Changes in phosphocreatine concentration of skeletal muscle during high-intensity intermittent exercise in children and adults
- 875 Downloads
The aim of the present study was to test the hypotheses that a greater oxidative capacity in children results in a lower phosphocreatine (PCr) depletion, a faster PCr resynthesis and a lower muscle acidification during high-intensity intermittent exercise compared to adults.
Sixteen children (9.4 ± 0.5 years) and 16 adults (26.1 ± 0.3 years) completed a protocol consisting of a dynamic plantar flexion (10 bouts of 30-s exercise at 25 % of one repetition maximum separated by 20-s recovery), followed by 10 min of passive recovery. Changes of PCr, ATP, inorganic phosphate, and phosphomonoesters were measured by means of 31Phosphorous-magnetic resonance spectroscopy during and post-exercise.
Average PCr (percentage of [PCr] at initial rest (%[PCr]i)) at the end of the exercise (adults 17 ± 12 %[PCr]i, children 38 ± 17 %[PCr]i, P < 0.01) and recovery periods (adults 37 ± 14 %[PCr]i, children 57 ± 17 %[PCr]i, P < 0.01) was significantly lower in adults compared to children, induced by a stronger PCr decrease during the first exercise interval (adults −73 ± 10 %[PCr]i, children −55 ± 15 %[PCr]i, P < 0.01). End-exercise pH was significantly higher in children compared to adults (children 6.90 + 0.20, −0.14; adults 6.67 + 0.23, −0.15, P < 0.05).
From our results we suggest relatively higher rates of oxidative ATP formation in children’s muscle for covering the ATP demand of high-intensity intermittent exercise compared to adults, enabling children to begin each exercise interval with significantly higher PCr concentrations and leading to an overall lower muscle acidification.
Keywords31P-MRS Intramuscular pH Maturation Muscle metabolism Recovery
Peak power output
Range of motion
Wingate anaerobic test
- W/kg mm
Watts per kilogram muscle mass
One repetition maximum
31Phosphorous-magnetic resonance spectroscopy
Percent of PCr at initial rest
- Chia M, Armstrong N, Childs D (1997) The assessment of children’s anaerobic performance using modifications of the Wingate anaerobic test. Pediatr Exerc Sci 9:80–89Google Scholar
- Gießing J (2003) Trainingsplanung und –steuerung beim Muskelaufbautraining. Das Konzept vom individuellen hypothetischen Maximalgewicht (h1RM) als methodische Alternative. Leistungssport 4/2003:26–31Google Scholar
- Inbar O, Bar-Or O, Skinner JS (1996) The Wingate anaerobic test. Human Kinetics, ChampaignGoogle Scholar
- Malina RM, Bouchard C, Bar-Or O (2004) Growth, maturation, and physical activity. Human Kinetics, ChampaignGoogle Scholar
- Rothman DL, Shulman RG, Shulman GI (1992) 31P nuclear magnetic resonance measurements of muscle glucose-6-phosphate. Evidence for reduced insulin-dependent muscle glucose transport or phosphorylation activity in non-insulin-dependent diabetes mellitus. J Clin Invest 89:1069–1075PubMedCrossRefGoogle Scholar