A flexion contracture occurs when a joint becomes stuck in the flexion position (bent) and cannot be straightened. In the case of a flexion contracture of the finger, the finger gets stuck in a bent position and cannot be straightened by either muscle strength or with the help of the opposite hand. The bend can occur in the joint at the tip of the finger, in the middle of the finger, or in the knuckle. A flexion contracture of the knee keeps the leg bent and prevents the it from straightening either passively or actively. Sitting for prolonged periods of time can lead to a hip flexion contracture, in which the iliopsoas (the main muscle pair that cross the anterior of the hip) gets stuck in its shortened state (the state it is in when sitting.) Injury, blockage, scar tissue, disuse, and muscle tightness or shortness can lead to a flexion contracture. Contractures can be temporary or permanent and may require physical therapy or surgery. Implementing stretches that run the joints through their full range of motion can be extremely helpful in preventing flexion contractures. To prevent a hip flexion, avoid prolonged sitting and instead take breaks that include exercises that stretch the iliopsoas (e.g., supine stretch or bridge pose).