Childhood aerobic fitness says little about aerobic fitness in mid-life: in 748 schoolchildren followed for 34 years, childhood cardiorespiratory fitness correlated r = 0.30 with young-adult and r = 0.16 with mid-adult fitness; a three-sentence abstract with no methods. From the abstract

Guo and colleagues report how cardiorespiratory fitness measured in childhood persisted into adulthood in a cohort of 748 schoolchildren followed for 34 years. Childhood fitness correlated with fitness in young adulthood at r = 0.30 and in mid-adulthood at r = 0.16. The abstract frames adult fitness as important for surviving major chronic diseases and keeping good health; it gives no methods.

748 schoolchildren followed over 34 years. Ages, sex split, country and numbers retained are not in the abstract; the record's funding statement names the Childhood Determinants of Adult Health study and Australian Commonwealth, heart foundation and research council funders.