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Gubler C.1, Price T.2, Hayes C.1, Irion J.1,3, Shelley-Tremblay J.4
1University of South Alabama, Physical Therapy, Mobile, United States, 2Univerisity of South Alabama, Physical Therapy, Mobile, United States, 3Emory and Henry College, Physical Therapy, Emory, United States, 4University of South Alabama, Psychology, Mobile, United States
Background: Non-contact anterior cruciate ligament (ACL) injuries are common in sports that involve cutting, jumping and pivoting. An estimated 70% of ACL injuries result from non-contact mechanisms. Female athletes have 4 to 8 times the injury risk of men in these high risk sports. There are likely differences in strength, agility, and plyometric demand among sports that can affect injury risk. Screening for risk factors in female athletes and identifying deficits common to specific sports can help better design injury prevention programs. Injury risk assessment is possible in the gym/clinic using existing equipment. Landing mechanics can be assessed with 2-D digital video and an app, such as Hudl. Strength ratios can be measured on an isokinetic device or other machines in the gym.
Purpose: To compare ACL injury risk among women's collegiate sports using strength ratios and 2D analysis.
Methods: Women intercollegiate basketball, soccer and volleyball athletes were tested for lower extremity strength and landing mechanics at the start of preseason. Hamstring and quadriceps (H/Q) ratios were calculated from strength tests. Frontal and sagittal plane views were recorded during drop box vertical jumps. Knee valgus and maximum hip and knee flexion were determined from video. Valgus was determined by measuring distance between the knees, ankles and hips and calculating ratios of distances knee to hip (KH) and ankle to hip (AH).
Results: Athletes, age range 17 to 21 (25 soccer, 13 basketball and 7 volleyball), were tested upon reporting for preseason training. No differences in age or BMI were noted among sports. Right and left leg H/Q ratios were 0.60 and 0.64 for basketball, 0.88 and 0.91 for volleyball, 0.89 and 0.90 for soccer respectively. The ankle hip (AH) ratio for volleyball players was 0.95 compared to soccer at 0.84 and basketball at 0.86. The knee to hip (KH) ratio was 0.96 for volleyball, 0.91 for soccer and 0.85 for basketball.
Conclusion(s): A H/Q ratio of 0.60-0.80 helps prevent ACL injuries. The H/Q ratios of basketball players were significantly less than volleyball and soccer but were at or above the suggested threshold for injury prevention at 0.60 on the right and 0.64 on the left. Knee to hip ratios of 1.0 indicate no valgus, while at 0.60, knee valgus is distinct.3,5 Despite volleyball having a wider stance than basketball (BB ratios of AH= .86 and KH = .85, VB ratios AH = .95 and KH = .96) both groups exhibited minimal valgus at maximum flexion during the jump landings. The demands and training of different sports may account for the differences in ratios of H/Q and landing mechanics however the measured factors did not fall into high risk categories for any of the sports tested.
Implications: Using existing gym equipment, apps and smartphone technology, one can inexpensively identify ACL risk in athletes and utilize results to adjust training to enhance performance and prevent injuries.
Funding acknowledgements: None
Topic: Sport & sports injuries
Ethics approval: Approval for this study was obtained from the University of South Alabama IRB.
All authors, affiliations and abstracts have been published as submitted.
