On the other hand, it is not recommended that a woman start a jogging program during pregnancy. As the pregnancy progresses, the woman should gradually decrease the speed and distance of her runs. Cycling is a good nonweightbearing activity during pregnancy. Many women find riding a stationary bicycle safer than riding on the road, as the changes in the body 's center of gravity can affect balance. The pregnant woman may continue her aerobics classes, provided she modifies some of the exercises to minimize ballistic movements and extended periods of time in the supine position.
Many women prefer to participate in an aerobics program in the water as the pregnancy progresses.
Swimming is a recommended sport during pregnancy. It is non weightbearing, good for cardiovascular fitness, and can be initiated during pregnancy. Diving and jumping into the pool are not advisable because of the risk of injury to the mother or the fetus, particularly after the first trimester when the uterus is no longer within the pelvis. Women involved in weight training may continue to lift light weights during pregnancy, provided that their goal is strength maintenance and that they practice proper breathing technique. Breathholding or provoking the Valsalva maneuver should be avoided.