The overall objective of this proposal is to conduct a longitudinal prospective study of overweight/obese (OW/OB) pregnant women and their offspring to determine which prenatal exercise mode will have the greatest impact on maternal and infant cardiometabolic health. This information may lead to clinical practice recommendations that improve childhood health. This randomized controlled trial will recruit 284 OW/OB pregnant women randomized to an exercise intervention (aerobic (AE), resistance (RE), or aerobic+resistance exercise (AERE)) or to no exercise; their infants will be measured at 1, 6, and 12 months of age. This design will test our central hypothesis that AERE and RE training during pregnancy will improve maternal and offspring cardiometabolic outcomes to a greater extent than AE alone. This hypothesis will be tested with two specific aims: Aim 1. Determine the influence of different exercise modes during OW/OB pregnancy on infant cardiometabolic health and growth trajectories. Hypothesis: AE, RE, and AERE by OW/OB pregnant women will improve offspring neuromotor and cardiometabolic measures at 1, 6, and 12 months postpartum (e.g. decreased %body fat, BMI z-score, heart rate \[HR\], non-HDL, and C-Reactive Protein (CRP); increased insulin sensitivity) compared to infants of OW/OB pregnant women that do not exercise; AERE and RE will have the greatest impact on improving infant measures. Aim 2. Determine the most effective exercise mode in OW/OB pregnancy on improving maternal cardiometabolic health outcomes. Hypothesis: AE, RE, and AERE by OW/OB pregnant women will improve both maternal cardiometabolic health measures (e.g. decreased BMI z-score, non-HDL, % body fat, HR, weight gain) across pregnancy (16-36 weeks' gestation) and overall pregnancy outcomes (e.g. lower incidence of gestational diabetes, pre-eclampsia, hypertension during gestation) compared to OW/OB pregnant women that do not exercise; AERE and RE will have the greatest impact on improving maternal health measures, with the AERE group having the highest compliance. The proposed study will be the first to provide an understanding of the influence of maternal exercise modes on the cardiometabolic health and growth trajectories of offspring who are at increased risk due to maternal OW/OB. This work will have a significant impact on reducing the cycle of OB, potentially providing the earliest and most efficacious intervention to decrease or prevent OB in the next generation.