Correlation of Player and Imaging Characteristics With Severity and Missed Time in National Football League Professional Athletes With Hamstring Strain Injury: A Retrospective Review.

BACKGROUND: Hamstring strain injuries (HSIs) are prevalent in US National Football League (NFL) players, but there is a paucity of information regarding imaging characteristics, injury severity, and player factors associated with time missed and risk of recurrent injury. PURPOSE: To describe player, football activity, clinical, and imaging characteristics of NFL players with HSIs, as well as determine player characteristics, clinical examination results, and magnetic resonance imaging (MRI) findings associated with injury occurrence, severity, and missed time. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A retrospective cohort of NFL players with acute HSI (n = 180) during the 2018-2019 season was identified. Injury data were collected prospectively through a league-wide electronic health record system. Three musculoskeletal radiologists graded MRI muscle injury parameters using the British Athletics Muscle Injury Classification (BAMIC) system. Player, football, clinical, and imaging characteristics were correlated with HSI incidence and severity and with missed time from sport. RESULTS: Of the 1098 HSIs identified during the 2018-2019 season, 416 (37.9%) were randomly sampled, and 180 (43.3%) had diagnostic imaging available. Game activity, preseason period, and wide receiver and defensive secondary positions disproportionately contributed to HSI. The biceps femoris was the most commonly injured muscle (n = 132, 73.3%), followed by the semimembranosus (n = 24, 13.3%) and semitendinosus (n = 17, 9.4%) muscles. The most common injury site was the distal third of the biceps femoris and semitendinosus muscles (n = 60, 45.5% and n = 10, 58.8%, respectively) and central part of the semimembranosus muscle (n = 17, 70.8%). Nearly half of the injuries (n = 83, 46.1%) were BAMIC grade 2; 25.6% (n = 46), grade 3; and 17.8% (n = 32), grade 4. MRI showed sciatic nerve abnormality in 30.6% (n = 55) of all HSIs and 81.3% (n = 26) of complete tendon injuries. BAMIC grade correlated with both median days and games missed. Combined biceps femoris and semitendinosus injuries resulted in the highest median days missed (27 days). CONCLUSION: Among NFL players with acute HSIs, the most common injury was a moderate-severity injury of the distal biceps femoris. BAMIC grade was associated with missed time.

Injury during U.S. Army basic combat training: a systematic review of risk factor studies.

CONTEXT: Approximately one quarter of men and half of women in U.S. Army basic combat training experience an injury. Preventing basic combat training-related injuries would reduce associated human and economic costs and discharges from the Army. Identification of risk factors for such injuries is a crucial step toward their prevention. Although some research has begun to address this need, prior studies of risk factors for training-related injury have not been reviewed systematically. This study systematically reviews the literature on risk factors for injury during U.S. Army basic combat training. EVIDENCE ACQUISITION: Original studies of risk factors for injury during U.S. Army basic combat training published since 1990 in peer-reviewed journals were identified using PubMed and manual searches of reference lists. This search was last performed in May 2013. Nineteen studies met the inclusion criteria. EVIDENCE SYNTHESIS: Methodologic quality and potential for bias were assessed. The findings of 11 studies deemed to be of high or medium quality were synthesized to determine the level of evidence supporting the association between each risk factor studied and risk of injury during basic combat training. Quality assessment and evidence synthesis were performed from June to September 2013. CONCLUSIONS: There is strong or moderate evidence supporting association of older age, history of smoking, and self-rated low physical activity level prior to basic combat training with increased risk of training-related injury among male trainees. There is limited, mixed, or insufficient evidence to identify risk factors for injury among female trainees.

Methodological challenges of using U.S. Army administrative data to identify a cohort of basic combat trainees and descriptive analysis of trends in characteristics that are potential risk factors for training-related injury.

OBJECTIVES: Training-related injury is a threat to military health and readiness. Prevalence of potential risk factors for training-related injury can change with U.S. Army recruitment goals and may influence basic combat training (BCT) injury rates. This article describes challenges of using administrative data to identify a trainee cohort and describes demographic and training characteristics across the five BCT locations. METHODS: Data from the Total Army Injury and Health Outcomes Database were used to identify a U.S. Army-wide cohort of first-time trainees from January 1, 2002 to September 30, 2007 and describe its characteristics. RESULTS: The cohort includes 368,102 first-time trainees. The annual number starting BCT increased from 52,187 in 2002 to 68,808 in 2004. The proportion of males increased from 81.57% in 2003 to 83.84% in 2007. Mean (SD) age increased from 20.67 (3.55) years in 2002 to 20.94 (3.65) years in 2007. Mean (SD) body mass index increased from 24.53 (3.56) kg/m(2) in 2002 to 24.94 (3.84) kg/m(2) in 2006. Other characteristics fluctuated by year, including proportions of race/ethnicity, accession waivers, and confirmed graduates. CONCLUSIONS: Fluctuations in trainee characteristics warrant further analysis of potential influence on BCT injury rates. For research uses, careful acquisition of administrative data is needed.