max, HR and [L−] attained at the limit of tolerance during Control, and fixed WR HIIT protocols performed at WR4, WR6 and WR8.

Values are means ± SD. max (maximal rate of pulmonary oxygen uptake); HR (heart rate) and [L−] (Lactate concentration) measured at the limit of tolerance during the constant-speed tests used to characterize the Speed-tolerable duration (S-tLIM) relationship (Control) and during HIIT performed at WR4, WR6 and WR8 (work rates predicted to induce exhaustion at 4, 6 and 8 min respectively).*Significantly higher [L−] than that attained in Control, WR6 and WR8 protocols.