Upper Quarter Y Balance Test

Reliability and Performance Comparison Between Genders in Active Adults

Abstract

Gorman, PP, Butler, RJ, Plisky, PJ, and Kiesel, KB. Upper Quarter Y Balance Test: Reliability and Performance Comparison Between Genders in Active Adults. J Strength Cond Res 26(11): 3043–3048, 2012—The inclusion of movement tests before performance training and sport participation is gaining popularity as part of musculoskeletal screening for injury. The identification of an athlete's asymmetries and poor performance in the preseason allows coaches and sports medicine clinicians the opportunity to proactively address these deficits to reduce the potential for injury. Currently, there are no tests reported in the literature that simultaneously require shoulder and core stability while taking the subjects through a large range of motion at the end range of their stability. Thus, the purpose of this article was to describe the Upper Quarter Y Balance Test and report the gender differences in the performance of the test. Upper extremity reach distances were measured in 95 active adults using a standardized upper extremity balance-and-reach protocol. Intraclass correlation coefficients were used to assess reliability, and gender differences were analyzed using an independent samples t-test, whereas bilateral differences were analyzed using a dependent samples t-test for the normalized composite reach scores. Intraclass correlation coefficient (3.1) for test-retest reliability ranged from 0.80 to 0.99. Intraclass correlation coefficient (3.1) for interrater reliability was 1.00. Average composite scores (right/left) reported as a percentage of limb length were 81.7/82.3% for men and 80.7/80.7% for women. The results of the study suggest that the Upper Quarter Y Balance Test is a reliable test for measuring upper extremity reach distance while in a closed-chain position. It was further determined that there was no significant difference in performance between genders or between sides on the test when normalized to limb length. Coaches and sports medicine professionals may consider incorporating the Upper Quarter Y Balance Test as part of their preprogram testing to identify movement limitations and asymmetries in athletes and thereby may reduce injury.

Introduction

Multiple sporting agencies suggest that suitable evidence-based screening tests for elite athletes are lacking (^1,7). They further state that such tests should be reliable, sensitive, specific, affordable, and acceptable to the intended screening population (¹⁵). Dynamic movement testing during the preparticipation examination is gaining popularity as a component of musculoskeletal screening with the goal of identifying increased injury risk (^3,14,20,21). Known injury risk factors include anthropometric measures, player position, skill level, amount of training time, flexibility, asymmetry, prior injury, playing surface, and shoe type (^{4,6,8,12,16–18,25}). Although these risk factors have been identified individually, injury risk is likely multifactorial. Recently, researchers have used tests involving comprehensive movement patterns to predict injury (^14,21). Although this has been reported in the literature for the lower extremity, only few studies have addressed this testing for the upper extremity.

To date, only 2 closed–kinetic chain upper extremity tests have been described in the literature: the one-arm hop test (⁵) and the closed–kinetic chain upper extremity stability test (CKCUEST) (^9,23). To perform the one-arm hop test, an athlete assumes a 1-arm push-up position on the floor and then uses the arm to hop onto a 10.2-cm step and back onto the floor. The time required to perform 5 repetitions as quickly as possible is recorded. The CKCUEST begins in a traditional push-up position with the hands placed 36 inches apart on strips of athletic tape. The athlete then reaches with alternating hands across the body to touch the piece of tape under the opposing hand; the number of cross-body touches performed in 15 seconds is recorded. Although these tests do place an athlete in a closed–kinetic chain position, they require power, speed, and stability and do not take into account mobility. Furthermore, these tests are performed within an athlete's comfortable base of support, and therefore, they do not challenge the athlete near the limits of his or her stability, nor do they require other essential aspects of sports, such as thoracic and scapular mobility.

Because of limitations of other testing procedures, the Upper Quarter Y Balance Test (YBT-UQ) was developed. The YBT-UQ is a tool that allows for the quantitative analysis of an athlete's ability to reach with the free hand while maintaining weight bearing on the contralateral upper limb. To perform the YBT-UQ, the athlete is asked to reach with the free hand in the medial, inferolateral, and superolateral directions while maintaining weight bearing on the stance hand that is placed in a standardized location (Figure 1). The YBT-UQ attempts to address some of the limitations of the previously described tests. First, mobility and stability are both maximally challenged during the test. Stability of the stance limb is challenged at the same time that mobility of the thorax and reach limb is required. During each reach, components of scapular stability and mobility, thoracic rotation, and core stability are combined as the athlete is encouraged to reach as far as possible without loss of balance. By reaching as far as possible outside of a narrow base of support, the athlete is required to use balance, proprioception, strength, and greater range of motion. Most healthy individuals should be able to perform the test without much training or cuing. However, before implementing the YBT-UQ as a screening tool for upper extremity injury, it is necessary to establish fundamental measurement properties for the test.

Figure 1: Test kit; Starting position and reach directions for the Upper Quarter Y Balance Test.

Because there is currently not a test of upper extremity performance reported in the literature that evaluates joint mobility and stability simultaneously at the limits of overall upper-body stability, the purpose of this study was to examine the fundamental measurement properties of a test that allows for this type of movement. The fundamental measurement properties that need to be established are reliability, gender differences, and bilateral differences. It is hypothesized that the utilization of the standardized protocol for the YBT-UQ will result in high interrater and test-retest reliabilities. It is also hypothesized that there will not be any differences in the normalized YBT-UQ performance between genders or between limbs.

Methods

Experimental Approach to the Problem

Researchers have hypothesized that using tests that require balance, strength, and range of motion at the limit of stability may improve the accuracy of identifying athletes at greatest risk for injury (²¹). As is true with any new measurement tool, the initial measurement aspects that need to be developed are the test-retest and intertester reliabilities and also gender and bilateral differences. By analyzing the performance of young healthy men and women on the test, the authors were able to report the summary of performance in a general population, and also the differences between sides and genders. To analyze the interrater reliability, all testing was performed and scored by 2 raters simultaneously blinded to each other's scoring, and the raters independently determined if a successful trial was completed. To analyze the test-retest reliability, a subset of subjects were tested the same day after a rest period. This initial study also allows us to obtain an indication of reliability before future studies in athletic populations.

Subjects

A sample of convenience of both genders was recruited to perform a unique upper extremity weight-bearing balance-and-reach test. This experiment was approved by the institutional review board of the researchers' university, and written informed consent was obtained from all subjects before enrollment in the study.

Ninety-six adults (51 men and 45 women) from the general population who were currently participating in recreational fitness activities (aged 19–47 years) were enrolled in the study. Subjects were healthy with no history of current or previous injury that would preclude them from participation. An additional test was performed on 22 subjects to establish the reliability (10 men and 12 women) of the testing protocol. These subjects were tested again no less than 20 minutes after the initial testing to determine reliability coefficients. Subjects were excluded from participating in the study if they had an upper or a lower extremity amputation; a vestibular disorder; a lack of medical clearance for participation in fitness or sport; an injury; current or undergoing treatment for inner ear, sinus, or upper respiratory tract infection or head cold; or a cerebral concussion within the previous 3 months.

Procedures

The Y Balance Test Kit (Move2Perform, Evansville, IN, USA; Figure 1), on which the YBT-UQ is performed, consists of a stance platform to which 3 pieces of polyvinyl chloride pipe are attached in the medial, inferolateral, and superolateral reach directions. The posterior pipes are positioned 135° from the anterior pipe, and there is 90° between the posterior pipes. Each pipe is marked in 0.5-cm increments for measurement. The subject pushes a target (reach indicator) along the pipe, which standardizes the reach height (i.e., how far off the ground the reach hand is), and the target remains over the tape measure during performance of the test, which improves the precision in determining reach distance.

The variables of interest for the study included normalized maximum reach distances for each reach direction along with composite reach distance. The greatest successful reach for each direction for each rater was used for analysis. The maximum reach distances were divided by the subject's upper limb length to normalize each reach distance. To measure upper limb length, the subject stood in an anatomical position while the investigator identified the C7 vertebrae. After C7 was identified, the investigator instructed the subject to raise (abduct) the right limb to shoulder height (90°). The examiner then measured the distance from the C7 spinous process to the most distal tip of the right middle finger (in centimeters) with a cloth tape measure. The composite reach distance was calculated by averaging the greatest trial in each of the 3 normalized reach distances for an analysis of overall performance on the test.

Before testing, all subjects viewed a video that provided standardized instructions, which included a demonstration by the examiner of the test position. All subjects performed the test with shoes off. To perform the YBT-UQ, the subject assumed the starting position with testing hand on the stance platform and the thumb adducted while being aligned behind the red starting line. The starting position for the reach hand was defined by positioning the reach hand on top of the medial reach indicator placed shoulder width from the stance plate. Performance on the test consisted of the subject reaching in the 3 reach directions with the free hand while maintaining a push-up position with feet shoulder width apart. The trial was discarded and repeated if the subject (a) failed to maintain unilateral stance on the platform (e.g., touched down to the floor with the reach hand or fell off the stance platform), (b) failed to maintain reach hand contact with the reach indicator on the target area while it was in motion (e.g., shoved the reach indicator), (c) used the reach indicator for stance support (e.g., placed fingers or hand on top of the reach indicator), (d) failed to return the reach hand to the starting position under control, or (e) lifted either foot off of the floor. This process was repeated until 3 trials in each direction on each hand had been performed. Subjects were allowed to stop and remove themselves from testing at any time.

To improve the reproducibility of the test and establish a consistent testing protocol, a standard testing order was developed and used. The testing order began with the right hand on the stance plate to allow the left hand to reach in the medial direction (right medial reach), followed immediately by reaching under the trunk in the inferolateral direction (right inferolateral reach), and then reaching in the superolateral direction (right superolateral reach) and returning under control to the start position. This procedure was repeated for 2 additional trials on the right limb. After 3 trials on the right limb, the testing order was repeated on the left limb. One practice trial was conducted on each side before the performance trials were completed to minimize the novel effects of the test while not causing excessive fatigue given the demanding nature of the test.

All testing was observed and scored by 2 raters simultaneously who were blinded to each other's scoring. The raters independently determined whether a successful trial was completed (i.e., that the hand was positioned correctly behind the line and that all the criteria were met for a successful trial). To reduce bias, the raters recorded the reach distances regardless of whether each rater thought the trial was successful. If the subject was unable to perform the test according to the aforementioned criteria in 4 attempts, the subject failed that side.

The maximum reach distance was measured by reading the tape measure at the edge of the reach indicator, at the point where the most distal part of the hand reached. All measurements were scored to the closest 0.5-cm increment.

Statistical Analyses

Descriptive statistics were performed for each limb for each of the 3 reach directions along with the composite score. Test-retest and interrater reliabilities were assessed using intraclass correlation coefficients (3.1). Intraclass correlation coefficient values above 0.75 were considered acceptable (²²). Gender differences on the YBT-UQ were determined using an independent samples t-test, with a cutoff of p < 0.05 to establish statistical significance. Interlimb differences were examined using a dependent samples t-test, with a cutoff of p < 0.05 to establish statistical significance. These tests were determined after establishing that the data met the criteria for parametric analysis. Data from the parameters for the population were combined with the reliability data to establish the minimal detectable change for each of the variables measured and calculated on each limb. All statistical analyses were performed using SPSS Statistics software (version 15.0; SPSS, Inc., Chicago, IL, USA).

Results

Test-retest reliability ranged from 0.80 to 0.99 for the tests. Interrater reliability was 1.00 for all tests. The reach direction that produced the highest test-retest reliability was the superolateral direction (0.92–0.99), whereas the reach direction that produced the lowest test-retest reliability was the inferolateral direction (0.80–0.96). All tests of reliability were adequate based on the criteria defined a priori.

The examination of gender differences on the YBT-UQ revealed no statistically significant differences between men and women for any of the 3 reach directions or the composite score (Figure 2). No differences existed for the reach distances between the left and right sides. The highest scores were recorded for the medial reach, followed by the inferolateral reach, and then the superolateral reach. The average composite reach score for the sample was 84.5 ± 8.3% of limb length (Table 1).

Figure 2: Gender differences (mean ± 95% confidence intervals) in reach scores for each reach direction between men (black) and women (gray) reported as a percentage of limb length (%LL).

Table 1: Average Upper Quarter Y Balance Test scores, reported as a percentage of limb length (%LL) for all reach directions and the composite. The SEM and minimal detectable difference (MDD, 95%) are also reported in centimeters.

Discussion

Before this study, there were few reports in the literature regarding upper extremity performance testing. None of the previously reported tests simultaneously assessed joint stability and mobility of the entire upper quarter and trunk at the limit of stability. This was the rationale for the development of the YBT-UQ. The findings of this study suggest that the YBT-UQ is reliable between sessions and between raters. Additional analyses from this study revealed no gender or bilateral differences for any of the normalized reach directions or the composite scores in this limited sample. The results of this study imply that the YBT-UQ is an appropriate tool to be used as a clinical measurement of upper quarter performance.

Although gender differences were not found in the performance of YBT-UQ in this population, this is a different finding than was discovered with the Lower Quarter Y Balance Test. Plisky et al. (¹⁹) found that the score varied according to gender, sport, and competition level. Furthermore, physical performance test requirements have been modified for gender in the military (²), and researchers have identified that varying the push-up technique influences performance (^10,24).

Some limitations of our study should be noted. Error could have been introduced by fatigue (¹¹) and practice effect (¹³). Additional limitations included the lack of control for training level, training cycle, nutrition, or hydration that may have affected the test scores.

There is a need to expand normative data using the YBT-UQ on varied populations (e.g., professional, high school, youth athletes in multiple sports). This would include a comparison of performance on the YBT-UQ to determine if there are differences in performance by sport and age, as has been previously noted with the Lower Quarter Y Balance Test (²¹). With normative data and prospective studies, we could better determine whether the YBT-UQ is predictive of injury in different populations and establish acceptable reach distances for each population. We recommend that future studies should use a similar standardized testing protocol so that results may be compared across studies.

The YBT-UQ has shown good reliability with the standardized equipment and methods. Future studies should examine the clinical efficacy of this newly developed tool, which may provide sports medicine clinicians and coaches an objective way to determine deficits and asymmetries in individuals. Future studies may demonstrate that injury prevention strategies and strength programs are appropriate to develop in response to limitations identified by the YBT-UQ; however, additional research is required.

Practical Applications

This study may assist sports professionals in identifying movement limitations and asymmetries in athletes before implementation of training and conditioning programs. The current findings solely apply to a healthy noninjured population. It is important to examine how these scores change based on populations. Future studies need to be conducted to determine whether asymmetries and poor performance in upper extremity movement testing are predictive of future injury. The results of the study suggest that the Upper Quarter Y Balance Test is a reliable test for measuring upper extremity reach distance while in a closed-chain position at the limits of overall upper-body stability. Coaches and sports medicine professionals may consider incorporating the Upper Quarter Y Balance Test as part of their preprogram testing to identify movement limitations and asymmetries in athletes and thereby may reduce injury.

Acknowledgments

The authors thank Beth Ross, DPT, SCS, OCS, for her assistance in data collection for this study. Phillip Plisky is the inventor of the Y Balance Test Kit used in this study. The results of this study do not constitute endorsement of the product by the authors or the National Strength and Conditioning Association.