Relationship between core stability and shoulder injuries in athletes

Core stability (neuromuscular control and muscle capacity of the trunk and pelvis) is theoretically linked to optimal shoulder function during sports-specific tasks despite limited evidence to support its use for the prevention or rehabilitation of extremity injuries in athletes. Impairments in core stability could theoretically result in less than optimal performance and abnormal force dissipation to the shoulder complex that could potentially lead to upper extremity injuries in athletes. Lower extremity postural control is also associated with athletic function and may be associated with upper extremity injuries. Clinical measures of core stability have not been validated against lab-based measures of core neuromuscular control. This has resulted in several knowledge gaps that hinder clinical identification of core stability deficits in athletes, as well as the determination of the role that core stability has in athletic injuries. The specific aims of this study are to 1) determine the strength of the association between clinical and lab-based measures of core stability in the athletic population and 2) identify the clinical and lab-based measures of core stability that are significant predictors of shoulder injuries in athletes. Eighty athletes (55 males, age: 21.2 + 3.3 years, 40 with shoulder pain) completed clinical and lab-based tests of core stability that assess aspects of both muscle capacity and neuromuscular control of the trunk and pelvis, as well as lower extremity postural stability. Athletes competed at a club, varsity, or competitive level, and were matched by age, gender, BMI, and sport type. Spearman’s rho (ρ) correlations were used to assess relationships between clinical and biomechanical measures of core stability. MANOVAs were used to assess differences between measures of core stability and lower extremity postural stability between groups. There were significant small-medium correlations between clinical and biomechanical measures of core stability. There were no statistically significant differences between athletes with and without shoulder injuries for the clinical or biomechanical core stability measures or clinical or biomechanical lower extremity postural stability measures. Our findings suggest that the clinical tests assessed require some static core neuromuscular mechanisms, although these tests primarily assess of core muscle capacity. Although core stability is widely incorporated in rehabilitation of athletes with shoulder injuries, these athletes may not present with impairments in core stability or lower extremity postural stability.Ph.D., Rehabilitation Sciences -- Drexel University, 201

Prediction of ACL Injuries from Vertical Jump Kinetics in Division 1 Collegiate Athletes

# Background The incidence of ACL injuries continues to rise secondary to an increase in sport participation. Evidence supports the use of force plate testing to quantify kinetics during rehabilitation after injury and recovery; however, there is limited current research regarding if jump kinetics can identify athletes who are at higher risk for injury. Altered kinetics could potentially lead to abnormal force dissipation and resultant injury. # Purpose The purpose of this investigation was to identify whether the force-time variables from vertical jumps could predict ACL injuries in collegiate athletes. # Study Design Retrospective cohort. # Methods Vertical jump testing is performed by all healthy varsity collegiate athletes at several intervals throughout the athletic year at a Division I institution using a commercially available force plate system with dedicated software. Athletes who sustained an ACL injury between 1/1/15 and 6/1/19 were identified (n=16) and compared to healthy athletes who participated in the same sports (n = 262). ACL injuries were considered for this study if they occurred no more than 10 weeks after a jump test. The outcome variables were load, explode, and drive, operationally defined as the average eccentric rate of force development, average relative concentric force, and concentric relative impulse, respectively, which the system normalized to T scores. Mann-Whitney U tests were used to assess group differences for load, explode, drive, and the ratio between the variables. Logistic regression was used to determine if the battery of variables could predict whether or not an athlete would sustain an ACL injury. The p-value was set to 0.10 for the Mann-Whitney U tests, and 0.05 for the logistic regression. # Results Significant differences between the ACL and healthy groups were seen for explode (*p*=0.08), drive (*p*=0.06), load:explode ratio (*p*=0.06), and explode:drive ratio (*p*=0.03). Explode and drive, when entered into the regression equation, showed the ability to predict injury, $\chi^{2}$= 6.8, df = 2, *p*=0.03. # Conclusions The vertical jump force plate variables were able to identify athletes who sustained an ACL injury within 66 days of testing. Athletes who sustained an ACL injury demonstrated altered kinetics and less ability to transmit forces during the vertical jump. # Level of Evidence 3\

Acute Delta Hepatitis in Italy spanning three decades (1991–2019): Evidence for the effectiveness of the hepatitis B vaccination campaign

Updated incidence data of acute Delta virus hepatitis (HDV) are lacking worldwide. Our aim was to evaluate incidence of and risk factors for acute HDV in Italy after the introduction of the compulsory vaccination against hepatitis B virus (HBV) in 1991. Data were obtained from the National Surveillance System of acute viral hepatitis (SEIEVA). Independent predictors of HDV were assessed by logistic-regression analysis. The incidence of acute HDV per 1-million population declined from 3.2 cases in 1987 to 0.04 in 2019, parallel to that of acute HBV per 100,000 from 10.0 to 0.39 cases during the same period. The median age of cases increased from 27 years in the decade 1991-1999 to 44 years in the decade 2010-2019 (p < .001). Over the same period, the male/female ratio decreased from 3.8 to 2.1, the proportion of coinfections increased from 55% to 75% (p = .003) and that of HBsAg positive acute hepatitis tested for by IgM anti-HDV linearly decreased from 50.1% to 34.1% (p < .001). People born abroad accounted for 24.6% of cases in 2004-2010 and 32.1% in 2011-2019. In the period 2010-2019, risky sexual behaviour (O.R. 4.2; 95%CI: 1.4-12.8) was the sole independent predictor of acute HDV; conversely intravenous drug use was no longer associated (O.R. 1.25; 95%CI: 0.15-10.22) with this. In conclusion, HBV vaccination was an effective measure to control acute HDV. Intravenous drug use is no longer an efficient mode of HDV spread. Testing for IgM-anti HDV is a grey area requiring alert. Acute HDV in foreigners should be monitored in the years to come