Research Study Participation

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)

• 18-35 years old with no current or history of low back pain or spine surgery
• Able to carry a 35 pound rucksack (heavy backpack)
• Able to perform a single leg squat on both legs

• 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

• At least 18 years old
• A licensed of certified healthcare provider
• A student in an accredited professional healthcare program

• Are an aerobically trained female (≥150 minutes per week of moderate to vigorous aerobic activity) between the ages of 18-35.
• Achieve a peak V̇O₂ of ≥33.6 ml∙kg^-1∙min^-1 on the first visit based on age- and sex-specific normative reference values for cycle ergometry provided by the American College of Sports Medicine
• Are willing to come in for all six visits

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

• Age 12-45 years
• History of knee injury (e.g., ACL tear, meniscus tear, patellofemoral pain, osteoarthritis) or surgery (e.g., ACL reconstruction, meniscectomy or repair, total knee arthroplasty) within the last 2 years