The Interval-Based Physiological and Mechanical Demands of Cross-Country Ski Training

Abstract

Purpose: To investigate fluctuations in speed, work rate, and heart rate (HR) when cross-country ski skating across varying terrains at different endurance-training intensities. Methods: Seven male junior Norwegian skiers performed maximal-speed (Vmax) tests in both flat and uphill terrains. Thereafter, 5-km sessions at low (LIT), moderate (MIT), and high intensity (HIT) were performed based on their own perception of intensity while monitored by a global navigation satellite system with integrated barometry and accompanying HR monitor. Results: Speed, HR, and rating of perceived exertion gradually increased from LIT to MIT and HIT, both for the total course and in flat and uphill terrains (all P < .05). Uphill work rates (214 [24] W, 298 [27] W, and 350 [54] W for LIT, MIT, and HIT, respectively) and the corresponding percentage of maximal HR (79.2% [6.1]%, 88.3% [2.4]%, and 91.0% [1.7]%) were higher than in flat terrain (159 [16] W, 206 [19] W, and 233 [72] W vs 72.3% [6.3]%, 83.2% [2.3]%, and 87.4% [2.0]% for LIT, MIT, and HIT, respectively) (all P < .01). In general, ∼13% point lower utilization of maximal work rate was reached in uphill than in flat terrain at all intensities (all P < .01). Conclusions: Cross-country ski training across varying terrains is clearly interval based in terms of speed, external work rate, and metabolic intensity for all endurance-training intensities. Although work rate and HR were highest in uphill terrain at all intensities, the utilization of maximal work rate was higher in flat terrain. This demonstrates the large potential for generating external work rate when uphill skiing and the corresponding downregulation of effort due to the metabolic limitations.

Development of a Framework for the Investigation of Speed, Power, and Kinematic Patterns in Para Cross-Country Sit-Skiing: A Case Study of an LW12 Athlete

“…This is partly attributed to delayed HR kinetics, where the demands of the heavy uphill sections are also reflected in the subsequent downhills. Although delayed HR kinetics have also been found in able-bodied skiers (Bolger et al, 2015;Solli et al, 2018;Haugnes et al, 2019), the able-bodied skiers seem to recover more in the downhill sections than the XC sit-skier in our study. This might be attributed to slower HR response when using the upper-body isolated when XC sit-skiing in steep uphill terrain, and/or less possibility for recovery in the following downhill sections when steering the sledge at high speeds and in challenging turns.…”

“…The relatively high metabolic intensity and effort in our case study in the uphill terrain during LIT can likely be explained by the constraints of uphill XC sit-skiing, where it is beneficial to maintain speed at a level where the system (i.e., sledge and skier) is constantly moving forward without any full stop in the steepest segments. This is more pronounced than in ablebodied XC skiers who are better able to regulate intensity in all terrain types including the uphill terrain during LIT (Haugnes et al, 2019). Overall, our findings highlight the relevance of such information to understand the demands of training and competition.…”

“…Accordingly, training in the sitting mode taxes the cardio-respiratory system to a lesser extent (Reybrouck et al, 1975;Hegge et al, 2015a;Baumgart et al, 2017). Furthermore, not only the absolute values but also the % of maximal speed and power output utilized during HIT and LIT were lower than what has previously been found in XC skiers (Stöggl and Holmberg, 2016;Solli et al, 2018;Haugnes et al, 2019). Why the relative values are lower in our case is not known, but it might be related to an earlier onset of muscular fatigue with isolated upper-body work compared to whole body work with variations in the use of multiple sub-techniques.…”

“…All propulsion during training and competition in XC sitskiing is done by UBP (Gastaldi et al, 2012), which is in contrast to able-bodied cross-country skiing where different whole-body exercise sub-techniques are employed in response to the varying terrain (Nilsson et al, 2004). Despite this difference, the most performance determining sections in XC sit-skiing are the uphill sections (Bernardi et al, 2013), which is in line with able-bodied XC skiing (Sandbakk et al, 2011;Bolger et al, 2015;Haugnes et al, 2019). Furthermore, a significant reduction in speed over the race has been observed in XC sit-skiing competitions, with accompanying reductions in cycle length both during an uphill and a flat section (Bernardi et al, 2013).…”

Analysis of a Biathlon Sprint Competition and Associated Laboratory Determinants of Performance

“…This theory is supported by findings in XC skiing, revealing higher variations in speed at the end of uphill sections and subsequent transition into downhill sections (Andersson et al, 2010), indicating the importance of skiing fast over hilltops in order to create speed in downhills. In addition, a recent study of XC skiers indicate a lag in the physiological response after hilltops and strengthens the importance of being able to create speed at the top of each downhill section (Haugnes et al, 2019).The stronger association between XC skiing performance and RPE or %HR max than the corresponding relationship with blood lactate concentration can likely be explained by the different physiological behavior of these variables; blood lactate concentration might be relatively similar between athletes of different performance levels at low submaximal speed (such as the aerobic steady-state conditions used here), whereas RPE and %HR max would increase more linearly with increased individual load-and thereby be higher in lower level athletes at the same speed.…”