Original Research Reliability of the Star Excursion Balance Test and Two New Similar Protocols to Measure Trunk Postural Control Q9 Diego Lo´pez-Plaza, PhD, Casto Juan-Recio, PhD, David Barbado, PhD, In˜akiRuiz-Pe ´rez, MSc, Francisco J. Vera-Garcia, PhD Q2 Abstract Background: Although the Star Excursion Balance test (SEBT) has shown a good intrasession reliability, the intersession reliability of this test has not been deeply studied. Furthermore, there is an evident high influence of the lower limbs in the performance of the SEBT, so even if it has been used to measure core stability, it is possibly not the most suitable measurement. Objective: The aims of this study were to (1) to assess the absolute and relative between-session reliability of the SEBT and 2 novel variations of this test to assess trunk postural control while sitting, ie, the Star Excursion Sitting Test (SEST) and the Star Excursion Timing Test (SETT); and (2) to analyze the relationships between these 3 test scores. Design: Correlational and reliability testeretest study. Setting: Controlled laboratory environment. Participants: Twenty-seven physically active men (age: 24.54  3.05 years). Method: Relative and absolute reliability of the SEBT, SEST, and SETT were calculated through the intraclass correlation coef- ficient (ICC) and standard error of measurement (SEM), respectively. A Pearson correlation analysis was carried out between the variables of the 3 tests. Main Outcome Measures: Maximum normalized reach distances were assessed for different SEBT and SEST directions. In addition, composite indexes were calculated for SEBT, SEST, and SETT. Results: The SEBT (dominant leg: ICC ¼ 0.87 [0.73-0.94], SEM ¼ 2.12 [1.66-2.93]; nondominant leg: ICC ¼ 0.74 [0.50-0.87], SEM ¼ 3.23 [2.54-4.45]), SEST (ICC ¼ 0.85 [0.68-0.92], SEM ¼ 1.27 [1.03-1.80]), and SETT (ICC ¼ 0.61 [0.30-0.80], SEM ¼ 2.31 [1.82-3.17]) composite indexes showed moderate-to-high 1-month reliability. A learning effect was detected for some SEBT and SEST directions and for SEST and SETT composite indexes. No significant correlations were found between SEBT and its 2 variations (r  .366; P > .05). A significant correlation was found between the SEST and SETT composite indexes (r ¼ .520; P > .01). Conclusions: SEBT, SEST, and SETT are reliable field protocols to measure postural control. However, whereas the SEBT assesses postural control in single-leg stance, SEST and SETT provide trunk postural control measures with lower influence of the lower- limbs. Level of Evidence: To be determined Q4 . Introduction The Star Excursion Balance Test (SEBT) is a field test widely used to assess dynamic postural control [1-6], which is expressed as the maximum distance that par- ticipants can reach with their feet in several directions while maintaining a single-leg stance [7]. The SEBT has been performed normally either in 8 or 4 directions and even simplified to 3 directions (SEBT variation known as Y-Balance Test). The popularity of the different SEBT protocols is mainly based on their relative low cost and ease of use in comparison to posturographic tests, as well as on their within-session reliability [1,3,7-9] and their ap- plications to injury prevention in clinical, sport, and research settings [10-17]. In this sense, low SEBT scores have been related with several injuries, such as recur- rent ankle sprain and chronic instability [13-15,18], anterior cruciate ligament injury [11,16,17,19,20], and chronic low-back pain [12]. Regarding the reliability of the SEBT protocols, most studies have examined the within-session consistency, reporting moderate-to-good intrarater reliability (intra- class correlation coefficient [ICC]: 0.67 < ICC < 0.97; PM R XXX (2018) 1-9 www.pmrjournal.org FLA 5.5.0 DTD  PMRJ2120_proof  31 May 2018  8:54 pm  ce 1934-1482/$ - see front matter ª 2018 by the American Academy of Physical Medicine and Rehabilitation https://doi.org/10.1016/j.pmrj.2018.05.012 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160