Association Between Lower Trapezius Isometric Strength and Y-Balance Test Upper Quarter Performance in College Volleyball Players

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.

Effects of core stability on shoulder and spine kinematics during upper limb elevation: A sex-specific analysis

BACKGROUND

Upper limb elevation begins with core stabilization, but the effects of core stability on shoulder and spine kinematics are unknown. Sex differences also exist in shoulder kinematics and core stability.

OBJECTIVE

To clarify the effects of core stability on shoulder and spine kinematics during upper limb elevation by taking sex into account.

DESIGN

Cross-sectional.

METHODS

The Sahrmann Core Stability Test, lumbar spine motor control test battery, and Y Balance Test (lower and upper quarters) were performed in 50 healthy young adults. For each test, a principal component (PC) analysis was conducted according to sex; the overall core stability score was calculated. The top and bottom third of the PC scores were defined as high and low score groups, respectively (each group: nine males and eight females). Shoulder and spine kinematics during upper limb elevation were compared separately for males and females.

RESULTS

Spinal extension was greater in the low score group by a maximum of 1.9° in males (P < .001; η² = 0.068) and 1.6° in females (P < .001; η² = 0.141). In the low score group of females, the scapular posterior tilt was a maximum of 5.6° smaller (P < .001; η² = 0.221) and glenohumeral elevation was a maximum of 4.5° larger (P < .001; η² = 0.113) than the high score group of females.

CONCLUSION

Core stability affected spine and female scapular and glenohumeral kinematics during upper limb elevation. Core stability may be one of the potential contributors to shoulder kinematics, particularly in females.

Role of active joint position sense on the upper extremity functional performance tests in college volleyball players

Background

It has been well established that proprioception plays a decisive role in shoulder stability and sport performance. Notwithstanding, there is a lack of clear association between active joint position sense (AJPS) and the performance of upper-extremity functional performance tests. The aim of this study was to determine whether the AJPS of the shoulder complex is associated with the performance of college volleyball players with the following functional tests: Y-Balance Test-Upper Quarter (YBT-UQ), Closed Kinetic Chain Upper-Extremity Stability Test (CKCUEST), and Seated Medicine Ball Throw (SMBT). The secondary aim was to investigate whether the magnitude of the proprioception error through the AJPS had the ability to act as a predictor for functional test scores.

Methods

Cross-sectional study with a convenience sampling. Healthy college volleyball players (≥12 h of training/week), 30 males and 22 females, between 18 and 26 years of age were included. AJPS of the shoulder (90° of flexion (90°Flex), 90° of internal rotation at 90° of abduction (90°IR/ABD), 90° of external rotation at 90° of abduction (90°ER/ABD)) and three upper-extremity functional performance tests (YBT-UQ, CKCUEST and SMBT) were assessed. A Pearson's test and a stepwise multiple linear regression analysis were used to determine possible associations and relationships between outcome measures, respectively.

Results

The analysis revealed that AJPS at 90°IR/ABD and 90°ER/ABD were the only proprioceptive variables with an association to the YBT-UQ and SMBT. Despite these relationships, only the AJPS at 90°IR/ABD was associated with the performance of the YBT-UQ in; superolateral direction (β = -0.7; 95% CI [-1.3 to 0.1]; p = 0.025); inferolateral direction (β = -1.5; 95% CI [-2.1 to -0.8]; p = 0.001); and composite score (β = -0.8; 95% CI [-1.3 to -0.3]; p = 0.002). From these, AJPS at 90°IR/ABD mainly explained the variability of YBT-UQ (inferolateral direction) performance (R² = 0.32; %R² = 0.32). Our findings allow for a possible expanded role for proprioception as a contributing factor in upper limb motor control during functional movements. Further research is required to explore and distinguish the associations between proprioception, motor control and sport performance involving the upper limbs.