Differences in pacing pattern and sub-technique selection between young and adult competitive cross-country skiers

The present study describes differences in pacing patterns and sub-technique selection in young compared to adult competitive cross-country skiers. Eleven young male skiers (YOS) (14.4 ± 0.5 years, $$ O_2peak 63.9 ± 2.8 mL∙kg^-1 ∙min^-1 ) and eight adult male skiers (ADS) (22.6 ± 4.3 years, $$ O_2peak 77.4 ± 4.4 mL∙kg^-1 ∙min^-1 ) performed a free technique rollerski time trial (TT) over a distance of 4.3 km (YOS) and 13.1 km (ADS) to simulate normal racing distances. A GNSS/IMU system was used to track position, speed, and classify sub-techniques. Skiing economy and $$ O_2peak were measured on an additional day to calculate the relative oxygen demand ( $$ O_2dem ) in 13 segments of the TT. YOS were slower than ADS in all types of terrain (mean speed difference of 13%), with differences for uphills of 19%, undulating terrain of 11% and downhills of 8% (all P < .05). The mean relative $$ O_2dem tended to be higher for YOS compared to ADS (120% vs 112% of $$ O_2peak , P = .09), and the difference was more pronounced in the initial four segments of the race (130% vs 110% of $$ O_2peak , P < .01). YOS used more of the sub-technique Gear 2 (23 ± 7 vs 14 ± 4%), less Gear 3 (36 ± 7 vs 45 ± 5%), and had more frequent transitions between sub-techniques (18 ± 2 vs 15 ± 3 km^-1 ) (all P < .05) than ADS. Over an age-related distance, young skiers tend to exhibit higher mean exercise intensity than adult elite skiers, with a more pronounced positive pacing pattern. Differences in physical ability affect speed and sub-technique selections, implying a need for differentiating technical training for different ages and levels.