The effect of lower limb loading on economy and kinematics of skate roller skiing
Reinking, Tyler Johnson.
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It has been proposed that skate skiing economy and racing performance have improved as a result of lighter equipment. Despite the many studies that have found running and walking economy to improve with lighter shoes, there are no published studies that show any relationship between the mass of skate skiing equipment and markers of skate skiing performance. To investigate the effects of skate skiing equipment mass on markers of performance, this study added mass to the lower limbs of skate roller skiers and measured changes in economy and gross movement kinematics. Twelve male (Mean±SD; Age (yrs): 21.4±3.9) and eight female (Mean±SD; Age (yrs): 19.9±2.2) competitive cross-country skiers completed two laboratory visits to roller ski on an oversized treadmill. In the first visit, subjects completed a graded exercise test to determine their lactate threshold. In the second visit, subjects completed 5 minutes of roller skiing at a low work rate (2 m/s for women and 3 m/s for men both at 2°) and a high work rate (2 m/s for women and 3 m/s for men both at 3.15°) for each of the four limb loading conditions (0 g, 200 g, 400 g, and 600 g). Oxygen consumption (VO2), heart rate (HR), and cycle rate were measured during the last 2 minutes of each stage and used for analysis. There were no significant differences in HR, VO2, or cycle rate between any of the limb loading conditions at either work rate. However, cycle rate neared significance (P = 0.06), with increases in cycle rate observed during greater limb loading. Interestingly, VO2 and HR significantly increased throughout testing, independent of limb loading condition. The most notable increases were observed in HR values, and increases began within the very first testing stage. Thus, it is likely that the subjects experienced cardiovascular drift due to mild hyperthermia. The effects of hyperthermia might have masked the true effects of lower limb loading. Therefore, future studies still need to investigate the effects of lower limb loading on skate skiing economy and kinematics