Keywords: Ageing; Human rectus abdominis skeletal muscle; Oxidative stress; Protein carbonylation; Proteomics; 1D; one-dimensional; 2D; bi-dimensional; ATP; adenosine triphosphate; CK; creatine kinase; DNP; 2-4-dinitrophenylhydrazone; DNPH; 2,4-dinitrophenylhydra