Effects of acetaminophen ingestion on the torque-duration relationship and fatigability during intermittent exercise...

This study aimed to determine the effects of acute ingestion of acetaminophen (ACT) on the magnitude of exercise-induced peripheral fatigue (ΔPtw) in patients with type 1 diabetes (T1D). In a randomized, placebo-controlled, double-blind design, 22 males (11 T1D and 11 control (CTR) completed 60 maximum voluntary contractions 60 min after ingesting 1 g of acetaminophen (ACT) or 1 g of placebo (PL) on two separate visits. Central and peripheral fatigue were assessed from pre- to post-exercise changes in quadriceps voluntary activation (ΔVA) and potentiated twitch force (ΔPtw), respectively. Critical torque (CT) was defined as the mean force produced during the final 12 contractions, and work performed (W') was computed as the impulse performed above CT. Maximal voluntary contraction (MVC), VA and Ptw decreased after exercise in both groups, with no significant difference between PL and ACT condition. Compared to PL, ACT increased root mean square/M_max and CT values in the T1D (+21% and 8% respectively) and CTR groups (+40% and +19%; respectively), with significant lower effect in the T1D compared to the CTR group (P < 0.05). No significant effect of ACT was observed for W' in the T1D (+7%) and CTR groups (+4%) (P = 0.68). These findings indicate that acute ACT ingestion increased CT and muscle activation during the repeated-MVC protocol in both groups, although the magnitude of these responses was smaller in the T1D than the CTR group.