Five Weeks of Sprint Interval Training Improve Muscle Glycolytic Content and Activity But Not Time to Task Failure in Severe-Intensity Exercise.

Purpose: This study examined the impact of a 5-wk sprint interval training (SIT) intervention on time to task failure (TTF) during severe-intensity constant work rate (CWR) exercise, as well as in glycolytic enzymatic content and activity, and glycogen content.

Methods: Fourteen active males were randomized into either a SIT group ( n = 8) composed of 15 SIT sessions over 5 wk, or a control group ( n = 6). At pretraining period, participants performed i) ramp incremental test to measure the cardiorespiratory function; ii) CWR cycling TTF at 150% of the power output (PO) at the respiratory compensation point (RCP-PO) with muscle biopsies at rest and immediately following task failure.