The plantar fascia (PF) extends over the calcaneal bone with a thin band corresponding to the calcaneal periosteum, continuing as the paratenon of the Achilles tendon.The triceps surae complex, serving as the main extensor and propulsion system of the foot, involves the Achilles tendon, posterior part of the calcaneus, and Plantar Aponeurosis, all integrated with the fibrous skeleton of the triceps surae. Plantar fasciitis, a prevalent musculoskeletal condition affecting individuals of various ages and activity levels (Hye Chang Rhim), is a primary cause of heel pain in adults. Studies have identified the superior efficacy of stretching protocols targeting the Achilles tendon and/or plantar fascia compared to alternative treatments. However, the limitations of traditional approaches become apparent when considering the intricate biomechanics of the foot and ankle. Conventional calf stretches often prove inadequate for addressing its specific lengthening requirements. While contemporary methods like PF-Specific Stretching integrate plantar fascia and calf stretches, their reliance on individual upper extremity strength introduces potential limitations.

Therefore, although the exact effect of stretching on the biomechanical properties of the plantar fascia is not known, it will be aimed to determine whether an instrument aid to be designed will have an effect and which method is more effective. In this way, it is planned to guide clinicians in the rehabilitation of possible pathologies specific to the plantar fascia in clinical practice.

Myotonometry is a convenient method to assess the stiffness of the plantar fascia because it is cheap, simple and fast. Previous studies have shown that MyotonPRO can reliably assess the stiffness of the plantar fascia. Although the exact effect of stretching on the biomechanical properties of the plantar fascia is not known, it will be determined whether stretching with an instrument to be designed will have an effect and which method is more effective with or without an instrument.

The intricate network of connective tissues in the foot, including the plantar aponeurosis (PA) originating from the calcaneus, sets the stage for a comprehensive understanding of conditions like plantar fasciitis. This broad and thick band runs longitudinally, forming distinct components crucial for maintaining the arch's integrity. Complementing this structure is the plantar fascia (PF), intricately connected to the superficial and deep muscles of the sole, creating a myofascial continuum with profound implications for foot biomechanics.

The interplay between the plantar fascia, Achilles tendon, and the Plantar Aponeurosis within the triceps surae complex emphasizes their collective role as the main extensor and propulsion system of the foot. The posterior compartment of the lower leg, housing various muscles, further underscores the complexity of this biomechanical system.

Nonoperative interventions, constituting approximately 90% effectiveness, encompass a range of approaches, including stretching exercises, modalities, and shock wave therapy, among others. Notably, studies have identified the superior efficacy of stretching protocols targeting the Achilles tendon and/or plantar fascia compared to alternative treatments.

However, the limitations of traditional approaches become apparent when considering the intricate biomechanics of the foot and ankle. Conventional calf stretches often prove inadequate for addressing its specific lengthening requirements. While contemporary methods like PF-Specific Stretching integrate plantar fascia and calf stretches, their reliance on individual upper extremity strength introduces potential limitations.

Myotonometry is a convenient method to assess the stiffness of the plantar fascia because it is cheap, simple and fast. Previous studies have shown that MyotonPRO can reliably assess the stiffness of the plantar fascia.

In the light of all this information, although the exact effect of stretching on the biomechanical properties of the plantar fascia is not known, it will be aimed to determine whether an instrument aid to be designed will have an effect and which method is more effective. In this way, it is planned to guide clinicians in the rehabilitation of possible pathologies specific to the plantar fascia in clinical practice.

Myotonometry is a convenient method to assess the stiffness of the plantar fascia because it is cheap, simple and fast. Previous studies have shown that MyotonPRO can reliably assess the stiffness of the plantar fascia. Although the exact effect of stretching on the biomechanical properties of the plantar fascia is not known, it will be determined whether stretching with an instrument to be designed will have an effect and which method is more effective with or without an instrument.

Inclusion Criteria:

• Healthy volunteers over 18 years of age with a body mass index below 30 kg/m²

Exclusion Criteria:

• pregnancy, presence of chronic musculoskeletal diseases, presence of lower extremity injury and/or surgery, presence of skin lesions above the measurement sites and use of medications affecting the musculoskeletal system