• Male or female between the ages of 18-40 years old.
• Healthy and ready for physical activity as determined by questionnaires you complete about your health status.
• Currently resistance training and have trained for a minimum of 6 months. To be included, you must have completed 3 resistance training sessions (defined as muscle strengthening activities such as free weights, weight machines, or calisthenics, etc.) per week with at least one lower body session. This will be determined by a Training History Questionnaire (THQ).
• Premenopausal, with a regular menstrual period as determined by the menstrual status questionnaire (female participants only).
• Currently not pregnant and do not intend to become pregnant (female participants
  only).
• Currently not taking dietary supplements that may affect study outcomes (e.g., creatine, beta-alanine) and willing refrain from taking such supplements while enrolled in the study. If you are currently using such supplements, you will be permitted to enroll in the study after not taking such supplements for a period of four weeks.
• Willing to adhere to all pre-testing visit instructions including abstaining from exercise for the duration of the study and abstaining from alcohol for 24 hours prior to each study visit.
• Currently consuming ≤ 300mg caffeine (≤ three 8oz cups of coffee) per day on average and willing to keep caffeine intake consistent throughout the duration of the study. Also willing to avoid caffeine intake for 12 hours prior to visits 3, 4 and 5 and not consume caffeine the morning of these visits.
• Free from previous or current lower body injuries that may limit your ability to complete either exercise or physical assessments.
• Highly likely to be successful at providing the required blood samples. This will be determined during visit 1 by a certified phlebotomist.
• Not regularly taking any type of prescription or over-the-counter medication which might affect the assessments, or having any chronic illnesses, which require medical care. This will be determined in your medical history questionnaire.

• Adults aged 18 years and older,
• Had lower extremity musculoskeletal surgery within the previous 6 months.

• 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).

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 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

• Are at least 18 years old
• Currently identify as:
  • a dancer
  • a dance parent
  • a dance teach/choreographer/coach
  • a dance studio/company/program director or equivalent

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

• Adult, aged 18-30 years old
• Native speaker of American English
• Either non-smoker / non-vaper for at least 5 years -OR- a daily vaper for a minimum of 6 months.

• 3;6 – 4;11 years of age
• Speech that is very difficult to understand and would benefit from augmentative and alternative communication (AAC)
• Diagnosis of cerebral palsy with typical language comprehension or
• Diagnosis of childhood apraxia with typical language comprehension or
• Diagnosis of Down syndrome
• Ability to directly select symbols on a tablet or speech generating device
• Available to attend 1-hour intervention sessions at UCF twice weekly for 2 years.

•   5 to 90+ years
•   Ability to understand and carry out test instructions in English