he optimal length, mass, and stiffness of poles are still a matter of debate in modern crosscountry ski racing. Therefore, this study examined the effect of adding pole mass on the metabolic cost and poling frequency during cross-country skiing with the double poling technique. Twelve sub-elite cross-country skiers performed 5-minute roller skiing trials on a motorized treadmill with three different added masses (50g, 100g, 150g) at the center of mass of the pole and with 100g at pole grip. We calculated metabolic rate from the rates of oxygen consumption and carbon dioxide production. We measured poling frequency by counting the number of cycles in 30 seconds twice in each trial and averaged them. Subjects also rated their perceived exertion (RPE) of five different muscle groups (forearm, biceps, triceps, upper back, and lower back). Added mass at the pole shaft significantly increased the oxygen uptake by 1.8% per 100g added and metabolic power by 2.2% per 100g added, while poling frequency significantly decreased by 2.6% per 100g added (p < .05). In terms of metabolic cost and frequency, there were no significant differences between added mass at the pole shaft vs. at the pole grip. Participants reported greater RPE (for all muscle groups) when double poling with +100g or +150g on their poles compared to baseline. Further, RPE was significantly greater in all muscle groups (except upper back) when double poling with +100g on each pole shaft vs. 100g at each pole grip. In conclusion, during roller skiing adding mass to the center of mass of the pole shaft increases oxygen uptake, metabolic power, and RPE and decreases poling frequency.