Effect of sub-technique transitions on energy expenditure and physiological load in the classical-style technique among elite male cross-country skiers.

To investigate whether sub-technique transitions in the classical-style technique are associated with increased energy expenditure and/or metabolic stress among elite male cross-country skiers. Fifteen elite male skiers completed three 10-min treadmill roller-skiing tests, each of which consisted of 5 min using the diagonal-stride technique (DS) and 5 min using the double-poling technique (DP), combined in three various modes all ensuring comparable mechanical workload, at an inclination of 2.5° and a speed of 13 km/h. In the first and third tests, the participants used 5 min continuous DS followed by 5 min continuous DP, or vice versa (no transition (NT) test), whereas in the second test, they made transitions between DS and DP every 6 s (repeated transition (RT) test). The last 3 min of each 5-min stage was used to calculate the mean values of oxygen uptake ( $${\dot{\text{V}}\text{O}}_{{2}}$$ ), respiratory exchange ratio (RER), metabolic rate (MR), mechanical work rate (MWR), and gross efficiency (GE). In addition, the pre–post-difference in blood lactate concentration (Ladiff) was determined for each test. Paired-samples t tests were used to investigate differences between tests. There were no significant differences between NT and RT tests regarding VO2, MR, MWR, or GE. Conversely, significant differences were found in RER and Ladiff, where the NT test was associated with higher RER and Ladiff values. Roller skiing with repeated sub-technique transitions is not associated with an additional aerobic energy contribution; instead, the anaerobic energy contribution was lower compared to that under continuous use of DS and DP.