Decreasing sprint duration from 20 to 10 s during reduced-exertion high-intensity interval training (REHIT) attenuates the increase in maximal aerobic capacity but has no effect on affective and perceptual responses

Abstract

Purpose: Recent studies have demonstrated that modifying the 'classic' 6x30-s 'all-out' sprint interval training (SIT) protocol by incorporating either shorter sprints (6x10-s or 15-s sprints) or fewer sprints (e.g. 2x20-s sprints; reduced-exertion high-intensity interval training (REHIT)) does not attenuate the training-induced improvements in maximal aerobic capacity (VȮ2max). The aim of the present study was to determine whether reducing the sprint duration in the REHIT protocol from 20 s to 10 s per sprint influences acute affective responses and the change in VȮ2max following training. ) were randomised to a group performing a 'standard' REHIT protocol involving 2x20-s sprints or a group who performed 2x10-s sprints. VȮ2max was determined before and after 6 weeks of 3 weekly training sessions. Acute affective responses and perceived exertion were assessed during training. Methods Results: Greater increases in

Affective and perceptual responses during reduced-exertion high-intensity interval training (REHIT)

“…They reported that affective valence decreased progressively (by ~1 point on the feeling scale) with each 'all-out' 20-s sprint and, in contrast to our findings, that REHIT was associated with more negative affective valence compared with MICT (Stork et al, 2018). The more negative affective response with REHIT reported in their study can be explained by: 1) the incorporation of the third sprint (which is unnecessary for achieving improvements in cardiometabolic risk factors (Metcalfe et al, 2012;Nalçakan et al, 2018;), and 2) the lack of sufficient familiarisation with REHIT prior to the main experiment. In our REHIT training studies (Metcalfe et al, 2012;Nalçakan et al, 2018), we have observed that progressively increasing sprint duration from 10 s to 20 s over the first few sessions completely prevents the feelings of nausea which were reported in early studies of 'classic' SIT.…”

“…The more negative affective response with REHIT reported in their study can be explained by: 1) the incorporation of the third sprint (which is unnecessary for achieving improvements in cardiometabolic risk factors (Metcalfe et al, 2012;Nalçakan et al, 2018;), and 2) the lack of sufficient familiarisation with REHIT prior to the main experiment. In our REHIT training studies (Metcalfe et al, 2012;Nalçakan et al, 2018), we have observed that progressively increasing sprint duration from 10 s to 20 s over the first few sessions completely prevents the feelings of nausea which were reported in early studies of 'classic' SIT. Therefore, in the present study we included three familiarisation sessions with participants performed increasing duration of allout sprints during each.…”

“…Indeed, a modified REHIT protocol was recently shown to be as enjoyable and preferable as MICT among inactive individuals (Stork et al, 2018). Furthermore, we have recently demonstrated that REHIT is not associated with an increase in negative affect in the immediate post-exercise period, and in contrast increases (with small effect sizes) positive affect and overall mood state (Nalçakan et al, 2018).…”

“…At least 1 week after completion of the familiarization sessions, participants commenced a randomized crossover study comparing three exercise conditions: MICT (30 minutes of cycling at 40% of Wmax (91±20 watts), HIIT (10 x 1-min cycle efforts at 100% of Wmax (229±49 watts) within a 22-min exercise session (Gillen et al, 2013;Little et al, 2011)), and REHIT (2x 20-s 'all-out' cycle sprints (against a resistance of 7.5% body mass) within a 10-min exercise session (Metcalfe, Fawkner, & Vollaard, 2016;Metcalfe et al, 2012;Metcalfe et al, 2015;Nalçakan et al, 2018)). Affective valence (eleven-point feeling scale (Hardy & Rejeski, 1989) and ratings of perceived exertion (RPE; 15-point Borg scale (Borg, 1982)) were assessed before exercise, every 2 min during exercise, and then 10 and 30 min post-exercise.…”

“…In a series of studies we have demonstrated that reducing the number of sprint repetitions (from 6-7 to 2) and the sprint duration (from 30 to 20 seconds) in Gibala's 'classic' SIT protocol (Burgomaster et al, 2006;Burgomaster et al, 2005;Gibala et al, 2006) does not attenuate the improvements in important markers of cardiometabolic health, including maximal aerobic capacity (Metcalfe, Tardif, Thompson, & Vollaard, 2016;Nalçakan et al, 2018;Vollaard, Metcalfe, & Williams, 2017), insulin sensitivity and glycaemic control (Metcalfe, Babraj, Fawkner, & Vollaard, 2012;Metcalfe et al, 2018), and blood pressure (Ruffino et al, 2017).…”