Backpack Weight (IMAGE) American Institute of Physics Caption A group of backpackers hike on an Outward Bound course in the La Sal Mountains, UT. Credit M.O'Shea/KSU Usage Restrictions This image may be used only with appropriate caption and credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.