This is a prospective study of two patient groups: 1) Patients with a giant incisional hernia and 2) controls undergoing open surgery on other indications. Assessment is done pre- and perioperatively and after 1 year including muscular function, lung function, abdominal wall anatomy as provided by CT-scan, and quality of life. Specified biopsies from muscles and connective tissue are examined for muscle fiber size/type and structure by various methods, including electron microscopy and atomic force microscopy. Lung function is monitored by blood gas concentrations, Chronic Obstructive Pulmonary Disease Assessment Test questionnaire, and regular spirometry analyses. The studies are carried out by Ph.D. student Kristian Kiim Jensen, and supervised by professor in surgery Lars Nannestad Jørgensen, professor in sports medicine Michael Kjær and professor in pulmonary medicine Vibeke Backer.