A night splint is a brace that you use at night to treat certain conditions like Achilles tendinopathy and plantar fasciitis. Night splints are designed to keep your foot and toes pointing up, in a flexed position, which applies constant gentle stretching to the tendons around the foot. The best orthopedic splints are designed to be worn both during the day and at night. There are a variety of orthopedic products you available for overnight use.