Fjallraven Bergtagen Stretch Trousers Women. Bergtagen Stretch Trousers give the perfect combination of freedom of movement, durability and protection on spring and summer alpine adventures. The robust double-weave stretch fabric releases moisture when you work up a sweat, and gives you the freedom you need for your most daring moves. Perfect as a robust work garment on demanding trips, where the simple design minimises the risk of them getting caught or interfering with a climbing harness or other equipment.