Inclusion Criteria:  Male or female, age 12 - 65 years old. Athlete at High School, Collegiate, Recreational, Olympic / Professional level.  Exclusion Criteria:  Indidividual under 12 or over 65 years old. Lower extremity injury in the past 6 months. History of neurological disease, vestibular or visual disturbance. Any other pathology that would impair motor performance.