• Participants must be between 18 and 30 years of age
• Participants must be able to read and write in English,

• are between the ages of 18-35 years,
• either have had an anterior cruciate ligament reconstruction (ACLR) surgery or have not had an injury to either of your knees,
• have not been medically diagnosed with a concussion in the previous 6 months,
• have not been medically diagnosed with colorblindness,
• have no known neurological (nervous system) disorder (i.e. Multiple Sclerosis),
• have not taken opioid medication (pain medication) in the last 2 weeks,
• are not pregnant of planning to become present during study participation, and
• have no contraindications to brain MRI (you will complete a screening form).

• Must be at least 18 years or older
• Must be a Cuban immigrant living in the U.S.A. who immigrated after July 11, 2021

• Physically Active Adults (Current Tegner Activity Scale of at least 5)
• Male and female adults, aged 18-30 years

Inclusion criteria – ACL group:

• Age 18-35 years
• History of primary unilateral ACL reconstruction (ACLR) within last 2 years
• No history of any lower limb surgery besides the current ACLR
• Medical clearance to initiate jogging

Inclusion criteria – Uninjured group:

• Age 18-35 years
• No history of lower extremity surgery
• No history of lower extremity injury (defined as seeking medical attention) within last 2 years

• Aged 60 years or older
• Have normal cognitive function (based on results from the Mini-Mental State Examination [MMSE] or Telephone Interview for Cognitive Status)
• Are willing to perform grip strength tests and provide informed consent
• Fluent in English

• Are 18–50 years old.
• Have had low back pain for more than 12 weeks, rated 3/10 or higher in the past 48 hours.
• Are resistance trained (2x/week for the past 8 weeks

ACL Group:

• Age of 18-35 years
• History of only one ACL reconstruction within the previous 2 years
• Medical clearance for return to unrestricted activity

Uninjured Group:

• Age of 18-35 years
• No history of lower limb surgery
• No history of significant lower limb injury within previous 6 months (defined as seeking medical attention, or missing >3 consecutive practices or games)

• At least 18 years old
• Either report having a history of low back pain (LBP) (at least 3 episodes of pain in the last year or 5 episodes in your lifetime) OR have no history of LBP throughout your lifetime to be in the non-LBP group
• An episode of LBP means that you had pain in the lower back region that made you change your daily activities for at least 24 hours.

• At least 14 years old
  • Individuals under the age of 18 must be accompanied by a parent
• Have at least 3 years of ballet experience
• Currently practice dance technique
  • At least 1 hour per week over the past 6 months
• Are familiar with basic ballet terminology