Following a Long-Distance Classical Race the Whole-Body Kinematics of Double Poling by Elite Cross-Country Skiers Are Altered

Abstract

Introduction: Although short-term (approximately 10-min) fatiguing DP has been reported not to alter the joint kinematics or displacement of the centre of mass (COM) of high-level skiers, we hypothesize that prolonged DP does change these kinematics, since muscular strength is impaired following endurance events lasting longer than 2 h.Methods: During the 58-km Marcialonga race in 2017, the fastest 15 male skiers were videofilmed (100 fps, FHD resolution in the sagittal plane) on two 20-m sections (inclines: 0.7 ± 0.1°) 48 km apart (i.e., 7 and 55 km from the start), approximating 50- km Olympic races. The cameras were positioned perpendicular to and about 40 m from the middle of each section and spatial dimensions adjusted for each individual track skied. Pole and joint kinematics, as well as displacement of the COM during two DP cycles were assessed.Results: The 10 skiers who fulfilled our inclusion criteria finished the race in 2 h 09 min 19 s ± 28 s. Displacements of the joints and COM were comparable to previous observations on skiers roller skiing on a flat treadmill at similar speeds in the laboratory. 55 km after the start, cycle velocity and length were lower (P < 0.001 and P = 0.002, respectively) and the angular range of elbow joint flexion during the initial part of the poling phase reduced, while shoulder angle was greater during the first 35% of the DP cycle (all P < 0.05). Moreover, the ankle angle was increased and forward displacement of the COM reduced during the first 80% of the cycle.Conclusion: Prolonged DP reduced the forward displacement of the COM and altered arm kinematics during the early poling phase. The inefficient utilization of COM observed after 2 h of competition together with potential impairment of the stretch-shortening of arm extensor muscles probably attenuated generation of poling force. To minimize these effects of fatigue, elite skiers should focus on maintaining optimal elbow and ankle kinematics and an effective forward lean during the propulsive phase of DP.

The Training Characteristics of World-Class Male Long-Distance Cross-Country Skiers

“…Specifically, these MIT sessions were performed using DP, either with long intervals (8–15 min) with short breaks (1–2 min) or as continuous 45- to 75-min sessions. Such sessions aim to delay the duration-related fatigue of long-distance races, which leads to reduced coordination, and this directly or indirectly affects the ability to maintain muscle power throughout the competition (Zoppirolli et al, 2018 ).…”

“…While the Olympic disciplines include the use of and transition between many different subtechniques (Sandbakk and Holmberg, 2017 ; Solli et al, 2018 , 2020 ), the relatively flat terrain profiles in long-distance events are often won on skis without grip wax, using solely the double-poling (DP) subtechnique (Sagelv et al, 2018 ; Zoppirolli et al, 2018 , 2020 ; Skattebo et al, 2019 ; Stöggl et al, 2020 ) As a consequence of these demands and the increasing popularity of long-distance XC skiing, such as the Visma Ski Classics (VSC) series, long-distance XC skiers have fully specialized their training for performance in long-distance events (Skattebo et al, 2019 ). However, in contrast to the detailed examinations of physiological profiles and training characteristics of Olympic XC skiers (Sandbakk et al, 2011 , 2016 ; Tønnessen et al, 2014 ; Sandbakk and Holmberg, 2017 ; Solli et al, 2017 ), these factors have been almost unexplored among skiers who have specialized in long-distance XC.…”

Double-Poling Physiology and Kinematics of Elite Cross-Country Skiers: Specialized Long-Distance Versus All-Round Skiers

“…During the last decade, the DP technique has been extensively analyzed, with studies focusing on different inclines, 6 poling frequencies, 7 subgroups of athletes, 8 and kinematic changes during a race. 9 However, to our knowledge, studies investigating the physiology and the technique of DP specialists are lacking. The only study to date found lower submaximal O 2 cost and blood lactate concentrations ([La -]) in DP and equal VO 2 peak in both DP and diagonal skiing in elite long-distance skiers compared with all-round skiers.…”

Methodological Guidelines Designed to Improve the Quality of Research on Cross-Country Skiing

“…To date, 2-D video recordings have been most commonly employed for kinematic analysis. As long as certain conditions are met, the reliability of such data is comparable to that collected in the laboratory with more advanced optoelectronic motion capture systems [59].…”

“…Calibration requires filming (in the plane of the skier´s movements) a frame (or set of objects) whose dimension (or distance) is as large as possible and precisely known. With multiple skiing lanes, each lane should be calibrated individually [59].…”