Cross-country skier going uphill (IMAGE) Norwegian University of Science and Technology Caption New research shows that too many hard hills during cross-country ski training affect skiers’ training volume. Credit Trine M. Seeberg Usage Restrictions Credit must be given to the creator. Only noncommercial uses of the work are permitted. Adaptations must be shared under the same terms. License CC BY-NC-SA 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.