Although delayed onset muscle soreness and increased serum creatine kinase activity (SCKA) following unaccustomed exercise is common in adults, little is known concerning these responses in children. The perception of muscle soreness and SCKA in children (n = 16) (M age = 10.4±.30 yr) was compared to a control group of adults (n = 15) (M age = 27.1±.87 yr) following a single bout of downhill running (30 min − 10% grade). Preexercise SCKA was not significantly different between the children (91.7±8.5 μmol•L−1•min−1) and the adults (77.1±5.9 μmol•L−1•min−1). The difference in SCKA (pre to 24 hours post) was significantly less (p<.01) for the children (68.6±16.2 μmol•L−1•min−1) than for the adults (188.7±36.8 μmol•L−1•min−1). When the groups were adjusted for weight differences, SCKA was not significantly different between the adults and the children. Regardless of age, males demonstrated a significantly greater increase in SCKA postexercise when compared to females. Soreness ratings (verbally anchored scale from 1 to 10) 24 hours following the downhill run were not significantly different between the children (3.8±.6) and the adults (4.5±.7). Following an eccentrically biased exercise task, children exhibited less of a SCKA response compared to adults that is related to body weight.
