What causes muscles to cramp?

Muscles cramp for multiple reasons. The most common causes are fatigue and overuse, dehydration, holding one position for too long, and poor circulation. The more tired and overworked your muscles are, the more likely they will seize up when you continue to use them. Without sufficient water in your body, your muscles are prone to cramping as well. Holding one position for too long stresses your muscle tissues in several ways, which can make a cramp more likely. Poor circulation means your lower limbs aren’t able to get the oxygen and nutrients they need, and so leads to painful problems.