Background:Anterior cruciate ligament (ACL) injuries are among the most common and devastating sports-related knee injuries. Neuromuscular training (NMT) has demonstrated efficacy as a preventive intervention for ACL injury and has been associated with improvements in measures of sports performance, but the specific physiologic mechanisms that serve as protective factors and contribute to improved performance haven not been well-defined.Hypothesis/Purpose:The purpose of this study is to investigate the association between NMT and biomechanical efficiency among high school athletes. We hypothesized that the performance of NMT is associated with improved biomechanical efficiency during the performance of fundamental movements and agility tests when compared to a group of untrained control subjects.Methods:Eight high school soccer and basketball teams (111 athletes, 53.1% male, mean age 15.6 years) were recruited and assigned to either an intervention or control group. The intervention group performed NMT as part of their warm-up prior to each practice and competition for 12 weeks. NMT was administered by experienced sports medicine clinicians who provided exercise instruction, technique cues, and performance feedback throughout each training session. The control group performed their customary warm-up under the direction of the team’s coaches. Biomechanical efficiency was assessed through performance of static and dynamic tests using an FDA-approved wireless sensor system. Agility was assessed using a timed three-cone agility test. All tests were administered immediately prior to and following each competitive sports season.Results:Matched pre-/post-season data was collected from 74 athletes (67%). Significant improvements [point estimate (95% CI) p-value] were observed in the intervention group for left lower extremity [0.25 (0.06,0.45) p = 0.01] and right lower extremity [0.21 (0.05,0.37) p = 0.01] loading/landing speed ratios during a single leg hop test, left lower extremity [-136.34 (-225.74,-46.95) p = 0.003] and right lower extremity [-110 (-211.36,-8.64) p = 0.03] ground reaction force, left lower extremity [-1.03, (-.189,-0.18) p = 0.02] and right lower extremity [-0.94 (-1.73,-0.14) p = 0.02] initial peak acceleration, and cadence [-12.12 (-21.60,-2.65) p = 0.01] during a straight-line running acceleration/deceleration test, and time [0.51 (0.24,0.78) p = 0.0003] during a three-cone agility test.Conclusion:Results demonstrate that season-long, sport-specific, age-appropriate NMT administered by sports medicine clinicians can significantly improve biomechanical efficiency during the performance of fundamental movements and agility tests by high school athletes. To achieve similar results, sports coaches should be trained to provide exercise instruction, technique cues, and performance feedback when administering NMT in real-world settings.Table 1.Participant DemographicsDemographicsControl (N=40)Intervention (N=71)Sex (%) Male47.556.3Female52.543.7Race (%) American Indian2.5.90Asian05.6Black/African American62.59.9Middle Eastern04.2White/Caucasian054.9Other27.522.5Unknown10.02.8Ethnicity (%) Hispanic or Latino47.536.6Not Hispanic or Latino52.560.6Unknown02.8Age in years (Mean)15.415.8BMI (Mean)23.421.9Upper Extremity Limb Dominance (%) Left5.014.1Right95.085.9Lower Extremity Limb Dominance (%) Left10.016.9Right90.083.1Previous ACL Injury (%)2.51.4Table 2.T-test ResultsTestMeasureNPost-Preseason Control MeanPost-Preseason Intervention MeanDifference Control-Intervention95% CIP-ValueSingle Leg SquatSquat speed Translation Average Left74-1.88-4.382.5(-1.47,6.46)0.21Squat speed Translation Average Right74-5.23-3.55-1.68(-6.06,2.69)0.45Medial/Lateral Tibial Translation Average Left740.050.22-0.17(-0.44,0.08)0.17Medial/Lateral Tibial Translation Average Right740.30.10.2(-0.14,0.53)0.25Double Leg SquatSquat Speed Translation Average Left73-3.77-3.39-0.38(-3.44,2.67)0.8Squat Speed Translation Average Right73-0.39-4.343.95(0.21,7.87)0.04Medial/Lateral Tibial Translation Average Left730.030.11-0.08(-0.52,0.37)0.73Medial/Lateral Tibial Translation Average Right730.030.32-0.29(-0.80,0.21)0.25Single Leg HopHop Speed Ratio Average left740.12-0.130.25(0.06,0.45)0.01Hop Speed Ratio Average Right730.11-0.10.21(0.05,0.37)0.01Hop Flight Time Average Left74-0.03-0.01-0.02(-0.06,0.02)0.39Hop Flight Time Average Right73-0.06-0.02-0.04(-0.09,0.01)0.11Medial/Lateral Tibial Translation Average Left740.010.21-0.2(-0.50,0.09)0.17Medial/Lateral Tibial Translation Average Right730.050.09-0.04(-0.53,0.46)0.87Acceleration DecelerationGround Force Reaction Left74-98.4137.93-136.34(-225.74,-46.95)0.003Ground Force Reaction Right74-92.0717.93-110(-211.36,-8.64)0.03Initial Peak Acceleration left74-1.1-0.07-1.03(-1.89,-0.18)0.02Initial Peak Acceleration right74-1.38-0.44-0.94(-1.73,-0.14)0.02Ground Contact Time Left747.07-2.569.63(-0.32,19.57)0.06Ground Contact Time Right747.590.317.28(-3.07,17.62)0.16Cadence74-7.414.71-12.12(-21.60,-2.65)0.013 Cone TestTime760.14-0.370.51(0.24,0.78)0.0003