Which of the following is NOT a cause of plantar fasciitis?

Plantar fasciitis is commonly associated with several biomechanical and lifestyle factors that lead to the overuse or strain of the plantar fascia, which is a thick band of connective tissue on the bottom of the foot. Increased hydration is not typically linked to the development of plantar fasciitis. While hydration is important for overall health and can influence muscle performance and recovery, it does not directly impact the structural integrity or function of the plantar fascia.

In contrast, flat feet can lead to an improper distribution of weight and increased strain on the plantar fascia. Reduced range of dorsiflexion can restrict the ankle's ability to flex properly during activities, subsequently placing unusual stress on the foot and the plantar fascia. Similarly, inappropriate or poorly designed footwear can contribute significantly to the risk of developing plantar fasciitis by not providing adequate support or cushioning, exacerbating stress on the feet during movement.

Thus, among the choices given, increased hydration stands apart from the biomechanical and structural causes associated with plantar fasciitis.