Plantar fasciitis is a common cause of heel pain, and although stretching exercises are a standard first-line treatment, current evidence on adding proprioception or knee-strengthening exercises remains limited. This study investigates whether adding knee strengthening or proprioception exercises to a standard stretching program improves pain, function, and disability in patients with chronic plantar fasciitis, and whether these interventions produce measurable changes in the biomechanical and kinesiological properties of the foot, ankle, and knee.