Abstract
Cross-country (XC) skiing is an endurance sport performed outdoors in varying terrain and cold conditions, with competition formats ranging from 3-minute sprint races to 2-hour distance races. The race courses consist of ascending, flat, and descending terrain, designed so each of these sections is relatively short and lasts for less than a minute (typically ranging between 10 s and 35 s).1 Accordingly, XC skiing involves constant variations in speed, external power, metabolic intensity, as well as frequent transitions between various subtechniques of the skating and classical style, and modification of cycle rate and length according to the course topography, conditions, and race dynamics.2,3 Since all these parameters interplay, XC skiing is not only dependent on endurance capacity but also on technical and tactical skills.2
An essential factor in endurance competitions is to optimize the pacing strategy, that is, to use energetic resources as effectively as possible from start to finish.4 The varying terrain in XC skiing requires a continuous decision-making process based on anticipation of effort, information about the course profile and snow conditions, as well as perception of the current physiological and psychological state. Accordingly, XC skiers employ a variable pacing pattern with higher metabolic rates and power production during uphill than flat and downhill terrain,5,6 with the uphill sections being the most performance determining terrain.7–10 To further improve performance, refining XC skiers’ micropacing strategy, by adjustments of speed and/or transitions between subtechniques within or between terrain sections, can be beneficial. Still, only 2 previous studies have investigated different aspects of micropacing in XC skiing. A recent intervention study by Losnegard et al11 found that skiers with a high start speed improved performance by employing a more even pacing strategy. Furthermore, Ihalainen et al12 investigated micropacing strategies during a classical sprint time trial and showed that the instant speed during the acceleration phase over hilltops was significantly correlated with speed in the subsequent downhill section. This study also indicated that performance in downhill terrain influences overall performance, which is especially relevant when the margins between skiers are small.12 Therefore, we hypothesize that increasing speed over specific hilltops to save time in the subsequent downhill without reducing speed in other parts of the track could improve XC skiing performance.
XC skiers typically perform training sessions on the specific race courses prior to competitions to optimize technical and tactical solutions. Still, the pacing strategies developed in such sessions are typically based on the experiences of the athlete and coach. In this context, objective feedback would be valuable for helping athletes and coaches to optimize micropacing strategies and thereby improve performance in the upcoming competition. Currently, objective feedback on speed and technical patterns can be gained from the combined use of various sensors with adapted signal processing and smart classification and detection models.13–16 This could be combined with video that is recently reported as a promising tool for improving individual feedback when coaching large groups.17 Therefore, the aim of this study was to investigate the performance effects of using video- and sensor-based feedback for implementing a terrain-specific micropacing strategy when preparing for an XC skiing competition.
An essential factor in endurance competitions is to optimize the pacing strategy, that is, to use energetic resources as effectively as possible from start to finish.4 The varying terrain in XC skiing requires a continuous decision-making process based on anticipation of effort, information about the course profile and snow conditions, as well as perception of the current physiological and psychological state. Accordingly, XC skiers employ a variable pacing pattern with higher metabolic rates and power production during uphill than flat and downhill terrain,5,6 with the uphill sections being the most performance determining terrain.7–10 To further improve performance, refining XC skiers’ micropacing strategy, by adjustments of speed and/or transitions between subtechniques within or between terrain sections, can be beneficial. Still, only 2 previous studies have investigated different aspects of micropacing in XC skiing. A recent intervention study by Losnegard et al11 found that skiers with a high start speed improved performance by employing a more even pacing strategy. Furthermore, Ihalainen et al12 investigated micropacing strategies during a classical sprint time trial and showed that the instant speed during the acceleration phase over hilltops was significantly correlated with speed in the subsequent downhill section. This study also indicated that performance in downhill terrain influences overall performance, which is especially relevant when the margins between skiers are small.12 Therefore, we hypothesize that increasing speed over specific hilltops to save time in the subsequent downhill without reducing speed in other parts of the track could improve XC skiing performance.
XC skiers typically perform training sessions on the specific race courses prior to competitions to optimize technical and tactical solutions. Still, the pacing strategies developed in such sessions are typically based on the experiences of the athlete and coach. In this context, objective feedback would be valuable for helping athletes and coaches to optimize micropacing strategies and thereby improve performance in the upcoming competition. Currently, objective feedback on speed and technical patterns can be gained from the combined use of various sensors with adapted signal processing and smart classification and detection models.13–16 This could be combined with video that is recently reported as a promising tool for improving individual feedback when coaching large groups.17 Therefore, the aim of this study was to investigate the performance effects of using video- and sensor-based feedback for implementing a terrain-specific micropacing strategy when preparing for an XC skiing competition.