ARTIGO_ Gribble - 2003 - The star excursion balance test as a measurement tool

SAVE OFFLINE

RESEARCH DIGEST

Thomas W. Kaminski, PhD, ATC/R, Column Editor

The Star Excursion Balance Test as a Measurement Tool Phillip Gribble, MA, ATC • The Pennsylvania State University

M

EASURING POSTURAL CONTROL is important for establishing levels of function for the purposes of injury prevention and rehabilitation. Postural control, or balance, is often described as either static (maintaining a position with minimal movement) or dynamic (maintaining a stable base of support while completing a prescribed movement).1 Static balance can be quantified through instrumented measurements or less sophisticated means. A clinician or researcher might assess it by having an individual try to maintain a stationary position while standing on one or both feet. Ground-reaction forces can be measured by having an athlete balance on or move across a force plate. Postural control is computed through measures of velocity, area, or variability of ground-reaction forces or a related variable.2 Noninstrumented measures include variables such as the amount of time an athlete can maintain a stance3 or error-scoring systems that monitor stance performance.4 Testing dynamic postural control often involves completing a functional task without compromising one’s base of support. The advantage of assessing dynamic postural control is that additional demands of proprioception, ROM, and strength are required along with the ability to remain upright and steady. Numerous tests have been developed to assess dynamic postural control in the pediatric5 and geriatric6-9 populations, but very few that truly stress athletes’ dynamic balance capabilities. The Star Excursion Balance Test (SEBT)10 is one such test that significantly challenges an athlete’s postural-control system. First introduced by Gray,10 the SEBT is a simple test that uses a star on the floor of strips of athletic tape positioned at 45° angles to one another. The test re-

quires having an athlete maintain a base of support with one leg while maximally reaching in eight different directions with the opposite leg, without compromising the base of support on the stance leg. If both legs are being tested, the participant reaches in all eight directions before switching to the opposite leg. The reach-direction labels are changed for right- versus leftstance leg (Figure 1). The participant is instructed to reach as far as possible in the designated direction, make a light touch on the ground without coming to a rest, and return back to the center of the star while maintaining the base of support with the stance leg. The evaluator marks the tape with a pen at the spot that the participant touches down. The distance from the center of the grid to the spot on the tape is then measured. If the participant makes a heavy touch, comes to rest, loses balance, or cannot return to the beginning position under control, the trial is discarded and the participant is asked to repeat it. For research purposes, three trials are typically performed in each direction and the mean calculated. The order of testing typically follows a clockwise or counterclockwise direction, but the beginning reach direction and testing leg can be randomly chosen. When used for research, the order of these variables should be predetermined; for clinical purposes, the clinician can determine the testing order. Intrarater reliability of the SEBT has been demonstrated to be very strong by Kinzey and Armstrong11 (ICC[2,1]: .67–.87) and Hertel et al12 (ICC[2,1]: .81– .96). Hertel et al12 showed that in order to reduce any potential learning effect, participants needed to perform six practice trials in each of the eight directions before any data were recorded. This familiarized them with the test and their own reaching strategy and is a © 2003 Human Kinetics • ATT 8(2), pp. 46-47

46 ❚ MARCH 2003

ATHLETIC THERAPY TODAY

formance on dynamic-balance tasks might help further enlighten researchers and clinicians as to athletes’ functional capabilities. The SEBT appears to be a valuable instrument for assessing a level of dynamic balance, has high interrater reliability, and is sensitive in detecting performance deficits related to musculoskeletal injury. In addition, its usefulness in the clinical setting as a valid rehabilitation tool after lower extremity injury is being demonstrated. ❚ Figure 1

Reaching directions for the Star Excursion Balance Test.

Downloaded by Northern Illinois University on 09/18/16, Volume 8, Article Number 2

References protocol that is followed when using the test for research. Because performance of the task depends on the ability to reach as far as possible without compromising the base of support, participants with more height or longer legs fair better than those with shorter limbs. A recent study examined the contributions of various factors to performance of the SEBT, including leg length, height, foot type, and ROM measures.13 We discovered that foot type and deficits in hip and dorsiflexion ROM did not affect performance, but men performed better on the SEBT than did women. When the raw scores were normalized to leg length (dividing the distance reached by leg length), however, there were no significant effects as a result of gender. We recommend that data from the SEBT be normalized to leg length. This will enable researchers to compare data among participants and genders and clinicians to compare performance among teammates to determine progress during rehabilitation. There is evidence that the SEBT is sensitive for screening musculoskeletal impairments such as chronic ankle instability,14 quadriceps strength deficits,15 and patellofemoral pain syndrome.16 Earl and Hertel17 demonstrated its usefulness in the recruitment of lower extremity muscle fibers and discussed its application in rehabilitating lower extremity musculoskeletal injuries. Their findings have implications for designing rehabilitation protocols with the SEBT directed at specific lower extremity structures. Balance is one component of an athlete’s level of neuromuscular control. Static postural-control measurements are useful but can only play a limited role in defining an athlete’s degree of functional ability. Per-

ATHLETIC THERAPY TODAY

1. 2. 3. 4.

5.

6. 7. 8.

9.

10. 11.

12. 13. 14.

15. 16.

17.

Winter D, Patla A, Frank JS, Walt SE. Biomechanical walking pattern changes in the fit and healthy elderly. Phys Ther. 1990;70(6):340-347. Guskiewicz K, Perrin D. Research and clinical applications of assessing balance. J Sport Rehabil. 1996;5:45-63. Freeman M, Dean M. The etiology and prevention of functional instability of the foot. J Bone Joint Surg Br. 1965;47(4):678-685. Riemann BL, Guskiewickz K, Shields E. Relationship between clinical and forceplate measures of postural stability. J Sport Rehabil. 1999; 8:71-82. Donahoe B, Turner D, Worrell T. The use of functional reach as a measurement of balance in boys and girls without disabilities age 5 to 15 years. Pediatr Phys Ther. 1994;6:189-193. Tinetti ME. Performance-oriented assessment of mobility problems in elderly patients. J Am Geriatr Soc. 1986;34:119-126. Duncan P, Weiner D, Chandler J, Studenski S. Functional reach: a new clinical measure of balance. J Gerontol. 1990;48(6):192-197. Berg K, Wood-Dauphinee S, Williams JI. The Balance Scale: reliability assessment for elderly residents and patients with an acute stroke. Scand J Rehabil Med. 1995;27:27-36. Rossiter-Fornoff JE, Wolf SL, Wolfson LI, Buchner DM. A cross-sectional validation study of the FICSIT common data base static balance measures. Frailty and injuries: cooperative studies of intervention techniques. J Gerontol. 1995;50(6):M291-M297. Gray GW. Lower Extremity Functional Profile. Adrian, Mich: Wynn Marketing, Inc; 1995. Kinzey S, Armstrong C. The reliability of the Star-Excursion test in assessing dynamic balance. J Orthop Sports Phys Ther. 1998;27(5):356360. Hertel J, Miller S, Denegar CR. Intratester and intertester reliability during the Star Excursion Balance Tests. J Sport Rehabil. 2000;9:104-116. Gribble PA, Hertel J. Considerations for normalizing measures of the Star Excursion Balance Test. Meas Phys Educ Exerc Sci. In press. Olmsted LC, Carcia CR, Hertel J, Shultz SJ. Efficacy of the Star Excursion Balance Test in detecting reach deficits in subjects with chronic ankle instability. J Athletic Train. 2002;37(4):501-507. Miller S. Biomechanical Analysis of the Anterior Balance Reach Test. Kinesiology. University Park, Pa: Pennsylvania State University; 2001. Earl J. Relationships Among Dynamic Malalignment, Neuromuscular Rehabilitation, and Patellofemoral Pain Syndrome. Kinesiology. University Park, Pa: Pennsylvania State University; 2002. Earl J, Hertel J. Lower-extremity muscle activation during the Star Excursion Balance Tests. J Sport Rehabil. 2001;10:93-104.

Phillip Gribble is a doctoral candidate in athletic training in the Department of Kinesiology at The Pennsylvania State University.

MARCH 2003 ❚ 47