Figure 1. Schematic representation of the experimental trial.

Subjects reported to the laboratory after an overnight fast where a constant infusion of L-[ring-¹³C₆] phenylalanine was commenced (3 h in first trial; 1 h in trial 2/3), and subjects completed the concurrent exercise (8×5 repetitions at 80% one repetition maximum (1RM), 5 min rest, 30 min cycling at ∼63% peak power output (PPO), 2 min rest, 10×30 s high intensity intervals at ∼110% PPO). Immediately after exercise completion, and 4 h later, subjects consumed 500-mL of protein (25 g whey) or carbohydrate (25 g maltodextrin).