Research Study Participation

• Are a recreationally active (≥150 minutes per week of physical activity) male between the ages of 18-35.
• Are willing to come in for all five visits.

• Participants must either be defined as resistance trained (engaging in resistance exercise with weights at least 2x/week for the past 8 weeks) OR untrained (do not meet ACSM criteria for being physically active: strength training less than 2x/week and less than 150 minutes of aerobic exercise per week)
• 18-50 years old
• Healthy (no pain or injury)

• Male or female adult (18-40 years old)
• Complete less than 150 minutes per week of aerobic exercise and less than 2 full-body
  resistance training sessions per week
• Free from implanted pacemakers/defibrillators
• Free from open cuts/wounds on your right hand and foot
• Metabolically healthy (we will determine this using a health history questionnaire,
  fasting blood glucose < 100mg/dL, and a resting blood pressure < 140/90 mmHg)
• Not actively attempting to gain/lose weight

• 18+ years of age
• Free from implanted pacemakers/defibrillators
• Free from open cuts/wounds on the right hand/foot

• 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).

• 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

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.