The Acute Effects of an Isometric Loading Intervention on Lower Extremity Landing Biomechanics in Individuals With Patellar Tendinopathy

Inclusion criteria

The investigators will recruit a convenience sample of participants who meet the following overall criteria:

• Age 15 and post-pubertal (confirmed by Pubertal Development Scale Questionnaire) - 28 years
• Actively participating within an organized sport setting (high school, collegiate, club, competitive intramural sports) in their respective team's weekly training and competitions, quantified by a Tegner Activity Level Scale of at least 5.

Exclusion criteria

The following exclusion criteria will be applied to all participants:

• Any anterior knee pain with no patellar tendon abnormality on ultrasound assessment.
• History of any knee joint surgery ever.
• History of other (non-knee) lower extremity surgery in the last 1 year.
• History of lower extremity injury in last 6 months (other than patellar tendinopathy).
• An injection (corticosteroids, plasma-rich-protein, etc.) to the patellar tendon in the last 3 months.
• Known history of osteoarthritis or current symptoms related to osteoarthritis (i.e. stiffness, swelling).
• Participation in formal rehabilitation for patellar tendinopathy in prior 3 months
• Known neurological disorders, including: stroke, multiple sclerosis, ALS, diabetic neuropathy, epilepsy, traumatic brain injury resulting in loss of consciousness, concussion within the last 6 months, cranial neural surgery, balance disorders.
• Use of pacemaker or another implantable electronic device.
• History of cardiac arrhythmia or any cardiac condition.
• History of psychiatric disorder. *
• History of cancer in the brain or thigh musculature.
• Pubertal Development Scale Score < 12 (Stages 1-4)

• Note: Rationale for exclusion of individuals with a history of psychiatric disorders is that these individuals may have taken or be taking pharmacological agents that could affect pain or neuromuscular control.