Phosphocreatine and ATP content in human single muscle fibres before and after maximum dynamic exercise

• Published in: Pflügers Archiv 2001-06, Vol.442 (3), p.467-474
• Main Authors: Karatzaferi, C, de Haan, A, Ferguson, R A, van Mechelen, W, Sargeant, A J
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphate - metabolism; Adult; Exercise Test; Humans; Inosine Monophosphate - metabolism; Isomerism; Male; Muscle Fatigue - physiology; Muscle Fibers, Fast-Twitch - chemistry; Muscle Fibers, Fast-Twitch - metabolism; Muscle Fibers, Slow-Twitch - chemistry; Muscle Fibers, Slow-Twitch - metabolism; Muscular system; Myosin Heavy Chains - analysis; Myosin Heavy Chains - chemistry; Phosphocreatine - metabolism; Physical Exertion - physiology; Proteins
• ISSN: 0031-6768; 1432-2013
• DOI: 10.1007/s004240100552

The recovery of high-energy phosphate levels in single human skeletal muscle fibres following short-term maximal (all-out) exercise was investigated. Three male volunteers exercised maximally for 25 s on an isokinetic cycling ergometer. Muscle biopsy samples from the vastus lateralis were collected at rest, immediately post-exercise and at 1.5 min of recovery. The subjects also performed a second exercise bout 1.5 min after the first, on a separate occasion. Single muscle fibres were dissected, characterized and assigned to one of four groups according to their myosin heavy chain (MyHC) isoform content; namely, type I, IIA, IIAx and IIXa (the latter two groups containing either less or more than 50% IIX MyHC). Fibres were analysed for adenosine 5'-triphosphate (ATP), inosine-5'-monophosphate (IMP), phosphocreatine (PCr) and creatine (Cr) levels. Type I fibres had a lower Cr content than type II fibres (P