Power and pacing calculations based on real-time locating data from a cross-country skiing sprint race

Abstract

Pacing strategies in cross-country skiing have been investigated in several studies. However, none of the previous studies have been verified by collected skiing data giving the skiing velocities along a measured track. These can be used to calculate the propulsive power output. Collected real-time positioning data from a cross-country sprint skiing race were used to estimate the propulsive power by applying a power balance model. Analyses were made for the time-trial and the final for one female and one male skier. The average propulsive power over the whole race times were 311 and 296 W during the time trial and 400 and 386 W during the final, for the female and male skier, respectively. Compared to the average propulsive power over the whole race, the average active propulsive phases were calculated as 33 and 44% higher in the time trials and 36 and 37% higher in the finals for the female and male, respectively. The current study presents a novel approach to use real-time positioning data to estimate continuous propulsive power during cross-country sprint skiing, enabling in-depth analyses of power output and pacing strategies.

Pacing and predictors of performance during cross-country skiing races: A systematic review

“…In the only comparison of sprint skiing by males and females known to us, Swarén and Eriksson 7 found that in the first 20 m of the final race, the average propulsive power for the 1 female skier analyzed was 11% higher than in the qualification heat (345 W vs. 308 W, respectively), whereas for the 1 male skier this power was 17% lower (356 W vs. 430 W, respectively). The pattern for the final spurt was the same, with higher values than in the qualification heat for the female (380 W vs. 361 W, respectively), and lower for the male (411 W vs. 475 W, respectively).…”

“…sprint race Skating Male 12 elite XC sprint skiers (VO 2max : 70.0 mL/min/kg; F.I.S. sprint points: 44.1) 2D video analysis (10 synchronized cameras; section times) on a specific uphill section; no wind, with stable air and snow temperature –4°C and relative humidity 75% Swarén and Eriksson 7 1400 m, qualification time trial & 3 heats during the Scandinavian Cup Classic Female and male 2 elite XC skiers Continuous monitoring of the position of the skiers by the Quuppa real-time locating system (50 Hz) Distance races Norman and Komi 19 15 km Classic Male 7 of the top 10 finishers and 4 of the skiers who placed 30th–60th in the 15 km 1978 Lahti World Championships 2D video analysis uphill, split times Norman et al 26 30 km Classic Male The first 5 ranked and all Canadian and American skiers in the 30 km 1988 Calgary Winter Olympics 2D video analysis uphill, split times Bilodeau et al 25 30 km/50 km Skating & classic Male Members of the Canadian National XCS Training Centers and International elite racers 2D video analysis uphill, split times, HR; snow temperature –1.0°C to –0.5°C, air temperature 1°C–4.9°C Rundell and McCarthy 24 10 km Skating Female Top US XC skiers 2D video analysis; air temperature –17°C Welde et al 22 6.2 km/6.2 km Classic & skating Female High-level female XC skiers (VO 2max : 67 mL/min/kg) Ergospirometry, blood lactate concentration, HR; no wind, air temperature 2°C–6°C Bolger et al 20 10 km/15 km Classic & skating Female and male Norwegian XCS National Team (VO 2max : 81.7 and 71.0 mL/min/kg for male and female, respectively; F.I.S. Points 4.0 and 8.0, respectively) Low-cost GNSS c...…”

“…This study used a 2D video recording during the last 30 m sprint with the double poling technique. Swarén and Eriksson 7 utilized a real-time locating system (Quuppa Oy; Espoo, Finland) to follow 70 skiers (30 females and 40 males) during the 1.4 km Scandinavian XCS classical sprint race. Stöggl et al 8 simulated a complete classical sprint race protocol (3 heats based on the Stockholm sprint World Cup) with roller skiing on a treadmill at self-controlled velocity and used a 2D video analysis to monitor performance and physiological (ergo spirometry, blood lactate, and heart rate (HR)) and kinematic variables during the fastest sprint.…”

Exercise Intensity During Cross-Country Skiing Described by Oxygen Demands in Flat and Uphill Terrain

“…Recent advances in wearable sensor technology allow tracking of athletes as a point mass model for position, speed, and acceleration, by using a differential global navigational satellite system (dGNSS), during outdoor roller skiing ( Larsson and Henriksson-Larsen, 2005 ; Andersson et al, 2010 ). Using this wearable technology, the external work load can be determined ( Swaren and Eriksson, 2017 ) and the metabolic cost of roller ski racing can be estimated to illustrate the exercise intensity during a race.…”

Tracking Performance in Endurance Racing Sports: Evaluation of the Accuracy Offered by Three Commercial GNSS Receivers Aimed at the Sports Market

“…Video-based tracking is only applicable if the athletes are in the field of view of a camcorder throughout the race and are therefore not often used in racing and endurance sports. LPS is typically used for indoor sports but can also be used in outdoor sports that are held in limited space, such as on track loops ( Self et al, 2012 ; Swarén et al, 2016 ; Swarén and Eriksson, 2017 ). GNSS does not have the two limitations described above and is therefore the most commonly applied wearable technology used to track athletes in outdoor sports.…”