Ski economy and physiological responses while double poling : curved vs. straight poles

Abstract

Christina Mishica (2015). Ski economy and physiological responses while double poling: curved vs. straight poles. Department of Biology of Physical Activity, University of Jyväskylä, Master’s Thesis in Exercise Physiology. 57 pp.

Introduction. Double poling (DP) is commonly used in cross country skiing (XC). It is becoming more and more popular and in some competitions it is the exclusive technique. Ski poles allow a skier to apply power and force to the snow and their composition and design have a significant effect on performance. Different pole lengths and cross sections are some of the differences that have been tested. Advancements in equipment will continue to be introduced so it is important to have research that supports the possible benefits and physiological reasoning behind these changes. The purpose of this study was to investigate and compare ski economy and physiological responses in XC skiing while performing the DP technique with curved and straight ski poles.

Methods. Ten well-trained XC skiers - five males (age 24.2 ±6.8 years 77.1 ± 2.4 kg) and five females (21.8 ± 3.4 years, 60.2 ± 7.0 kg) performed DP in a laboratory with roller skis on a treadmill with one degree of inclination using both straight and curved poles. A sub-maximal test protocol was developed that utilized three speeds (men: 13, 17, 21 km/h/; women: 8, 12, 16 km/h) and 60 seconds of max speed at the end of each test. Tests, in a randomized order, were performed with each pole type for five minutes for reaching a steady state. Heart rate, blood lactate, VO2max and pole forces were collected for analysis. Results were analyzed separately for each gender due to changes in the protocol because faster speeds were needed for male subjects.

Results. No differences were found in heart rate values when comparing pole types with both male (± ˂4 bpm) and female (± ˂2 bpm) subjects. There were slightly higher (n.s) blood lactate values with both male and female subjects with curved poles. Although no differences were found with VO2 values there were significant differences (p<0.05) found in VE values in speed 1 (8 km/h) for women (curved: 36.9 ± 4.2, straight: 35.3 ± 4.6 L/min) and significant differences (p<0.05) in speed 3 (21 km/h) for men (curved: 116.9 ± 23.7, straight: 112.7 ± 21.5 L/min). Gross efficiency did not differ between the two pole types at the tested speeds.

Conclusion. Even though some changes in the studied parameters were visible with curved poles the differences were not significant. This could be due to the testing protocol or because of the subjects' unfamiliarity of skiing with curved poles. It is well known that ski economy has a great effect on performance so it is important to research and search for any possible improvements. Less than one second is often the difference between winning or losing a medal. In the future, research with a testing protocol that is more similar to ski competitions should be used to further investigate the possible gains of using curved ski poles.