Figure 1. Skeletal muscle maximal in vitro K⁺ stimulated 3-O-methylfluorescein phosphatase activity (3-O-MFPase, Na⁺,K⁺-pump activity), measured preinfusion at rest, after 45 min cycling at 71% V˙_O2peak, and then after cycling at 92% V˙_O2peak continued to fatigue.

Subjects were well trained individuals and were infused intravenously with either saline (CON, filled bar), or N-acetylcysteine (NAC, open bar). The muscle maximal 3-O-MFPase activity is expressed as nmol min⁻¹ (g wt weight)⁻¹ *less than preinfusion (time main effect; P < 0.001). Values are means ± s.e.m.; n = 8.