Fig. 3.

Relationship between quadriceps fatigue and intramuscular metabolites. Data are expressed as % difference from baseline to end exercise for intramuscular pH and hydrogen ion ([H⁺]), inorganic phosphate ([P_i]), and diprotonated phosphate ([${\mathrm{H}}_{\mathrm{2}}\mathrm{P}{\mathrm{O}}_{\mathrm{4}}^{\mathrm{-}}$]) concentrations vs. preexercise-to-postexercise % difference for the potentiated quadriceps twitch force (Q_tw).