One long vs. two short sessions? Physiological and perceptual responses to low-intensity training at self-selected speeds in cross-country skiers

Abstract

Purpose: To compare self-selected speeds and corresponding physiological responses and perceived training stress between 1 long session versus 2 shorter sessions of low-intensity training (LIT) in 1 day among cross-country skiers. Methods: Thirteen national-level skiers performed 2 different LIT types during classical roller-skiing matched for the same distance in a counterbalanced order. The training consisted of either 1 long (approximately 3 h) session (1LIT) or 2 shorter (approximately 1.5 h each) sessions (2LIT) with 7 hours of recovery in between. Speed, heart rate, rating of perceived exertion, and blood lactate concentrations were measured, and perceived training stress (1–10) was assessed after sessions. Results: 2LIT was performed at mean (SD) 1.9% (2.0%) higher speeds versus 1LIT (P ≤ .01). Higher speeds were also found in the second versus first session of 2LIT and the second versus first part of 1LIT (1.9% [3.2%] and 3.2% [3.6%], respectively, both P ≤ .01). There were no significant differences between LIT types in heart rate, although rating of perceived exertion increased in the second versus first part of 1LIT (0.9 [0.8] point, P ≤ .01). Blood lactate concentration was reduced in the second versus first session/part of both LIT types (approximately 0.16 [0.20] mmol·L−1, P ≤ .05). There were no differences in perceived training stress between LIT types 7 and 23 hours after training, although higher perceived muscular exertion (2.0 [1.1] points, P ≤ .01) was found directly after 1LIT. Conclusions: Compared with a distance-matched long session, skiers perform 2LIT at slightly higher self-selected speeds with the same physiological responses elicited, although minor differences in perceived training stress were observed.