Start standing with your feet together and your knees relaxed and slightly bent, hands at your side.
Jump into a lunge position, landing softly with your left leg forward and right leg back. As you jump, simultaneously swing your arms in a running motion, with your right arm forward and left arm going back. When you land, your front knee should be in line with your toes and bent at about 90 degrees, with your thigh parallel to the ground.
Drive through your feet to jump back to the starting position, standing with your feet together and simultaneously bringing your arms together in front of your chest. Land softly.
Repeat on the other side, jumping into a lunge with your right leg forward and left leg back.
Jump your feet back together again, landing softly with your arms together in front of your chest.
This completes one rep. Complete as many reps as you can with proper form in 20 seconds.