The LESS is a valid and reliable tool for identifying potentially high-risk movement patterns during a jump-landing task.

The purpose of this investigation was to determine the association between gender and the prevalence and incidence of patellofemoral pain syndrome (PFPS). One thousand five hundred and twenty-five participants from the United States Naval Academy (USNA) were followed for up to 2.5 years for the development of PFPS. Physicians and certified athletic trainers documented the cases of PFPS. PFPS was defined as retropatellar pain during at least two of the following activities: ascending/descending stairs, hopping/jogging, prolonged sitting, kneeling, and squatting, negative findings on examination of knee ligament, menisci, bursa, and synovial plica, and pain on palpation of either the patellar facets or femoral condyles. Poisson and logistic regressions were performed to determine the association between gender and the incidence and prevalence of PFPS, respectively. The incidence rate for PFPS was 22/1000 person-years. Females were 2.23 times (95% CI: 1.19, 4.20) more likely to develop PFPS compared with males. While not statistically significant, the prevalence of PFPS at study enrollment tended to be higher in females (15%) than in males (12%) (P50.09). Females at the USNA are significantly more likely to develop PFPS than males. Additionally, at the time of admission to the academy, the prevalence of PFPS was not significantly different between genders.

Background Patellofemoral pain syndrome (PFPS) is one of the most common chronic knee injuries; however, little research has been done to determine the risk factors for this injury. Hypothesis Altered lower extremity kinematics and kinetics, decreased strength, and altered postural measurements will be risk factors. Study Design Prospective cohort. Methods 1597 participants were enrolled in this investigation and prospectively followed from the date of their enrollment (July 2005, July 2006, or July 2007) through January 2008. Each participant underwent baseline data collection during their pre-freshman summer at the United States Naval Academy. Baseline data collection included three-dimensional motion analysis during a jump-landing task, six lower extremity isometric strength tests, and postural alignment measurements (navicular drop and Q-angle). Participants were prospectively followed from their date of enrollment to January 2008 (maximum of 2.5 years of follow up). Results Risk factors for the development of PFPS included decreased knee flexion angle, decreased vertical ground reaction force, and increased hip internal rotation angle during the jump-landing task. Additionally, decreased quadriceps and hamstring strength, increased hip external rotator strength, and increased navicular drop were risk factors for the development of PFPS. Conclusions Multiple modifiable risk factors for PFPS pain have been identified in this investigation. In order to decrease the incidence of this chronic injury, the risk factors for PFPS need to be targeted in injury prevention programs. Clinical Relevance Prevention programs should focus on increasing strength of the lower extremity musculature along with instructing proper mechanics during dynamic movements in order to decrease the incidence of PFPS.

Context: Identifying neuromuscular screening factors for anterior cruciate ligament (ACL) injury is a critical step toward large-scale deployment of effective ACL injury-prevention programs. The Landing Error Scoring System (LESS) is a valid and reliable clinical assessment of jump-landing biomechanics.Objective: To investigate the ability of the LESS to identify individuals at risk for ACL injury in an elite-youth soccer population.Design: Cohort study. Setting: Field-based functional movement screening performed at soccer practice facilities.Patients or Other Participants: A total of 829 elite-youth soccer athletes (348 boys, 481 girls; age ¼ 13.9 6 1.8 years, age range ¼ 11 to 18 years), of whom 25% (n ¼ 207) were less than 13 years of age.Intervention(s): Baseline preseason testing for all participants consisted of a jump-landing task (3 trials). Participants were followed prospectively throughout their soccer seasons for diagnosis of ACL injuries (1217 athlete-seasons of follow-up).Main Outcome Measure(s): Landings were scored for ''errors'' in technique using the LESS. We used receiver operator characteristic curves to determine a cutpoint on the LESS. Sensitivity and specificity of the LESS in predicting ACL injury were assessed.Results: Seven participants sustained ACL injuries during the follow-up period; the mechanism of injury was noncontact or indirect contact for all injuries. Uninjured participants had lower LESS scores (4.43 6 1.71) than injured participants (6.24 6 1.75; t 1215 ¼ À2.784, P ¼ .005). The receiver operator characteristic curve analyses suggested that 5 was the optimal cutpoint for the LESS, generating a sensitivity of 86% and a specificity of 64%.Conclusions: Despite sample-size limitations, the LESS showed potential as a screening tool to determine ACL injury risk in elite-youth soccer athletes.Key Words: children, knee, biomechanics, movement patterns Key PointsThe Landing Error Scoring System (LESS) score may effectively identify elite-youth soccer athletes at higher risk of sustaining anterior cruciate ligament (ACL) injuries. Elite-youth soccer athletes with LESS scores of 5 or more were at higher risk of sustaining ACL injuries than athletes with LESS scores less than 5. Individuals with LESS scores of 5 or more may be targeted for ACL injury-prevention exercise programs.

There was no discernable change in rate of anterior cruciate ligament injury in men or women during the study period. Men's lacrosse is a high-risk sport for anterior cruciate ligament injury. Unlike basketball and soccer, the rates of anterior cruciate ligament injury are essentially the same in men's and women's lacrosse. The level of allowed contact in pivoting sports may be a factor in determining sport-specific anterior cruciate ligament risk.