Purpose: In girls and women, the authors studied the effects of an acute bout of low-impact, moderate-intensity exercise serum on myoblast and osteoblast proliferation in vitro. Methods: A total of 12 pre/early pubertal girls (8–10 y old) and 12 women (20–30 y old) cycled at 60% VO₂max for 1 hour followed by 1-hour recovery. Blood samples were collected at rest, mid-exercise, end of exercise, mid-recovery, and end of recovery. C2C12 myoblasts and MC3T3E1 osteoblasts were incubated with serum from each time point for 1 hour, then monitored for 24 hours (myoblasts) or 36 hours (osteoblasts) to examine proliferation. Cells were also monitored for 6 days (myoblasts) to examine myotube formation and 21 days (osteoblasts) to examine mineralization. Results: Exercise did not affect myoblast or osteoblast proliferation. Girls exhibited lower cell proliferation relative to women at end of exercise (osteoblasts, P = .041; myoblasts, P = .029) and mid-recovery (osteoblasts, P = .010). Mineralization was lower at end of recovery relative to rest (P = .014) in both girls and women. Myotube formation was not affected by exercise or group. Conclusion: The systemic environment following one acute bout of low-impact moderate-intensity exercise in girls and women does not elicit osteoblast or myoblast activity in vitro. Differences in myoblast and osteoblast proliferation between girls and women may be influenced by maturation.

目的：作者在女孩和女性中研究了急性发作的低强度、中等强度运动血清对体外成肌细胞和成骨细胞增殖的影响。方法：共有 12 名青春期前/青春期早期女孩（8-10 岁）和 12 名女性（20-30 岁）以 60% VO ₂ max循环1 小时，然后恢复 1 小时。在休息、运动中期、运动结束、恢复中期和恢复结束时收集血液样本。C2C12 成肌细胞和 MC3T3E1 成骨细胞与每个时间点的血清孵育 1 小时，然后监测 24 小时（成肌细胞）或 36 小时（成骨细胞）以检查增殖。还监测细胞 6 天（成肌细胞）以检查肌管形成和 21 天（成骨细胞）以检查矿化。结果：运动不影响成肌细胞或成骨细胞的增殖。在运动结束时（成骨细胞， P  = .041；成肌细胞， P  = .029）和恢复中期（成骨细胞， P  = .010），女孩的细胞增殖率低于女性。相对于休息时 ，女孩和女性的矿化在恢复结束时较低 ( P = .014)。肌管形成不受运动或团体的影响。结论：女孩和女性在进行一次低强度中等强度的急性运动后的全身环境不会在体外引起成骨细胞或成肌细胞的活性。女孩和女性之间成肌细胞和成骨细胞增殖的差异可能受成熟的影响。