Knee injuries, especially those to the ACL, are common among physically active people. Preventing these injuries from happening is critical to limiting the long-term pain, disability, and arthritis associated with these injuries. Our study is going to examine new ways to provide feedback about the way people move to determine if these are better at modifying movement patterns to prevent injury than current standard treatments. If you participate, you will be asked to undergo a movement analysis in a research laboratory while you perform tasks such as landing from a box and running and cutting. After this initial assessment, you will be randomly allocated to one of 3 treatment groups. Each treatment group will perform 4 weeks (3x/week) of exercises to change the way people land from a jump. Participants will then report for follow-up movement analysis testing 1- and 4-weeks after completing the intervention.

Despite the popularity of injury prevention programs, anterior cruciate ligament (ACL) injuries continue to occur at a rate of 250,000 per year in the United States. It is believed that 75% of these injuries are preventable, thus alternative strategies to reduce the risk of injury are necessary. One reason current prevention strategies are not wholly successful may be their reliance on internal focus of attention (InFOCUS) feedback, which constrains movement and increases injury risk. Our project will examine an alternative approach, testing two different modes of external focus of attention (ExFOCUS) feedback to remove constrains on the way people move to reduce injury risk. We will also examine cortical activity to determine if there are differences in neuroplasticity that occur following each form of feedback to better understand how each works. Collectively, the knowledge gained from this study will inform the development of programs to reduce injury risk.

Specific Aim 1: Determine ExFOCUS's ability to reduce the risk of noncontact ACL injury by retaining improved biomechanics compared to InFOCUS. Hypothesis 1.1: the combined auditory and visual ExFOCUS groups will demonstrate greater improvements in biomechanics and will retain these improvements 1 month after cessation of the intervention.

Specific Aim 2: Determine differences in the ability of the two modes (visual and auditory) of ExFOCUS to change biomechanics. Hypothesis 2.1: Auditory ExFOCUS feedback will elicit superior results compared to visual ExFOCUS feedback immediately following the intervention. Specific Aim 3: To quantify differences in cortical activity following external focus of attention and internal focus of attention feedback. Hypothesis 3.1: External focus of attention feedback will increase cortical activity in both groups while there will be no changes in cortical activity during internal focus of attention feedback Hypothesis 3.2: Auditory feedback will elicit greater changes in auditory regions of the brain, while visual feedback will elicit greater changes in regions of the brain responsible for processing visual information.

Inclusion Criteria:

• exercise 30+ minutes 3+ days/week

Exclusion Criteria:

• Body mass index >40 kg/m2
• History of lower extremity fracture or surgery to either limb
• History of ACL tear, meniscus, or collateral ligament injury at the knee to either limb
• History of ankle sprains to either limb
• History of musculoskeletal injury sustained in the 6 months prior to enrollment
• History of concussion or neurological disorders that may influence electroencephalography activity
• Visual or hearing impairments that would limit receiving the appropriate feedback
• Inability to comprehend and repeat back directions in English
• Current smoker