Flexibility as a determinant of rollerskiing economy in cross-country skiers

Abstract

The purpose of this study was to examine the correlational relationship between selected measures of flexibility and roller-ski economy (E). Twelve male competitive cross-country skiers (Mean±SD: 21±3 yrs, 183.2±6.5 cm, 76.7±6.8 kg and 60.4±3.4 ml/kg/min VO2max) completed a VO2max test on a motorized treadmill to volitional exhaustion utilizing the Australian XC Ski-Striding protocol. Heart rate (HR) and oxygen consumption (VO2) were recorded with a metabolic cart using standard indirect calorimetry procedures. Immediately following the VO2max test, seven flexibility tests were administered bilaterally twice each by the same administrator in a counterbalanced order. Flexibility measures included rotation of spine, lateral flexion of spine, shoulder rotation, standing and lying horizontal hip abduction, modified sit-and-reach test, and passive leg raise (Flex1-Flex7). During a second lab visit, subjects performed three 10-min trials at preset heart rates (65%, 75%, and 85% of HRmax) using roller-skis on an indoor track oval.

Average HR and VO2 values (ml/kg/min) obtained during the last four minutes of each 10-min trial were plotted against speed to produce line graphs. The slopes (VO2 and HR slopes) of these graphs were used as indicators of roller-skiing E. Pearson product-moment correlations were used to examine associations between the measures of flexibility and VO2 and HR slopes at the 0.05 alpha level. The correlational analysis revealed no significant relationships between any of the flexibility measures and either VO2 or HR slopes. The findings of this study indicate that flexibility is not a good determinant of economy in a homogenous group of cross-country skiers. Although correlations between flexibility and E were non-significant, there were weak trends observable that might aid in designing protocols for future studies examining flexibility and E in cross-country skiers.