Effect of Sitting Posture on Sit-Skiing Economy in Non-disabled Athletes.

Kimmo Lajunen,Walter Rapp,Stefan J Lindinger,Juha P Ahtiainen,Vesa Linnamo

doi:10.3389/fspor.2020.00044

Kimmo Lajunen, Walter Rapp + Show 3 more

Open Access

https://doi.org/10.3389/fspor.2020.00044

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Abstract

This study focused on resolving the differences in economy between two common sit-skiing postures used by disabled athletes, suspected to be the most and least effective. Ten experienced non-disabled male cross-country skiers went through an incremental testing protocol with an ergometer simulating double poling in two sitting postures “kneeing” and “knee-high.” The protocol consisted of 3 × 4 min steady-state stages (13, 22, and 34% of maximal sprint power output). Subjects' respiratory gases and heart rate were measured and blood lactate concentrations were determined. In addition, pulling forces and motion capture recordings were collected. Oxygen consumption was 15.5% (p < 0.01) higher with “knee-high” compared to “kneeing” at stage three. At stage three cycle rate was 13.8% higher (p < 0.01) and impulse of force 13.0% (p < 0.05) and hip range of motion 46.6% lower (p < 0.01) with “knee-high” compared to “kneeing.” “Kneeing” was found to be considerably more economical than “knee-high” especially at 34% of maximum sprint power output. This might have been due to higher cycle rate, lower impulse of force and smaller hip range of motion with “knee-high” compared to “kneeing.” This indicates that sit-skiers should adopt, if possible, posture more resembling the “kneeing” than the “knee-high” posture. Combining such physiological and biomechanical measurements and to further develop them to integrated miniature wearable sensors could offer new possibilities for training and testing both in the laboratory and in the field conditions.

Highlights

Cross-country skiing is one of the six sports in the winter Paralympic Games (International Paralympic Committee, 2020d) and sit-skiers form one of the three major sport classes in crosscountry skiing (International Paralympic Committee, 2020b)
Oxygen consumption was 15.5% (P < 0.01) higher with “knee-high” compared to “kneeing” posture at stage three (Figure 2A)
No significant differences were observed in blood lactate concentration at any stage, despite a significant overall difference observed in ANOVA (Figure 2C)

Summary

Introduction

Cross-country skiing is one of the six sports in the winter Paralympic Games (International Paralympic Committee, 2020d) and sit-skiers form one of the three major sport classes in crosscountry skiing (International Paralympic Committee, 2020b). In a sit-skiing event, each athlete sits on a sledge mounted on top of a pair of traditional cross-country skis and creates forward propulsion using the double poling (DP) technique (Gastaldi et al, 2012). DP in general refers to a skiing technique in which both poles are planted to the ground simultaneously and trunk flexion is synchronized with shoulder and elbow extension to create propulsive force (Smith et al, 1996). Able-bodied skiers can utilize their full body mass to produce impulse to the poles (Holmberg et al, 2005), while disabled skiers are not able to do so

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