The Assessment of Hamstring Related Deficiencies in Collegiate Football Athletes With a Prior History of Hamstring Strains: A Retrospective Case Control Study
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Objective: To examine commonly established hamstring strain injury risk factors in collegiate football athletes with a history of previous hamstring strain compared to football athletes that have never incurred a hamstring injury. Design: Retrospective case-control study. Participants: A total of 30 participants that engage in competitive football (age = 20.77±1.22; weight = 214.47±23.33 pounds; height = 72.97±4.09), were screened and evaluated for eligibility to partake in this study. Participants in the HSI group (n=15) suffered from at least one activity-limiting hamstring strain diagnosed by a healthcare professional in the past 2 years but not within 6 months of participation in the study. An activity limiting hamstring strain must have resulted in limitations in practice or competition. The healthy group (n=15) consisted of participants that have never experienced a diagnosis of a hamstring strain. Neither group suffered a lower extremity injury at least 3 weeks prior to testing procedures. Methods: Five dependent variables were assessed: 1.) health-related quality of life assessed through a self-reported outcomes assessment instrument, 2.) pelvis position measured with a CHEK Inclinometer, 3.) flexibility measured with the active straight leg (ASLR) test measured in degrees, 4.) hamstring endurance measured during the performance of a single-leg bridge test (SLHB) to fatigue and 5.) isokinetic strength calculation using the functional equation of eccentric hamstring strength, to concentric quadriceps strength (H:Qfunc) at 60°/s,180°/s, and 300°/s. Results: The baseline disability assessment measured by DPA scores was significantly different between the HSI group and the healthy control (t(14) = -3.66, p=.003) with the HSI group displaying some low levels of disability. There were no significant differences between the HSI and healthy groups in regards to pelvic tilt, ALSR, and H:Qfunc scores @60°/s, 180°/s, and 300°/s. No statistically significant difference were noted between the two groups in the SLHB scores, but the interaction between group and injured limb approached significance (p=.059). Conclusions: This case-control study did not find significant differences in groups (HSI and healthy) in regards to strength, posture, flexibility, and endurance. The demands of other sports primarily researched such as soccer, rugby, and Australian Rules football have different work demands; therefore previous research may have limited applicability to football Although this data was unable to support other statistical findings in previous research, important information regarding future testing considerations, based on sample size and protocol methodology has been acknowledged. Keywords: Hamstring strain injury, football, hamstring deficiency, strength, flexibility, endurance, pelvis position.