The association between Y-balance test scores, injury, and physical performance in elite adolescent Australian footballers

Correlation of absolute and relative limb differences in Y-balance test and asymmetry indices of CMJ, SJ and IMTP

OBJECTIVE

Determine the relationship between Y-Balance Test (YBT) and force platform-based assessments, including squat jump (SJ), countermovement jump (CMJ), and isometric mid-thigh pull (IMTP), to evaluate lower limb stability and asymmetry.

METHOD

Sixty-one recruited active professional firefighters were assessed for YBT absolute limb differences (anterior, posteromedial, and posterolateral directions) using the YBT classic formula or a force platform built-in formula, and for asymmetry indices of CMJ, SJ and IMTP derived from the force platform.

RESULTS

The absolute limb differences in YBT anterior (YBT-A) showed a moderate correlation (r > 0.4) with asymmetry indices of SJ concentric peak force (SJ-CPF), IMTP peak force component (IMTP-PFC), and IMTP peak force (IMTP-PF). Subsequently, limb relative differences for YBT-A were calculated using the built-in formula of the force platform, which also showed a moderate correlation (r > 0.4) with asymmetry indices of SJ-CPF, IMTP-PFC, and IMTP-PF. However, when considering either absolute or relative differences, YBT posteromedial asymmetry (YBT-PMA) or YBT posterolateral asymmetry (YBT-PLA) showed weak or negative correlations with asymmetry indices derived from the force platform.

CONCLUSION

This study demonstrated that YBT anterior asymmetry (YBT-AA) calculated by using either the YBT classic formula or the built-in formula of the force platform, showed a moderate correlation with asymmetry indices derived from the force platform. This study provides clinicians and researchers with different test methods for assessing lower limb stability.

Poor Sleep Quality Worsens Static and Dynamic Balance Control in Individuals With Chronic Low Back Pain: A Cross-Sectional Study

Objective: To investigate the influence of sleep quality and associated factors on balance control in individuals with chronic low back pain (CLBP). Methods: 85 participants (mean age 33.2 ± 12.5 years) with CLBP were recruited. Physical and emotional well-beings were evaluated using a battery of questionnaires. Sleep quality over the last month was assessed using the Pittsburgh Sleep Quality Index (PSQI). Participants were dichotomized into the good sleep quality (GSQ) and poor sleep quality (PSQ) groups if their PSQI scores were ≤ 5 and > 5, respectively. Balance control was measured using the one-leg stance with eyes closed and Y-balance test. Results: The GSQ group included 37 participants, while the PSQ group comprised 48 participants. After controlling for confounds (including gender, age, disability, anxiety, depression, and fear avoidance beliefs), participants with PSQ displayed significantly poorer performance in the one-leg stance with eyes closed and lower normalized posteromedial, posterolateral, and composite scores of the Y-balance test compared with participants with GSQ. Additionally, sleep quality accounted for 16.9%-24.9% of the variance in balance control, while age explained an additional 5.2%-13.2% of the variance. Additionally, higher levels of physical disability and anxiety were associated with poorer balance control. Conclusions: Individuals with concurrent CLBP and PSQ exhibit significantly worse balance control than those with CLBP alone. Future studies should investigate whether improving sleep quality, physical disability, and anxiety can enhance balance in individuals with CLBP.

Strength and dynamic balance performance in soccer players in the United States: age, sex, and bilateral differences

Quantification of asymmetries between the two limbs is informative in assessing the risk of injury and performance deficits, but there is a paucity of studies investigating the effects of age and sex on bilateral asymmetry in young soccer players. This cross-sectional study aimed to investigate the effects of age and sex on strength and dynamic balance in 7- to 24-year-old soccer players in the United States. A total of 174 young soccer players participated in the study (Age 7-9 years: 26 females and 16 males; Age 10-12 years: 32 females and 31 males; Age 13-17 years: 17 females and 25 males; Age >18 years: 13 females and 14 males). Jump displacement, peak force, and asymmetry during countermovement jump with arm swing and landing, peak force and asymmetry during push-up, and normalized reaching distances for upper and lower extremity reaching tests were quantified. Preferred legs and arms were defined as the preferred kicking leg or throwing arm. As age increased, both preferred and non-preferred sides demonstrated decreased landing forces, increased jump displacement, and increased normalized peak forces during push-ups in both males and females (p < 0.05). Males showed greater jump displacement, normalized landing forces, and normalized peak forces in push-ups compared to females in several age groups (p < 0.05). No significant differences were observed for asymmetry variables between ages or sexes, and on average, most bilateral asymmetry variables were less than 5%. Age was associated with strength but not dynamic balance performance in healthy soccer players in the United States. Male and female players demonstrated similar changes, and bilateral asymmetries were on average small. Soccer players may need more dynamic balance training over time as they progress to higher levels of competition. Landing technique training may be implemented for young soccer players to decrease the high impact landing forces and landing related injury risk. Asymmetries and their relationships with injury risk should be evaluated on an individual basis, as their relationships with age and sex were weak. Future longitudinal and cohort studies are warranted to further elucidate the relationship among strength, dynamic balance, and injury risk in soccer players.

Test-retest, intra- and inter-rater reliability of the reactive balance test in patients with chronic ankle instability

Introduction

The Reactive Balance Test (RBT) could be a valuable addition to research on chronic ankle instability (CAI) and clinical practice, but before it can be used in clinical practice it needs to be reliable. It has already been proven reliable in healthy recreational athletes, but not yet in patients with CAI who have shown persistent deficits in dynamic balance. The study aimed to determine the test-retest, intra-, and inter-rater reliability of the RBT in patients with CAI, and the test-retest and inter-rater reliability of the newly developed RBT score sheet.

Methods

We used a repeated-measures, single-group design to administer the RBT to CAI patients on three occasions, scored by multiple raters. We included 27 participants with CAI. The study used multiple reliability measures, including Pearson r, intra-class correlations (ICC), standard error of measurement (SEM), standard error of prediction (SEP), minimal detectable change (MDC), and Bland-Altman plots, to evaluate the reliability of the RBT's outcome measures (visuomotor response time and accuracy). It also assessed the test-retest and inter-rater reliability of the RBT score sheet using the same measures.

Results

The ICC measures for test-retest reliability were similar for accuracy (0.609) and VMRT (0.594). Intra-rater reliability had high correlations and ICCs for accuracy (r = 0.816, ICC = 0.815) and VMRT (r = 0.802, ICC = 0.800). Inter-rater reliability had a higher ICC for VMRT (0.868) than for accuracy (0.690).

Conclusion

Test-retest reliability was moderate, intra-rater reliability was good, and inter-rater reliability showed moderate reliability for accuracy and good reliability for VMRT. Additionally, the RBT shows robust SEM and mean difference measures. The score sheet method also demonstrated moderate test-retest reliability, while inter-rater reliability was good to excellent. This suggests that the RBT can be a valuable tool in assessing and monitoring balance in patients with CAI.

Evaluation of the Value of the Y-Balance Test to Predict Lower Limb Injuries in Professional Male Footballers

CONTEXT

The aim of this prospective cohort study was to identify whether Y-Balance Test (YBT) performance and asymmetry are associated with lower limb injury in elite adult football athletes.

DESIGN

A prospective cohort study.

METHODS

Preseason YBT measures were obtained from 121 male footballers participating in National League One across the 2021-2022 season. Lower limb injuries were tracked across the season to determine the relationship between YBT variables and injury incidence using logistic regression analysis. The statistical significance level was .05.

RESULTS

The average YBT score was 111.0 (5.8) cm on the left limb and 112.0 (5.5) cm on the right limb, with an average asymmetry of 2.3 (1.4) cm. Athletes with lower YBT scores on both the left (odds ratio = 2.9; 95% confidence interval, 1.7 to 4.8: P ≤ .001) and right (odds ratio = 2.3; 95% confidence interval, 1.6 to 3.2: P ≤ .001) limbs were at a greater risk of injury. Similarly, athletes with greater amounts of asymmetry were also more likely to get injured (odds ratio = 2.1; 95% confidence interval, 1.3 to 3.3: P = .002).

CONCLUSIONS

Results indicate that lower and asymmetrical YBT scores have a significant relationship with future lower limb injuries in professional male footballers. The YBT offers a simple, reliable, and effective screening tool that can be used by practitioners in football to help identify players at a greater risk of injury before the season commences.

The influence of different levels of physical activity and sports performance on the accuracy of dynamic lower limbs balance assessment among Chinese physical education college students

Background: Balance ability is the basis of human actions. Improving the accuracy of dynamic balance assessment can increase the efficiency of sports injury prediction. Objectives: This study aimed to investigate how physical activity and sports performance affect the dynamic balance ability of lower limbs and validate whether the Lower Quarter Y-Balance Test (YBT-LQ) is a reliable predictor of sports injury risk among Chinese physical education college students. Materials and Methods: In total, 169 voluntary participants completed the YBT-LQ at the beginning of a semester and provided some physiological information and an injury report at the end of the semester. The correlation between YBT-LQ performance and selected factors that can affect the dynamic balance control was analyzed based on data statistics. The receiver operating characteristic (ROC) and the area under curve (AUC) of the composite scores of the YBT-LQ were calculated to explore an optimal cutoff value for predicting sports injury risk. Results: The composite scores of the YBT-LQ exhibited strong correlations with both the sports performance level and sports injury, as well as a moderate correlation with physical activity level, age (negative), and metabolic equivalent (MET). In the entire study population, the area under the receiver operating characteristic (ROC) curves for the binary classification of composite YBT-LQ scores of the left and right legs to predict sports injury risk were 0.78 and 0.74, respectively. Stratifying the study participants based on their levels of physical activity and sports performance had an effect on the AUC values of ROC curves. The optimal cutoff scores of the YBT-LQ for predicting sports injury risk were variable, with values more or less than 95%. Specifically, the cutoff scores for participants with the highest level of sports performance were notably higher, reaching up to 106.5% (left) and 107.2% (right). Conclusion: Physical activity and sports performance can influence human dynamic balance control. Composite scores of the YBT-LQ can be used with acceptable efficiency to predict sports injury. Stratifying participants based on their levels of physical activity and sports performance leads to different optimal cutoff values of the YBT-LQ composite scores in predicting sports injury. This approach is preferable to relying solely on a uniform 95% cutoff. It is recommended to analyze individuals with higher levels of sports performance, such as elite athletes, separately from those with lower levels. This is because the former group has a higher optimal cutoff value compared to the latter.

Associations between upper quarter Y-balance test performance and sport-related injuries in adolescent handball players

Handball players are at a high risk of suffering a sport-related injury. Recent studies in various adult populations (e.g., US Army soldiers/warrior athletes, and military members) showed that poor scores in the upper quarter Y-balance test (YBT-UQ) are related to an increased risk of injury. Yet, it is unclear whether this also applies to adolescent handball players. Thus, the present study aims to determine if pre-season YBT-UQ performance is associated with sport-related injuries during the competitive season in adolescent handball players. One hundred and thirty-three adolescent handball players (age: 15.4 ± 1.7 years; m = 99, f = 42) who competed in the second highest league in the Rhine-Ruhr region, Germany, during the 2021/2022 season participated in the study. Before the competitive season, the players performed the YBT-UQ to assess upper extremity mobility and stability of the throwing and non-throwing arm. Over the 8-month competitive season, the coaches monitored the occurrence of sports-related injuries once a week, using an injury report form from the legal accident insurance. Fifty-seven players (43%) incurred a sport-related injury during the competitive season, of which 27 (47%) had upper body injuries, and 30 (53%) were lower body injuries. The YBT-UQ performance of the throwing and non-throwing arm did not significantly differ between injured and non-injured players. Further, Cox proportional hazard survival regression model analyses revealed that only the presence of an inferolateral reach asymmetry score ≥7.75% arm length was associated with a moderate increase in the risk (hazard ratio = 2.18, 95% confidence interval = 1.02–4.68, p = 0.045) of lower but not upper or whole-body injuries. Our findings suggest that the YBT-UQ has limited value as a field-based screening tool to assess the risk of sport-related injuries in adolescent handball players.

Lower Quarter Y-Balance Test Anterior Reach Asymmetry and Noncontact Lower Limb Injury in Subelite Young Male Soccer Players With Different Training Experiences

Poor single-leg balance performance is associated with an increased risk of sustaining lower limb injuries in team sports. However, it is unclear whether this relationship is modified by the level of training experience (years of training experience). The objective of the present study was to evaluate whether soccer players’ single-leg balance performance is related to lower limb injuries in noncontact situations with different levels of training experience. Subelite young male soccer players performed the Lower Quarter Y-Balance Test with the dominant and the nondominant leg at the beginning of the preseason. Due to COVID-19 rules, the occurrence of lower limb injuries during the second half of the competitive season was documented. The odds of injury were calculated based on a previously reported Lower Quarter Y-Balance Test cut-off score for side-to-side anterior reach difference (≥4 cm). Twelve soccer players sustained a lower leg injury in noncontact situations. Only four of them had an anterior reach difference equal to or above the cut-off score. Soccer training experience has no significant influence on the association between Lower Quarter Y-Balance Test anterior reach asymmetry and noncontact lower limb injury in young male players.

Relationships between Functional Movement Quality and Sprint and Jump Performance in Female Youth Soccer Athletes of Team China

This study aimed to determine the optimal functional movement screen (FMS) cut score for assessing the risk of sport injury, and to investigate the correlations between functional movement quality and sprint and jump performance. Twenty-four (N = 24) athletes performed all tests in one day at 10−30 min intervals, and the FMS test was performed first, without a warm-up session. After a standard warm-up, athletes then completed the Y-balance Test (YBT), sprint, counter-movement jump (CMJ), and standing long jump (SLJ), in turn. For each test, the best of three attempts was recorded for further analysis. A receiver operating characteristic (ROC) curve and area-under-the-curve (AUC) were used to determine the optimal FMS cut score for assessing the risk of sport injuries, and Spearman’s rank correlation analysis was used to quantify associations between functional movement scores and athletic performance. The average FMS score was 16.2 and the optimal FMS cut score for assessing the risk of sport injuries was 14.5. There were moderate relationships between total FMS score and 10−20 m sprint time (r = −0.46, p < 0.05), between In-line Lunge and 0−20 m sprint time (r = −0.47, p < 0.05), between Shoulder Mobility and 0−10 m sprint time (r = −0.48, p < 0.05), and between Trunk-stability Push-up and 10−20 m sprint time (r = −0.47, p < 0.05). Moreover, Hurdle Step score was largely correlated with 0−10 m time (r = −0.51, p < 0.05). For Y-balance, moderate correlations were observed between CMJ height and anterior asymmetry score (r = −0.47, p < 0.05) and posteromedial asymmetry score (r = −0.44, p < 0.05). However, there were no significant associations between YBT performance (asymmetric in three directions and composite score) and sprint performance (p > 0.05). Taken together, the results indicate that a FMS score of 14 is not a gold standard for assessing the risk of injury in all populations; we recommend that the FMS cut score of 14.5 should be the optimal score for assessing risk of injury in young female elite soccer players. Moreover, the FMS and YBT were introduced to assess the quality of functional movements, and they cannot be used to assess sprint and jump performance. Practitioners can use components of the FMS that have similar characteristics to specific sports to assess athletic performance.

Change of Direction Speed and Reactive Agility in Prediction of Injury in Football; Prospective Analysis over One Half-Season

Agility is an important factor in football (soccer), but studies have rarely examined the influences of different agility components on the likelihood of being injured in football. This study aimed to prospectively evaluate the possible influences of sporting factors, i.e., flexibility, reactive agility (RAG), and change of direction speed (CODS), on injury occurrence over one competitive half-season, in professional football players. Participants were 129 football professional players (all males, 24.4 ± 4.7 years), who underwent anthropometrics, flexibility, and RAG and CODS (both evaluated on non-dominant and dominant side) at the beginning of second half-season 2019/20 (predictors). Over the following half-season, occurrence of injury was registered (outcome). To identify the differences between groups based on injury occurrence, t-test was used. Univariate and multivariate logistic regressions were calculated to identify the associations between predictors and outcome. Results showed incidence of 1.3 injuries per 1000 h of training/game per player, with higher likelihood for injury occurrence during game than during training (Odds Ratio (OR) = 3.1, 95%CI: 1.63–5.88) Univariate logistic regression showed significant associations between players’ age (OR = 1.65, 95%CI: 1.25–2.22), playing time (OR = 2.01, 95%CI: 1.560–2.58), and RAG (OR = 1.21, 95%CI: 1.09–1.35, and OR = 1.18, 95%CI: 1.04–1.33 for RAG on dominant- and non-dominant side, respectively), and injury occurrence. The multivariate logistic regression model identified higher risk for injury in those players with longer playing times (OR = 1.81, 95%CI: 1.55–2.11), and poorer results for RAG for the non-dominant side (OR = 1.15, 95%CI: 1.02–1.28). To target those players who are more at risk of injury, special attention should be paid to players who are more involved in games, and those who with poorer RAG. Development of RAG on the non-dominant side should be beneficial for reducing the risk of injury in this sport.