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BACKGROUND: Deficits in dynamic neuromuscular control have been associated with post-injury sequelae and increased injury risk. The Y-Balance Test Lower Quarter (YBT-LQ) has emerged as a tool to identify these deficits. PURPOSE: To review the reliability of the YBT-LQ, determine if performance on the YBT-LQ varies among populations (i.e., sex, sport/activity, and competition level), and to determine the injury risk identification validity of the YBT-LQ based on asymmetry, individual reach direction performance, or composite score. STUDY DESIGN: Systematic Review. METHODS: A comprehensive search was performed of 10 online databases from inception to October 30, 2019. Only studies that tested dynamic single leg balance using the YBT-LQ were included. Studies were excluded if the Y-Balance Test kit was not utilized during testing or if there was a major deviation from the Y-Balance test procedure. For methodological quality assessment, the modified Downs and Black scale and the Newcastle-Ottawa Scale were used. RESULTS: Fifty-seven studies (four in multiple categories) were included with nine studies assessing reliability, 36 assessing population differences, and 16 assessing injury prediction were included. Intra-rater reliability ranged from 0.85-0.91. Sex differences were observed in the posteromedial direction (males: 109.6 [95%CI 107.4-111.8]; females: 102.3 [95%CI 97.2-107.4; p = 0.01]) and posterolateral direction (males: 107.0 [95%CI 105.0-109.1]; females: 102.0 [95%CI 97.8-106.2]). However, no difference was observed between sexes in the anterior reach direction (males: 71.9 [95%CI 69.5-74.5]; females: 70.8 [95%CI 65.7-75.9]; p=0.708). Differences in composite score were noted between soccer (97.6; 95%CI 95.9-99.3) and basketball (92.8; 95%CI 90.4-95.3; p <0.01), and baseball (97.4; 95%CI 94.6-100.2) and basketball (92.8; 95%CI 90.4-95.3; p=0.02). Given the heterogeneity of injury prediction studies, a meta-analysis of these data was not possible. Three of the 13 studies reported a relationship between anterior reach asymmetry reach and injury risk, three of 10 studies for posteromedial and posterolateral reach asymmetry, and one of 13 studies reported relationship with composite reach asymmetry. CONCLUSIONS: There was moderate to high quality evidence demonstrating that the YBT-LQ is a reliable dynamic neuromuscular control test. Significant differences in sex and sport were observed. If general cut points (i.e., not population specific) are used, the YBT-LQ may not be predictive of injury. Clinical population specific requirements (e.g., age, sex, sport/activity) should be considered when interpreting YBT-LQ performance, particularly when used to identify risk factors for injury. LEVEL OF EVIDENCE: 1b.
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BACKGROUND: Limited ankle dorsiflexion (DF) is associated with ankle sprains and other lower extremity injuries. Current ankle measurements can be laborious to perform in an athletic environment. PURPOSE: The purpose of this study was to determine the reliability and discriminant validity of a novel closed-chain ankle DF ROM test, the standing ankle dorsiflexion screen (SADS). STUDY DESIGN: Reliability and validity study. METHODS: Thirty-seven healthy subjects participated in the study. Two raters measured closed-chain ankle DF range of motion (ROM) using a modified lunge position with an electronic inclinometer. Four raters measured ankle DF using the SADS. Reliability was calculated using intraclass correlation coefficients (ICC) and kappa coefficients for the raters using an electronic inclinometer and the SADS scale, respectively. An independent t-test compared the SADS categories of "behind" and "beyond" to the modified lunge test ROM (p<0.05). RESULTS: Excellent ICC values (0.95 [95% CI (0.92,0.97)]) and high kappa values were observed (0.61-0.81), with high percent agreement (86-94%). There was a significant difference in ankle DF ROM between the nominally scored "behind" and "beyond" categories, regardless of rater or trial analyzed (behind: 41.3° ± 4.7°; beyond: 51.8°± SD 6.1°, p <0.001). CONCLUSIONS: The SADS was observed to have excellent interrater reliability and high discriminant validity. Furthermore, there was a distinct closed chain ankle DF ROM difference between the "behind" and "beyond" SADS nominal scores. CLINICAL RELEVANCE: The SADS can be used as a quick and efficient closed chain ankle DF ROM screen. LEVEL OF EVIDENCE: 2b.
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INTRODUCTION: Dysfunctional breathing (DB) is common (60-80%) in adults. Individuals with DB may have decreased pain thresholds, impaired motor control and balance, and movement dysfunction. These impairments likely adversely affect performance. Research has demonstrated that DB is multi-dimensional and includes biochemical, biomechanical, and psychophysiological categories. PURPOSE: The purpose of this study was to test the impact of breathing exercises in an otherwise healthy population of individuals diagnosed with at least one category of DB. It was hypothesized that the exercise program would normalize at least one category of DB. METHODS: An experimental group with DB was recruited, then the control group was matched for gender, age, BMI and activity. Baseline breathing metrics were obtained for each category of breathing dysfunction: capnography for biochemical (ETCO2 of < 35mmHg at rest = DB), HI-LO for biomechanical (upper chest or paradoxical patterns = DB), and Self-Evaluation of Breathing Questionnaire (SEBQ ≥ 25 = DB) and Nijmegen Questionnaire ( ≥ 22 = DB) for psychophysiological. The experimental group performed a four-week progression of home breathing exercises, once daily and the control group continued normal activities (no interventions). Re-testing of all outcome measures was performed after four weeks. RESULTS: Thirty-five individuals comprised the participant sample (16 experimental, 19 control, mean age 26.0 years, mean BMI of 24.3). There were no statistically significant differences between groups at baseline. Eighty-one percent of subjects in the experimental group improved in at least one category compared to 21% of subjects in the control group. Seventy-eight percent of subjects with biomechanical category of DB in the experimental group normalized this dysfunction, while none normalized in the control group, which was statistically significantly different. Twenty-seven percent of subjects with biochemical DB in the experimental group normalized, while only 25% in the control group which was not statistically different. There were only two subjects in each group with the psychophysiological category, therefore no analysis was performed. CONCLUSION: Home exercises were effective in reversing the biomechanical category of DB in 78% of young, otherwise healthy adults versus no exercise. However, the exercises did not affect the biochemical category of DB. Performing a set of home exercises may be an effective option for fitness and rehabilitation providers to suggest for clients to normalize biomechanical breathing dysfunction. LEVEL OF EVIDENCE: 2b.