EFFECT OF ROLLING RESISTANCE ON POLING FORCES AND METABOLIC DEMANDS OF ROLLER SKIING

Objective: To examine the effect of an increase in roller ski rolling resistance on the physiological and upper body demands of roller skiin g with the V2-alternate technique. Methods: Nine highly skilled cross- country skiers roller skied at three paced speeds on a flat oval loop using roller skis with high (HiR) and low (LowR) rolling resistance. O xygen uptake (VO2), heart rate, and poling forces were measured during the last 30 s and rating of perceived exertion (RPE) was requested im mediately after each 4-min bout of roller skiing. Results: VO2 and all force-related variables increased significantly with speed and were h igher (P < 0.01) for HiR at given speeds. Poling time was similar betw een HiR and LowR, whereas poling recovery time was shorter (P = 0.0002 ) and cycle rate was higher (P = 0.002) for HiR. Forgiven VO2 levels, peak and average forces, heart rates, and RPE values were similar betw een HiR and LowR, whereas average poling force across the cycle was gr eater (P = 0.006) and duty cycle (i.e., percentage of cycle when polin g forces were applied) was higher (P = 0.0001) with HiR. Conclusions: 1) The decrease in poling recovery time and increase in cycle rate ass ociated with an increase in roller ski rolling resistance is comparabl e to the effect previously observed from increasing grade and probably occurs as a means of limiting deceleration. 2) Since changes in rolli ng resistance do not alter the relationships of RPE and heart rate wit h VO2, the central cardiovascular adaptations from roller ski training should not be affected by the rolling resistance of the roller skis. 3) Higher resistance roller skis are likely to induce greater upper bo dy aerobic adaptations than lower resistance roller skis.