ankle orthosis on talocalcaneal function. ] Orthop Sports Ph ys Ther 1 1 : , Greene T, Wight C: A comparative support evaluation of three ankle orthoses before, during and after exercise. J Orthop Sports Phys Ther 11: , Gross M, Ballard C, Mears H, Watkins E: Comparison of Donloy ankle ligament protector and Aircast sportstirrup orthoses in resisting foot ankle motion before and after exercise. J Orthop Sports Phys Ther 16:60-67, I. Gross M, Bradshaw M, Ventry L, Weller K: Comparison of support provided by ankle taping and semirigid orthosis. J Orthop Sports Phys Ther 9:33-39, Gross M, Lapp A, Davis M: Compari- son of Swede-0-Universal ankle support and Aircast Sport-Stirrup orthoses and ankle tape in restricting eversion inversion before and after exercise. J Orthop Sports Phys Ther l3:ll-l9, Hughes L, Stetts D: A comparison of ankle taping and a semirigid support. Phys Sports Med 1 1 :90-103, Jackson D, Ashley R, Powell J: Ankle sprains in young athletes. Clin Orthop 10 1 : , Kimura I, Nawoczenski D, Epler M, Owen M: Effects of Airstirrup in controlling ankle inversion stress. ] Orthop Sports Phys Ther 9: , Lassiter T, Malone T, Garret W: Injury to the lateral ligaments of the ankle. Orthop Clin North Am 20: , Myburgh K, Vaughan C, lsaacs S: The effects of ankle guards and taping on joint motion before, during, and after exercise. J Sports Med 72: , Paris D: The effects of the Swede-0, New Cross and McDavid ankle braces and adhesive ankle taping on speed, balance, agility and vertical jump. J Athl Train 27: , Powell J: The 636,000 injuries annually in high school football. J Athl Train 22:19-22, Rarick G, Bigley G, Karst R, Malina R: The measurable support of the ankle joint by conventional methods of taping. J Bone Joint Surg 44A: , Robinson J, Frederick E, Cooper L: Systematic ankle stabilization and the effect on performance. Med Sci Sport Exerc l8: , Rovere G, Clarke T, Yates C, Burley K: Retrospective comparison of taping and ankle stabilizers in preventing ankle injuries. Am J Sports Med l6: , Sitler M, Ryan J, Wheeler B, McBride J, Arciero R, Anderson 1, Horodyski M: Efficacy of a semirigid ankle brace to reduce acute ankle injuries in basketball: A randomized clinical study at West Point. Am J Sports Med 22: , Stover C: Air stirrup management of ankle injuries in the athlete. Am J Sports Med l3: , Troop H, Askling C, Gillquist J: Prevention of ankle sprains. Am 1 Sports Med l3: , 1985 Volume 21 Number 3 March 1995 JOSPT