It may also help to put pillows on the floor and let it jump off a low sofa or baby chair. For older kids, a bouncy ball with a handle is a way to enjoy the "lift off" and it also trains the ability to kick off with both feet.
If your child is more of a quieter person then promote walking and jumping by connecting it to something that your child likes. Played nursery rhymes ("That's just, that's awkward" or "Ten little fidgety men") can help. Walk with him in the park and let him run back and forth between them. (Hint: If it is hugged at the respective target or whirled through the air, then it runs the faster!)
Use chalk to paint a "racetrack" on the playground floor or on the sand on the beach or paint different squares and circles on the floor and suggest that you jump from one to the next. If it's just learning letters, paint some huge letters and let it run along the lines.